Impacts and mechanisms of alternative mRNA splicing in cancer metabolism, immune response, and therapeutics.

Alternative pre-mRNA splicing (AS) provides the potential to produce diversity at RNA and protein levels. Disruptions in the regulation of pre-mRNA splicing can lead to diseases. With the development of transcriptome and genome sequencing technology, increasing diseases have been identified to be associated with abnormal splicing of mRNAs. In tumors, abnormal alternative splicing frequently plays critical roles in cancer pathogenesis and may be considered as new biomarkers and therapeutic targets for cancer intervention. Metabolic abnormalities and immune disorders are important hallmarks of cancer. AS produces multiple different isoforms and diversifies protein expression, which is utilized by the immune and metabolic reprogramming systems to expand gene functions. The abnormal splicing events contributed to tumor progression, partially due to effects on immune response and metabolic reprogramming. Herein, we reviewed the vital role of alternative splicing in regulating cancer metabolism and immune response. We discussed how alternative splicing regulates metabolic reprogramming of cancer cells and antitumor immune response, and the possible strategies to targeting alternative splicing pathways or splicing-regulated metabolic pathway in the context of anticancer immunotherapy. Further, we highlighted the challenges and discuss the perspectives for RNA-based strategies for the treatment of cancer with abnormally alternative splicing isoforms.

Chondroitin sulfate proteoglycan 4, a targetable oncoantigen that promotes ovarian cancer growth, invasion, cisplatin resistance and spheroid formation.

Epithelial ovarian cancer (EOC) is a highly heterogeneous disease encompassing several distinct molecular subtypes and clinical entities. Despite the initial success of surgical debulking and adjuvant chemotherapy, recurrence with chemotherapy resistant tumors is common in patients with EOC and leads to poor overall survival. The extensive genetic and phenotypic heterogeneity associated with ovarian cancers has hindered the identification of effective prognostic and predictive biomarkers in EOC patients. In the current studies, we identify a tumor cell surface oncoantigen, chondroitin sulfate proteoglycan 4 (CSPG4), as an independent risk factor for decreased survival of patients with EOC. Our results show that CSPG4 promotes EOC cell invasion, cisplatin resistance and spheroid formation in vitro and tumor expansion in vivo. Mechanistically, spheroid formation and tumor cell invasion are due to CSPG4-stimulated expression of the mesenchymal transcription factor ZEB1. Furthermore, we have developed a novel monoclonal anti-CSGP4 antibody against the juxtamembrane domain of the core protein that limits CSPG4-stimulated ZEB1 expression, tumor cell invasion and promotes EOC apoptosis within spheroid cultures. We therefore propose that CSPG4 expression drives phenotypic heterogeneity and malignant progression in EOC tumors. These studies further demonstrate that CSPG4 expression levels are a potential diagnostic biomarker in EOC and indicate that targeting cells which express this oncoantigen could limit recurrence and improve outcomes in patients with EOC.

Renal protective effect of Rosa laevigata Michx. by the inhibition of oxidative stress in streptozotocin-induced diabetic rats.

Diabetic nephropathy (DN) is a long-term complication of diabetic mellitus. Numerous reports have suggested that oxidative stress is defined as the excessive production of reactive oxygen species (ROS) surpassing existing anti-oxidative defense mechanisms, and plays a critical role in the pathogenesis of diabetic nephropathy. Rosa laevigata Michx. (RLM) is the commonly used traditional Chinese medicine for the treatment of chronic urinary tract infections and anti-oxidative treatments, and has been shown to have a renal protective effect in diabetic rats. In the present study, we further investigate the effects of RLM on oxidative stress in the kidneys of streptozotocin-induced diabetic rats with DN. Our results suggest that RLM significantly ameliorates renal dysfunction in diabetic rats. The protection against the development of DN by RLM treatment involves increasing the activity of superoxide dismutase and total anti-oxidant capacity, decreasing the levels of malondialdehyde and ROS, and inhibiting the expression of nuclear factor-κB p65 and monocyte chemoattractant protein-1 at both the protein and mRNA levels with a concomitant increase in the expression of the IκBα protein. These results highlight the potential therapeutic application of RLM for the treatment of DN.

Diallyl disulfide suppresses growth of HL-60 cell through increasing histone acetylation and p21WAF1 expression in vivo and in vitro.

AIM: To examine the differentiation induction and growth inhibition of HL-60 cells by diallyl disulfide (DADS), and its relationship with the alterations of histone acetylation and p21(WAF1) expression in vitro and in vivo. METHODS: Differentiation was studied by nitroblue tetrazolium (NBT) reduction of HL-60 cell in vitro. HL-60 cells 5x10(6) were injected into the right side of the peritoneal cavity of severe combined immunodeficiency (SCID) mice. When the peritoneal neoplasms were detected, the SCID mice were randomly divided into 3 groups and received an ip injection of vehicle alone (NS), DADS or sodium butyrate (SB). The growth inhibition of peritoneal neoplasms induced by DADS was observed by a growth curve. The cycle distribution of HL-60 cells in SCID mice was monitored by flow cytometry. The expression of acetylated histone H3, H4 and p21(WAF1) were measured by Western blot. RESULTS: After treatment with DADS for 0-72 h, the NBT reduction ability of HL-60 cells increased in a time-dependent manner, compared with no treatment of HL-60 cells. In the HL-60 cells treated with DADS for 24 h, the expression of acetylated histone H3, H4, and p21(WAF1) increased obviously. After treatment with DADS, tumor growth was markedly suppressed. HL-60 cells from mice treated with DADS were blocked in the G1 phase, from 25.4% to 63.4%. The tumors from the mice treated with DADS showed an increase of acetylated histone H3, H4, and p21(WAF1). CONCLUSION: DADS could induce differentiation and inhibit the growth of HL-60 cells through increasing the expression of acetylated histone H3, H4, and p21(WAF1) in vitro and in vivo.