Induction of Apoptosis in Intestinal Toxicity to a Histone Deacetylase Inhibitor in a Phase I Study with Pelvic Radiotherapy

Effect of MicroRNA-210 on the Growth of Ovarian Cancer Cells and the Efficacy of Radiotherapy

OBJECTIVE

The objective of this study is to explore the role of miR-210 in the growth of ovarian cancer cells and the correlation with radiotherapy and to elucidate underlying molecular mechanisms.

METHODS

Human ovarian cancer cell lines OVCAR3 and SKOV3 were cultured in vitro, and miR-210 over-expression and low-expression ovarian cancer cell models were established by cell transfection. MTT assay was used to detect the proliferation activity. Transwell was used to detect the migration and invasion abilities. Western blot measured the expression of proteins related to cell proliferation, migration, and invasion. The cells were treated with different doses of ionizing radiation, and then the cell proliferation activity was detected by MTT. The expression of apoptosis-related proteins was detected by Western blot. The Caspase-Glo® Kit was used to detect the activity of cellular caspase 3/7 enzymes.

RESULTS

The proliferation, migration, and invasion abilities of miR-210 over-expression ovarian cancer cells were increased (p < 0.05), the expressions of PTEN and E-cadherin were decreased, and the expression of p-Protein kinase B (AKT), N-cadherin, Snail, and Vimentin were elevated. After ionizing radiation, the sensitivity of miR-210 over-expression cells to radiotherapy was decreased, the expression of apoptosis-related protein Bax was decreased, the expression of Bcl-2 was increased, and the activity of cellular caspase 3/7 enzyme was reduced (p < 0.05).

CONCLUSION

miR-210 can promote the proliferation, migration, and invasion of ovarian cancer cells by activating the AKT signaling pathway and regulating the expression of Epithelial-mesenchymal transition-related proteins. miR-210 can reduce the sensitivity of ovarian cancer cells to radiotherapy by inhibiting apoptosis, which might serve as a potential target for the treatment of ovarian tumors.

Valproic Acid Downregulates Cytokine Expression in Human Macrophages Infected with Dengue Virus

Natural infection with dengue virus (DENV) induces an increase in the production of cytokines that play an important role in disease pathogenesis. Despite numerous scientific studies, there are still no commercially available disease-specific therapeutics. Previous evidence shows that inhibiting histone deacetylase enzymes (HDACs) regulates the immune response in several inflammatory disease models. The aim of the current study was to evaluate the effect of HDAC inhibition in the production of inflammatory cytokines in human monocyte-derived macrophages infected with DENV serotype 2 (DENV-2). To this end, human monocyte-derived macrophages (MDMs) were treated with valproic acid (VPA) before or after infection and the inflammatory cytokine concentration was quantified by flow cytometry. We found that infected MDMs secreted IL-8, IL-1b, IL-6, TNF-alpha, and IL-10, but not IL-12. Strikingly, treatment of infected cells with VPA had a differential and concentration-dependent effect on the production of specific cytokines without eliciting significant changes in cell viability. Using the highest concentration of VPA, a significant reduction in the production of all cytokines was observed. These results suggest that HDAC inhibition during DENV-2 infection could exert an important regulatory effect in the production of inflammatory cytokines, representing a significant advance in the design of novel therapeutic dengue treatments.

Radiosensitization In Vivo by Histone Deacetylase Inhibition with No Increase in Early Normal Tissue Radiation Toxicity

As the population ages, more elderly patients require radiotherapy-based treatment for their pelvic malignancies, including muscle-invasive bladder cancer, as they are unfit for major surgery. Therefore, there is an urgent need to find radiosensitizing agents minimally toxic to normal tissues, including bowel and bladder, for such patients. We developed methods to determine normal tissue toxicity severity in intestine and bladder in vivo, using novel radiotherapy techniques on a small animal radiation research platform (SARRP). The effects of panobinostat on in vivo tumor growth delay were evaluated using subcutaneous xenografts in athymic nude mice. Panobinostat concentration levels in xenografts, plasma, and normal tissues were measured in CD1-nude mice. CD1-nude mice were treated with drug/irradiation combinations to assess acute normal tissue effects in small intestine using the intestinal crypt assay, and later effects in small and large intestine at 11 weeks by stool assessment and at 12 weeks by histologic examination. In vitro effects of panobinostat were assessed by qPCR and of panobinostat, TMP195, and mocetinostat by clonogenic assay, and Western blot analysis. Panobinostat resulted in growth delay in RT112 bladder cancer xenografts but did not significantly increase acute (3.75 days) or 12 weeks' normal tissue radiation toxicity. Radiosensitization by panobinostat was effective in hypoxic bladder cancer cells and associated with class I HDAC inhibition, and protein downregulation of HDAC2 and MRE11. Pan-HDAC inhibition is a promising strategy for radiosensitization, but more selective agents may be more useful radiosensitizers clinically, resulting in fewer systemic side effects. Mol Cancer Ther; 17(2); 381-92. ©2017 AACRSee all articles in this MCT Focus section, "Developmental Therapeutics in Radiation Oncology."