Dietary molecules and experimental evidence of epigenetic influence in cancer chemoprevention: An insight

Alpha-linolenic acid-mediated epigenetic reprogramming of cervical cancer cell lines

Cervical cancer, the fourth most common cancer globally and the second most prevalent cancer among women in India, is primarily caused by Human Papilloma Virus (HPV). The association of diet with cancer etiology and prevention has been well established and nutrition has been shown to regulate cancer through modulation of epigenetic markers. Dietary fatty acids, especially omega-3, reduce the risk of cancer by preventing or reversing the progression through a variety of cellular targets, including epigenetic regulation. In this work, we have evaluated the potential of ALA (α linolenic acid), an ω-3 fatty acid, to regulate cervical cancer through epigenetic mechanisms. The effect of ALA was evaluated on the regulation of histone deacetylases1, DNA methyltransferases 1, and 3b, and global DNA methylation by ELISA. RT-PCR was utilized to assess the expression of tumor regulatory genes (hTERT, DAPK, RARβ, and CDH1) and their promoter methylation in HeLa (HPV18-positive), SiHa (HPV16-positive) and C33a (HPV-negative) cervical cancer cell lines. ALA increased DNA demethylase, HMTs, and HATs while decreasing global DNA methylation, DNMT, HDMs, and HDACs mRNA expression/activity in all cervical cancer cell lines. ALA downregulated hTERT oncogene while upregulating the mRNA expression of TSGs (Tumor Suppressor Genes) CDH1, RARβ, and DAPK in all the cell lines. ALA reduced methylation in the 5' CpG island of CDH1, RARβ, and DAPK1 promoters and reduced global DNA methylation in cervical cancer cell lines. These results suggest that ALA regulates the growth of cervical cancer cells by targeting epigenetic markers, shedding light on its potential therapeutic role in cervical cancer management.

Natural Bioactive Agents: Testable Stem Cell-Targeting Alternatives for Therapy-Resistant Breast Cancer

Long-term treatment options for conventional chemo-endocrine therapy and molecular-pathway-based targeted therapy are associated with acquired therapy resistance and the emergence of drug-resistant cancer-initiating stem cell populations, leading to the progression of metastatic disease. These treatment options are based on the expression status of estrogen receptor-α (ER-α), progesterone receptor (PR) hormone receptors, and/or of human epidermal growth factor receptor-2 (HER-2). The breast cancer subtypes Luminal A, Luminal B, and HER-2-enriched express hormone/growth factor receptors and exhibit a favorable response to hormone receptor modulators and growth factor receptor antagonists. The triple-negative breast cancer subtype lacks the expression of hormone/growth factor receptors and responds only to cytotoxic conventional chemotherapy. The clinical limitations, due to the modest therapeutic responses of chemo-resistant cancer-initiating stem cells, emphasize the need for the identification of stem cells targeting testable alternatives for therapy-resistant breast cancer. Developed drug-resistant stem cell models exhibit upregulated expression of select cellular biomarker tumor spheroid (TS) formations and cluster of differentiation44 (CD44), DNA-binding protein (NANOG), and octamer-binding protein-4 (OCT-4) molecular biomarkers that represent novel experimentally modifiable quantitative endpoints. Naturally occurring dietary phytochemicals and nutritional herbs containing polyphenols, flavones, terpenes, saponins, lignans, and tannins have documented human consumption, lack systemic toxicity, lack phenotypic drug resistance, and exhibit preclinical efficacy. Constituent bioactive agents may provide testable stem cell-targeting alternatives. The present report provides an overview of (i) clinically relevant cellular models and drug-resistant cancer stem cell models for breast cancer subtypes, (ii) evidence for preclinical efficacy and mechanistic leads for natural phytochemicals and nutritional herbs, and (iii) the potential for the stem cell-targeting efficacy of natural bioactive agents as testable drug candidates for therapy-resistant breast cancer.

Targeting oncogenic transcription factors in skin malignancies: An update on cancer stemness and therapeutic outcomes

The skin is the largest organ of the human body and prone to various diseases, including cancer; thus, provides the first line of defense against exogenous biological and non-biological agents. Skin cancer, a complex and heterogenic process, with steep incidence rate often metastasizes due to poor understanding of the underlying mechanisms of pathogenesis and clinical challenges. Indeed, accumulating evidence indicates that deregulation of transcription factors (TFs) due to genetic, epigenetic and signaling distortions plays essential role in the development of cutaneous malignancies and therapeutic challenges including cancer stemness features and reprogramming. This review highlights the recent developments exploring underlying mechanisms how deregulated TFs (e.g., NF-κB, AP-1, STAT etc.,) orchestrates cutaneous onco-pathogenesis, reprogramming, stemness and poor clinical outcomes. Along this line, bioactive drugs, and their derivatives from natural and or synthetic origin has gained attention due to their multitargeting potential, potentially safer and effective therapeutic outcome for human malignancies. We also discussed therapeutic importance of targeting aberrantly expressed TFs in skin cancers with bioactive natural products and or synthetic agents.

Diet-derived small molecules (nutraceuticals) inhibit cellular proliferation by interfering with key oncogenic pathways: an overview of experimental evidence in cancer chemoprevention

Discouraging statistics of cancer disease has projected an increase in the global cancer burden from 19.3 to 28.4 million incidences annually within the next two decades. Currently, there has been a revival of interest in nutraceuticals with evidence of pharmacological properties against human diseases including cancer. Diet is an integral part of lifestyle, and it has been proposed that an estimated one-third of human cancers can be prevented through appropriate lifestyle modification including dietary habits; hence, it is considered significant to explore the pharmacological benefits of these agents, which are easily accessible and have higher safety index. Accordingly, an impressive embodiment of evidence supports the concept that the dietary factors are critical modulators to prevent, retard, block, or reverse carcinogenesis. Such an action reflects the ability of these molecules to interfere with multitude of pathways to subdue and neutralize several oncogenic factors and thereby keep a restraint on neoplastic transformations. This review provides a series of experimental evidence based on the current literature to highlight the translational potential of nutraceuticals for the prevention of the disease through consumption of enriched diets and its efficacious management by means of novel interventions. Specifically, this review provides the current understanding of the chemopreventive pharmacology of nutraceuticals such as cucurbitacins, morin, fisetin, curcumin, luteolin and garcinol toward their potential as anticancer agents.