Osthole (7‑methoxy‑8‑isopentenoxycoumarin) is an O‑methylated coumarin, originally extracted from Chinese herbal medicine. It has been demonstrated that osthole has antitumor effects in various cancer cells in vitro. The present study assessed the effects of osthole on the regulation of cervical cancer cell viability, apoptosis, and radiation sensitization. HeLa, SiHa, C‑33A and CaSki cervical cancer cell lines were cultured and treated with osthole and/or irradiation and then subjected to 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑-diphenyl‑tetrazolium bromide cell viability, colony formation, apoptosis, acridine orange/ethidium bromide fluorescence staining, wound‑healing, Transwell migration and invasion, immunofluorescence, Comet and western blot assays. The data showed that osthole dose‑dependently reduced cervical cancer cell viability, proliferation, and migration and invasion, but induced apoptosis. At the protein level, osthole affected the expression of cervical cancer cell epithelial‑mesenchymal transition markers, which showed that the expression of E‑cadherin was increased, whereas that of vimentin was decreased. Osthole treatment also sensitized cervical cancer cells to irradiation, showing increased DNA damage as assessed by the Comet assay, and inhibited nuclear factor‑κB signaling. In conclusion, osthole is an herbal agent that may offer potential for used as an adjuvant treatment for cervical cancer.

Paclitaxel is utilized as the first-line chemotherapeutic regimen for the majority of advanced non-small-cell lung carcinoma. However, whether paclitaxel could suppress cancer progression through modulating RNA alternative splicing remains largely unknown. Here, we demonstrated the effects of paclitaxel on cell proliferation inhibition, cell cycle arrest, and apoptosis. Mechanistically, paclitaxel leads to transcriptional alteration of networks involved in DNA replication and repair, chromosome segregation, chromatin silencing at rDNA, and mitosis at the transcriptional level. Moreover, paclitaxel regulates a number of cancer-associated RNA alternative splicing events, including genes involved in cellular response to DNA damage stimulus, preassembly of GPI anchor in ER membrane, transcription, and DNA repair. In particular, paclitaxel modulates the splicing of ECT2, a key factor involved in the regulation of cytokinesis. Briefly, paclitaxel favors the production of ECT2-S, the short splicing isoforms of ECT2, thereby inhibiting cancer cell proliferation. Our study provides mechanistic insights of paclitaxel on RNA alternative splicing regulation, thus to offer a potential novel route for paclitaxel to inhibit cancer progression.

Epirubicin is a first-line chemotherapeutic drug for the clinical treatment of diffuse large B cell lymphoma (DLBCL), but the overexpression of multidrug resistance (MDR) transporter proteins, especially P-glycoprotein (P-gp), renders epirubicin ineffective. Some studies reveal the potential role of melatonin in chemotherapeutic synergy and MDR. The cell viability and apoptosis were determined by CCK-8 assay and acridine orange/ethidium bromide (AO/EB) fluorescence staining assay. Immunofluorescence and immunohistochemical staining were used to detect the expression of P-gp in DLBCL cells and tissues. Rhodamine-123 accumulation assay was used to evaluate the pump function of P-gp. The possible mechanisms of melatonin sensitize DLBCL cells to epirubicin were explored by western blotting, cytochrome C release, and pulldown assay. Melatonin significantly enhanced the epirubicin-induced cell proliferation suppression, epirubicin-induced apoptosis, and reduced the IC50 value of epirubicin. Further, melatonin synergized with epirubicin to promote the activation of the mitochondria-mediated apoptosis pathway and increased the accumulation of epirubicin in DLBCL cells by inhibiting the expression and function of P-gp. Immunohistochemical staining studies revealed that P-gp expression was positively correlated with P65 expression. Epirubicin was subsequently discovered to upregulate the expression of P-gp by activating the NF-κB pathway in the DLBCL cells. Melatonin reduced the amount of P65 protein in the nucleus and abrogated the ability of P65 to bind to the ABCB1 promoter, decisively suppressing P-gp expression. Our results demonstrated that melatonin inactivates the NF-κB pathway and downregulates the expression of P-gp, ultimately sensitizing DLBCL cells to the epirubicin that suppresses their growth.