The human protein tyrosine phosphatase, non‑receptor type 6 (PTPN6) gene is located on chromosome 12p13 and encodes an Mr 68,000 non‑receptor type protein‑tyrosine phosphatase. The PTPN6 gene has been considered as a candidate tumor suppressor in hematological and solid malignancies, and promoter methylation may be an epigenetic modification silencing its expression. However, the detailed role of PTPN6 and its promoter methylation status in the pathogenesis of esophageal squamous cell carcinoma (ESCC) has not been fully elucidated. The aim of the present study was to investigate PTPN6 expression in ESCC tissues and esophageal cancer cell lines, detect the effect of CpG hypermethylation on the activity of PTPN6, and additionally elucidate the role and prognostic significance of PTPN6 in ESCC tumorigenesis and progression. The expression of PTPN6 was identified to be significantly downregulated in esophageal cancer cell lines and ESCC tissues. Marked upregulation of PTPN6 was detected in 5‑aza‑2'‑deoxycytidine‑treated esophageal cancer cells, and frequent hypermethylation of the CpG sites within the P2 promoter (P2) was detected in ESCC tissues and esophageal cancer cell lines. The expression and methylation status of PTPN6 was associated with tumor node metastasis stage, pathological differentiation and lymph node metastasis in patients with ESCC. Aberrant hypermethylation of the P2 exhibited marked tumor specificity and was identified to be associated with the expression level of PTPN6. Downregulation and hypermethylation of PTPN6 were identified to be associated with poor ESCC patient survival. Furthermore, upregulation of PTPN6 inhibited the proliferation and invasion of esophageal cancer cells in vitro. The results of the present study suggest that PTPN6 may serve as a tumor suppressor in ESCC, and it may serve as a potential target for antitumor therapy.

Spatial and subclonal genetic heterogeneity in multiple myeloma (MM) have been demonstrated by sequencing of plasma cells from multi-focal regions, but studies of spatial epigenetic heterogeneity are scanty. Herein, promoter methylation status of genes implicated in disease progression (CDKN2A and SHP1) and marrow escape (CDH1, CD56, and CXCR4) was studied in two patients with multi-focal extramedullary relapses. Patient 1 developed simultaneous chest wall and duodenal plasmacytoma at relapse. While SHP1 and CDKN2A were hypermethylated in both plasmacytomas, CDH1 hypermethylation was detected only in the chest wall. In patient 2, SHP1 methylation was found in the extradural plasmacytoma but not bone marrow (BM) at diagnosis, and the circulating PCs but not the BM at relapse. As the clonality, based on sequence of the complementarity-determining region 3 (CDR3) of the immunoglobulin gene, was conserved in plasma cells at diagnosis and relapse, differential methylation of CDH1 in patient 1 and SHP1 in patient 2 was an illustration of spatial epigenetic heterogeneity. Furthermore, subclonal epigenetic heterogeneity was identified by the presence of subclonal SHP1 promoter methylation within the chest wall plasmacytoma of patient 1. In summary, our data showed distinct promoter methylation profile of plasma cells from multiple regions. This is the first report of spatial epigenetic heterogeneity in MM.

BACKGROUND/AIMS: T-Cell Acute Lymphoblastic Leukemia (T-ALL) [corrected] is an aggressive disease which is highly resistant to chemotherapy. Studies show that enhanced ability of DNA damage repair (DDR) in cancer cells plays a key role in chemotherapy resistance. Here, we suggest that defect in DDR related genes might be a promising target to destroy the genome stability of tumor cells.
METHODS: Since KU70 is highly expressed in Jurkat cells, one of the most representative cell lines of ATL, we knocked down KU70 by shRNA and analyzed the impact of KU70 deficiency in Jurkat cells as well as in NOD-SCID animal models by western blot, immunofluorescence, flow cytometry and measuring DNA repair efficiency.
RESULTS: It is observed that silencing of KU70 resulted in accumulated DNA damage and impaired DDR in Jurkat cells, resulting in more apoptosis, decreased cell proliferation and cell cycle arrest. DNA damage leads to DNA double-strand breaks (DSBs), which are processed by either non-homologous end joining(NHEJ) or homologous recombination(HR). In our study, both NHEJ and HR are impaired because of KU70 defect, accompanied with increased protein level of SHP-1, a dephosphorylation enzyme. In turn, SHP-1 led to dephosphorylation of SIRT1, which further impaired HR repair efficiency. Moreover, KU70 deficiency prolonged survival of Jurkat-xenografted mice.
CONCLUSION: These findings suggest that targeting KU70 is a promising target for ATL and might overcome the existing difficulties in chemotherapy.

Kaposi sarcoma (KS) is an incurable, human immunodeficiency virus (HIV)-associated malignancy. We reviewed 320 immunotherapy-treated patient records. Seventeen had HIV-associated malignancies, including nine men with KS. Median viral load was 20 copies/mL (range, undetectable to 549,704) and median CD4 count was 256 cells/μL (range, 10-603). Eight patients received nivolumab and one received pembrolizumab. Six patients (67%) achieved partial (

The function of the E3 ligase RNF38 is still unknown in gastric cancer. Here, we found that RNF38 is upregulated in gastric cancer, and it is associated with the overall survival of gastric cancer patients. Further studies showed that RNF38 interacts with the nonreceptor tyrosine phosphatase SH2-containing protein tyrosine phosphatase 1 (SHP-1) and induces the polyubiquitination of SHP-1, which leads to destabilization of SHP-1 and promotion of STAT3 signaling in gastric cancer cells. In addition, overexpression or knockdown of RNF38 induces or suppresses gastric cancer cell growth in vitro, respectively, and silencing RNF38 delays tumor growth in vivo. These findings demonstrate that RNF38 is functional in gastric cancer and promotes STAT3 signaling by destabilizing SHP-1; thus, RNF38 could be a novel target for gastric cancer therapy.

BACKGROUND/AIMS: As a natural antioxidant, verbascoside (VB) is proved to be a promising method for the treatment of oxidative-stress-related neurodegenerative diseases. Thus, this study aimed to investigate the effects of VB on glioblastoma cell proliferation, apoptosis, migration, and invasion as well as the mechanism involving signal transducer and activator of transcription 3 (STAT3) and Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP-1).
METHODS: U87 cells were assigned to different treatments. The MTT assay was used to test cell proliferation, flow cytometry was used to detect cell apoptosis, and a Transwell assay was used for cell migration and invasion. We analyzed the glioblastoma tumor growth in a xenograft mouse model. Western blot analysis was employed to determine the protein expression of related genes.
RESULTS: Glioblastoma cells exhibited decreased cell proliferation, migration, invasion, and increased apoptosis when treated with VB or TMZ. Western blot analysis revealed elevated SHP-1 expression and reduced phosphorylated (p)-STAT3 expression in glioblastoma cells treated with VB compared with controls. Correspondingly, in a xenograft mouse model treated with VB, glioblastoma tumor volume and growth were decreased. Glioblastoma xenograft tumors treated with VB showed elevated SHP-1, Bax, cleaved caspase-3, and cleaved PARP expression and reduced p-STAT3, Bcl-2, survivin, MMP-2, and MMP-9 expression. siRNA-SHP-1 inhibited the VB effects on glioblastoma.
CONCLUSION: This study demonstrates that VB inhibits glioblastoma cell proliferation, migration, and invasion while promoting apoptosis via SHP-1 activation and inhibition of STAT3 phosphorylation.

STAT5 is an important transcription factor that is constitutively activated in various types of malignancies, including chronic myelogenous leukemia (CML). Whether the antitumor effects of resveratrol (RES) are linked to its capability to inhibit STAT5 activation in CML cells was investigated. We found that RES inhibited STAT5 activation in K562 and KU812 cell lines; RES also reduced the STAT5 concentration in the nucleus of K562 and KU812 cells. Protein tyrosine phosphatase (PTP) inhibitor, sodium pervanadate, reversed the RES-induced downregulation of STAT5, suggesting the involvement of a PTP. Indeed, we observed that RES decreased the expression of tyrosine phosphatase SHP-1 and SHP-2; moreover, the deletion of SHP-1 and SHP-2 genes by siRNA abolished the ability of RES to inhibit STAT5 activation, which suggested the critical role of both SHP-1 and SHP-2 in its possible mechanism of action. RES downregulated the expression of STAT5-regulated gene products such as Bcl-xL, Bcl-2, Cyclin D1, and Mcl-1, and increased the expression of Bax. This correlated with the suppression of proliferation and induction of apoptosis. Overall, our results suggest that RES is a blocker of STAT5 activation and thus may be potentially useful for the treatment of CML.

Patients with mycosis fungoides (MF) developing tumors or extracutaneous lesions usually have a poor prognosis with no cure has so far been available. To identify potential novel biomarkers for MF at the tumor stage, a genomic mapping of 41 cutaneous lymphoma biopsies was used to explore for significant genes.The gene expression profiling datasets of MF were obtained from Gene Expression Omnibus database (GEO). Gene modules were simulated using Weighted Gene Co-expression Network Analysis (WGCNA) and the top soft-connected genes (hub genes) were filtrated with a threshold (0.5). Subsequently, module eigengenes were calculated and significant biological pathways were enriched based on the KEGG database.Four genetic modules were simulated with 3263 genes collected from the whole genomic profile based on cutoff values. Significant diseases genetic terminologies associated with tumor stage MF were found in black module. Subsequently, 13 hub genes including CFLAR, GCNT2, IFNG, IL17A, IL22, MIP, PLCG1, PTH, PTPN6, REG1A, SNAP25, SUPT7L, and TP63 were shown to be related to cutaneous T-cell lymphoma (CTCL) and adult T-cell lymphoma/leukemia (ATLL).In summary, in addition to the reported genes (IL17F, PLCG1, IFNG, and PTH) in CTCL/ATLL, the other high instable genes may serve as novel biomarkers for the regulation of the biological processes and molecular mechanisms of CTLT (MF/SS).

DNA methylation is a dynamic process influencing gene expression by altering either coding or non-coding loci. Despite advances in treatment of Acute Lymphoblastic Leukemia (ALL); relapse occurs in approximately 20% of patients. Nowadays, epigenetic factors are considered as one of the most effective mechanisms in pathogenesis of malignancies. These factors are reversible elements which can be potentially regarded as therapy targets and disease prognosis. DNA methylation, which primarily serves as transcriptional suppressor, mostly occurs in CpG islands of the gene promoter regions. This was shown as a key epigenetic factor in inactivating various tumor suppressor genes during cancer initiation and progression. We aimed to review methylation status of key genes involved in hematopoietic malignancies such as IKZF1, CDKN2B, TET2, CYP1B1, SALL4, DLC1, DLX family, TP73, PTPN6, and CDKN1C; and their significance in pathogenesis of ALL. The DNA methylation alterations in promoter regions of the genes have been shown to play crucial roles in tumorigenesis. Methylation -based inactivation of these genes has also been reported as associated with prognosis in acute leukemia. In this review, we also addressed the association of gene expression and methylation pattern in ALL patients.

Inflammatory genes serve a crucial role in the pathogenesis of inflammation‑associated tumors. However, as recent studies have mainly focused on the effects of single inflammatory genes on colorectal cancer (CRC), but not on the global interactions between genes, the underlying mechanisms between inflammatory genes and CRC remain unclear. In the current study, two inflammation‑associated networks were constructed based on inflammatory genes, differentially expressed genes (DEGs) in CRC vs. normal samples, and protein‑protein interactions (PPIs). These networks included an inflammation‑related neighbor network (IRNN) and an inflammation‑related DEG network (IRDN). Notably, the results indicated that the inflammatory genes served as important CRC‑associated genes in the IRNN. Certain inflammatory genes were more likely to be network hubs and exhibited higher betweenness centralities, indicating that these inflammatory hub genes had central roles in the communication between genes in the IRNN. By contrast, in the IRDN, functional enrichment analysis revealed that genes were enriched in numerous cancer‑associated functions and pathways. Subsequently, 14 genes in a module were identified in the IRDN as the potential biomarkers associated with disease‑free survival (DFS) in CRC patients in the GSE24550 dataset, the prognosis of which was further validated using three independent datasets (GSE24549, GSE34551 and GSE103479). All 14 genes (including BCAR1, CRK, FYN, GRB2, LCP2, PIK3R1, PLCG1, PTK2, PTPN11, PTPN6, SHC1, SOS1, SRC and SYK) in this module were inflammatory genes, emphasizing the critical role of inflammation in CRC. In conclusion, these findings based on integrated inflammation‑associated networks provided a novel insight that may help elucidate the inflammation‑mediated mechanisms involved in CRC.

Aberrant methylation of tumour suppressor genes is associated with the progression to a blast crisis in chronic myeloid leukaemia (CML). Methyl-CpG-binding domain protein 2 (MBD2) has been studied as a "reader" of DNA methylation in many cancers, but its role in CML is unclear. We constructed cell models of a homozygous deletion mutation of MBD2 using gene-editing technology in K562 cells and BV173 cells. Here, we demonstrated that the deletion of MBD2 inhibited cell proliferation capacity in vitro. MBD2 deletion also significantly inhibited K562 cell proliferation in a xenograft tumour model in vivo. Additionally, the JAK2/STAT3 signalling pathway, which is abnormally active in CML, was inhibited by MBD2 deletion, and MBD2 deletion could up-regulate the expression of SHP1. In conclusion, our findings suggest that MBD2 is a candidate therapeutic strategy for the CML blast phase.

Tripartite motif-containing 14 (TRIM14) is abnormally expressed in several human cancers. However, the function and expression of TRIM14 in human breast cancer are still largely unknown. To understand the biological function of TRIM14 in breast cancer, we measured the expression level of TRIM14. Cell proliferation and cell apoptosis were measured after TRIM14 overexpression or knockdown. Upregulation of TRIM14 was found in human breast cancer specimens and cell lines. Reduction of TRIM14 inhibited cell proliferation but increased cell apoptosis in the BT474 and MDA-MB-231 cell lines. Further study showed that knockdown of TRIM14 upregulated the expression of BAX while downregulating the expression of BCL2. In addition, the expression of SHP-1 was increased, and the phosphorylation of STAT3 (p-STAT3) was inhibited. Conversely, overexpression of TRIM14 had the opposite effects. Additionally, cryptotanshinone, a STAT3 inhibitor, inhibited cell proliferation but increased cell apoptosis in the BT474 and MDA-MB-231 cell lines. In conclusion, TRIM14 may act as an oncogene in human breast cancer and may be a novel strategy for human breast cancer.

Castleman disease (CD) is a rare lymphoproliferative disorder subclassified as unicentric CD (UCD) or multicentric CD (MCD) based on clinical features and the distribution of enlarged lymph nodes with characteristic histopathology. MCD can be further subtyped based on human herpes virus 8 (HHV8) infection into HHV8-associated MCD, HHV8

BACKGROUND: Our previous study has demonstrated that hepatocyte nuclear factor 1α (HNF1α) exerts potent therapeutic effects on hepatocellular carcinoma (HCC). However, the molecular mechanisms by which HNF1α reverses HCC malignancy need to be further elucidated.
METHODS: lncRNA microarray was performed to identify the long noncoding RNAs (lncRNAs) regulated by HNF1α. Chromatin immunoprecipitation and luciferase reporter assays were applied to clarify the mechanism of the transcriptional regulation of HNF1α to HNF1A antisense RNA 1 (HNF1A-AS1). The effect of HNF1A-AS1 on HCC malignancy was evaluated in vitro and in vivo. RNA pulldown, RNA-binding protein immunoprecipitation and the Bio-Layer Interferometry assay were used to validate the interaction of HNF1A-AS1 and Src homology region 2 domain-containing phosphatase 1 (SHP-1).
RESULTS: HNF1α regulated the expression of a subset of lncRNAs in HCC cells. Among these lncRNAs, the expression levels of HNF1A-AS1 were notably correlated with HNF1α levels in HCC cells and human HCC tissues. HNF1α activated the transcription of HNF1A-AS1 by directly binding to its promoter region. HNF1A-AS1 inhibited the growth and the metastasis of HCC cells in vitro and in vivo. Moreover, knockdown of HNF1A-AS1 reversed the suppressive effects of HNF1α on the migration and invasion of HCC cells. Importantly, HNF1A-AS1 directly bound to the C-terminal of SHP-1 with a high binding affinity (KD = 59.57 ± 14.29 nM) and increased the phosphatase activity of SHP-1. Inhibition of SHP-1 enzymatic activity substantially reversed the HNF1α- or HNF1A-AS1-induced reduction on the metastatic property of HCC cells.
CONCLUSIONS: Our data revealed that HNF1A-AS1 is a direct transactivation target of HNF1α in HCC cells and involved in the anti-HCC effect of HNF1α. HNF1A-AS1 functions as phosphatase activator through the direct interaction with SHP-1. These findings suggest that regulation of the HNF1α/HNF1A-AS1/SHP-1 axis may have beneficial effects in the treatment of HCC.

Signal transducer and activator of transcription 3 (STAT3) is involved in the survival, proliferation, angiogenesis, invasion and metastasis of tumor cells. In addition, interleukin-6 (IL-6) has been reported to be closely related to STAT3 activity. In the present study, we investigated whether crocin, a major glycosylated carotenoid derived from saffron, can modulate the IL-6/STAT3 pathway to induce growth inhibition and sensitivity to cancer cell apoptosis. We determined that crocin inhibited STAT3 activation induced by IL-6 in hepatocellular carcinoma Hep3B and HepG2 cells. STAT3 suppression was mediated through the inactivation of Janus kinase 1/2(JAK1, JAK2) and Src kinase in both liver cancer cell lines. Furthermore, crocin induced the expression of protein tyrosine phosphatase (PTP) SHP-1, which led to STAT3 dephosphorylation. Deletion of the SHP-1 gene by siRNA recovered the inhibitory effects of crocin, suggesting an important role for SHP-1. Moreover, crocin downregulated the expression of STAT3-regulated anti-apoptotic (Bcl-2, survivin), proliferative (cyclin D1), invasive (CXCR4) and angiogenic (VEGF) proteins. Conversely, crocin increased the pro-apoptotic (BAX) protein, which was correlated with the induction of apoptosis and inhibition of proliferation. Overall, these results provide evidence that crocin has the potential for anticancer activity through inhibition of the IL-6/STAT3 signaling pathway, especially in liver cancer.

The B-cell receptor (BCR) signaling pathway is of great importance for B-cell survival and proliferation. The BCR expressed on malignant B-CLL cells contributes to the disease pathogenesis, and its signaling pathway is currently the target of several therapeutic strategies. Although various BCR alterations have been described in B-CLL at the protein level, the mRNA expression levels of tyrosine kinases in B-CLL compared to that in normal CD5-high and CD5-low B-lymphocytes remain unknown. In the current study, we measured the mRNA expression levels of CD79A, CD79B, LYN, SYK, SHP1, and ZAP70 in purified populations of CD5-high B-CLL cells, CD5-low B-cells from the peripheral blood of healthy donors, and CD5-high B-cells from human tonsils. Here, we report a clear separation in the B-CLL dataset between the ZAP70-high and ZAP70-low subgroups. Each subgroup has a unique expression profile of BCR signaling components that might reflect the functional status of the BCR signaling pathway. Moreover, the ZAP70-low subgroup does not resemble either CD5-high B-lymphocytes from the tonsils or CD5-low lymphocytes from PBMC (P < 0.05). We also show that ZAP70 is the only gene that is differentially expressed in CD5-high and CD5-low normal B-lymphocytes, confirming the key role of Zap-70 tyrosine kinase in BCR signaling alterations in B-CLL.

The purpose of this study was to investigate the antiproliferative effect of active hexose correlated compound (AHCC), derived from basidiomycete mushroom culture, on ovarian cancer cell lines. An in vitro growth inhibition assay was performed using AHCC in ovarian cancer cell lines. Western blotting was performed to investigate the mechanism of the observed antiproliferative effect of AHCC. We identified that ovarian cancer cell viability was significantly reduced through treatment with AHCC compared to that in the control. AHCC inhibited constitutive signal transducer and activator of transcription 3 (STAT3) phosphorylation in ovarian cancer cell lines. In contrast, treatment with pervanadate, a protein tyrosine phosphatase inhibitor, reversed AHCC-induced STAT3 suppression. AHCC treatment induced the expression of SHP-1, a protein tyrosine phosphatase, and suppressed the expression of cyclin D1, Bcl-2, Mcl-1, survivin, and VEGF, which are STAT3-regulated gene products that are associated with cell proliferation or apoptosis. These results suggest that AHCC has an antiproliferative effect on ovarian cancer cell lines, via STAT3 phosphorylation; thus, this compound has the potential to be a complementary and alternative anticancer therapy for the treatment of ovarian cancer.

Chikungunya virus (CHIKV)-induced myositis is an emerging affliction with high incidence globally. Given the essential regulatory role of protein tyrosine phosphatase non-receptor 6 (PTPN6) in virus-induced myositis, the expression of the PTPN6 and TNF-α genes in a CHIKV-infected muscle cell line was examined by quantitative PCR, and the expression of PTPN6 and STAT 3 was examined by immunoblotting. In addition, the effect of PTPN6 siRNA treatment on TNF-α gene expression was assessed. Increased higher expression of PTPN6 and TNF-α, and significant upregulation of TNF-α upon PTPN6 siRNA treatment were observed, suggesting that CHIKV has the ability to induce host PTPN6 gene expression, which may lead to a decreased pro-inflammatory immune response in the host.

Diffuse low-grade glioma (DLGG) is a well-differentiated, slow-growing tumour with an inherent tendency to progress to high-grade glioma. The potential roles of genetic alterations in DLGG development have not yet been fully delineated. Therefore, the current study performed an integrated gene expression meta-analysis of eight independent, publicly available microarray datasets including 291 DLGGs and 83 non-glioma (NG) samples to identify gene expression signatures associated with DLGG. Using INMEX, 708 differentially expressed genes (DEGs) (385 upregulated and 323 downregulated genes) were identified in DLGG compared to NG. Furthermore, 497 DEGs (222 upregulated and 275 downregulated genes) corresponding to two histological types were identified. Of these, high expression of HIP1R significantly correlated with increased overall survival, whereas high expression of TBXAS1 significantly correlated with decreased overall survival. Additionally, network-based meta-analysis identified FN1 and APP as the key hub genes in DLGG compared with NG. PTPN6 and CUL3 were the key hub genes identified in the astrocytoma relative to the oligodendroglioma. Further immunohistochemical validation revealed that MTHFD2 and SPARC were positively expressed in DLGG, whereas RBP4 was positively expressed in NG. These findings reveal potential molecular biomarkers for diagnosis and therapy in patients with DLGG and provide a rich and novel candidate reservoir for future studies.

Signal transducer and activator of transcription 3 (STAT3) is involved in the growth and metastasis of breast cancer, and represents a potential target for developing new anti-tumor drugs. The purpose of this study is to investigate whether Lycorine, a pyrrolo[de]phenanthridine ring-type alkaloid extracted from Amaryllidaceae genera, could inhibit breast cancer by targeting STAT3 signaling pathway. The human breast cancer cell lines were incubated with various concentrations of Lycorine, and cell proliferation, colony formation, cell cycle distribution, apoptosis, migration and invasion were assayed by several in vitro approaches. Results showed that Lycorine significantly suppressed cell proliferation, colony formation, migration and invasion, as well as induced cell apoptosis, but showed no apparent impact on cell cycle. In addition, the effect of Lycorine on tumor growth and metastasis in nude mouse models was investigated, and results showed that Lycorine significantly inhibited tumor growth and metastasis in vivo. Mechanistically, Lycorine significantly inhibited STAT3 phosphorylation and transcriptional activity through upregulating SHP-1 expression. Lycorine also downregulated the expressions of STAT3 target genes, including Mcl-1, Bcl-xL, MMP-2, MMP-9, which are involved in apoptosis and invasion of breast cancer. Taken together, these findings suggest that Lycorine may be a promising candidate for the prevention and treatment of human breast cancer.

Triptolide, an active component extracted from the medicinal plant Tripterygium wilfordii Hook F., has been used to treat various diseases, including lupus, cancer, rheumatoid arthritis and nephritic syndrome. The present study investigated the effects of triptolide on multiple myeloma using western blotting and an electrophoretic mobility shift assay. Triptolide was found to suppress the inducible and constitutive activation of signal transducer and activator of transcription 3 (STAT3), which is closely associated with inflammation and tumorigenesis. Triptolide also inhibited the DNA binding of STAT3. This correlated with the downregulation of Src kinase and Janus kinase 1 and 2, and with the upregulation of protein tyrosine phosphatase non‑receptor type 6 (also known as SHP‑1). In addition, triptolide downregulated the expression of the STAT3‑regulated antiapoptotic (Bcl‑xL and myeloid cell leukemia‑1), proliferative (cyclin D1), and angiogenic (vascular endothelial growth factor) genes, suggesting that triptolide can induce apoptosis of tumor cells. These results suggest that triptolide may be a potential therapeutic anticancer agent for the prevention and treatment of multiple myeloma; thus further in‑depth investigations into its efficacy and toxicity are warranted.

Hepatocellular carcinoma (HCC) is the third leading form of cancer worldwide, and its incidence is increasing rapidly in the United States, tripling over the past 3 decades. The current chemotherapeutic strategies against localized and metastatic HCC are ineffective. Here we report that 6-methoxyethylamino-numonafide (MEAN) is a potent growth inhibitor of murine xenografts of 2 human HCC cell lines. At the same dose and with the same treatment strategies, MEAN was more efficacious in inhibiting tumor growth in mice than sorafenib, the only approved drug for HCC. Treatment by MEAN at an effective dose for 6 wk was well tolerated by animals. Combined therapy using both sorafenib and MEAN enhanced tumor growth inhibition over monotherapy with either agent. Additional experiments revealed that MEAN inhibited tumor growth through mechanisms distinct from those of either its parent compound, amonafide, or sorafenib. MEAN suppressed C-MYC expression and increased expression of several tumor suppressor genes, including Src homology region 2 domain-containing phosphatase-1 (

Triple-negative breast cancer (TNBC) remains difficult to treat and urgently needs new therapeutic options. Nintedanib, a multikinase inhibitor, has exhibited efficacy in early clinical trials for HER2-negative breast cancer. In this study, we examined a new molecular mechanism of nintedanib in TNBC. The results demonstrated that nintedanib enhanced TNBC cell apoptosis, which was accompanied by a reduction of p-STAT3 and its downstream proteins. STAT3 overexpression suppressed nintedanib-mediated apoptosis and further increased the activity of purified SHP-1 protein. Moreover, treatment with either a specific inhibitor of SHP-1 or SHP-1-targeted siRNA reduced the apoptotic effects of nintedanib, which validates the role of SHP-1 in nintedanib-mediated apoptosis. Furthermore, nintedanib-induced apoptosis was attenuated in TNBC cells expressing SHP-1 mutants with constantly open conformations, suggesting that the autoinhibitory mechanism of SHP-1 attenuated the effects of nintedanib. Importantly, nintedanib significantly inhibited tumor growth via the SHP-1/p-STAT3 pathway. Clinically, SHP-1 levels were downregulated, whereas p-STAT3 was upregulated in tumor tissues, and SHP-1 transcripts were associated with improved disease-free survival in TNBC patients. Our findings revealed that nintedanib induces TNBC apoptosis by acting as a SHP-1 agonist, suggesting that targeting STAT3 by enhancing SHP-1 expression could be a viable therapeutic strategy against TNBC.

Most hepatocellular carcinomas (HCC) develop as a result of chronic liver inflammation. We have shown that the oncoprotein gankyrin is critical for inflammation-induced tumorigenesis in the colon. Although the in vitro function of gankyrin is well known, its role in vivo remains to be elucidated. We investigated the effect of gankyrin in the tumor microenvironment of mice with liver parenchymal cell-specific gankyrin ablation (Alb-Cre;gankyrin

Renal cell carcinoma (RCC) is one of the most aggressive urologic cancers, however, the mechanism on supporting RCC carcinogenesis is still not clear. By using gene expression profile analysis and functional clustering, PDZ domain-containing 1 (PDZK1) was revealed to be downregulated in human clear cell renal cell carcinoma (ccRCC) samples, which was also verified in several independent public ccRCC data sets. Using PDZK1 overexpression and knockdown models in ccRCC cell lines, we demonstrated that PDZK1 inhibited cell proliferation, cell cycle G1/S phase transition, cell migration and invasion, indicating a tumor-suppressor role in the development and progression of ccRCC. Our study further demonstrated that PDZK1 inhibited cell proliferation and migration of ccRCC via targeting SHP-1. PDZK1 was further identified to suppress cell proliferation by blocking SHP-1 phosphorylation at Tyr536 via inhibition of the association between SHP-1 and PLCβ3, and then retarding Akt phosphorylation and promoting STAT5 phosphorylation in ccRCC cells. Moreover, the inhibitive effects of PDZK1 on SHP-1 phosphorylation and the tumor growth were verified in vivo by xenograft tumor studies. Accordingly, PDZK1 expression was negatively correlated with SHP-1 activation and phosphorylation, advanced pathologic stage, tumor weight and size, and prognosis of ccRCC patients. These findings have provided first lines of evidences that PDZK1 expression is negatively correlated with SHP-1 activation and poor clinical outcomes in ccRCC. PDZK1 was identified as a novel tumor suppressor in ccRCC by negating SHP-1 activity.

The cancer-promoting activity of senescent peritoneal mesothelial cells (HPMCs) has already been well evidenced both in vitro and in vivo. Here we sought to determine if ovarian cancer cells may activate senescence in HPMCs. The study showed that conditioned medium (CM) from ovarian cancer cells (OVCAR-3, SKOV-3, A2780) inhibited growth and promoted the development of senescence phenotype (increased SA-β-Gal, γ-H2A.X, 53BP1, and decreased Cx43) in HPMCs. An analysis of tumors isolated from the peritoneum of patients with ovarian cancer revealed an abundance of senescent HPMCs in proximity to cancerous tissue. The presence of senescent HPMCs was incidental when fragments of peritoneum free from cancer were evaluated. An analysis of the cells' secretome followed by intervention studies with exogenous proteins and neutralizing antibodies revealed hepatocyte growth factor (HGF) as the mediator of the pro-senescence impact of the cancer cells. The activity of cancerous CM and HGF was associated with an induction of mitochondrial oxidative stress. Signaling pathways involved in the senescence of HPMCs elicited by the cancer-derived CM and HGF included p38 MAPK, AKT and NF-κB. HPMCs that senesced prematurely in response to the cancer-derived CM promoted adhesion of ovarian cancer cells, however this effect was effectively prevented by the cell protection against oxidative stress. Collectively, our findings indicate that ovarian cancer cells can elicit HGF-dependent senescence in HPMCs, which may contribute to the formation of a metastatic niche for these cells within the peritoneal cavity.

Triple negative breast cancer (TNBC) is an aggressive cancer for which prognosis remains poor. Combination therapy is a promising strategy for enhancing treatment efficacy. Blockade of STAT3 signaling may enhance the response of cancer cells to conventional chemotherapeutic agents. Here we used a SHP-1 agonist SC-43 to dephosphorylate STAT3 thereby suppressing oncogenic STAT3 signaling and tested it in combination with docetaxel in TNBC cells. We first analyzed messenger RNA (mRNA) expression of SHP-1 gene (PTPN6) in a public TNBC dataset (TCGA) and found that higher SHP-1 mRNA expression is associated with better overall survival in TNBC patients. Sequential combination of docetaxel and SC-43 in vitro showed enhanced anti-proliferation and apoptosis associated with decreased p-STAT3 and decreased STAT3-downstream effector cyclin D1 in the TNBC cell lines MDA-MB-231, MDA-MB-468, and HCC-1937. Ectopic expression of STAT3 reduced the increased cytotoxicity induced by the combination therapy. In addition, this sequential combination showed enhanced SHP-1 activity compared to SC-43 alone. Furthermore, the combination treatment-induced apoptosis was attenuated by small interfering RNA (siRNA) against SHP-1 or by ectopic expression of SHP-1 mutants that caused SC-43 to lose its SHP-1 agonist capability. Moreover, combination of docetaxel and SC-43 showed enhanced tumor growth inhibition compared to single-agent therapy in mice bearing MDA-MB-231 tumor xenografts. Our results suggest that the novel SHP-1 agonist SC-43 enhanced docetaxel-induced cytotoxicity by SHP-1 dependent STAT3 inhibition in human triple negative breast cancer cells. TNBC patients with high SHP-1 expressions show better survival. Docetaxel combined with SC-43 enhances cell apoptosis and reduces p-STAT3. SHP-1 inhibition reduces the enhanced effect of docetaxel-SC-43 combination. Docetaxel-SC-43 combination suppresses xenograft tumor growth and reduces p-STAT3.
KEY MESSAGES: TNBC patients with high SHP-1 expressions show better survival. Docetaxel combined with SC-43 enhances cell apoptosis and reduces p-STAT3. SHP-1 inhibition reduces the enhanced effect of docetaxel-SC-43 combination. Docetaxel-SC-43 combination suppresses xenograft tumor growth and reduces p-STAT3.

PTPN6, a tyrosine phosphatase protein, plays a negative role in cell signal transduction and is negatively correlated with tumour formation and growth. However, epigenetic regulation mechanism of the PTPN6 gene in advanced chronic myeloid leukaemia (CML) remains unclear. This study investigated bone marrow or blood samples from 44 CML patients and 10 healthy volunteers. KCL22 and K562 cells were cultured and treated with demethylation drugs and histone deacetylase inhibitors. Real time quantitative polymerase chain reaction (qPCR), methylation-specific PCR, bisulfite sequencing PCR, Western blotting, co-immunoprecipitation and chromatin immunoprecipitation (ChIP) was performed. PTPN6 was down-regulated in cell lines and patients with advanced phase CML, whereas DNMT1, DNMT3A, MECP2, MBD2 and HDAC1 were up-regulated. Treatment with 5-azacytidine, decitabine, sodium valproate and LBH589 increased PTPN6 expression, but decreased that of DNMT1, DNMT3A, MECP2, MBD2 and HDAC1. Immunoprecipitation and mass spectrometry showed that HDAC1 combined directly with PTPN6. ChIP-seq showed that HDAC1 did not combine with the promoter region of PTPN6, while MAPK, AKT, STAT5, JAK2 and MYC promoter regions all combined with HDAC1. PTPN6 is associated with progression of CML. Low expression level of PTPN6 was associated with DNA methylation and regulated by histone acetylation. HDAC1 participates in the regulation of PTPN6.

Shp-1 (Src homology region 2 domain-containing protein tyrosine phosphatase-1) is a phosphatase that is highly expressed in hematopoietic and epithelial cells. Whereas its function is largely characterized in hematopoietic cells, its role in epithelial cells, such as intestinal epithelial cells (IECs), is not well known. Here, we generated mice with an IEC-specific knockout of

INTRODUCTION: Extensive studies on SHP-1 protein and SHP-1 mRNA revealed that the diminishment or abolishment of the expression of SHP-1 in leukemias/lymphomas was due to aberrant promoter methylation. Thus far, the mechanism of epigenetic silencing of the SHP-1 tyrosine phosphatase gene that occurs in chronic myelogenous leukemia cells remains poorly understood.
METHODS: The expressions of the target molecules were determined by quantitative real time PCR and western blot, respectively. Bisulfite sequencing PCR was used to detect methylation status of DNA CpG. The lentiviral vectors were applied to modify gene expression.
RESULTS: In the present study, we found that the promoter 2 of SHP-1 gene is located between positions from -577bp to +300bp, and 22 CpG sites contained in positions -353bp∼+182bp are aberrantly methylated in K562 cells. In vitro, we demonstrated that DNMT1 silencing induced demethylation of the 22 CpG sites located in the SHP-1 promoter and re-expression of SHP-1 gene in K562 cells. Moreover, we proved that the expression levels of DNMT1 and SHP-1 mRNA and protein were negatively correlated in K562 cells and BM aspirates mononuclear cells from CML patients.
CONCLUSION: Collectively, these results indicate that DNMT1 mediates aberrant methylation and silencing of SHP-1 gene in chronic myelogenous leukemia cells, and provide a novel therapeutic target for CML.