Cyanidin 3-O-Glucoside Induces the Apoptosis in the Osteosarcoma Cells through Upregulation of the PPARγ and P21: An <i>In Vitro</i> Study

The Involvement of Natural Polyphenols in Molecular Mechanisms Inducing Apoptosis in Tumor Cells: A Promising Adjuvant in Cancer Therapy

Various literature data show how a diet rich in vegetables could reduce the incidence of several cancers due to the contribution of the natural polyphenols contained in them. Polyphenols are attributed multiple pharmacological actions such as anti-inflammatory, anti-oxidant, antibiotic, antiseptic, anti-allergic, cardioprotective and even anti-tumor properties. The multiple mechanisms involved in their anti-tumor action include signaling pathways modulation associated with cell proliferation, differentiation, migration, angiogenesis, metastasis and cell death. Since the dysregulation of death processes is involved in cancer etiopathology, the natural compounds able to kill cancer cells could be used as new anticancer agents. Apoptosis, a programmed form of cell death, is the most potent defense against cancer and the main mechanism used by both chemotherapy agents and polyphenols. The aim of this review is to provide an update of literature data on the apoptotic molecular mechanisms induced by some representative polyphenol family members in cancer cells. This aspect is particularly important because it may be useful in the design of new therapeutic strategies against cancer involving the polyphenols as adjuvants.

Natural flavonoids exhibit potent anticancer activity by targeting microRNAs in cancer: A signature step hinting towards clinical perfection

Cancer prevalence and its rate of incidence are constantly rising since the past few decades. Owing to the toxicity of present-day antineoplastic drugs, it is imperative to explore safer and more effective molecules to combat and/or prevent this dreaded disease. Flavonoids, a class of polyphenols, have exhibited multifaceted implications against several diseases including cancer, without showing significant toxicity towards the normal cells. Shredded pieces of evidence suggest that flavonoids can enhance drug sensitivity and suppress proliferation, metastasis, and angiogenesis of cancer cells by modulating several oncogenic or oncosuppressor microRNAs (miRNAs, miRs). They play pivotal roles in regulation of various biological and pathological processes, including various cancers. In the present review, the structure, chemistry and miR targeting efficacy of quercetin, luteolin, silibinin, genistein, epigallocatechin gallate, and cyanidin against several cancer types are comprehensively discussed. miRs are considered as next-generation medicine of recent times, and their targeting by naturally occurring flavonoids in cancer cells could be deemed as a signature step. We anticipate that our compilations related to miRNA-mediated regulation of cancer cells by flavonoids might catapult the clinical investigations and affirmation in the future.

Cyanidin-3-O-glucoside inhibits the β-catenin/MGMT pathway by upregulating miR-214-5p to reverse chemotherapy resistance in glioma cells

Overcoming resistance to alkylating agents has important clinical significance in glioma. Cyanidin-3-O-glucoside (C3G) has a tumor-suppressive effect on tumor cells. However, whether it plays a role in temozolomide resistance in glioma is still unclear. We constructed a TMZ-resistant LN-18/TR glioma cell line, observed the effect of C3G on TMZ resistance in this cell line, and explored the role of miR-214-5p in chemoresistance. Results showed that β-catenin and MGMT were significantly upregulated in LN-18/TR cells. C3G upregulated miR-214-5p and enhanced the cytotoxic effect of temozolomide on LN-18/TR cells. Contrarily, C3G downregulated β-catenin and MGMT. Moreover, the miR-214-5p mimic downregulated β-catenin and MGMT in LN-18/TR cells, whereas the miR-214-5p inhibitor had the opposite effect; the miR-214-5p inhibitor significantly blocked the C3G-induced downregulation of β-catenin and MGMT. C3G or the miR-214-5p mimic enhanced temozolomide-induced apoptosis in LN-18/TR cells, whereas the miR-214-5p inhibitor blocked this effect. Furthermore, C3G or miR-214-5p agomir combined with TMZ significantly inhibited the growth of LN-18/TR tumors. Collectively, our research discovered the potential signaling mechanism associated with C3G-mediated suppression of TMZ resistance in LN-18/TR cells through miR-214-5p, which can facilitate the treatment of MGMT-induced resistance in glioma cells.