The incidence of aggressive and resistant breast cancers is growing at alarming rates, indicating a necessity to develop better treatment strategies. Recent epidemiological and preclinical studies detected low serum levels of vitamin D in cancer patients, suggesting that vitamin D may be effective in mitigating the cancer burden. However, the molecular mechanisms of vitamin D3 (cholecalciferol, vit-D3)-induced cancer cell death are not fully elucidated. The vit-D3 efficacy of cell death activation was assessed using breast carcinoma cell lines in vitro and a widely used Ehrlich ascites carcinoma (EAC) breast cancer model in vivo in Swiss albino mice. Both estrogen receptor-positive (ER+, MCF-7) and -negative (ER-, MDA-MB-231, and MDA-MB-468) cell lines absorbed about 50% of vit-D3 in vitro over 48 h of incubation. The absorbed vit-D3 retarded the breast cancer cell proliferation in a dose-dependent manner with IC50 values ranging from 0.10 to 0.35 mM. Prolonged treatment (up to 72 h) did not enhance vit-D3 anti-proliferative efficacy. Vit-D3-induced cell growth arrest was mediated by the upregulation of p53 and the downregulation of cyclin-D1 and Bcl2 expression levels. Vit-D3 retarded cell migration and inhibited blood vessel growth in vitro as well as in a chorioallantoic membrane (CAM) assay. The intraperitoneal administration of vit-D3 inhibited solid tumor growth and reduced body weight gain, as assessed in mice using a liquid tumor model. In summary, vit-D3 cytotoxic effects in breast cancer cell lines in vitro and an EAC model in vivo were associated with growth inhibition, the induction of apoptosis, cell cycle arrest, and the impediment of angiogenic processes. The generated data warrant further studies on vit-D3 anti-cancer therapeutic applications.

Despite a thorough understanding of the structure of human papillomavirus (HPV) and its genotypic variations (high-risk and low-risk variants), the mechanisms underlying HPV-induced cervical cancer (CC) pathogenesis and the molecular signatures of drug resistance remain to be fully understood. Accumulating evidence has shown the involvement of kinase targets in the induction of drug resistance in high-risk (HR) HPV-CC. Molecularly, the genome of high-risk HPV is reported to control the expression of host kinases. In particular, Aurora kinases A, B, and C (ARKA, ARKB, and ARKC), phosphotidylinositol–trisphosphate kinase (PI3K)-Akt, and Glycogen synthase kinase3-α/β (GSK3 α/β) promote the transformation of infected cells, and also enhance the resistance of cells to various chemotherapeutic agents such as nelfinavir and cisplatin. However, the precise mechanisms through which HPV activates these kinases are yet to be fully elucidated. Furthermore, there is still ambiguity surrounding whether targeting HPV-induced kinases along with HPV-targeted therapies (such as phytopharmaceuticals and PROTAC/CRISPR-CAS-based systems) synergistically inhibit cervical tumor growth. Given the critical role of kinases in the pathogenesis and treatment of CC, a comprehensive review of current evidence is warranted. This review aims to provide key insights into the mechanisms of HPV-induced CC development, the involvement of kinases in drug resistance induction, and the rationale for combination therapies to improve clinical outcomes.