MST2 methylation by PRMT5 inhibits Hippo signaling and promotes pancreatic cancer progression.

The Hippo signaling axis is a tumor suppressor pathway that is activated by various extra-pathway factors to regulate cell differentiation and organ development. Recent studies have reported that autophosphorylation of the core kinase cassette stimulates activation of the Hippo signaling cascade. Here, we demonstrate that protein arginine methyltransferase 5 (PRMT5) contributes to inactivation of the Hippo signaling pathway in pancreatic cancer. We show that the Hippo pathway initiator serine/threonine kinase 3 (STK3, also known as MST2) of Hippo signaling pathway can be symmetrically di-methylated by PRMT5 at arginine-461 (R461) and arginine-467 (R467) in its SARAH domain. Methylation suppresses MST2 autophosphorylation and kinase activity by blocking its homodimerization, thereby inactivating Hippo signaling pathway in pancreatic cancer. Moreover, we also show that the specific PRMT5 inhibitor GSK3326595 re-activates the dysregulated Hippo signaling pathway and inhibits the growth of human pancreatic cancer xenografts in immunodeficient mice, thus suggesting potential clinical application of PRMT5 inhibitors in pancreatic cancer.

Albumin Difference as a New Predictor of Postoperative Complications following Pancreatectomy.

BACKGROUND: Postoperative complications after pancreatectomy are a challenging problem due to their high incidence and serious consequences. The majority of studies have focused on a specific complication, but data on predictors of overall postoperative complications (OPCs) are limited. METHODS: The data of patients who underwent pancreatectomy at a single institute between 2017 and 2019 were analyzed retrospectively. Univariate and multivariate logistic regression were used to investigate predictors of the outcomes of interest. The Clavien-Dindo classification and comprehensive complication index (CCI) were used to assess postoperative complications and the severity of postoperative complications. The relationship between predictors and the CCI was evaluated by linear regression. RESULTS: A total of 490 patients were divided into a training group (n = 339) and a validation group (n = 151). The rate of OPCs was 44.25%. Fluid transfusion and albumin difference (AD) were predictors of OPCs. AD showed a good discrimination (AUC = 0.70) and good calibration in the validation cohort. AD was associated with complications, including pancreatic fistula, intra-abdominal hemorrhage, intra-abdominal infection, delayed gastric emptying, and re-intervention, and was positively correlated with complication severity. Intraoperative blood loss and preoperative albumin were independent predictors of AD. CONCLUSIONS: AD, a variable that reflects dynamic physiological changes is a new and accessible predictor of OPCs following pancreatectomy.

The prognostic value of modified Glasgow Prognostic Score in pancreatic cancer: a meta-analysis.

BACKGROUND: Several studies were conducted to explore the prognostic value of modified Glasgow Prognostic Score (mGPS) in pancreatic cancer, which reported contradictory results. The purpose of this meta-analysis was to summarize and further investigate the correlation between mGPS and overall survival (OS) in pancreatic cancer. METHODS: A systematic literature search was performed in PubMed, EMBASE, ISI Web of Science, Cochrane library databases and OVID to identify eligible studies published from Jan 1, 2011 to June 20, 2020. Pooled hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) were used to detect the prognostic significance of mGPS in patients with pancreatic cancer. RESULTS: A total of 222 non-repetitive studies were identified, and 20 related studies that explored the association between survival outcomes and mGPS in pancreatic cancer patients were finally enrolled in this meta-analysis. The results showed a significant correlation between high level of mGPS and poor OS (HR = 1.50, 95% CI 1.20-1.89, P < 0.0001). Similar results were observed in the subgroup analyses based on the treatment regimen and research region. CONCLUSIONS: Our study suggested the close association between poor prognosis and high level of mGPS, which will be helpful for future clinical applications in patients with pancreatic cancer.

Intra-Ampullary Papillary-Tubular Neoplasm: A Population-Based Analysis.

BACKGROUND Intra-ampullary papillary-tubular neoplasm (IAPN) is recognized as a precancerous lesion with a great tendency to evolve into pancreatic cancer. The Surveillance, Epidemiology, and End Results (SEER) database is now large enough to study unusual cancers. Based on pathologic and epidemiologic characteristics of IAPN available in SEER, important clinicopathological correlations can be made. MATERIAL AND METHODS Cases of IAPN and other intraductal papillary mucinous neoplasms of the bile duct (OBIPMN) diagnosed between 1973 and 2014 were searched in the SEER database. The analysis was carried out with respect to patient clinical characteristics, tumor characteristics, incidence, and survival. RESULTS In total, 685 patients with IAPN were identified compared with 2465 patients with OBIPMN in the same period. The incidence rate of IAPN was decreased, with a 4.882% annual percent change. The patient characteristics of IAPN were quite different from OBIPMN in many characteristics, including age, gender, marital status, and survival. Compared with OBIPMN, the tumor characteristics of IAPN indicated that more patients were diagnosed at an earlier stage in multiple stage systems such as pathological grade (P<0.001), sixth American Joint Committee on Cancer stage (P<0.001), TNM stage (P<0.001), and SEER historic stage (P<0.001). In the survival analysis, the cancer-specific survival of IAPN was significantly better than OBIPMN (P<0.001) and the cancer-specific survival get worse at higher stages (P<0.001). Moreover, the 5-year cancer-specific survival rate of IAPN was also significantly better than that of OBIPMN (36.5% versus 25.4%, P<0.001). Finally, the multivariate analysis showed a correlation between cancer-specific survival and age of diagnosis and N stage (P<0.001). CONCLUSIONS Analysis of the SEER database clearly demonstrated that IAPN was a precancerous lesion tend to be diagnosed earlier compared with OBIPMN, which contributed to the better prognosis, and surgery was suggested if possible.

CK2-dependent degradation of CBX3 dictates replication fork stalling and PARP inhibitor sensitivity.

DNA replication is a vulnerable cellular process, and its deregulation leads to genomic instability. Here, we demonstrate that chromobox protein homolog 3 (CBX3) binds replication protein A 32-kDa subunit (RPA2) and regulates RPA2 retention at stalled replication forks. CBX3 is recruited to stalled replication forks by RPA2 and inhibits ring finger and WD repeat domain 3 (RFWD3)-facilitated replication restart. Phosphorylation of CBX3 at serine-95 by casein kinase 2 (CK2) kinase augments cadherin 1 (CDH1)-mediated CBX3 degradation and RPA2 dynamics at stalled replication forks, which permits replication fork restart. Increased expression of CBX3 due to gene amplification or CK2 inhibitor treatment sensitizes prostate cancer cells to poly(ADP-ribose) polymerase (PARP) inhibitors while inducing replication stress and DNA damage. Our work reveals CBX3 as a key regulator of RPA2 function and DNA replication, suggesting that CBX3 could serve as an indicator for targeted therapy of cancer using PARP inhibitors.

Ubiquitin ligase TRIM15 promotes the progression of pancreatic cancer via the upregulation of the IGF2BP2-TLR4 axis.

BACKGROUND: The tripartite motif family, predominantly characterized by its E3 ubiquitin ligase activities, is involved in various cellular processes including signal transduction, apoptosis and autophagy, protein quality control, immune regulation, and carcinogenesis. Tripartite Motif Containing 15 (TRIM15) plays an important role in melanoma progression through extracellular signal-regulated kinase activation; however, data on its role in pancreatic tumors remain lacking. We previously demonstrated that TRIM15 targeted lipid synthesis and metabolism in pancreatic cancer; however, other specific regulatory mechanisms remain elusive. METHODS: We used transcriptomics and proteomics, conducted a series of phenotypic experiments, and used a mouse orthotopic transplantation model to study the specific mechanism of TRIM15 in pancreatic cancer in vitro and in vivo. RESULTS: TRIM15 overexpression promoted the progression of pancreatic cancer by upregulating the toll-like receptor 4. The TRIM15 binding protein, IGF2BP2, could combine with TLR4 to inhibit its mRNA degradation. Furthermore, the ubiquitin level of IGF2BP2 was positively correlated with TRIM15. CONCLUSIONS: TRIM15 could ubiquitinate IGF2BP2 to enhance the function of phase separation and the maintenance of mRNA stability of TLR4. TRIM15 is a potential therapeutic target against pancreatic cancer.

A novel FBW7/NFAT1 axis regulates cancer immunity in sunitinib-resistant renal cancer by inducing PD-L1 expression.

BACKGROUND: Tyrosine kinase inhibitors (TKIs) alone and in combination with immune checkpoint inhibitors (ICIs) have been shown to be beneficial for the survival of metastatic renal cell carcinoma (mRCC) patients, but resistance to targeted therapy and ICIs is common in the clinic. Understanding the underlying mechanism is critical for further prolonging the survival of renal cancer patients. Nuclear factor of activated T cell 1 (NFAT1) is expressed in immune and nonimmune cells, and the dysregulation of NFAT1 contributes to the progression of various type of malignant tumors. However, the specific role of NFAT1 in RCC is elusive. As a regulator of the immune response, we would like to systemically study the role of NFAT1 in RCC. METHODS: TCGA-KIRC dataset analysis, Western blot analysis and RT-qPCR analysis was used to determine the clinic-pathological characteristic of NFAT1 in RCC. CCK-8 assays, colony formation assays and xenograft assays were performed to examine the biological role of NFAT1 in renal cancer cells. RNA-seq analysis was used to examine the pathways changed after NFAT1 silencing. ChIP-qPCR, coimmunoprecipitation analysis, Western blot analysis and RT-qPCR analysis were applied to explore the mechanism by NAFT1 was regulated in the renal cancer cells. RESULTS: In our study, we found that NFAT1 was abnormally overexpressed in RCC and that NFAT1 overexpression was associated with an unfavorable prognosis. Then, we showed that NFAT1 enhanced tumor growth and regulated the immune response by increasing PD-L1 expression in RCC. In addition, we demonstrated that NFAT1 was stabilized in sunitinib-resistant RCC via hyperactivation of the PI3K/AKT/GSK-3ß signaling pathway. Furthermore, our study indicated that downregulation of the expression of FBW7, which promotes NFAT1 degradation, was induced by FOXA1 and SETD2 in sunitinib-resistant RCC. Finally, FBW7 was found to contribute to modulating the immune response in RCC. CONCLUSIONS: Our data reveal a novel role for the FBW7/NFAT1 axis in the RCC response to TKIs and ICIs. NFAT1 and its associated signaling pathway might be therapeutic targets for RCC treatment, especially when combined with ICIs and/or TKIs.

USP22-mediated deubiquitination of PTEN inhibits pancreatic cancer progression by inducing p21 expression.

Phosphatase and tensin homolog deleted on chromosome ten (PTEN) is a dual lipid and protein phosphatase. Multiple mechanisms contributing to the regulation of PTEN levels have been identified thus far, including post-translational modifications, epigenetic mechanisms, and transcriptional mechanisms. In the present study, we identified ubiquitin-specific peptidase 22 (USP22) as a novel deubiquitination-modifying enzyme of PTEN. Furthermore, by inducing deubiquitination and inhibiting the degradation of PTEN, USP22 could induce cyclin-dependent kinase inhibitor 1A (CDKN1A, also symboled as p21) expression in pancreatic cancer. Besides, MDM2 proto-oncogene (MDM2) inhibitor enhanced the antipancreatic cancer effects of USP22 overexpression. In addition to its regulation of MDM2-tumor protein p53 (p53) signaling, we found that PTEN could induce p21 expression by interacting with ankyrin repeat and KH domain containing 1 (ANKHD1) and inhibiting ANKHD1 binding to the p21 promoter. Taken together, our results indicate that ANKHD1 and MDM2 might be novel therapeutic targets in pancreatic cancer.

SGLT2 inhibitor activates the STING/IRF3/IFN-ß pathway and induces immune infiltration in osteosarcoma.

SGLT2 (sodium-glucose cotransporter 2) is an important mediator of epithelial glucose transport and has been reported that SGLT2, robustly and diffusely expressed in malignant cancer cells, was overexpressed in various tumors, and inhibiting the SGLT2 expression significantly inhibited tumor progression. By blocking the functional activity of SGLT2, SGLT2 inhibitors have shown anticancer effects in several malignant cancers, including breast cancer, cervical cancer, hepatocellular cancer, prostate cancer, and lung cancer. However, the anticancer effect of SGLT2 inhibitors in osteosarcoma and the specific mechanism are still unclear. In the present study, we found that SGLT2 was overexpressed at the protein level in osteosarcoma. Furthermore, our results showed that the SGLT2 inhibitor significantly inhibited osteosarcoma tumor growth and induced infiltration of immune cells in vivo by upregulating STING expression and activating the IRF3/IFN-ß pathway, which could attribute to the suppression of AKT phosphorylation. In addition, the combined treatment with SGLT2 inhibitor and STING agonist 2'3'-cGAMP exerted synergistic antitumor effects in osteosarcoma. Furthermore, the overexpression of SGLT2 at the protein level was correlated with the degradation of SGLT2 induced by TRIM21. This result demonstrated that SGLT2 is a novel therapeutic target of osteosarcoma, and that the SGLT2 inhibitor, especially in combination with 2'3'-cGAMP, is a potential therapeutic drug.

Overexpressed integrin alpha 2 inhibits the activation of the transforming growth factor ß pathway in pancreatic cancer via the TFCP2-SMAD2 axis.

BACKGROUND: Integrin alpha 2 (ITGA2) has been recently reported to be an oncogene and to play crucial roles in tumor cell proliferation, invasion, metastasis, and angiogenesis. Our previous study showed that ITGA2 was overexpressed in pancreatic cancer and promoted its progression. However, the mechanism of ITGA2 overexpression and other mechanisms for promoting the progression of pancreatic cancer are still unclear. METHODS: The GEPIA database was used to confirm the expression of ITGA2 in pancreatic cancer. To verify the influence of ITGA2 and TGF-ß on the morphological changes of pancreatic cancer and tumor cell progression, we conduct CCK8 test, plate cloning, flow cytometry experiments and animal experiments. Then we conduct Western blot, RT-qPCR to explore the relationship between ITGA2 and TGF-ß, and then find the key molecules which can regulate them by immunoprecipitation, Western blot, RT-qPCR, CHIP, nuclear and cytoplasmic separation test. RESULTS: The results of the present study show that the abnormal activation of KRAS induced the overexpression of ITGA2 in pancreatic cancer. Moreover, ITGA2 expression significantly suppressed the activation of the TGF-ß pathway. ITGA2 silencing enhanced the anti-pancreatic cancer proliferation and tumor growth effects of TGF-ß. Mechanistically, ITGA2 expression suppressed the activation of the TGF-ß pathway by inhibiting the SMAD2 expression transcriptionally. In addition, it interacted with and inhibited the nuclear translocation of TFCP2, which induced the SMAD2 expression as a transcription factor. Furthermore, TFCP2 also induced ITGA2 expression as a transcription factor, and the TFCP2 feedback regulated the ITGA2-TFCP2-SMAD2 pathway. CONCLUSIONS: Taken together, these results indicated that ITGA2 expression could inhibit the activation of the TGF-ß signaling pathway in pancreatic cancer via the TFCP2-SMAD2 axis. Therefore, ITGA2, by effectively enhancing the anti-cancer effects of TGF- ß, might be a potential clinical therapeutic target for pancreatic cancer.