Studies on the Epigenetic Regulations Involved in Lantana camara Leaf Extract Mediated Alterations of Proliferation, Survival, and Migration of Triple Negative MDA-MB-231 Breast Cancer Cells

Sanyal, Sourav (2026) Studies on the Epigenetic Regulations Involved in Lantana camara Leaf Extract Mediated Alterations of Proliferation, Survival, and Migration of Triple Negative MDA-MB-231 Breast Cancer Cells. PhD thesis, Indian Institute of Science Education and Research Kolkata.

Text (PhD thesis of Sourav Sanyal (20RS122)) 20RS122.pdf - Submitted Version Restricted to Repository staff only Download (5MB)

Abstract

Cancer is a major cause of death that accounted for approximately 20 million new cases and 9.7 million deaths globally in 2022. Breast cancer was the 2nd highest in incidence and 4th highest in terms of mortality, with around 2.2 million new cases and 0.7 million deaths. Breast cancer can be categorized into four molecular subtypes, and triple-negative breast cancer is the most aggressive among all, with limited treatment options and often showing chemoresistance. Epigenetic alterations also play a crucial role in promoting the aggressiveness of triple-negative breast cancer, including increased proliferation, migration, and resistance to cell death. Lantana camara, an invasive weed belonging to the Verbenaceae family, exhibits various medicinal properties, and a growing body of research suggests its cytotoxic potential against cancer cells. However, its effect on triple-negative breast cancer remains unexplored. This study investigated the effects of Lantana camara leaf ethanolic extract on MDA-MB-231 triple-negative breast cancer cells, predominantly from an epigenetic perspective. MDA-MB-231 cells were treated with the extract, followed by assessment of cytomorphological features and determination of the cytotoxic effect by performing a cell viability assay. Cell cycle phase distribution was evaluated using flow cytometry. To study the nuclear morphology and decipher the mode of cell death, nuclear-stained cells were visualized using epifluorescence microscopy, and an apoptosis assay was performed using flow cytometry. Cellular migration was analyzed through wound healing assay. Real-time polymerase chain reaction and immunoblotting were used to check the mRNA and protein levels of some key genes involved in the aforementioned cellular phenomena. Furthermore, the expression of DNA methyltransferase 1 (DNMT1) was analyzed at the mRNA and protein levels. Expression of some key tumor suppressor genes was assessed at the mRNA level, and functional assays were conducted following DNMT1 overexpression to examine its impact on extract-mediated effects. Expression of methyl-CpG binding domain protein 2 (MBD2), histone deacetylase 1 (HDAC1), and histone deacetylase 2 (HDAC2) was also evaluated at the mRNA level. Lantana camara leaf extract was found to induce cytomorphological changes and reduce the viability of MDA-MB-231 cells in both dose- and time-dependent manner. Lantana camara leaf extract also triggered G0/G1 cell cycle arrest. Induction of nuclear condensation and flow cytometric analysis confirmed the apoptotic mode of cell death. Lantana camara leaf extract impeded the migration of MDA-MB-231 cells. Expression levels of some pivotal genes also supported the above observations. Moreover, Lantana camara leaf extract downregulated the expression of DNMT1 and upregulated the expression of some key tumour suppressor genes. Ectopic overexpression of DNMT1 attenuated the extract-induced reduction in cell viability and induction of G0/G1 cell cycle arrest and apoptosis, while restoring the migratory potential and suppressing the expression of those tumour suppressor genes. The above observations confirm the mechanistic role of DNMT1 in mediating the anti-cancer effects of the extract. Lantana camara leaf extract also downregulated the mRNA expression of other crucial epigenetic regulators, such as MBD2, HDAC1, and HDAC2. In conclusion, G0/G1 cell cycle arrest, apoptosis, and impediment of migration of MDA-MB-231 triple-negative breast cancer cells are the outcomes of the anti-cancer properties of Lantana camara leaf extract, which is partially mediated by the reduction of DNMT1 and other epigenetic regulators. These observations demonstrate that Lantana camara is a potent natural source of epigenetic modulatory and chemotherapeutic agents for the treatment of triple-negative breast cancer.

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