Resveratrol reverses drug resistance of esophageal cancer cell line Eca109/DDP via regulating ferroptosis

BACKGROUND

Resveratrol not only has anti-tumor effects, but also can enhance the chemosensitivity of tumor cells to a variety of chemotherapeutic agents. However, its effect on cisplatin sensitivity of drug-resistant esophageal cancer cells remains unclear.

AIM

To investigate whether resveratrol reverses the drug resistance of esophageal cancer Eca109/DDP cells and to explore the potential mechanism involved from the perspective of ferroptosis.

METHODS

The optimal treatment time and concentration of resveratrol and cisplatin were determined by MTT assay. Cell proliferation and the intracellular levels of malon-dialdehyde (MDA), glutathione (GSH), reactive oxygen species (ROS), and ferrous iron were detected. The protein expression of the ferroptosis-related molecules acyl coenzyme A synthetase long chain family member 4 (ACSL4), ferritin heavy chain (FTH), glutathione peroxidase 4 (GPX4), and tumor protein 53 (P53) was detected by Western blot assay.

RESULTS

MTT assay showed that compared with cisplatin alone, resveratrol combined with cisplatin significantly inhibited the growth of Eca109/DDP cells (P < 0.05). The combination of resveratrol and cisplatin not only reduced the number of colonies formed (P < 0.05), but also increased the levels of ferrous iron, MDA, and ROS (P < 0.05) and decreased the level of GSH (P < 0.05) in Eca109/DDP cells. The inhibitory effect of resveratrol on Eca109/DDP cell proliferation was partially reversed by ferrostatin-1 (Fer-1) and deferoxamine (DFO) (P < 0.05). Western blot analysis showed that compared with other groups, the protein expression of FTH and GPX4 in the resveratrol and cisplatin combination group was significantly decreased (P < 0.05), and the protein expression of ACSL4 and P53 was significantly increased (P < 0.05).

CONCLUSION

Resveratrol can inhibit cell proliferation and reverse cisplatin resistance by regulating ferroptosis in Eca109/DDP cells.

Schizandrin A enhances killing effect of oxaliplatin on colorectal cancer cells

BACKGROUND

Schizandrin A (SchA) has anticancer and multidrug resistance-reversing effects in a variety of tumors, but its effect on oxaliplatin (L-OHP) in colorectal cancer cells is not clear.

AIM

To investigate whether SchA can enhance the killing effect of L-OHP on colorectal cancer cells, and to analyze the possible mechanism involved.

METHODS

Colorectal cancer cells were divided into control group, SchA treatment group, L-OHP treatment group, and SchA + L-OHP treatment group. Cell viability was detected by MTT assay. Cell apoptosis was detected by flow cytometry. The contents of reactive oxygen species (ROS) in cells was detected using a ROS probe. Mitochondrial membrane potential was evaluated by using the 1,1',3,3'-tetraethyl-5,5',6,6'-tetrachloroimidacarbocyanine iodide (JC-1) probe. Western blot was used to detect the expression of B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X protein (Bax), cytochrome c (Cyt c), and cleaved cysteine proteinase-3 (caspase-3) in the cells.

RESULTS

Compared with the L-OHP treatment group, the viability of colorectal cancer cells in the SchA + L-OHP treatment group was significantly decreased, while apoptosis was significantly increased. SchA could enhance ROS accumulation, Bax and cleaved caspase-3 expression, and mitochondrial Cyt c release, and decrease Bcl-2 expression in colorectal cancer cells induced by L-OHP.

CONCLUSION

SchA enhances the killing effect of L-OHP on colorectal cancer cells, and the mechanism may be related to the enhancement of intracellular ROS accumulation and the expression of apoptosis-related proteins.

MiR-10b induces cisplatin resistance in gastric cancer cells by inhibiting KLF4 expression

BACKGROUND

Gastric cancer (GC) chemotherapy is prone to acquired chemotherapy resistance. MiR-10b has been found to be involved in regulating cisplatin (DDP) resistance of esophageal and nasopharyngeal carcinoma cells, but its relationship with DDP chemotherapy sensitivity in GC is unclear.

AIM

To investigate whether miR-10b is related to DDP chemoresistance in GC cells and the underlying molecular mechanism.

METHODS

SGC-7901/DDP and MGC-803/DDP cell lines were established by repeated stimulation of SGC-7901 and MGC-803 cells with increasing concentrations of DDP. The expression levels of miR-10b and KLF4 in SGC-7901/DDP and MGC-803/DDP cells were detected. After SGC-7901 and MGC-803 cells were infected with a lentiviral vector overexpressing miR-10b, cell proliferation was detected by MTT assay, apoptosis was detected by Annexin V-FITC/PI staining, and KLF4 mRNA and protein expression was detected by RT- qPCR and Western blot, respectively. In addition, these cells were further used to construct a xenograft tumor model, and after DDP chemotherapy, tumor morphology was observed macroscopically and tumor weight was measured. After co-transfection of SGC-7901 and MGC-803 cells with miR-10b and KLF4, the sensitivity of cells to DDP was detected by MTT assay.

RESULTS

Compared with SGC-7901 and MGC-803 cells, miR-10b expression levels in SGC-7901/DDP and MGC-803/DDP cells were significantly increased (P < 0.01), and KLF4 mRNA and protein levels were significantly decreased (P < 0.01). In vitro experiments showed that overexpression of miR-10b promoted DDP resistance in GC cells and inhibited KLF4 expression (P < 0.01). In vivo, after DDP treatment, tumor weight in the miR-10b group was significantly higher than that of the control group (P < 0.01). Overexpression of KLF4 could partially reverse DDP resistance of GC cells induced by overexpression of miR-10b.

CONCLUSION

MiR-10b promotes DDP resistance in GC cells by inhibiting the expression of KLF4, however, the DDP resistance induced by miR-10b overexpression can be reversed by up-regulation of KLF4.