CDK2; cyclin-dependent kinase 2 (12q13)

Gene Summary

Gene:CDK2; cyclin-dependent kinase 2
Aliases: CDKN2, p33(CDK2)
Summary:This gene encodes a member of a family of serine/threonine protein kinases that participate in cell cycle regulation. The encoded protein is the catalytic subunit of the cyclin-dependent protein kinase complex, which regulates progression through the cell cycle. Activity of this protein is especially critical during the G1 to S phase transition. This protein associates with and regulated by other subunits of the complex including cyclin A or E, CDK inhibitor p21Cip1 (CDKN1A), and p27Kip1 (CDKN1B). Alternative splicing results in multiple transcript variants. [provided by RefSeq, Mar 2014]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:cyclin-dependent kinase 2
Updated:10 February, 2015


What does this gene/protein do?
Show (46)


What pathways are this gene/protein implicaed in?
- CDK Regulation of DNA Replication BIOCARTA
- Cell Cycle BIOCARTA
- Cyclin E Destruction Pathway BIOCARTA
- Cyclins and Cell Cycle Regulation BIOCARTA
- E2F1 Destruction Pathway BIOCARTA
- Estrogen-responsive protein Efp controls cell cycle and breast tumors growth BIOCARTA
- Influence of Ras and Rho proteins on G1 to S Transition BIOCARTA
- p53 Signaling Pathway BIOCARTA
- RB Tumor Suppressor/Checkpoint Signaling in response to DNA damage BIOCARTA
- Regulation of p27 Phosphorylation during Cell Cycle Progression BIOCARTA
- Cell cycle KEGG
Data from KEGG and BioCarta [BIOCARTA terms] via CGAP

Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 10 February 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 10 February, 2015 using data from PubMed, MeSH and CancerIndex

Notable (2)

Scope includes mutations and abnormal protein expression.

Entity Topic PubMed Papers
Breast CancerCDK2 and Breast Cancer View Publications84
Thymoma and Thymic CarcinomaCDK2 and Thymoma and Thymic Carcinoma View Publications1

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Related Links

Latest Publications: CDK2 (cancer-related)

Moore NL, Edwards DP, Weigel NL
Cyclin A2 and its associated kinase activity are required for optimal induction of progesterone receptor target genes in breast cancer cells.
J Steroid Biochem Mol Biol. 2014; 144 Pt B:471-82 [PubMed] Article available free on PMC after 01/10/2015 Related Publications
A role for the cell cycle protein cyclin A2 in regulating progesterone receptor (PR) activity is emerging. This study investigates the role of cyclin A2 in regulating endogenous PR activity in T47D breast cancer cells by depleting cyclin A2 expression and measuring PR target genes using q-RT-PCR. Targets examined included genes induced by the PR-B isoform more strongly than PR-A (SGK1, FKBP5), a gene induced predominantly by PR-A (HEF1), genes induced via PR tethering to other transcription factors (p21, p27), a gene induced in part via extra-nuclear PR signaling mechanisms (cyclin D1) and PR-repressed genes (DST, IL1R1). Progestin induction of target genes was reduced following cyclin A2 depletion. However, cyclin A2 depletion did not diminish progestin target gene repression. Furthermore, inhibition of the associated Cdk2 kinase activity of cyclin A2 also reduced progestin induction of target genes, while Cdk2 enhanced the interaction between PR and cyclin A2. These results demonstrate that cyclin A2 and its associated kinase activity are important for progestin-induced activation of endogenous PR target genes in breast cancer cells.

Related: Breast Cancer

Zheng Q, Liu WW, Li B, et al.
Anticancer effect of icaritin on human lung cancer cells through inducing S phase cell cycle arrest and apoptosis.
J Huazhong Univ Sci Technolog Med Sci. 2014; 34(4):497-503 [PubMed] Related Publications
Icaritin, a prenylflavonoid derivative from Epimedium Genus, has been shown to exhibit many pharmacological and biological activities. However, the function and the underlying mechanisms of icaritin in human non-small cell lung cancer have not been fully elucidated. The purpose of this study was to investigate the anticancer effects of icaritin on A549 cells and explore the underlying molecular mechanism. The cell viability after icaritin treatment was tested by MTT assay. The cell cycle distribution, apoptosis and reactive oxygen species (ROS) levels were analyzed by flow cytometry. The mRNA and protein expression levels of the genes involved in proliferation and apoptosis were respectively detected by RT-PCR and Western blotting. The results demonstrated that icaritin induced cell cycle arrest at S phase, and down-regulated the expression levels of S regulatory proteins such as Cyclin A and CDK2. Icaritin also induced cell apoptosis characterized by positive Hoechst 33258 staining, accumulation of the Annexin V-positive cells, increased ROS level and alteration in Bcl-2 family proteins expression. Moreover, icaritin induced sustained phosphorylation of ERK and p38 MAPK. These findings suggested that icaritin might be a new potent inhibitor by inducing S phase arrest and apoptosis in human lung carcinoma A549 cells.

Related: Apoptosis Lung Cancer

Huang M, Tang SN, Upadhyay G, et al.
Rottlerin suppresses growth of human pancreatic tumors in nude mice, and pancreatic cancer cells isolated from Kras(G12D) mice.
Cancer Lett. 2014; 353(1):32-40 [PubMed] Related Publications
The purpose of the study was to examine the molecular mechanisms by which rottlerin inhibited growth of human pancreatic tumors in Balb C nude mice, and pancreatic cancer cells isolated from Kras(G12D) mice. AsPC-1 cells were injected subcutaneously into Balb c nude mice, and tumor-bearing mice were treated with rottlerin. Cell proliferation and apoptosis were measured by Ki67 and TUNEL staining, respectively. The expression of components of Akt, Notch, and Sonic Hedgehog (Shh) pathways were measured by the immunohistochemistry, Western blot analysis, and/or q-RT-PCR. The effects of rottlerin on pancreatic cancer cells isolated from Kras(G12D) mice were also examined. Rottlerin-treated mice showed a significant inhibition in tumor growth which was associated with suppression of cell proliferation, activation of capase-3 and cleavage of PARP. Rottlerin inhibited the expression of Bcl-2, cyclin D1, CDK2 and CDK6, and induced the expression of Bax in tumor tissues compared to untreated control. Rottlerin inhibited the markers of angiogenesis (Cox-2, VEGF, VEGFR, and IL-8), and metastasis (MMP-2 and MMP-9), thus blocking production of tumorigenic mediators in tumor microenvironment. Rottlerin also inhibited epithelial-mesenchymal transition by up-regulating E-cadherin and inhibiting the expression of Slug and Snail. Furthermore, rottlerin treatment of xenografted tumors or pancreatic cancer cells isolated from Kras(G12D) mice showed a significant inhibition in Akt, Shh and Notch pathways compared to control groups. These data suggest that rottlerin can inhibit pancreatic cancer growth by suppressing multiple signaling pathways which are constitutively active in pancreatic cancer. Taken together, our data show that the rottlerin induces apoptosis and inhibits pancreatic cancer growth by targeting Akt, Notch and Shh signaling pathways, and provide a new therapeutic approach with translational potential for humans.

Related: Angiogenesis Inhibitors Apoptosis Angiogenesis and Cancer Cancer of the Pancreas Pancreatic Cancer AKT1 Signal Transduction

Jiang XR, Yu XY, Fan JH, et al.
RFT2 is overexpressed in esophageal squamous cell carcinoma and promotes tumorigenesis by sustaining cell proliferation and protecting against cell death.
Cancer Lett. 2014; 353(1):78-86 [PubMed] Related Publications
Human riboflavin transporter 2 (RFT2, also termed as SLC52A3) was recently identified as a susceptibility gene to esophageal squamous cell carcinoma (ESCC), however, its expression and biologic function has remained unclear in ESCC. In this study, we demonstrated that RFT2 was frequently overexpressed in tumor samples compared with normal adjacent tissue in ESCC patients. Knockdown of RFT2 in ESCC cells resulted in decreases of intracellular flavin status, mitochondrial membrane potential and cellular ATP levels, and inhibitions of cell proliferation, colony formation and anchorage-independent growth. Knockdown of RFT2 increased p21 and p27 protein levels, decreased their downstream targets cyclin E1 and Cdk2 protein levels and caused pRb hypophosphorylation, leading to cell cycle arrest at G1-G1/S. Knockdown of RFT2 also reduced anti-apoptotic proteins Bcl-2, Bcl-xl and survivin levels, caused activation of caspase-3 and apoptosis. In contrast, ectopic overexpression of RFT2 in ESCC cells promoted cell proliferation under restricted conditions (soft agar), conferred resistance to cisplatin, and enhanced tumorigenicity in nude mice. These results suggest that RFT2 contributes to ESCC tumorigenesis and may serve as a potential therapeutic target.

Related: Apoptosis Cisplatin Cancer of the Esophagus Esophageal Cancer

Li W, Li K, Zhao L, Zou H
Bioinformatics analysis reveals disturbance mechanism of MAPK signaling pathway and cell cycle in Glioblastoma multiforme.
Gene. 2014; 547(2):346-50 [PubMed] Related Publications
BACKGROUND & OBJECTIVES: To analyze the reversal gene pairs and identify featured reversal genes related to mitogen-activated protein kinases (MAPK) signaling pathway and cell cycle in Glioblastoma multiforme (GBM) to reveal its pathogenetic mechanism.
METHODS: We downloaded the gene expression profile GSE4290 from the Gene Expression Omnibus database, including 81 gene chips of GBM and 23 gene chips of controls. The t test was used to analyze the DEGs (differentially expressed genes) between 23 normal and 81 GBM samples. Then some perturbing metabolic pathways, including MAPK (mitogen-activated protein kinases) and cell cycle signaling pathway, were extracted from KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway database. Cancer genes were obtained from the database of Cancer Gene Census. The reversal gene pairs between DEGs and cancer genes were further analyzed in MAPK and cell cycle signaling pathway.
RESULTS: A total 8523 DEGs were obtained including 4090 up-regulated and 4433 down-regulated genes. Among them, ras-related protein rab-13(RAB13), neuroblastoma breakpoint family member 10 (NBPF10) and disks large homologue 4 (DLG4) were found to be involved in GBM for the first time. We obtained MAPK and cell cycle signaling pathways from KEGG database. By analyzing perturbing mechanism in these two pathways, we identified several reversal gene pairs, including NRAS (neuroblastoma RAS) and CDK2 (cyclin-dependent kinase 2), CCND1 (cyclin D1) and FGFR (fibroblast growth factor receptor). Further analysis showed that NRAS and CDK2 were positively related with GBM. However, FGFR2 and CCND1 were negatively related with GBM.
INTERPRETATION & CONCLUSIONS: These findings suggest that newly identified DEGs and featured reversal gene pairs participated in MAPK and cell cycle signaling pathway may provide a new therapeutic line of approach to GBM.

Related: NRAS

Juengel E, Nowaz S, Makarevi J, et al.
HDAC-inhibition counteracts everolimus resistance in renal cell carcinoma in vitro by diminishing cdk2 and cyclin A.
Mol Cancer. 2014; 13:152 [PubMed] Article available free on PMC after 01/10/2015 Related Publications
BACKGROUND: Targeted therapies have improved therapeutic options of treating renal cell carcinoma (RCC). However, drug response is temporary due to resistance development.
METHODS: Functional and molecular changes in RCC Caki-1 cells, after acquired resistance to the mammalian target of rapamycin (mTOR)-inhibitor everolimus (Cakires), were investigated with and without additional application of the histone deacetylase (HDAC)-inhibitor valproic acid (VPA). Cell growth was evaluated by MTT assay, cell cycle progression and apoptosis by flow cytometry. Target molecules of everolimus and VPA, apoptotic and cell cycle regulating proteins were investigated by western blotting. siRNA blockade was performed to evaluate the functional relevance of the proteins.
RESULTS: Everolimus resistance was accompanied by significant increases in the percentage of G2/M-phase cells and in the IC50. Akt and p70S6K, targets of everolimus, were activated in Cakires compared to drug sensitive cells. The most prominent change in Cakires cells was an increase in the cell cycle activating proteins cdk2 and cyclin A. Knock-down of cdk2 and cyclin A caused significant growth inhibition in the Cakires cells. The HDAC-inhibitor, VPA, counteracted everolimus resistance in Cakires, evidenced by a significant decrease in tumor growth and cdk2/cyclin A.
CONCLUSION: It is concluded that non-response to everolimus is characterized by increased cdk2/cyclin A, driving RCC cells into the G2/M-phase. VPA hinders everolimus non-response by diminishing cdk2/cyclin A. Therefore, treatment with HDAC-inhibitors might be an option for patients with advanced renal cell carcinoma and acquired everolimus resistance.

Related: Everolimus (Afinitor)

Park GB, Choi Y, Kim YS, et al.
Silencing of PKCη induces cycle arrest of EBV(+) B lymphoma cells by upregulating expression of p38-MAPK/TAp73/GADD45α and increases susceptibility to chemotherapeutic agents.
Cancer Lett. 2014; 350(1-2):5-14 [PubMed] Related Publications
PKCη is involved in proliferation, differentiation, and drug resistance. However, PKCη function in EBV(+) B lymphoma remains poorly understood. Gene silencing of PKCη through siRNA knockdown inhibited cellular proliferation, induced cell cycle arrest in G0/G1 and G2/M phases, and sensitized cells to chemotherapeutic drugs. Upon PKCη knockdown, expression levels of p21, GADD45α, and TAp73 were all increased, whereas expression levels of CDK2, CDK4, CDK6, cyclin E, cyclin B1, and cdc2 were all downregulated. PKCη silencing also activated p38-MAPK, which in turn contributed to the expression of cell cycle arrest-related molecules. These results suggest that siRNA-mediated silencing of PKCη can be a potent tool to complement existing chemotherapy regimens for treating EBV(+) B lymphoma.

Related: Apoptosis CDKN1A GADD45A TP73 Bortezomib Sorafenib (Nexavar)

Qu S, Liu B, Guo X, et al.
Independent oncogenic and therapeutic significance of phosphatase PRL-3 in FLT3-ITD-negative acute myeloid leukemia.
Cancer. 2014; 120(14):2130-41 [PubMed] Article available free on PMC after 01/10/2015 Related Publications
BACKGROUND: Internal tandem duplication of FMS-like tyrosine kinase (FLT3-ITD) is well known to be involved in acute myeloid leukemia (AML) progression, but FLT3-ITD-negative AML cases account for 70% to 80% of AML, and the mechanisms underlying their pathology remain unclear. This study identifies protein tyrosine phophatase PRL-3 as a key mediator of FLT3-ITD-negative AML.
METHODS: A total of 112 FLT3-ITD-negative AML patients were sampled between 2010 and 2013, and the occurrence of PRL-3 hyperexpression in FLT3-ITD-negative AML was evaluated by multivariate probit regression analysis. Overexpression or depletion of endogenous PRL-3 expression with the specific small interfering RNAs was performed to investigate the role of PRL-3 in AML progression. Xenograft models were also used to confirm the oncogenic role of PRL-3.
RESULTS: Compared to healthy donors, PRL-3 is upregulated more than 3-fold in 40.2% of FLT3-ITD-negative AML patients. PRL-3 expression level is adversely correlated to the overall survival of the AML patients, and the AML relapses accompany with re-upregulation of PRL-3. Mechanistically, aberrant PRL-3 expression promoted cell cycle progression and enhanced the antiapoptotic machinery of AML cells to drug cytotoxicity through downregulation of p21 and upregulation of Cyclin D1 and CDK2 and activation of STAT5 and AKT. Depletion of endogenous PRL-3 sensitizes AML cells to therapeutic drugs, concomitant with apoptosis by upregulation of cleaved PARP (poly ADP ribose polymerase) and apoptosis-related caspases. Xenograft assays further confirmed PRL-3's oncogenic role in leukemogenesis.
CONCLUSIONS: Our results demonstrated that PRL-3 is a novel independent crucial player in both FLT3-ITD-positive and FLT3-ITD-negative AML and could be a potential therapeutic target.

Related: Apoptosis CDKN1A Acute Myeloid Leukemia (AML) AKT1 BCL1 Gene (CCND1)

Yang Y, Ma B, Li L, et al.
CDK2 and CDK4 play important roles in promoting the proliferation of SKOV3 ovarian carcinoma cells induced by tumor-associated macrophages.
Oncol Rep. 2014; 31(6):2759-68 [PubMed] Related Publications
A large quantity of M2-polarized tumor-associated macrophages (TAMs) is present in the tissue, ascitic fluid and peritoneum of ovarian cancer patients. A thorough understanding of the roles of M2-TAM in the development of ovarian cancer may provide new insight into the treatment of this disease. The rapid advancement of omics techniques presents a great challenge to biologists to extract meaningful biological information from vast pools of data. In the present study, using microarray method, we identified 996 genes in SKOV3 ovarian carcinoma cells that underwent expression level changes under the influence of TAMs. Subsequently, based on the protein-protein interactions network and the differentially expressed genes, a network showing the influence of TAMs on SKOV3 cells was constructed. The resulting network was analyzed with CFinder software and four modules were found; these modules were further analyzed using David software to perform functional annotations. It was found that module I was mainly related to tumorigenesis and cell cycle. Hence, 31 genes in module I were analyzed with Cytoscape software to generate a gene-function network, which revealed that four gene proteins (E2F1, RB1, CDK2 and CDK4) were functional. Based on literature review, we postulated that CDK2 and CDK4 were key players in the network. In the subsequent molecular experiments, western blot analysis and kinase activity detection demonstrated that TAMs can significantly boost the expression levels and activities of CDK2 and CDK4 in SKOV3 cells. With 3H-TdR incorporation and flow cytometry assay, the proliferation and cell cycle distribution of SKOV3 cells were detected in the absence or presence of CDK2 and CDK4 inhibitors and the results confirmed that the two kinases played a key role in TAM cells enhancing SKOV3 cell proliferation by promoting G0/G1 to S transition. In the present study, we identified the specific changes in the gene expression profile of SKOV3 cells under the influence of TAMs and explored a method for analyzing the gene expression profile data. The results may aid in the design of subsequent molecular experiments.

Related: CDK4 Ovarian Cancer

Jang HJ, Han IH, Kim YJ, et al.
Anticarcinogenic effects of products of heat-processed ginsenoside Re, a major constituent of ginseng berry, on human gastric cancer cells.
J Agric Food Chem. 2014; 62(13):2830-6 [PubMed] Related Publications
Ginsenoside Re is a triol type triterpene glycoside and is abundantly present in ginseng berry. In the present study, we verified that ginsenoside Re can be transformed into less-polar ginsenosides, namely, Rg2, Rg6, and F4, by heat-processing. The products of heat-processed ginsenoside Re inhibited phosphorylation of CDK2 at Thr160 by upregulation of p21 level, resulting in S phase arrest. The products of heat-processed ginsenoside Re also activated caspase-8, caspase-9, and caspase-3, followed by cleavage of PARP, a substrate of caspase-3, in a dose-dependent manner. Concurrently, alteration of mitochondrial factors such as Bcl-2 and Bax was also observed. Moreover, pretreatment with Z-VAD-fmk abrogated caspase-8, -9, and -3 activations by the products of heat-processed ginsenoside Re. We further confirmed that the anticancer effects of the products of heat-processed ginsenoside Re in AGS cells are mainly mediated via generation of less-polar ginsenosides Rg6 and F4.

Related: Apoptosis CASP3 Stomach Cancer Gastric Cancer

Dressing GE, Knutson TP, Schiewer MJ, et al.
Progesterone receptor-cyclin D1 complexes induce cell cycle-dependent transcriptional programs in breast cancer cells.
Mol Endocrinol. 2014; 28(4):442-57 [PubMed] Article available free on PMC after 01/04/2015 Related Publications
The progesterone receptor (PR) and its coactivators are direct targets of activated cyclin-dependent kinases (CDKs) in response to peptide growth factors, progesterone, and deregulation of cell cycle inhibitors. Herein, using the T47D breast cancer model, we probed mechanisms of cell cycle-dependent PR action. In the absence of exogenous progestin, the PR is specifically phosphorylated during the G2/M phase. Accordingly, numerous PR target genes are cell cycle regulated, including HSPB8, a heat-shock protein whose high expression is associated with tamoxifen resistance. Progestin-induced HSPB8 expression required cyclin D1 and was insensitive to antiestrogens but blocked by antiprogestins or inhibition of specificity factor 1 (SP1). HSPB8 expression increased with or without ligand when cells were G2/M synchronized or contained high levels of cyclin D1. Knockdown of PRs abrogated ligand-independent HSPB8 expression in synchronized cells. Notably, PRs and cyclin D1 copurified in whole-cell lysates of transiently transfected COS-1 cells and in PR-positive T47D breast cancer cells expressing endogenous cyclin D1. PRs, cyclin D1, and SP1 were recruited to the HSPB8 promoter in progestin-treated T47D breast cancer cells. Mutation of PR Ser345 to Ala (S345A) or inhibition of CDK2 activity using roscovitine disrupted PR/cyclin D1 interactions with DNA and blocked HSPB8 mRNA expression. Interaction of phosphorylated PRs with SP1 and cyclin D1 provides a mechanism for targeting transcriptionally active PRs to selected gene promoters relevant to breast cancer progression. Understanding the functional linkage between PRs and cell cycle regulatory proteins will provide keys to targeting novel PR/cyclin D1 cross talk in both hormone-responsive disease and HSPB8-high refractory disease with high HSPB8 expression.

Related: Breast Cancer

Stolfi C, De Simone V, Colantoni A, et al.
A functional role for Smad7 in sustaining colon cancer cell growth and survival.
Cell Death Dis. 2014; 5:e1073 [PubMed] Article available free on PMC after 01/04/2015 Related Publications
Initially identified as an inhibitor of transforming growth factor (TGF)-β mainly owing to its ability to bind TGF-β receptor type I and abrogate TGF-β-driven signaling, Smad7 can interact with additional intracellular proteins and regulate TGF-β-independent pathways, thus having a key role in the control of neoplastic processes in various organs. Genome-wide association studies have shown that common alleles of Smad7 influence the risk of colorectal cancer (CRC), even though the contribution of Smad7 in colon carcinogenesis is not fully understood. In this study, we assessed the expression and role of Smad7 in human and mouse models of sporadic CRC. We document a significant increase of Smad7 in human CRC relative to the surrounding nontumor tissues and show that silencing of Smad7 inhibits the growth of CRC cell lines both in vitro and in vivo after transplantation into immunodeficient mice. Knockdown of Smad7 results in enhanced phosphorylation of the cyclin-dependent kinase (CDK)2, accumulation of CRC cells in S phase and enhanced cell death. Smad7-deficient CRC cells have lower levels of CDC25A, a phosphatase that dephosphorylates CDK2, and hyperphosphorylated eukaryotic initiation factor 2 (eIF2)α, a negative regulator of CDC25 protein translation. Consistently, knockdown of Smad7 associates with inactivation of eIF2α, lower CDC25A expression and diminished fraction of proliferating cells in human CRC explants, and reduces the number of intestinal tumors in Apc(min/+) mice. Altogether, these data support a role for Smad7 in sustaining colon tumorigenesis.

Related: APC Signal Transduction SMAD7

Ran Q, Hao P, Xiao Y, et al.
CRIF1 interacting with CDK2 regulates bone marrow microenvironment-induced G0/G1 arrest of leukemia cells.
PLoS One. 2014; 9(2):e85328 [PubMed] Article available free on PMC after 01/04/2015 Related Publications
BACKGROUND: To assess the level of CR6-interacting factor 1 (CRIF1), a cell cycle negative regulator, in patients with leukemia and investigate the role of CRIF1 in regulating leukemia cell cycle.
METHODS: We compared the CRIF1 level in bone marrow (BM) samples from healthy and acute myeloid leukemia (AML), iron deficiency anemia (IDA) and AML-complete remission (AML-CR) subjects. We also manipulated CRIF1 level in the Jurkat cells using lentivirus-mediated overexpression or siRNA-mediated depletion. Co-culture with the BM stromal cells (BMSCs) was used to induce leukemia cell cycle arrest and mimic the BM microenvironment.
RESULTS: We found significant decreases of CRIF1 mRNA and protein in the AML group. CRIF1 overexpression increased the proportion of Jurkat cells arrested in G0/G1, while depletion of endogenous CRIF1 decreased cell cycle arrest. Depletion of CRIF1 reversed BMSCs induced cell cycle arrest in leukemia cells. Co-immunoprecipitation showed a specific binding of CDK2 to CRIF1 in Jurkat cells during cell cycle arrest. Co-localization of two proteins in both nucleus and cytoplasm was also observed with immunofluorescent staining.
CONCLUSION: CRIF1 may play a regulatory role in the BM microenvironment-induced leukemia cell cycle arrest possibly through interacting with CDK2 and acting as a cyclin-dependent kinase inhibitor.

Related: Leukemia Childhood Leukaemia Leukemia - Molecular Biology

Wei G, Chang Y, Zheng J, et al.
Notch1 silencing inhibits proliferation and invasion in SGC‑7901 gastric cancer cells.
Mol Med Rep. 2014; 9(4):1153-8 [PubMed] Related Publications
Downregulation of Notch1 has been shown to exert antineoplastic effects in vivo and in vitro. However, the role of the Notch1 gene in the proliferative and invasive ability of gastric cancer cells is not clear. In this study, we investigated the effect of Notch1 gene silencing on the proliferation and invasion of gastric cancer SGC‑7901 cells. Small interfering RNA (siRNA) targeting Notch1 was transfected into SGC‑7901 cells using Lipofectamine 2000. Proliferation of SGC‑7901 cells was then determined by the MTT assay. Notch1 mRNA expression was determined by reverse transcription‑polymerase chain reaction (RT‑PCR). Invasion of the SGC‑7901 cells was detected by the Transwell assay. The protein levels of cyclin D1, cyclin A1 and cyclin-dependent kinase 2 (CDK2) were determined by western blotting. The mRNA levels of matrix metalloproteinase‑2 (MMP‑2) and cyclooxygenase‑2 (COX‑2) were determined by RT‑PCR. Compared to the control group, the Notch1 mRNA level was significantly decreased following transfection. The growth and invasion rates of SGC‑7901 cells were significantly reduced after Notch1 silencing. Additionally, the expression of cyclin D1 and cyclin A1 proteins and of the MMP‑2 and COX‑2 mRNAs was markedly attenuated. From these results, it was concluded that Notch1 gene silencing inhibits the proliferation of gastric SGC‑7901 cells by decreasing the expression of cyclins D1 and A1, and reduces the invasive ability of SGC‑7901 cells through the downregulation of MMP‑2 and COX‑2 genes. Thus, silencing of the Notch1 pathway may be a novel approach in the treatment of gastrointestinal cancer.

Related: COX2 (PTGS2) MMP2 Stomach Cancer Gastric Cancer NOTCH1 gene

Giacoia EG, Miyake M, Lawton A, et al.
PAI-1 leads to G1-phase cell-cycle progression through cyclin D3/cdk4/6 upregulation.
Mol Cancer Res. 2014; 12(3):322-34 [PubMed] Article available free on PMC after 01/03/2015 Related Publications
UNLABELLED: The canonical function of plasminogen activator inhibitor-1 (PAI-1/SERPINE1) is as an inhibitor of urokinase-type plasminogen activator for blood clot maintenance, but it is now also considered a pleiotropic factor that can exert diverse cellular and tumorigenic effects. However, the mechanism controlling its pleiotropic effects is far from being understood. To elucidate the tumorigenic role of PAI-1, we tested the effects of PAI-1 after manipulation of its expression or through the use of a small-molecule inhibitor, tiplaxtinin. Downregulation of PAI-1 significantly reduced cellular proliferation through an inability to progress from the G(0-G1) phase of the cell cycle. Accordingly, overexpression of PAI-1 augmented proliferation by encouraging S-phase entry. Biochemically, cell-cycle arrest was associated with the depletion of the G(1)-phase transition complexes, cyclin D3/cdk4/6 and cyclin E/cdk2, in parallel with the upregulation of the cell-cycle inhibitors p53, p21Cip1/Waf1, and p27Kip1. PAI-1 depletion significantly decreased the tumor size of urothelial T24 and UM-UC-14 xenografts, and overexpression of PAI-1 substantially increased the tumor size of HeLa xenografts. Finally, immunohistochemical analysis of human bladder and cervical tumor tissue microarrays revealed increased expression of PAI-1 in cancerous tissue, specifically in aggressive tumors, supporting the relevance of this molecule in human tumor biology.
IMPLICATIONS: Targeting PAI-1 has beneficial antitumoral effects and should be further investigated clinically.

Related: CDK4 CDK6 Bladder Cancer Bladder Cancer - Molecular Biology

Huang HH, Chen CH, Huang SC, et al.
Expression of 14-3-3 sigma, cyclin-dependent kinases 2 and 4, p16, and Epstein-Barr nuclear antigen 1 in nasopharyngeal carcinoma.
J Laryngol Otol. 2014; 128(2):134-41 [PubMed] Related Publications
OBJECTIVE: The protein 14-3-3 sigma plays a role in cell cycle arrest by sequestering cyclin-dependent kinase 1 cyclin B1 complexes, as well as cyclin-dependent kinases 2 and 4, hence its definition as a cyclin-dependent kinase inhibitor. However, the nature of the interaction between these biological markers in nasopharyngeal carcinoma is unknown. This study aimed to investigate whether altered expression of these markers contributes to nasopharyngeal carcinogenesis.
METHODS: The study population consisted of 30 nasopharyngeal carcinoma patients and 10 patients without nasopharyngeal carcinoma. The nasopharyngeal carcinoma cell lines TW02, TW04 and Hone-1 were also assessed. We analysed levels of messenger RNA and protein for the p16 gene and the 14-3-3 sigma, Epstein-Barr nuclear antigen 1, and cyclin-dependent kinase 2 and 4 proteins, in nasopharyngeal carcinoma tissue specimens and cell lines and in normal nasopharyngeal tissue.
RESULTS: Protein and messenger RNA levels for cyclin-dependent kinase 2 and Epstein-Barr nuclear antigen 1 were significantly higher in nasopharyngeal carcinoma compared with normal tissue, while levels of cyclin-dependent kinase 4 generally were not; results for 14-3-3 sigma varied. Nasopharyngeal carcinoma patients had diminished p16 gene expression, compared with normal tissue.
CONCLUSION: Levels of cyclin-dependent kinase 2 and Epstein-Barr nuclear antigen 1 were significantly higher in nasopharyngeal carcinoma than in normal tissue, while p16 gene expression was diminished. These three proteins may contribute to nasopharyngeal carcinogenesis.

Related: CDK4 Nasopharyngeal Cancer

Liu J, Yang XY, Shi WJ
Identifying differentially expressed genes and pathways in two types of non-small cell lung cancer: adenocarcinoma and squamous cell carcinoma.
Genet Mol Res. 2014; 13(1):95-102 [PubMed] Related Publications
Non-small cell lung carcinoma, NSCLC, accounts for 80-85% of lung cancers. NSCLC can be mainly divided into two types: adenocarcinoma (ADC) and squamous cell carcinoma (SCC). The purpose of our study was to identify and differentiate the pathogenesis of ADC and SCC at the molecular level. The gene expression profiles of ADC and SCC were downloaded from Gene Expression Omnibus under accession No. GSE10245. Accordingly, differentially expressed genes (DEGs) were identified by the limma package in R language. In addition, DEGs were functionally analyzed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment. A total of 4124 DEGs were identified, including CDK1, CDK2, CDK4, and SKP2. The DEGs were mainly involved in 16 pathways related to cell proliferation, cell signal transduction and metabolism. We conclude that the molecular mechanisms of ADC and SCC are considerably different, and that they are involved in immune response, cell signal transduction, metabolism, cell division, and cell proliferation. Therefore, the two diseases should be treated differently. This study offers new insight into the diagnosis and therapy of these two types of lung cancer.

Related: CDK4

Kang J, Sergio CM, Sutherland RL, Musgrove EA
Targeting cyclin-dependent kinase 1 (CDK1) but not CDK4/6 or CDK2 is selectively lethal to MYC-dependent human breast cancer cells.
BMC Cancer. 2014; 14:32 [PubMed] Article available free on PMC after 01/03/2015 Related Publications
BACKGROUND: Although MYC is an attractive therapeutic target for breast cancer treatment, it has proven challenging to inhibit MYC directly, and clinically effective pharmaceutical agents targeting MYC are not yet available. An alternative approach is to identify genes that are synthetically lethal in MYC-dependent cancer. Recent studies have identified several cell cycle kinases as MYC synthetic-lethal genes. We therefore investigated the therapeutic potential of specific cyclin-dependent kinase (CDK) inhibition in MYC-driven breast cancer.
METHODS: Using small interfering RNA (siRNA), MYC expression was depleted in 26 human breast cancer cell lines and cell proliferation evaluated by BrdU incorporation. MYC-dependent and MYC-independent cell lines were classified based on their sensitivity to siRNA-mediated MYC knockdown. We then inhibited CDKs including CDK4/6, CDK2 and CDK1 individually using either RNAi or small molecule inhibitors, and compared sensitivity to CDK inhibition with MYC dependence in breast cancer cells.
RESULTS: Breast cancer cells displayed a wide range of sensitivity to siRNA-mediated MYC knockdown. The sensitivity was correlated with MYC protein expression and MYC phosphorylation level. Sensitivity to siRNA-mediated MYC knockdown did not parallel sensitivity to the CDK4/6 inhibitor PD0332991; instead MYC-independent cell lines were generally sensitive to PD0332991. Cell cycle arrest induced by MYC knockdown was accompanied by a decrease in CDK2 activity, but inactivation of CDK2 did not selectively affect the viability of MYC-dependent breast cancer cells. In contrast, CDK1 inactivation significantly induced apoptosis and reduced viability of MYC-dependent cells but not MYC- independent cells. This selective induction of apoptosis by CDK1 inhibitors was associated with up-regulation of the pro-apoptotic molecule BIM and was p53-independent.
CONCLUSIONS: Overall, these results suggest that further investigation of CDK1 inhibition as a potential therapy for MYC-dependent breast cancer is warranted.

Related: Breast Cancer CDK4 CDK6 Signal Transduction TP53 MYC gene

Fagan-Solis KD, Pentecost BT, Gozgit JM, et al.
SKP2 overexpression is associated with increased serine 10 phosphorylation of p27 (pSer10p27) in triple-negative breast cancer.
J Cell Physiol. 2014; 229(9):1160-9 [PubMed] Related Publications
S-phase kinase-associated protein 2 (SKP2) is an important cell cycle regulator, targeting the cyclin-dependent kinase (CDK) inhibitor p27 for degradation, and is frequently overexpressed in breast cancer. p27 regulates G1 /S transition by abrogating the activity of cyclin/CDK complexes. p27 can undergo phosphorylation at serine 10 (pSer10p27). This phosphorylation event is associated with increased cell proliferation and poor prognosis in patients with glioma. The relationship between SKP2 and pSer10p27 in breast cancer has not been previously investigated. Immunohistochemistry (IHC) of SKP2, p27, pSer10p27, and other genes involved in this pathway, was analyzed in 188 breast tumors and 50 benign reduction mammoplasty samples. IHC showed SKP2 to be more highly expressed in estrogen receptor α (ERα)-negative breast cancers and demonstrated that triple-negative tumors were more likely to have high expression of SKP2 than were non-triple negative, ERα-negative tumors. A significant positive relationship was discovered for SKP2 and pSer10p27. High levels of SKP2 and pSer10p27 were observed significantly more often in ERα-negative and triple-negative than in ERα-positive breast cancers. Use of the triple-negative TMX2-28 breast cancer cell line to address the role of SKP2 in cell cycle progression confirmed that SKP2 contributes to a more rapid cell cycle progression and may regulates pSer10p27 levels. Together, the results indicate that presence of high SKP2 plus high pSer10p27 levels in triple-negative breast cancers is associated with aggressive growth, and highlight the validity of using SKP2 inhibitors as a therapeutic approach for treating this subset of breast cancers.

Related: CDKN1B Signal Transduction BCL1 Gene (CCND1) ESR1

Yuan X, Srividhya J, De Luca T, et al.
Uncovering the role of APC-Cdh1 in generating the dynamics of S-phase onset.
Mol Biol Cell. 2014; 25(4):441-56 [PubMed] Article available free on PMC after 01/03/2015 Related Publications
Cdh1, a coactivator of the anaphase-promoting complex (APC), is a potential tumor suppressor. Cdh1 ablation promotes precocious S-phase entry, but it was unclear how this affects DNA replication dynamics while contributing to genomic instability and tumorigenesis. We find that Cdh1 depletion causes early S-phase onset in conjunction with increase in Rb/E2F1-mediated cyclin E1 expression, but reduced levels of cyclin E1 protein promote this transition. We hypothesize that this is due to a weakened cyclin-dependent kinase inhibitor (CKI)-cyclin-dependent kinase 2 positive-feedback loop, normally generated by APC-Cdh1-mediated proteolysis of Skp2. Indeed, Cdh1 depletion increases Skp2 abundance while diminishing levels of the CKI p27. This lowers the level of cyclin E1 needed for S-phase entry and delays cyclin E1 proteolysis during S-phase progression while corresponding to slowed replication fork movement and reduced frequency of termination events. In summary, using both experimental and computational approaches, we show that APC-Cdh1 establishes a stimulus-response relationship that promotes S phase by ensuring that proper levels of p27 accumulate during G1 phase, and defects in its activation accelerate the timing of S-phase onset while prolonging its progression.

Related: CDKN1B E2F1 Transcription Factor RB1 Signal Transduction CCNE1 CDH1

Wang L, Yao J, Zhang X, et al.
miRNA-302b suppresses human hepatocellular carcinoma by targeting AKT2.
Mol Cancer Res. 2014; 12(2):190-202 [PubMed] Related Publications
UNLABELLED: miRNAs (miR) play a critical role in human cancers, including hepatocellular carcinoma. Although miR-302b has been suggested to function as a tumor repressor in other cancers, its role in hepatocellular carcinoma is unknown. This study investigated the expression and functional role of miR-302b in human hepatocellular carcinoma. The expression level of miR-302b is dramatically decreased in clinical hepatocellular carcinoma specimens, as compared with their respective nonneoplastic counterparts, and in hepatocellular carcinoma cell lines. Overexpression of miR-302b suppressed hepatocellular carcinoma cell proliferation and G1-S transition in vitro, whereas inhibition of miR-302b promoted hepatocellular carcinoma cell proliferation and G1-S transition. Using a luciferase reporter assay, AKT2 was determined to be a direct target of miR-302b. Subsequent investigation revealed that miR-302b expression was inversely correlated with AKT2 expression in hepatocellular carcinoma tissue samples. Importantly, silencing AKT2 recapitulated the cellular and molecular effects seen upon miR-302b overexpression, which included inhibiting hepatocellular carcinoma cell proliferation, suppressing G1 regulators (Cyclin A, Cyclin D1, CDK2) and increasing p27Kip1 phosphorylation at Ser10. Restoration of AKT2 counteracted the effects of miR-302b expression. Moreover, miR-302b was able to repress tumor growth of hepatocellular carcinoma cells in vivo.
IMPLICATIONS: Taken together, miR-302b inhibits HCC cell proliferation and growth in vitro and in vivo by targeting AKT2.

Related: Liver Cancer MicroRNAs AKT1 Signal Transduction AKT2

Lee YS, Choi KM, Kim W, et al.
Hinokitiol inhibits cell growth through induction of S-phase arrest and apoptosis in human colon cancer cells and suppresses tumor growth in a mouse xenograft experiment.
J Nat Prod. 2013; 76(12):2195-202 [PubMed] Related Publications
Hinokitiol (1), a tropolone-related natural compound, induces apoptosis and has anti-inflammatory, antioxidant, and antitumor activities. In this study, the inhibitory effects of 1 were investigated on human colon cancer cell growth and tumor formation of xenograft mice. HCT-116 and SW-620 cells derived from human colon cancers were found to be similarly susceptible to 1, with IC50 values of 4.5 and 4.4 μM, respectively. Compound 1 induced S-phase arrest in the cell cycle progression and decreased the expression levels of cyclin A, cyclin E, and Cdk2. Conversely, 1 increased the expression of p21, a Cdk inhibitor. Compound 1 decreased Bcl-2 expression and increased the expression of Bax, and cleaved caspase-9 and -3. The effect of 1 on tumor formation when administered orally was evaluated in male BALB/c-nude mice implanted intradermally separately with HCT-116 and SW-620 cells. Tumor volumes and tumor weights in the mice treated with 1 (100 mg/kg) were decreased in both cases. These results suggest that the suppression of tumor formation by compound 1 in human colon cancer may occur through cell cycle arrest and apoptosis.

Related: Apoptosis BCL2

Tran KQ, Tin AS, Firestone GL
Artemisinin triggers a G1 cell cycle arrest of human Ishikawa endometrial cancer cells and inhibits cyclin-dependent kinase-4 promoter activity and expression by disrupting nuclear factor-κB transcriptional signaling.
Anticancer Drugs. 2014; 25(3):270-81 [PubMed] Article available free on PMC after 01/03/2015 Related Publications
Relatively little is known about the antiproliferative effects of artemisinin, a naturally occurring antimalarial compound from Artemisia annua, or sweet wormwood, in human endometrial cancer cells. Artemisinin induced a G1 cell cycle arrest in cultured human Ishikawa endometrial cancer cells and downregulated cyclin-dependent kinase-2 (CDK2) and CDK4 transcript and protein levels. Analysis of CDK4 promoter-luciferase reporter constructs showed that the artemisinin ablation of CDK4 gene expression was accounted for by the loss of CDK4 promoter activity. Chromatin immunoprecipitation demonstrated that artemisinin inhibited nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) subunit p65 and p50 interactions with the endogenous Ishikawa cell CDK4 promoter. Coimmunoprecipitation revealed that artemisinin disrupts endogenous p65 and p50 nuclear translocation through increased protein-protein interactions with IκB-α, an NF-κB inhibitor, and disrupts its interaction with the CDK4 promoter, leading to a loss of CDK4 gene expression. Artemisinin treatment stimulated the cellular levels of IκB-α protein without altering the level of IκB-α transcripts. Finally, expression of exogenous p65 resulted in the accumulation of this NF-κB subunit in the nucleus of artemisinin-treated and artemisinin-untreated cells, reversed the artemisinin downregulation of CDK4 protein expression and promoter activity, and prevented the artemisinin-induced G1 cell cycle arrest. Taken together, our results demonstrate that a key event in the artemisinin antiproliferative effects in endometrial cancer cells is the transcriptional downregulation of CDK4 expression by disruption of NF-κB interactions with the CDK4 promoter.

Related: CDK4 Endometrial (Uterus) Cancer Endometrial Cancer Signal Transduction

Georgantas RW, Streicher K, Luo X, et al.
MicroRNA-206 induces G1 arrest in melanoma by inhibition of CDK4 and Cyclin D.
Pigment Cell Melanoma Res. 2014; 27(2):275-86 [PubMed] Related Publications
Expression profiling of microRNAs in melanoma lesional skin biopsies compared with normal donor skin biopsies, as well as melanoma cell lines compared with normal melanocytes, revealed that hsa-miR-206 was down-regulated in melanoma (-75.4-fold, P = 1.7 × 10(-4)). MiR-206 has been implicated in a large number of cancers, including breast, lung, colorectal, ovarian, and prostate cancers; however, its role in tumor development remains largely unknown, its biologic function is poorly characterized, and its targets affecting cancer cells are largely unknown. MiR-206 reduced growth and migration/invasion of multiple melanoma cell lines. Bioinformatics identified cell cycle genes CDK2, CDK4, Cyclin C, and Cyclin D1 as strong candidate targets. Western blots and 3'UTR reporter gene assays revealed that miR-206 inhibited translation of CDK4, Cyclin D1, and Cyclin C. Additionally, hsa-miR-206 transfection induced G1 arrest in multiple melanoma cell lines. These observations support hsa-miR-206 as a tumor suppressor in melanoma and identify Cyclin C, Cyclin D1, and CDK4 as miR-206 targets.

Related: CASP3 CDK4 Melanoma MicroRNAs Skin Cancer

Sengupta S, Jana S, Bhattacharyya A
TGF-β-Smad2 dependent activation of CDC 25A plays an important role in cell proliferation through NFAT activation in metastatic breast cancer cells.
Cell Signal. 2014; 26(2):240-52 [PubMed] Related Publications
In late stages of cancer, TGF-β promotes the metastasis process by enhancing the invasiveness of cancer cells and inducing the epithelial-to-mesenchymal transition (EMT), a process that is concomitantly associated with breast cancer metastasis. Metastasis comprises of multiple steps with the regulation of complex network of signaling. Metastasis is associated with both the EMT and cell proliferation, but yet it has not been clearly distinguished how the balance between the cell proliferation and EMT is maintained together. Recently, it has been accounted that a transcription factor, NFAT has an important role for switching tumor suppressive to progressive effect of TGF-β and NFAT has a role in TGF-β mediated EMT by regulating N-cadherin. CDC 25A phosphatase, an important cell cycle regulator is overexpressed in breast cancer. Our results demonstrate that TGF-β regulating the CDC 25A in a Smad2 dependent way, translocates NFAT to nucleus and NFAT in co-operation with Smad2 promotes the tumor progression by upregulating the CDK2, CDK4, and cyclin E. This result signifies that TGF-β by regulating NFAT in different ways maintains the balance between EMT and cell proliferation mechanism concurrently during the late stage of breast cancer.

Related: Apoptosis Breast Cancer CDK4 Signal Transduction SMAD2

Du YR, Chen Y, Gao Y, et al.
Effects and mechanisms of anti-CD44 monoclonal antibody A3D8 on proliferation and apoptosis of sphere-forming cells with stemness from human ovarian cancer.
Int J Gynecol Cancer. 2013; 23(8):1367-75 [PubMed] Related Publications
OBJECTIVE: CD44(+) human ovarian cancer stem cells (CSCs) and CSC-like cells have been identified and characterized. Compelling evidence has revealed that CD44 is involved in the occurrence and development of cancers. Our previous study showed that sphere-forming cells (SFCs) from the human ovarian cancer cell line SKOV-3 had CSC capacity. Therefore, in the present study, we aimed to investigate the effects and mechanisms of the anti-CD44 monoclonal antibody A3D8 on the proliferation and apoptosis of SFCs to explore novel strategies for the treatment of ovarian cancer.
METHODS: We investigated the effects and mechanisms of A3D8 on the proliferation and apoptosis of SFCs using the MTS assay, cell cycle analysis, an annexin V-fluorescein isothiocyanate/propidium iodide kit, Rh123 apoptosis detection kit, real-time reverse transcription polymerase chain reaction and Western blotting.
RESULTS: After CD44 ligation by A3D8, SFC cell proliferation was notably attenuated, cell cycle progression was arrested in the S phase, and apoptosis was significantly increased. The effect of A3D8 was enhanced in a dose- and time-dependent manner, and the effect of apoptosis induction by DDP was enhanced by combination treatment with A3D8. Furthermore, the messenger RNA expression levels of p21 and caspase-3 were up-regulated, whereas those of CDK2, cyclinA, and Bcl-2 were down-regulated. The protein expression levels of caspase-3 were up-regulated, whereas those of CDK2, cyclinA, and Bcl-2 were down-regulated.
CONCLUSIONS: Our findings indicate that anti-CD44 monoclonal antibodies may be a potential strategy for the treatment of human ovarian cancer after conventional therapy via inhibition of growth and the promotion of apoptosis in SFCs with stemness.

Related: Monoclonal Antibodies Apoptosis CASP3 Cisplatin CDKN1A Ovarian Cancer

Etemadmoghadam D, Weir BA, Au-Yeung G, et al.
Synthetic lethality between CCNE1 amplification and loss of BRCA1.
Proc Natl Acad Sci U S A. 2013; 110(48):19489-94 [PubMed] Article available free on PMC after 01/03/2015 Related Publications
High-grade serous ovarian cancers (HGSCs) are characterized by a high frequency of TP53 mutations, BRCA1/2 inactivation, homologous recombination dysfunction, and widespread copy number changes. Cyclin E1 (CCNE1) gene amplification has been reported to occur independently of BRCA1/2 mutation, and it is associated with primary treatment failure and reduced patient survival. Insensitivity of CCNE1-amplified tumors to platinum cross-linking agents may be partly because of an intact BRCA1/2 pathway. Both BRCA1/2 dysfunction and CCNE1 amplification are known to promote genomic instability and tumor progression. These events may be mutually exclusive, because either change provides a path to tumor development, with no selective advantage to having both mutations. Using data from a genome-wide shRNA synthetic lethal screen, we show that BRCA1 and members of the ubiquitin pathway are selectively required in cancers that harbor CCNE1 amplification. Furthermore, we show specific sensitivity of CCNE1-amplified tumor cells to the proteasome inhibitor bortezomib. These findings provide an explanation for the observed mutual exclusivity of CCNE1 amplification and BRCA1/2 loss in HGSC and suggest a unique therapeutic approach for treatment-resistant CCNE1-amplified tumors.

Related: Ovarian Cancer CCNE1 Bortezomib

De U, Chun P, Choi WS, et al.
A novel anthracene derivative, MHY412, induces apoptosis in doxorubicin-resistant MCF-7/Adr human breast cancer cells through cell cycle arrest and downregulation of P-glycoprotein expression.
Int J Oncol. 2014; 44(1):167-76 [PubMed] Related Publications
New potential chemotherapeutic strategies are required to overcome multidrug resistance (MDR) in cancer. This study investigated the anticancer effect of a novel anthracene derivative MHY412 on doxorubicin-resistant human breast cancer (MCF-7/Adr) cells. We measured cell viability and the expression of apoptosis-related genes; in addition, the antitumor activity of MHY412 was confirmed using an in vivo tumor xenograft model. MHY412 significantly inhibited the proliferation of MCF-7/Adr and MCF-7 cells in a concentration-dependent manner. Notably, the half-maximal inhibitory concentration (IC50) values of MHY412 in MCF-7/Adr (0.15 µM) and MCF-7 (0.26 µM) cells were lower than those of doxorubicin (MCF-7/Adr, 13.6 µM and MCF-7, 1.26 µM) after treatment for 48 h. MHY412 at low concentrations induced S phase arrest, but at high concentrations, the number of MCF-7/Adr cells in the sub-G1 phase significantly increased. MHY412-induced sub-G1 phase arrest was associated with inhibition of cyclin, cyclin-dependent kinase 2 (CDK2) and p21 expression in MCF-7/Adr cells. MHY412 markedly reduced P-glycoprotein (P-gp) expression and increased apoptotic cell death in MCF-7/Adr cells. Cleavage of poly-ADP ribose polymerase, reduced Bcl-2 expression, and increased in cytochrome c release in MCF-7/Adr cells confirmed the above results. In addition, MHY412 markedly inhibited tumor growth in a tumor xenograft model of MCF-7/Adr cells. Our data suggest that MHY412 exerts antitumor effects by selectively modulating the genes related to cell cycle arrest and apoptosis. In particular, MHY412 is a new candidate agent for the treatment of Bcl-2 overexpressed doxorubicin-resistant human breast cancer.

Related: Apoptosis Breast Cancer Doxorubicin

Zhan Y, Wang L, Liu J, et al.
Choline plasmalogens isolated from swine liver inhibit hepatoma cell proliferation associated with caveolin-1/Akt signaling.
PLoS One. 2013; 8(10):e77387 [PubMed] Article available free on PMC after 01/03/2015 Related Publications
Plasmalogens play multiple roles in the structures of biological membranes, cell membrane lipid homeostasis and human diseases. We report the isolation and identification of choline plasmalogens (ChoPlas) from swine liver by high performance thin layer chromatography (HPTLC) and high performance liquid chromatography (HPLC)/MS. The growth and viability of hepatoma cells (CBRH7919, HepG2 and SMMC7721) was determined following ChoPlas treatment comparing with that of human normal immortal cell lines (HL7702). Result indicated that ChoPlas inhibited hepatoma cell proliferation with an optimal concentration and time of 25 μmol/L and 24 h. To better understand the mechanism of the ChoPlas-induced inhibition of hepatoma cell proliferation, Caveolin-1 and PI3K/Akt pathway signals, including total Akt, phospho-Akt(pAkt) and Bcl-2 expression in CBRH7919 cells, were determined by western blot. ChoPlas treatment increased Caveolin-1 expression and reduced the expression of phospho-Akt (pAkt) and Bcl-2, downstream targets of the PI3K/Akt pathway. Further cell cycle analysis showed that ChoPlas treatment induced G1 and G1/S phase transition cell cycle arrest. The expression of essential cell cycle regulatory proteins involved in the G1 and G1/S phase transitions, cyclin D, CDK4, cyclin E and CDK2, were also analyzed by western blot. ChoPlas reduced CDK4, cyclin E and CDK2 expression. Taken together, the results indicate that swine liver-derived natural ChoPlas inhibits hepatoma cell proliferation associated with Caveolin-1 and PI3K/Akt signals.

Related: Liver Cancer AKT1 Signal Transduction

Gubanova E, Issaeva N, Gokturk C, et al.
SMG-1 suppresses CDK2 and tumor growth by regulating both the p53 and Cdc25A signaling pathways.
Cell Cycle. 2013; 12(24):3770-80 [PubMed] Article available free on PMC after 01/03/2015 Related Publications
The DNA damage response is coordinated by phosphatidylinositol 3-kinase-related kinases, ATM, ATR, and DNA-PK. SMG-1 is the least studied stress-responsive member of this family. Here, we show that SMG-1 regulates the G 1/S checkpoint through both a p53-dependent, and a p53-independent pathway. We identify Cdc25A as a new SMG-1 substrate, and show that cells depleted of SMG-1 exhibit prolonged Cdc25A stability, failing to inactivate CDK2 in response to radiation. Given an increased tumor growth following depletion of SMG-1, our data demonstrate a novel role for SMG-1 in regulating Cdc25A and suppressing oncogenic CDK2 driven proliferation, confirming SMG-1 as a tumor suppressor.

Related: Cancer Prevention and Risk Reduction Signal Transduction TP53


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Cite this page: Cotterill SJ. CDK2, Cancer Genetics Web: http://www.cancerindex.org/geneweb/CDK2.htm Accessed: date

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