Gene Summary

Gene:BCL2L2; BCL2 like 2
Aliases: BCLW, BCL-W, PPP1R51, BCL2-L-2
Summary:This gene encodes a member of the BCL-2 protein family. The proteins of this family form hetero- or homodimers and act as anti- and pro-apoptotic regulators. Expression of this gene in cells has been shown to contribute to reduced cell apoptosis under cytotoxic conditions. Studies of the related gene in mice indicated a role in the survival of NGF- and BDNF-dependent neurons. Mutation and knockout studies of the mouse gene demonstrated an essential role in adult spermatogenesis. Alternative splicing results in multiple transcript variants. Read-through transcription also exists between this gene and the neighboring downstream PABPN1 (poly(A) binding protein, nuclear 1) gene. [provided by RefSeq, Dec 2010]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:bcl-2-like protein 2
Source:NCBIAccessed: 11 March, 2017


What does this gene/protein do?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 11 March 2017 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 11 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (6)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

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

Latest Publications: BCL2L2 (cancer-related)

Lu W, Feng L, Zhang Y, et al.
miR-15a induces cell apoptosis by targeting BCL2L2 and BCL2 in HPV-positive hypopharyngeal squamous cell carcinoma.
Oncol Rep. 2016; 36(4):2169-76 [PubMed] Related Publications
Aberrant expression of miR-15a was recently reported in several types of cancers; however, its role in HPV-positive hypopharyngeal squamous cell carcinoma (HSCC) remains obscure. In the present study, we investigated the mechanism by which miR-15a induces HPV-positive HSCC apoptosis. Synthetic miR-15a mimics were transfected into FaDu cells (HPV-negative), and the miR-15a inhibitor was transfected into HPV-positive HSCC cells. miR-15a expression was analyzed by RT-PCR, and BCL2L2 and BCL2 were analyzed by western blotting. The Hochest 33342/propidium iodide (PI) and caspase-3/-9 assays, and Annexin V staining were used to assess the effect of miR-15a on apoptosis. After transfection, overexpression of miR-15a in the FaDu cells was associated with significantly decreased BCL2L2 and BCL2 expression and a significant increase in the apoptosis rate. The opposite results were observed in HPV-positive HSCC, where downregulation of miR-15a suppressed apoptosis. These findings indicate that miR-15a acts as a tumor suppressor in HPV-positive HSCC.

Asif M, Shafaei A, Jafari SF, et al.
Isoledene from Mesua ferrea oleo-gum resin induces apoptosis in HCT 116 cells through ROS-mediated modulation of multiple proteins in the apoptotic pathways: A mechanistic study.
Toxicol Lett. 2016; 257:84-96 [PubMed] Related Publications
Colorectal cancer (CRC) is one of the most common human malignant tumors worldwide. Arising from the transformation of epithelial cells in the colon and/or rectum into malignant cells, the foundation of CRC pathogenesis lies in the progressive accumulation of mutations in oncogenes and tumor-suppressor genes, such as KRAS and APC. Resistance to apoptosis is one of the key mechanisms in the development of CRC as it is for any other kind of cancer. Natural products have been shown to induce the expression of apoptosis regulators that are blocked in cancer cells. In the present study, a series of in vitro assays were employed to study the apoptosis-inducing attributes of Isoledene rich sub-fraction (IR-SF) collected from the oleo-gum resin of M. ferrea. Data obtained, showed that IR-SF inhibited cell proliferation and induced typical apoptotic changes in the overall morphology of all the CRC cell lines tested. Fluorescent staining assays revealed characteristic nuclear condensation, and marked decrease in mitochondrial outer membrane potential in the treated cells. In addition, an increment in the levels of ROS, caspase-8, -9 and -3 was observed. Proteomic analysis revealed that IR-SF up-regulated the expression of pro-apoptotic proteins, i.e., Bid, Bim and cytochrome c. Cytochrome c in turn activated caspases cascade resulting in the induction of apoptosis. Moreover, IR-SF significantly down-regulated Bcl-2, Bcl-w, survivin, xIAP and HSPs pro-survival proteins and induced DNA fragmentation and G0/G1-phase arrest in HCT 116 cells. Chemical characterization of IR-SF by GC-MS and HPLC methods identified Isoledene as one of the major compounds. Altogether, results of the present study demonstrate that IR-SF may induce apoptosis in human colorectal carcinoma cells through activation of ROS-mediated apoptotic pathways.

Witek Ł, Janikowski T, Bodzek P, et al.
Expression of tumor suppressor genes related to the cell cycle in endometrial cancer patients.
Adv Med Sci. 2016; 61(2):317-324 [PubMed] Related Publications
PURPOSE: Endometrial cancer is the most common gynecological malignancy in developed countries. The role of tumor suppressor genes (TSG) in endometrioid endometrial adenocarcinoma (EEC) has an important impact on patient survival prognosis. Thus, it is important to identify TSG transcripts that differentiate endometrial adenocarcinoma into various pathomorphological grades. The aim of this study was to analyze the expression profile of tumor suppressor genes related to the cell cycle in patients with endometrial adenocarcinoma across histological differentiation and to identify transcripts which differentiate endometrium into various pathomorphological grades.
MATERIAL AND METHODS: Gene expression analysis was completed for 19 endometrial endometrioid adenocarcinomas and 5 normal specimens (obtained from women with diagnosed uterine fibroids, benign ovarian tumors and a prolapsed uterus with histopathologically confirmed endometrium in the proliferative phase) using Affymetrix HG-U133A oligonucleotide microarrays. The statistical analysis was performed using the GeneSpring13.0 software and PANTHER classification system.
RESULTS: Significant changes in gene expression were observed across histological differentiation. The WT-1, CYR 61, TSPYL5 genes were statistically and biologically significant in all cancer grades, and were considered to be primary for the G1 grade in endometrial cancer. The G2 cancer specific genes were BCL2L2 and HNRNPA0, whereas in G3 there was only BAK.
CONCLUSION: In conclusion, the WT-1, CYR61 and TSPYL5 gene expressions are potentially correlated with patient survival in all endometrial cancer grades. The TSGs identified are considered to be important in EEC pathogenesis and further research is needed to confirm this.

You HY, Xie XM, Zhang WJ, et al.
Berberine modulates cisplatin sensitivity of human gastric cancer cells by upregulation of miR-203.
In Vitro Cell Dev Biol Anim. 2016; 52(8):857-63 [PubMed] Related Publications
Chemotherapeutic resistance is the main reason of the failure in clinical treatment of gastric cancer. Berberine (BER) is the active compound of traditional Chinese medicine Huang Lian. The aim of this present study is to evaluate the effect of BER on cisplatin resistance in gastric cancer cells and to investigate its possible mechanism. Gastric cancer cell lines SGC-7901 and BGC-823 and their respective cisplatin-resistant variants SGC-7901/DDP and BGC-823/DDP were used in this study. We found that BER treatment significantly reversed cisplatin sensitivity and induced caspase-dependent apoptosis in SGC-7901/DDP and BGC-823/DDP cells; BER treatment induced miR-203 expression, and overexpression of miR-203 mimicked the cisplatin-sensitizing effect of BER. Importantly, we showed that miR-203 was able to target the 3'UTR of Bcl-w. Therefore, we conclude that BER treatment reduces cisplatin resistance of gastric cancer cells by modulating the miR-203/Bcl-w apoptotic axis. BER may be a novel agent to enhance chemotherapeutic responses in cisplatin-resistant gastric cancer patients.

Tang X, Tang J, Liu X, et al.
Downregulation of miR-129-2 by promoter hypermethylation regulates breast cancer cell proliferation and apoptosis.
Oncol Rep. 2016; 35(5):2963-9 [PubMed] Related Publications
Aberrant expression of the miR-129 family has been found in several types of cancer, yet its expression and potential biologic role in breast cancer remain largely unknown. In the present study, we found that miR-129-2 was consistently downregulated in the breast cancer specimens and cell lines. Overexpression of miR-129-2-3p markedly suppressed breast cancer cell proliferation and induced its apoptosis. In addition, a luciferase reporter assay revealed that miR-129-2-3p suppressed BCL2L2 expression. Furthermore, BCL2L2 was able to reverse miR-129-2-3p-mediated cell apoptosis, indicating that BCL2L2 plays a crucial role in mediating the tumor-suppressive role of miR-129-2-3p. Moreover, bisulfite DNA sequencing PCR (BSP) analysis identified that promoter hypermethylation was responsible for the downregulation of miR-129-2 in breast cancer. Collectively, our findings indicate that miR-129-2 is downregulated in breast cancer cells by promoter hypermethylation. Moreover, downregulation of miR-129-2 results in BCL2L2 overexpression and disease progression in breast cancer patients.

Datta S, Ray A, Singh R, et al.
Sequence and expression variations in 23 genes involved in mitochondrial and non-mitochondrial apoptotic pathways and risk of oral leukoplakia and cancer.
Mitochondrion. 2015; 25:28-33 [PubMed] Related Publications
Oral cancer is usually preceded by pre-cancerous lesion and related to tobacco abuse. Tobacco carcinogens damage DNA and cells harboring such damaged DNA normally undergo apoptotic death, but cancer cells are exceptionally resistant to apoptosis. Here we studied association between sequence and expression variations in apoptotic pathway genes and risk of oral cancer and precancer. Ninety nine tag SNPs in 23 genes, involved in mitochondrial and non-mitochondrial apoptotic pathways, were genotyped in 525 cancer and 253 leukoplakia patients and 538 healthy controls using Illumina Golden Gate assay. Six SNPs (rs1473418 at BCL2; rs1950252 at BCL2L2; rs8190315 at BID; rs511044 at CASP1; rs2227310 at CASP7 and rs13010627 at CASP10) significantly modified risk of oral cancer but SNPs only at BCL2, CASP1and CASP10 modulated risk of leukoplakia. Combination of SNPs showed a steep increase in risk of cancer with increase in "effective" number of risk alleles. In silico analysis of published data set and our unpublished RNAseq data suggest that change in expression of BID and CASP7 may have affected risk of cancer. In conclusion, three SNPs, rs1473418 in BCL2, rs1950252 in BCL2L2 and rs511044 in CASP1, are being implicated for the first time in oral cancer. Since SNPs at BCL2, CASP1 and CASP10 modulated risk of both leukoplakia and cancer, so, they should be studied in more details for possible biomarkers in transition of leukoplakia to cancer. This study also implies importance of mitochondrial apoptotic pathway gene (such as BCL2) in progression of leukoplakia to oral cancer.

Wang P, Yuan X, Wang Y, et al.
Licochalcone C induces apoptosis via B-cell lymphoma 2 family proteins in T24 cells.
Mol Med Rep. 2015; 12(5):7623-8 [PubMed] Related Publications
The current study investigated the mechanisms by which licochalcone C induces apoptosis of T24 human malignant bladder cancer cells. Cell viability was evaluated using an MTT assay. Apoptosis was investigated using a morphological assay, flow cytometry and a caspase‑3 activity assay. Alterations in the gene expression levels of Bcl‑2 family members were measured by semi‑quantitative reverse transcription‑polymerase chain reaction assays. The protein levels of pro‑caspase‑3 and cleaved poly(ADP ribose) polymerase were measured using western blotting. The results indicated that licochalcone C induced T24 cell apoptosis in a concentration‑dependent manner. Licochalcone C treatment reduced the levels of the anti‑apoptotic mRNAs (Bcl‑2, Bcl‑w and Bcl‑XL) and increased expression of the pro‑apoptotic mRNAs (Bax and Bim). The Bcl‑2 family inhibitor (ABT‑737) reduced apoptosis induced by licochalcone C in T24 cells. The current study demonstrated that licochalcone C may be a potential adjuvant therapeutic agent for bladder cancer.

Huang H, Zhu Y, Li S
MicroRNA-122 mimic transfection contributes to apoptosis in HepG2 cells.
Mol Med Rep. 2015; 12(5):6918-24 [PubMed] Related Publications
There is currently a requirement for effective treatment strategies for human hepatocellular carcinoma (HCC), a leading cause of cancer‑associated mortality. MicroRNA-122 (miR-122), a repressor of the endogenous apoptosis regulator Bcl‑w, is frequently downregulated in HCC. Thus, it is hypothesized that the activation of miR‑122 may induce selective hepatocellular apoptosis via caspase activation in a model of HCC. In the present study, an miR‑122 mimic transfection was performed in HepG2 cells, and used to investigate the role and therapeutic potential of miR‑122 in the regulation of HCC‑derived cell lines. The apoptotic rates of HepG2 cells were significantly increased following miR‑122 mimic transfection. Reverse transcription‑polymerase chain reaction analysis revealed that Bcl‑w mRNA was significantly reduced, while the mRNA levels of caspase‑9 and caspase‑3 were markedly increased. The immunocytochemistry results supported the mRNA trends. Collectively, the present results suggest that endogenous miR‑122 contributes to HepG2 apoptosis and that transfection of mimic miR‑122 normalizes apoptotic levels in a model of HCC.

Zhang Y, Yu J, Liu H, et al.
Novel Epigenetic CREB-miR-630 Signaling Axis Regulates Radiosensitivity in Colorectal Cancer.
PLoS One. 2015; 10(8):e0133870 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: miR-630 has been reported to be a modulator of several cancers, but the mechanism by which is it influences radioresistance remains unknown. We aimed to identify the molecular function of miR-630 and its regulatory mechanism in colorectal cancer (CRC) cell lines.
METHODOLOGY: Overexpression and loss-of-function analyses of miR-630 were performed in CRC cell lines by measuring their levels of growth and apoptosis after ionic radiation (IR). Target genes were detected via a dual-luciferase assay and Western blot. Chromatin immunoprecipitation assay was carried out to identify the transcription factor regulating miR-630, and a demethylation experiment was also conducted.
RESULTS: miR-630 expression was found to be positively correlated with radiosensitivity in CRC cell lines (p<0.05). After IR treatment, miR-630 induced apoptosis in cells; however, the opposite was observed when miR-630 was downregulated (p<0.05). BCL2L2 and TP53RK were identified as the target genes of miR-630, and the function of miR-630 was found to depend on these two genes (p<0.05). In addition, evidence showed that CREB regulates the level of miR-630, and demethylation can elevate miR-630 levels (p<0.05).
CONCLUSION: CREB-miR-630-BCL2L2 and TP53RK comprise a novel signaling cascade regulating radiosensitivity in CRC cell lines by inducing cell apoptosis and death.

Chung HJ, Choi YE, Kim ES, et al.
miR-29b attenuates tumorigenicity and stemness maintenance in human glioblastoma multiforme by directly targeting BCL2L2.
Oncotarget. 2015; 6(21):18429-44 [PubMed] Free Access to Full Article Related Publications
Glioblastoma multiforme (GBM) is the most common malignant brain tumor and exhibits aggressive and invasive behavior. We previously identified four miRNAs-miR-29b, 494, 193a-3p, and 30e-with enhanced expression in GBM following treatment of ionizing radiation by miRNA microarray analysis. In this study, we found that only miR-29b inhibited tumor cell migration and invasion by reducing MMP-2 activity via phospho-AKT/β-catenin signaling, and stimulated a more epithelial-like morphology. Moreover, miR-29b inhibits angiogenesis by attenuating tube formation and the expression of VEGF and Ang-2, and stemness maintenance in GBM cells, as demonstrated by decreasing neurosphere formation and cancer stem cell marker protein expression. These findings support the anti-tumor properties of miR-29b in human GBM cells. Furthermore, miR-29b expression was inversely proportional to that of BCL2L2 mRNA or protein in various cancer cell types. Interestingly, BCL2L2 mRNA is highly expressed in the mesenchymal type of GBM. To further elucidate the relationship between miR-29b and BCL2L2 in GBM, we performed co-transfection reporter assays and determined that miR-29b downregulates BCL2L2 expression by directly binding its 3'UTR. Finally, we confirmed that BCL2L2 repression is of central importance to miR-29b anti-tumor activity using functional assays to examine cell migration, invasion, angiogenesis, and stemness. From these data, we propose that miR-29b may be a useful therapeutic agent in GBM.

Shang Y, Wang LQ, Guo QY, Shi TL
MicroRNA-196a overexpression promotes cell proliferation and inhibits cell apoptosis through PTEN/Akt/FOXO1 pathway.
Int J Clin Exp Pathol. 2015; 8(3):2461-72 [PubMed] Free Access to Full Article Related Publications
MicroRNAs (miRNAs) are endogenous, non-coding, small RNAs, which play a critical role in regulating varieties of the biological and pathologic processes. MiR-196a has been reported to take part in tumorigenic progression of osteosarcoma (OS). However, the effects of miR-196a on OS are still unclear. The objective of this study is to investigate the molecular mechanism of miR-196a in osteosarcoma cells. In the present study, the expression of miR-196a in OS cell lines was detected by real-time PCR. We found that the expression level of miR-196a was markedly up-regulated in osteosarcoma cell lines compared with normal osteoblastic cells. Then, the miR-196a mimic was transiently transfected into MG63 and U2OS cells using Lipofectamine™ 2000 reagent. Subsequently, the MTT and Brdu-ELISA results showed that up-regulation of miR-196a promoted the cell viability and proliferation. Our results also showed that miR-196a mimic accelerated cell cycle progression of MG63 and U2OS cells by down regulation of p21 and p27, and upregulation of cyclin D1. In addition, overexpression of miR-196a suppressed apoptosis of MG63 and U2OS cells due to increasing BCL2L2 and MCL-1 expressions, and then inactivating caspase-3. Eventually, the effect of miR-196a mimic on the PTEN/phosphoinositide 3-kinase (PI3K)/Akt signaling pathway was explored by Western blot. From our results, transfection of miR-196a decreased the expression of PTEN and increased the phosphorylation of PI3K and Akt. Taken together, miR-196a should be an oncogene in osteosarcoma. The possible mechanism was that overexpression of miR-196a promoted proliferation of MG63 and U2OS cells by modulating the PTEN/PI3K/Akt signaling pathway.

Xiao Y, Nimmer P, Sheppard GS, et al.
MCL-1 Is a Key Determinant of Breast Cancer Cell Survival: Validation of MCL-1 Dependency Utilizing a Highly Selective Small Molecule Inhibitor.
Mol Cancer Ther. 2015; 14(8):1837-47 [PubMed] Related Publications
Hyperexpression of antiapoptotic BCL-2 family proteins allows cells to survive despite the receipt of signals that would ordinarily induce their deletion, a facet frequently exploited by tumors. Tumors addicted to the BCL-2 family proteins for survival are now being targeted therapeutically. For example, navitoclax, a BCL-2/BCL-XL/BCL-W inhibitor, is currently in phase I/II clinical trials in numerous malignancies. However, the related family member, MCL-1, limits the efficacy of navitoclax and other chemotherapeutic agents. In the present study, we identify breast cancer cell lines that depend upon MCL-1 for survival and subsequently determine the mechanism of apoptosis mediated by the MCL-1 selective inhibitor A-1210477. We demonstrate that apoptosis resulting from a loss in MCL-1 function requires expression of the proapoptotic protein BAK. However, expression of BCL-XL can limit apoptosis resulting from loss in MCL-1 function through sequestration of free BIM. Finally, we demonstrate substantial synergy between navitoclax and MCL-1 siRNA, the direct MCL-1 inhibitor A-1210477, or the indirect MCL-1 inhibitor flavopiridol, highlighting the therapeutic potential for inhibiting BCL-XL and MCL-1 in breast cancer.

Yuan Y, Zhang X, Zeng X, et al.
Glutathione-mediated release of functional miR-122 from gold nanoparticles for targeted induction of apoptosis in cancer treatment.
J Nanosci Nanotechnol. 2014; 14(8):5620-7 [PubMed] Related Publications
MiRs was efficiently bound to water-soluble positively charged gold nanoparticles through complementary electrostatic interaction. MiR-122 has been considered to be specifically expressed in liver and involved in inducing hepatocyte apoptosis through bcl-w pathway, which could be efficiently bound to water dispersible positively charged gold nanoparticles and conjugated with folic acid (FA) to target specific cancer cells, through complementary electrostatic interaction. These gold nanoparticles-miR-122-FA nanocomplexes (GMN) were disrupted and miR-122 was released by glutathione (GSH) at intracellular concentrations. In contrast, there was almost no detectable miR-122 released from GMN by extracellular concentration of GSH. The formation of GMN and GSH-mediated miR-122 release from the complexes were corroborated by dye displacement assay, electrophoresis experiment and transmission electron microscopy (TEM). With FA funcition, the GMN can target to the HepG2 cell membrane efficiently revealed by scanning electron microscopy (SEM). The released miR-122 retained apoptosis-inducing activity after being transfected into HepG2 cells. The transfection efficiency measured by MTT assay and flow cytometry was comparable with the positive control. We determined the effects of GMN on HepG2 cells viability and apoptosis by using fluorescence light microscopy and SDS-PAGE/immunoblots. The obvious concentration gradient of GSH in nature between the intra- and extracellular environments as well as the GSH concentration-dependent release suggest that these positively charged gold nanoparticles can be used as a novel visible vehicle for gene delivery and open up promising opportunities for target applications in the future.

Yang T, Thakur A, Chen T, et al.
MicroRNA-15a induces cell apoptosis and inhibits metastasis by targeting BCL2L2 in non-small cell lung cancer.
Tumour Biol. 2015; 36(6):4357-65 [PubMed] Related Publications
MicroRNAs (miRNAs) play a critical role in cancer development and progression. Aberrant expression of miR-15a has recently been reported in several cancers, but its role in non-small cell lung cancer (NSCLC) still remains obscure. We investigated the effects of miR-15a on proliferation, apoptosis, and metastasis in A549 cells. Eighteen paired NSCLC and adjacent non-tumor lung tissues were surgically removed and immediately snap frozen until total RNA was extracted and confirmed by two independent pathologists. The targets of miR-15a were predicted by bioinformatics tools. RNA isolation and quantitative real-time PCR (qRT-PCR), Western blot analysis, cell proliferation assay, cell cycle analysis, cell apoptosis assay, and migration and invasion assays were done. The wild type (WT) or mutant type (MT) 3'-untranslated region (UTR) vectors were co-transfected with miR-15a or negative control into A549 cells, and after 24 h of transfection, luciferase activity was measured using the Dual-Glo luciferase assay kit. Statistical analysis was performed using SPSS 13.0 software (SPSS, Chicago, IL, USA). P values of less than 0.05 were considered statistically significant. miR-15a was significantly downregulated in NSCLC than in adjacent non-cancerous tissues. miR-15a overexpression remarkably inhibited cell viability, invasion, and migration and promoted the apoptosis of NSCLC cells. Additionally, inhibition of miR-15a expression had the opposite effects on tumor progression, while cell cycle remained unaltered. Furthermore, we identified that BCL2L2 was a target of miR-15a and negatively regulated by miR-15a at the translational level. miR-15a acts as a tumor suppressor in NSCLC by directly targeting BCL2L2 and may serve as a potential diagnostic biomarker and therapeutic target for NSCLC.

Wang K, Chen X, Zhan Y, et al.
miR-335 inhibits the proliferation and invasion of clear cell renal cell carcinoma cells through direct suppression of BCL-W.
Tumour Biol. 2015; 36(9):6875-82 [PubMed] Related Publications
Increasing evidence has demonstrated that small non-coding microRNAs (miRNAs) play important roles in cancer development and progression. Recent studies have shown that microRNA-335 (miR-335) functions as an oncogene or a tumor suppressor in various human cancer types, but its role in clear cell renal cell carcinoma (ccRCC) remains poorly understood. In our study, we firstly found that the expression level of miR-335 was significantly downregulated in ccRCC tissues versus corresponding non-tumor tissues and the low expression of miR-335 was significantly associated with lymph node metastasis, larger tumor size, and poor T stage. Then, we found that overexpression of miR-335 significantly suppressed the proliferation and invasion of 786-O and CaKi-1 ccRCC cell lines. We subsequently found that miR-335 could interact with the 3'-untranslated regions (3'UTR) of B-cell CLL/lymphoma 2 like 2 (BCL-W or BCL2L2) messenger RNA (mRNA) and repress its expression. In addition, re-expression of BCL-W (without the 3'UTR) could partially abrogate the miR-335-induced 786-O and CaKi-1 ccRCC cell proliferation and invasion inhibition. Furthermore, we found that expression patterns of miR-335 were inversely correlated with those of BCL-W mRNA in ccRCC tissues. Taken together, these results indicate that miR-335 acts as a novel tumor suppressor to regulate ccRCC cell proliferation and invasion through downregulation of BCL-W expression.

Leverson JD, Phillips DC, Mitten MJ, et al.
Exploiting selective BCL-2 family inhibitors to dissect cell survival dependencies and define improved strategies for cancer therapy.
Sci Transl Med. 2015; 7(279):279ra40 [PubMed] Related Publications
The BCL-2/BCL-XL/BCL-W inhibitor ABT-263 (navitoclax) has shown promising clinical activity in lymphoid malignancies such as chronic lymphocytic leukemia. However, its efficacy in these settings is limited by thrombocytopenia caused by BCL-XL inhibition. This prompted the generation of the BCL-2-selective inhibitor venetoclax (ABT-199/GDC-0199), which demonstrates robust activity in these cancers but spares platelets. Navitoclax has also been shown to enhance the efficacy of docetaxel in preclinical models of solid tumors, but clinical use of this combination has been limited by neutropenia. We used venetoclax and the BCL-XL-selective inhibitors A-1155463 and A-1331852 to assess the relative contributions of inhibiting BCL-2 or BCL-XL to the efficacy and toxicity of the navitoclax-docetaxel combination. Selective BCL-2 inhibition suppressed granulopoiesis in vitro and in vivo, potentially accounting for the exacerbated neutropenia observed when navitoclax was combined with docetaxel clinically. By contrast, selectively inhibiting BCL-XL did not suppress granulopoiesis but was highly efficacious in combination with docetaxel when tested against a range of solid tumors. Therefore, BCL-XL-selective inhibitors have the potential to enhance the efficacy of docetaxel in solid tumors and avoid the exacerbation of neutropenia observed with navitoclax. These studies demonstrate the translational utility of this toolkit of selective BCL-2 family inhibitors and highlight their potential as improved cancer therapeutics.

Cecen E, Altun Z, Ercetin P, et al.
Promoting effects of sanguinarine on apoptotic gene expression in human neuroblastoma cells.
Asian Pac J Cancer Prev. 2014; 15(21):9445-51 [PubMed] Related Publications
Neuroblastoma is the most common extracranial solid tumor in children. Approximately half of the affected patients are diagnosed with high-risk poor prognosis disease, and novel therapies are needed. Sanguinarine is a benzophenanthridine alkaloid which has anti-microbial, anti-oxidant and anti-inflammatory properties. The aim of this study is whether sanguinarine has in vitro apoptotic effects and which apoptotic genes might be affected in the human neuroblastoma cell lines SH-SY5Y (N-myc negative), Kelly (N-myc positive, ALK positive), and SK- N-BE(2). Cell viability was analysed with WST-1 and apoptotic cell death rates were determined using TUNEL. After RNA isolation and cDNA conversion, expression of 84 custom array genes of apoptosis was determined. Sanguinarine caused cell death in a dose dependent manner in all neuroblastoma cell lines except SK-N-BE(2) with rates of 18% in SH-SY5Y and 21% in Kelly human neuroblastoma cells. Cisplatin caused similar apoptotic cell death rates of 16% in SH-SY5Y and 23% in Kelly cells and sanguinarine-cisplatin combinations caused the same rates (18% and 20%). Sanguinarine treatment did not affect apoptototic gene expression but decreased levels of anti-apoptotic genes NOL3 and BCL2L2 in SH-SY5Y cells. Caspase and TNF related gene expression was affected by the sanguinarine-cisplatin combination in SH-SY5Y cells. The expression of regulation of apoptotic genes were increased with sanguinarine treatment in Kelly cells. From these results, we conclude that sanguinarine is a candidate agent against neuroblastoma.

Zubor P, Hatok J, Moricova P, et al.
Gene expression abnormalities in histologically normal breast epithelium from patients with luminal type of breast cancer.
Mol Biol Rep. 2015; 42(5):977-88 [PubMed] Related Publications
The gene expression profile of breast cancer has been described as a great breakthrough on the way to comprehend differences in cancer origin, behavior and therapy. However, gene expression profile in histologically normal epithelium (HNEpi) which could harbor genetic abnormalities predisposing breast tissue to develop malignancy was minor scope for scientists in the past. Thus, we aimed to analyze gene expressions in HNEpi and breast cancer tissue (BCTis) in order to establish its value as potential diagnostic marker for cancer development. We evaluated a panel of disease-specific genes in luminal type (A/B) of breast cancer and tumor surrounding HNEpi by qRT-PCR Array in 32 microdissected samples. There was 20.2 and 2.4% deregulation rate in genes with at least 2-fold or 5-fold over-expression between luminal (A/B) type breast carcinomas and tumor surrounding HNEpi, respectively. The high-grade luminal carcinomas showed higher number of deregulated genes compared to low-grade cases (50.6 vs. 23.8% with at least 2-fold deregulation rate). The main overexpressed genes in HNEpi were KLK5, SCGB1D2, GSN, EGFR and NGFR. The significant differences in gene expression between BCTis and HNEpi samples were revealed for BAG1, C3, CCNA2, CD44, FGF1, FOSL1, ID2, IL6R, NGFB, NGFR, PAPPA, PLAU, SERPINB5, THBS1 and TP53 gene (p < 0.05) and BCL2L2, CTSB, ITGB4, JUN, KIT, KLF5, SCGB1D2, SCGB2A1, SERPINE1 (p < 0.01), and EGFR, GABRP, GSN, MAP2K7 and THBS2 (p < 0.001), and GSN, KLK5 (p < 0.0001). The ontological gene analyses revealed high deregulations in gene group directly associated with breast cancer prognosis and origin.

Zubor P, Hatok J, Moricova P, et al.
Gene expression profiling of histologically normal breast tissue in females with human epidermal growth factor receptor 2‑positive breast cancer.
Mol Med Rep. 2015; 11(2):1421-7 [PubMed] Related Publications
Gene expression profile‑based taxonomy of breast cancer (BC) has been described as a significant breakthrough in comprehending the differences in the origin and behavior of cancer to allow individually tailored therapeutic approaches. In line with this, we hypothesized that the gene expression profile of histologically normal epithelium (HNEpi) could harbor certain genetic abnormalities predisposing breast tissue cells to develop human epidermal growth factor receptor 2 (HER2)‑positive BC. Thus, the aim of the present study was to assess gene expression in normal and BC tissue (BCTis) from patients with BC in order to establish its value as a potential diagnostic marker for cancer development. An array study evaluating a panel of 84 pathway‑ and disease‑specific genes in HER2‑positive BC and tumor‑adjacent HNEpi was performed using quantitative polymerase chain reaction in 12 patients using microdissected samples from frozen tissue. Common prognostic and predictive parameters of BC were assessed by immunohistochemistry and in situ hybridization. In the BCTis and HNEpi samples of 12 HER2‑positive subjects with BC, the expression of 2,016 genes was assessed. A total of 39.3% of genes were deregulated at a minimal two‑fold deregulation rate and 10.7% at a five‑fold deregulation rate in samples of HNEpi or BCTis. Significant differences in gene expression between BCTis and HNEpi samples were revealed for BCL2L2, CD44, CTSD, EGFR, ERBB2, ITGA6, NGFB, RPL27, SCBG2A1 and SCGB1D2 genes (P<0.05), as well as GSN, KIT, KLK5, SERPINB5 and STC2 genes (P<0.01). Insignificant differences (P<0.07) were observed for CCNA1, CLU, DLC1, GABRP and IL6 genes. The ontological gene analyses revealed that the majority of the deregulated genes in the HNEpi samples were part of the functional gene group directly associated with BC origin and prognosis. Functional analysis showed that the most frequent gene deregulations occurred in genes associated with apoptosis and cell cycle regulation in BCTis samples, and with angiogenesis, regulation of the cell cycle and transcriptional activity in HNEpi samples. The molecular profiling of HNEpi breast tissue revealed gene expression abnormalities that may represent potential markers of increased risk for HER2‑positive malignant transformation of breast tissue, and may be able to be employed as predictors of prognosis.

Zhang Q, Padi SK, Tindall DJ, Guo B
Polycomb protein EZH2 suppresses apoptosis by silencing the proapoptotic miR-31.
Cell Death Dis. 2014; 5:e1486 [PubMed] Free Access to Full Article Related Publications
Enhancer of zeste homolog 2 (EZH2) is the catalytic subunit of the polycomb repressive complex 2 and suppresses gene expression by catalyzing histone H3 methylation on lysine 27. EZH2 is overexpressed in metastatic prostate cancer and has been shown to promote cell proliferation and metastasis. Here we show that EZH2 also suppresses prostate cancer apoptosis by coordinating the epigenetic silencing of two proapoptotic microRNAs (miRNA), miR-205 and miR-31. We previously reported that miR-205 promotes apoptosis by targeting antiapoptotic protein Bcl-w and miR-205 is silenced in prostate cancer through promoter methylation. In this study, we found that EZH2 suppresses miR-31 expression by trimethylation of lysine 27 on histone 3 on the miR-31 promoter. SiRNA knockdown of EZH2 increased miR-31 expression and decreased the antiapoptotic protein E2F6 (E2F transcription factor 6) (a target of miR-31), resulting in the sensitization of prostate cancer cells to docetaxel-induced apoptosis. Conversely, overexpression of EZH2 blocked docetaxel-induced apoptosis. We further demonstrated that miR-205 silencing is linked to miR-31 silencing through EZH2. Suppression of miR-205 with an miRNA inhibitor caused an increase of EZH2 protein, which in turn inhibited miR-31 expression. Conversely, overexpression of miR-205 decreased EZH2 protein and increased miR-31 expression. In paired human prostate cancer specimens and adjacent normal tissues, we observed that the decrease of miR-205 expression correlated with EZH2 overexpression and miR-31 silencing. Thus, EZH2 integrates the epigenetic silencing of miR-205 and miR-31 to confer resistance to chemotherapy-induced apoptosis.

Booher RN, Hatch H, Dolinski BM, et al.
MCL1 and BCL-xL levels in solid tumors are predictive of dinaciclib-induced apoptosis.
PLoS One. 2014; 9(10):e108371 [PubMed] Free Access to Full Article Related Publications
Dinaciclib is a potent CDK1, 2, 5 and 9 inhibitor being developed for the treatment of cancer. Additional understanding of antitumor mechanisms and identification of predictive biomarkers are important for its clinical development. Here we demonstrate that while dinaciclib can effectively block cell cycle progression, in vitro and in vivo studies, coupled with mouse and human pharmacokinetics, support a model whereby induction of apoptosis is a main mechanism of dinaciclib's antitumor effect and relevant to the clinical duration of exposure. This was further underscored by kinetics of dinaciclib-induced downregulation of the antiapoptotic BCL2 family member MCL1 and correlation of sensitivity with the MCL1-to-BCL-xL mRNA ratio or MCL1 amplification in solid tumor models in vitro and in vivo. This MCL1-dependent apoptotic mechanism was additionally supported by synergy with the BCL2, BCL-xL and BCL-w inhibitor navitoclax (ABT-263). These results provide the rationale for investigating MCL1 and BCL-xL as predictive biomarkers for dinaciclib antitumor response and testing combinations with BCL2 family member inhibitors.

Kunami N, Katsuya H, Nogami R, et al.
Promise of combining a Bcl-2 family inhibitor with bortezomib or SAHA for adult T-cell leukemia/lymphoma.
Anticancer Res. 2014; 34(10):5287-94 [PubMed] Related Publications
BACKGROUND: Adult T-cell leukemia/lymphoma (ATL) is an aggressive malignancy of peripheral T-lymphocytes and its prognosis still remains very poor.
MATERIALS AND METHODS: The potential of combining the Bcl-2 homology 3 mimetic ABT-737, which blocks Bcl-2, Bcl-XL, and Bcl-w, with either the proteasome inhibitor bortezomib or histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA) to inhibit the growth of human T-lymphotropic virus type-I (HTLV-1) infected T-cell lines and its mechanism was further evaluated.
RESULTS: ABT-737 synergistically induced apoptosis when combined with either bortezomib or SAHA in HTLV-1 infected T-cell lines and fresh ATL cells. Bortezomib increased the expression of Noxa, which subsequently enhanced the formation of Mcl-1-Noxa complexes, resulting in the functional neutralization of Mcl-1, an inducer of resistance to ABT-737. On the other hand, SAHA reduced the expression of survivin, an anti-apoptotic molecule that confers drug resistance on ATL cells.
CONCLUSION: The combination of ABT-737 with bortezomib or SAHA is promising for the treatment of ATL.

Ma J, Wu Q, Zhang Y, et al.
MicroRNA sponge blocks the tumor-suppressing functions of microRNA-122 in human hepatoma and osteosarcoma cells.
Oncol Rep. 2014; 32(6):2744-52 [PubMed] Related Publications
MicroRNAs (miRNAs), as gene expression regulators, have been identified to be closely associated with tumorigenesis. Thus a loss-of-function study is more likely to reveal the biological roles of endogenous miRNAs. Genetic knockout, antisense oligonucleotide inhibitors, and miRNA sponge (miR‑SP) are usually performed to inhibit the activities of miRNAs of interest. In the present study, we utilized the miR-SP method, which has long-term rather than short-term effects of antisense oligonucleotide inhibitors, to generate a microRNA-122 sponge (miR-122-SP) mediated by lentivirus, and identified its silencing role in the Huh7 hepatoma cell line and U2OS osteosarcoma cell line. The results showed that miR-122-SP effectively sequestered ectopic miR-122 and restored the expression of miR-122 which targets cyclin G1 (CCNG1), Bcl-w and disintegrin and metalloprotease 10. Moreover, miR-122-SP overexpression rescued the effects of ectopic miR-122 on suppressing proliferation, inhibiting cell migration and invasion, arresting cell cycle at G1 phase, and activating caspase-3/7, not only in Huh7 human hepatoma cells, but also in U2OS osteosarcoma cells. miR-122-SP also knocked down endogenous miR-122 expression in Huh7 and promoted tumorigenesis in vivo. miR-122-SP therefore is a useful tool that may be utilized to study the functions of miR-122 with regard to liver development and tumorigenesis in vitro and in vivo.

Beach JA, Nary LJ, Hovanessian R, Medh RD
Correlation of glucocorticoid-mediated E4BP4 upregulation with altered expression of pro- and anti-apoptotic genes in CEM human lymphoblastic leukemia cells.
Biochem Biophys Res Commun. 2014; 451(3):382-8 [PubMed] Free Access to Full Article Related Publications
In Caenorhabditiselegans, motorneuron apoptosis is regulated via a ces-2-ces-1-egl-1 pathway. We tested whether human CEM lymphoblastic leukemia cells undergo apoptosis via an analogous pathway. We have previously shown that E4BP4, a ces-2 ortholog, mediates glucocorticoid (GC)-dependent upregulation of BIM, an egl-1 ortholog, in GC-sensitive CEM C7-14 cells and in CEM C1-15mE#3 cells, which are sensitized to GCs by ectopic expression of E4BP4. In the present study, we demonstrate that the human ces-1 orthologs, SLUG and SNAIL, are not significantly repressed in correlation with E4BP4 expression. Expression of E4BP4 homologs, the PAR family genes, especially HLF, encoding a known anti-apoptotic factor, was inverse to that of E4BP4 and BIM. Expression of pro- and anti-apoptotic genes in CEM cells was analyzed via an apoptosis PCR Array. We identified BIRC3 and BIM as genes whose expression paralleled that of E4BP4, while FASLG, TRAF4, BCL2A1, BCL2L1, BCL2L2 and CD40LG as genes whose expression was opposite to that of E4BP4.

Chen CL, Wu JC, Chen GY, et al.
Baculovirus-mediated miRNA regulation to suppress hepatocellular carcinoma tumorigenicity and metastasis.
Mol Ther. 2015; 23(1):79-88 [PubMed] Free Access to Full Article Related Publications
MicroRNA 122 (miR-122) is a tumor suppressor for hepatocellular carcinoma (HCC) but is lowly expressed in HCC cells. MiR-151 is aberrantly overexpressed in HCC cells and promotes HCC metastasis yet its roles on HCC tumorigenicity are unknown. To combat HCC tumorigenicity/metastasis, we developed Sleeping Beauty (SB)-based hybrid baculovirus (BV) vectors that expressed (i) miR-122 precursors (pre-miR-122), (ii) miR-151 sponges, or (iii) pre-miR-122 and miR-151 sponges. Transduction of aggressive HCC cells (Mahlavu) with the pre-miR-122-expressing BV tremendously enhanced miR-122 levels for >6 weeks, suppressed the levels of downstream effectors (e.g., ADAM10 and Bcl-w), proliferation, anchorage-independent growth, motility and migration/invasion in vitro. Intratumoral injection of the pre-miR-122-expressing BV attenuated the HCC growth/metastasis. The miR-151 sponges-expressing BV diminished the miR-151 levels for 6 weeks, enhanced RhoGDIA expression, suppressed RhoGTPases, as well as motility and migration/invasion of Mahlavu cells. Intratumoral injection of the miR-151 sponge-expressing BV impeded not only HCC metastasis but also cell proliferation, MMP expression and tumor growth in vivo. The BV co-expressing pre-miR-122 and miR-151 sponges also simultaneously enhanced miR-122 expression and inhibited miR-151, and conferred antitumor/anti-metastasis effects albeit lack of synergism. These data implicate the potentials of the SB-based hybrid BV for persistently modulating miRNA and suppressing HCC tumorigenicity/metastasis.

Laetsch TW, Liu X, Vu A, et al.
Multiple components of the spliceosome regulate Mcl1 activity in neuroblastoma.
Cell Death Dis. 2014; 5:e1072 [PubMed] Free Access to Full Article Related Publications
Cancer treatments induce cell stress to trigger apoptosis in tumor cells. Many cancers repress these apoptotic signals through alterations in the Bcl2 proteins that regulate this process. Therapeutics that target these specific survival biases are in development, and drugs that inhibit Bcl2 activities have shown clinical activity for some cancers. Mcl1 is a survival factor for which no effective antagonists have been developed, so it remains a principal mediator of therapy resistance, including to Bcl2 inhibitors. We used a synthetic-lethal screening strategy to identify genes that regulate Mcl1 survival activity using the pediatric tumor neuroblastoma (NB) as a model, as a large subset are functionally verified to be Mcl1 dependent and Bcl2 inhibitor resistant. A targeted siRNA screen identified genes whose knockdown restores sensitivity of Mcl1-dependent NBs to ABT-737, a small molecule inhibitor of Bcl2, BclXL and BclW. Three target genes that shifted the ABT-737 IC50 >1 log were identified and validated: PSMD14, UBL5 and PRPF8. The latter two are members of a recently characterized subcomplex of the spliceosome that along with SART1 is responsible for non-canonical 5'-splice sequence recognition in yeast. We showed that SART1 knockdown similarly sensitized Mcl1-dependent NB to ABT-737 and that triple knockdown of UBL5/PRPF8/SART1 phenocopied direct MCL1 knockdown, whereas having no effect on Bcl2-dependent NBs. Both genetic spliceosome knockdown or treatment with SF3b-interacting spliceosome inhibitors like spliceostatin A led to preferential pro-apoptotic Mcl1-S splicing and reduced translation and abundance of Mcl1 protein. In contrast, BN82865, which inhibits the second transesterification step in terminal spliceosome processing, did not have this effect. These findings demonstrate a prominent role for the spliceosome in mediating Mcl1 activity and suggest that drugs that target either the specific UBL5/PRPF8/SART1 subcomplex or SF3b functions may have a role as cancer therapeutics by attenuating the Mcl1 survival bias present in numerous cancers.

Fares F, Azzam N, Fares B, et al.
Benzene-poly-carboxylic acid complex, a novel anti-cancer agent induces apoptosis in human breast cancer cells.
PLoS One. 2014; 9(2):e85156 [PubMed] Free Access to Full Article Related Publications
Some cases of breast cancer are composed of clones of hormonal-independent growing cells, which do not respond to therapy. In the present study, the effect of Benzene-Poly-Carboxylic Acid Complex (BP-C1) on growth of human breast-cancer cells was tested. BP-C1 is a novel anti-cancer complex of benzene-poly-carboxylic acids with a very low concentration of cis-diammineplatinum (II) dichloride. Human breast cancer cells, MCF-7 and T47D, were used. Cell viability was detected by XTT assay and apoptosis was detected by Flow Cytometry and by annexin V/FITC/PI assay. Caspases were detected by western blot analysis and gene expression was measured by using the Applied Biosystems® TaqMan® Array Plates. The results showed that exposure of the cells to BP-C1 for 48 h, significantly (P<0.001) reduced cell viability, induced apoptosis and activated caspase 8 and caspace 9. Moreover, gene expression experiments indicated that BP-C1 increased the expression of pro-apoptotic genes (CASP8AP1, TNFRSF21, NFkB2, FADD, BCL10 and CASP8) and lowered the level of mRNA transcripts of inhibitory apoptotic genes (BCL2L11, BCL2L2 and XIAP. These findings may lead to the development of new therapeutic strategies for treatment of human cancer using BP-C1 analog.

Zhao H, Li M, Li L, et al.
MiR-133b is down-regulated in human osteosarcoma and inhibits osteosarcoma cells proliferation, migration and invasion, and promotes apoptosis.
PLoS One. 2013; 8(12):e83571 [PubMed] Free Access to Full Article Related Publications
MicroRNAs (miRNAs) decrease the expression of specific target oncogenes or tumor suppressor genes and thereby play crucial roles in tumorigenesis and tumor growth. To date, the potential miRNAs regulating osteosarcoma growth and progression are not fully identified yet. In this study, the miRNA microarray assay and hierarchical clustering analysis were performed in human osteosarcoma samples. In comparison with normal human skeletal muscle, 43 miRNAs were significantly differentially expressed in human osteosarcomas (fold change ≥2 and p≤0.05). Among these miRNAs, miR-133a and miR-133b expression was decreased by 135 folds and 47 folds respectively and the decreased expression was confirmed in both frozen and paraffin-embedded osteosarcoma samples. The miR-133b precursor expression vector was then transfected into osteosarcoma cell lines U2-OS and MG-63, and the stable transfectants were selected by puromycin. We found that stable over-expression of miR-133b in osteosarcoma cell lines U2-OS and MG-63 inhibited cell proliferation, invasion and migration, and induced apoptosis. Further, over-expression of miR-133b decreased the expression of predicted target genes BCL2L2, MCL-1, IGF1R and MET, as well as the expression of phospho-Akt and FAK. This study provides a new insight into miRNAs dysregulation in osteosarcoma, and indicates that miR-133b may play as a tumor suppressor gene in osteosarcoma.

Preuss E, Hugle M, Reimann R, et al.
Pan-mammalian target of rapamycin (mTOR) inhibitor AZD8055 primes rhabdomyosarcoma cells for ABT-737-induced apoptosis by down-regulating Mcl-1 protein.
J Biol Chem. 2013; 288(49):35287-96 [PubMed] Free Access to Full Article Related Publications
The PI3K/mammalian Target of Rapamycin (mTOR) pathway is often aberrantly activated in rhabdomyosarcoma (RMS) and represents a promising therapeutic target. Recent evaluation of AZD8055, an ATP-competitive mTOR inhibitor, by the Preclinical Pediatric Testing Program showed in vivo antitumor activity against childhood solid tumors, including RMS. Therefore, in the present study, we searched for AZD8055-based combination therapies. Here, we identify a new synergistic lethality of AZD8055 together with ABT-737, a BH3 mimetic that antagonizes Bcl-2, Bcl-xL, and Bcl-w but not Mcl-1. AZD8055 and ABT-737 cooperate to induce apoptosis in alveolar and embryonal RMS cells in a highly synergistic fashion (combination index < 0.2). Synergistic induction of apoptosis by AZD8055 and ABT-737 is confirmed on the molecular level, as AZD8055 and ABT-737 cooperate to trigger loss of mitochondrial membrane potential, activation of caspases, and caspase-dependent apoptosis that is blocked by the pan-caspase inhibitor Z-VAD-fmk. Similar to AZD8055, the PI3K/mTOR inhibitor NVP-BEZ235, the PI3K inhibitor NVP-BKM120 and Akt inhibitor synergize with ABT-737 to trigger apoptosis, whereas no cooperativity is found for the mTOR complex 1 inhibitor RAD001. Interestingly, molecular studies reveal a correlation between the ability of different PI3K/mTOR inhibitors to potentiate ABT-737-induced apoptosis and to suppress Mcl-1 protein levels. Importantly, knockdown of Mcl-1 increases ABT-737-induced apoptosis similar to AZD8055/ABT-737 cotreatment. This indicates that AZD8055-mediated suppression of Mcl-1 protein plays an important role in the synergistic drug interaction. By identifying a novel synergistic interaction of AZD8055 and ABT-737, our findings have important implications for the development of molecular targeted therapies for RMS.

Scarfò L, Ghia P
Reprogramming cell death: BCL2 family inhibition in hematological malignancies.
Immunol Lett. 2013 Sep-Oct; 155(1-2):36-9 [PubMed] Related Publications
The BCL2 family members play a central role in regulating programmed cell death (apoptosis) and arbitrating the cellular fate through an accurate balance between pro-apoptotic (BAX, BAK, and BH3-only proteins) and pro-survival (BCL2 and its closest homologues, BCLXL, BCLW and MCL-1) factors. Deregulation of BCL2 family proteins contributes to programmed cell death evasion, that is a hallmark of human cancers and it is often related to (chemo)therapy resistance. High BCL2 levels have been detected in most human lymphoid malignancies, not limited to follicular lymphoma (where the role of BCL2 overexpression is driven by the t[14;18] translocation) but also B-cell chronic lymphocytic leukemia (CLL) and multiple myeloma. For all these reasons, the opportunity to induce apoptosis by targeting BCL2 proteins is considered a potentially promising therapeutic approach in hematological malignancies. BCL2 family inhibition strategies currently explored in phase 1, 2 and 3 clinical trials are essentially two: (1) the use of antisense-based strategies to knockdown BCL2 or BCLXL expression (e.g. oblimersen) or (2) the use of synthetic BH3 mimetics i.e. small molecules binding to anti-apoptotic inhibitors thereby allowing the pro-apoptotic activity of BH3-only molecules (e.g. obatoclax, AT-101, ABT-737 and its derivatives ABT-263 and ABT-199). Several of these drugs demonstrated relevant clinical activity as single-agent or in combination therapy, with the most significant drawbacks in clinical use being represented by challenging pharmacokinetic profile (e.g. iv administration, high-levels of plasma proteins binding) and on-target side effects (e.g. gastrointestinal toxicity and thrombocytopenia). Further clinical development of the current compounds (e.g. ABT-199), showing high efficacy but devoid of the most threatening drug-related toxicities, is eagerly awaited. Hopefully, in the next future, BCL2 inhibitors (alone or in combination with immuno- and/or chemo-therapeutic agents) will represent target-specific drugs expanding our therapeutic armamentarium in the fight against hematologic malignancies.

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