ABSTRACT
Capecitabine is recommended as one of the first-line chemotherapy treatments for advanced or metastatic colorectal cancer. Researches have been conducted on capecitabine's impact on the viability of human colon cancer cells and its potential to induce apoptosis. However, even in cases initially responsive to treatment, the development of acquired resistance significantly limits its efficacy. Challenges still exist in effectively treating patients with chemotherapy, and developing new cytotoxic drugs is hindered by drug resistance. Fisetin alters the cell cycle, inducing apoptosis, inhibiting cancer cell proliferation, and enhancing the therapeutic effectiveness of chemotherapy drugs. This work aims to create a plan for reversing capecitabine resistance. For this purpose, the role of capecitabine and/or fisetin combinations in cell proliferation and apoptosis has been determined in both wild-type and capecitabine-resistant HT29 cells (CR/HT29). We developed capecitabine-resistant cell line from wild-type HT29 cells. This study demonstrated the effects of capecitabine, fisetin, and their combinations on both resistant and wild-type cells through experiments including cell survival skills, cell proliferation, wound healing, colony formation, hoechst staining, and western blot analysis. We established capecitabine-resistant cell lines. P-gp expression increased in CR/HT29 cells. Capecitabine effects on a CR/HT29 cells less than wild-type HT29 cells. The combination of fisetin and capecitabine in cell proliferation caused greater reductions in wild-type HT29 cells than in capecitabine-resistant cells. Fisetin has also additive effects on the apoptotic pathway in CR/HT29 cells. This study provides new perspectives on the combination of capecitabine and/or flavonoid treatment in resistant cells.
ABSTRACT
BACKGROUND: Recent studies have analyzed the efficacy of various agents in experimental chemoprevention trials. In our study, the effects of melatonin (Mel) and its antagonist Luzindole (Luz) on Heme oxygenase-1 (HO-1) in a NMU (N-methyl-N-nitrosourea)-induced rat mammary carcinoma model are investigated. We aim to demonstrate the relationship between Mel and HO-1. METHODS: Spraque-Dawley rats were treated with NMU at age 55 days to induce mammary carcinoma. Forty-eight rats were divided into four groups consisting of: (a) physiological saline group (PSG); (b) control group, NMU is given; (c) Mel group (500 µg daily); (d) Mel antagonist Luz group (0.25 mg/kg/day i.p.). The animals were sacrificed; their serum and tissues were sampled for histopathologic evaluation, markers of endocrine derangement (serum prolactin, estradiol, and progesterone levels), apoptotic changes, DNA fragmentation, markers of oxidative stress and HO-1 immune expression were measured. RESULTS: Most tumors developed in the Luz group (42%), followed by the control group (33%), and the Mel group (17%). The tumor latency was longer in Mel-treated group (control and Luz at week 17, Mel at week 21). The maximum tumor volume was also smaller in Mel group when compared to control and Luz groups (p < .05). In Mel group estradiol, progesterone, and prolactin levels were decreased compared to control group (p < .001; p < .01; and p < .01) and levels of apoptotic activity and DNA fragmentation ratio increased. CONCLUSIONS: The increment of HO-1 expression with Mel is described; possible underlying mechanisms of these effects await further investigations.