CARM1 hypermethylates the NuRD chromatin remodeling complex to promote cell cycle gene expression and breast cancer development.

Protein arginine methyltransferase CARM1 has been shown to methylate a large number of non-histone proteins, and play important roles in gene transcriptional activation, cell cycle progress, and tumorigenesis. However, the critical substrates through which CARM1 exerts its functions remain to be fully characterized. Here, we reported that CARM1 directly interacts with the GATAD2A/2B subunit in the nucleosome remodeling and deacetylase (NuRD) complex, expanding the activities of NuRD to include protein arginine methylation. CARM1 and NuRD bind and activate a large cohort of genes with implications in cell cycle control to facilitate the G1 to S phase transition. This gene activation process requires CARM1 to hypermethylate GATAD2A/2B at a cluster of arginines, which is critical for the recruitment of the NuRD complex. The clinical significance of this gene activation mechanism is underscored by the high expression of CARM1 and NuRD in breast cancers, and the fact that knockdown CARM1 and NuRD inhibits cancer cell growth in vitro and tumorigenesis in vivo. Targeting CARM1-mediated GATAD2A/2B methylation with CARM1 specific inhibitors potently inhibit breast cancer cell growth in vitro and tumorigenesis in vivo. These findings reveal a gene activation program that requires arginine methylation established by CARM1 on a key chromatin remodeler, and targeting such methylation might represent a promising therapeutic avenue in the clinic.

The novel CDK9 inhibitor, XPW1, alone and in combination with BRD4 inhibitor JQ1, for the treatment of clear cell renal cell carcinoma.

BACKGROUND: Clear cell renal cell carcinoma (ccRCC) is a highly lethal malignancy with few therapeutic options. Cyclin­dependent kinase 9 (CDK9), a potential therapeutic target of many cancers, has been recently observed to be upregulated in ccRCC patients. Therefore, we aimed to investigate the therapeutic potential of CDK9 in ccRCC and develop a novel CDK9 inhibitor with low toxicity for ccRCC treatment. METHODS: The expression of CDK9 in ccRCC was checked using the online database and tissue microarray analysis. shRNA-mediated CDK9 knockdown and CDK inhibitor were applied to evaluate the effect of CDK9 on ccRCC. Medicinal chemistry methods were used to develop a new CDK9 inhibitor with drugability. RNA-seq and ChIP-seq experiments were conducted to explore the mechanism of action. MTS, western blotting, and colony formation assays were performed to evaluate the anti-ccRCC effects of CDK9 knockdown and inhibition in vitro. The in vivo anti-tumour efficacy was evaluated in a xenograft model. RESULTS: CDK9 is overexpressed and associated with poor survival in ccRCC. Knockdown or inhibition of CDK9 significantly suppressed ccRCC cells. XPW1 was identified as a new potent and selective CDK9 inhibitor with excellent anti-ccRCC activity and low toxicity. In mechanism, XPW1 transcriptionally inhibited DNA repair programmes in ccRCC cells, resulting in an excellent anti-tumour effect. CDK9 and BRD4 were two highly correlated transcriptional regulators in ccRCC patients, and the BRD4 inhibitor JQ1 enhanced XPW1's anti-ccRCC effects in vitro and in vivo. CONCLUSIONS: This work provides valuable insights into the therapeutic potential of CDK9 in ccRCC. The CDK9 inhibitor XPW1 would be a novel therapeutic agent for targeting ccRCC, alone or in rational combinations.

Vagus Nerve Stimulation Relives Irritable Bowel Syndrome and the Associated Depression via α7nAChR-mediated Anti-inflammatory Pathway.

OBJECTIVES: The present study is designed to investigate the role of vagus nerve in the treatments of irritable bowel syndrome (IBS) and the associated central nervous system disorders. METHODS: An IBS animal model was established by giving acetic acid and chronic-acute stress (AA-CAS) treatment in adult male Wistar rats. Subdiaphragmatic vagotomy (SDV) and vagus nerve stimulation (VNS) were performed to intervene the excitability of vagus nerve. Permeability of blood brain barrier (BBB) was measured and agonist and antagonist of α7 nicotinic acetylcholine receptor (α7nAChR) were used to explore the relevant mechanisms. RESULTS: AA-CAS treatment resulted in abnormal fecal output, increased visceral sensitivity, depressive-like behaviors, and overexpression of inflammatory mediators, all of which were reversed by VNS treatment. The effects of VNS could also be observed when α7nAChR agonist was applied. Whereas α7nAChR antagonist (methyllycaconitine, MLA) reversed VNS's effects. Interestingly, VNS also reduced the increased permeability of blood brain barrier (BBB) following AA-CAS treatment in IBS rats. SDV treatment only show temporary efficacy on AA-CAS-induced symptoms and had no effect on the permeability of BBB. CONCLUSION: The intestinal abnormalities and depressive symptoms in IBS rats can be improved by VNS treatment. This positive effect of VNS was achieved through α7nAChR-mediated inflammatory pathway and may also be associated with the decreased of BBB permeability.

Silencing of circ_002136 sensitizes gastric cancer to paclitaxel by targeting the miR-16-5p/HMGA1 axis.

The dysregulated expression of circRNA in gastric cancer (GC) induces paclitaxel (Tax) resistance of cancer cells, which in turn affects disease progression and prognosis. Here, we sought to investigate the role and mechanism of circ_002136 in Tax-resistant GC. In this study, we found the enriched circ_002136 level and the declined miR-16-5p level in Tax-resistant GC tissues and cells. Biologically, knockdown of circ_002136 elevated the Tax sensitivity of Tax-resistant GC cells, inhibited the cell motility properties, and simultaneously drove the apoptosis. Mechanically, circ_002136 promoted the HMGA1-mediated cellular Tax resistance and cell invasion by sponging miR-16-5p. Furthermore, circ_002136 silencing impeded the growth of Tax-resistant GC tumors in vivo. Overall, our study revealed a novel signaling pathway that could be used for future clinical applications, namely the circ_002136/miR-16-5p/HMGA1 axis to regulate the Tax resistance of GC cells.

Design and synthesis of N-(1-(6-(substituted phenyl)-pyridazin-3-yl)-piperidine-3-yl)-amine derivatives as JMJD6 inhibitors.

JMJD6 is a member of the JmjC domain-containing family and has been identified as a promising therapeutic target for treating estrogen-induced and triple-negative breast cancer. To develop novel anti-breast cancer agents, we synthesized a class of N-(1-(6-(substituted phenyl)-pyridazine-3-yl)-piperidine-3-yl)-amine derivatives as potential JMJD6 inhibitors. Among them, the anti-cancer compound A29 was an excellent JMJD6 binder (KD = 0.75 ± 0.08 µM). It could upregulate the mRNA and protein levels of p53 and its downstream effectors p21 and PUMA by inhibiting JMJD6. Besides, A29 displayed potent anti-proliferative activities against tested breast cancer cells by the induction of cell apoptosis and cell cycle arrest. Significantly, A29 also promoted a remarkable reduction in tumor growth, with a TGI value of 66.6% (50 mg/kg, i.p.). Taken together, our findings suggest that A29 is a potent JMJD6 inhibitor bearing a new scaffold acting as a promising drug candidate for the treatment of breast cancer.

Histone chaperone FACT complex coordinates with HIF to mediate an expeditious transcription program to adapt to poorly oxygenated cancers.

Cancer cells adapt to hypoxia through HIFs (hypoxia-inducible factors), which initiate the transcription of numerous genes for cancer cell survival in the hypoxia microenvironment. In this study, we find that the FACT (facilitates chromatin transcription) complex works cooperatively with HIFs to facilitate the expeditious expression of HIF targets for hypoxia adaptation. Knockout (KO) of the FACT complex abolishes HIF-mediated transcription by impeding transcription elongation in hypoxic cancer cells. Interestingly, the FACT complex is post-translationally regulated by PHD/VHL-mediated hydroxylation and proteasomal degradation, in similar fashion to HIF-1/2α. Metabolic tracing confirms that FACT KO suppresses glycolytic flux and impairs lactate extrusion, leading to intracellular acidification and apoptosis in cancer cells. Therapeutically, hepatic artery ligation and anti-angiogenic inhibitors adversely induce intratumoral hypoxia, while co-treatment with FACT inhibitor curaxin remarkably hinders the growth of hypoxic tumors. In summary, our findings suggest that the FACT complex is a critical component of hypoxia adaptation and a therapeutic target for hypoxic tumors.

SNAPIN Regulates Cell Cycle Progression to Promote Pancreatic ß Cell Growth.

In diabetes mellitus, death of ß cell in the pancreas occurs throughout the development of the disease, with loss of insulin production. The maintenance of ß cell number is essential to maintaining normoglycemia. SNAPIN has been found to regulate insulin secretion, but whether it induces ß cell proliferation remains to be elucidated. This study aimed to explore the physiological roles of SNAPIN in ß cell proliferation. SNAPIN expression increases with the age of mice and SNAPIN is down-regulated in diabetes. KEGG pathway and GO analysis showed that SNAPIN- interacting proteins were enriched in cell cycle regulation. B cell cycle was arrested in the S phase, and cell proliferation was inhibited after SNAPIN knockdown. The expression of CDK2, CDK4 and CCND1 proteins in the S phase of the cell cycle were reduced after SNAPIN knockdown, whereas they were increased after overexpression of SNAPIN. In addition, insulin protein and mRNA levels also increased or decreased after SNAPIN knockdown or overexpression, respectively. Conclusions: Our data indicate that SNAPIN mediates ß cells proliferation and insulin secretion, and provide evidences that SNAPIN might be a pharmacotherapeutic target for diabetes mellitus.