Caffeine Has a Synergistic Anticancer Effect with Cisplatin <i>via</i> Inhibiting Fanconi Anemia Group D2 Protein Monoubiquitination in Hepatocellular Carcinoma Cells

Abstract

Cisplatin is an anticancer agent and induces DNA interstrand cross-links (ICLs). ICLs activate various signaling processes and induce DNA repair pathways, including the Fanconi anemia (FA) pathway. FA complementation group D2 (FANCD2) is monoubiquitinated in response to DNA damage, leading to activation of the DNA double-strand-break repair protein, RAD51. Caffeine increases the anticancer activity of cisplatin by inhibiting DNA repair; however, details of the mechanism remain unclear. We investigated the mechanism responsible for the synergistic anticancer effect of cisplatin and caffeine in HepG2 human hepatocellular carcinoma cells, focusing on the FA pathway. Caffeine (≥100 µg/mL) significantly enhanced the antiproliferative activity induced by 3.8 µg/mL cisplatin. Caffeine (200 µg/mL) promoted apoptosis and inhibited the increase in the proportion of viable cells in S phase that occurred in the presence of 3.8 µg/mL cisplatin. Both FANCD2 monoubiquitination and RAD51 expression were significantly inhibited by co-treatment with 200 µg/mL caffeine and 3.8 µg/mL cisplatin compared with cisplatin alone. In conclusion, caffeine enhances the anticancer effect of cisplatin by inhibiting FANCD2 monoubiquitination. In HepG2 cells, caffeine might inhibit the FA pathway and thereby regulate DNA damage responses such as DNA repair and apoptosis. Key words caffeine; cisplatin; Fanconi anemia pathway; monoubiquitinationCisplatin is a platinum complex widely used for treating solid tumors.1) Its cytotoxic effects are the result of DNA interstrand cross-link (ICL) formation. Cisplatin ICLs are highly toxic DNA lesions that inhibit DNA strand separation.2)The homologous recombination (HR) DNA repair is induced by ICLs via the Fanconi anemia (FA) pathway.3) FA is a disease in which defective DNA repair leads to bone-marrow failure and the development of solid tumors, especially liver tumors.4) FA cells are hypersensitive to ICL-inducing agents, and FA pathway inhibition increases the anticancer effect of cisplatin.5) Therefore, the FA pathway plays an important role in repairing cisplatin-induced DNA damage.The FA pathway consists of at least 16 complementation groups and their associated genes. At least 10 FA proteins form the FA core complex, which mediates the monoubiquitination of FA complementation group D2 (FANCD2) at S phase of the cell cycle.6,7) Monoubiquitinated FANCD2 (FANCD2-Ub) is a key component of the FA pathway that functionally interacts with RAD51, which is essential for strand-pairing reactions during DNA recombination. 8)Caffeine is a methylxanthine alkaloid that is chemically related to the adenine and guanine bases of DNA and RNA. Caffeine increases the anticancer effect of cisplatin in hepatocellular carcinoma (HCC) cell lines via inhibiting DNA repair.9) In addition, a clinical trial of caffeine-potentiated chemotherapy previously reported positive results. 10) Caffeine suppresses HR by inhibiting both RAD51 accumulation and the activity of ataxia telangiectasia and Rad-3 related (ATR) kinase, which i...

Platinum-Based Combination Therapy: Molecular Rationale, Current Clinical Uses, and Future Perspectives

“…They enhance the anticancer activity of oxaliplatin in human colon, breast, and ovarian cancers by inhibiting DNA synthesis resulting from alternation of the pyrimidine pathway . Caffeine exerted a synergistic anticancer effect with cisplatin in hepatocellular carcinoma cells by inhibiting DNA repair resulting from the decreased monoubiquitination of the FANCD2 protein . Estrogen sensitizes prostate cancer cells LNCaP to cisplatin possibly by increasing the expression of HMG1 by methylation of estrogen receptor-α .…”

“…51 Caffeine exerted a synergistic anticancer effect with cisplatin in hepatocellular carcinoma cells by inhibiting DNA repair resulting from the decreased monoubiquitination of the FANCD2 protein. 52 Estrogen sensitizes prostate cancer cells LNCaP to cisplatin possibly by increasing the expression of HMG1 by methylation of estrogen receptor-α. 53 PARP inhibitors have also been reported to enhance the anticancer activity of platinum drugs by influencing the repair of DNA damage.…”

In silico Characterization of Rad51a Interactions with Cancer-Related Proteins

“…Patients with a disrupted structure of FANCD2, mainly carriers of Fanconi anemia, have higher risk of cancer development [64,65]. The most frequent cancer types related to FANCD2 are ovarian [66], hepatic [67], lung [68], breast cancer [69] and leukemia [70]. FANCD2 co-localizes with RAD51a following DNA damage is an indication that FANCD2 and RAD51a share roles in DNA repair through physical interactions [16,17,71].…”

Caffeine Enhances the Toxicity of Platinum-Based Drugs at the Molecular Level Even Outside of the Intracellular Environment: A Single-Molecule Force Spectroscopy Study

“…For example, it was shown that caffeine increases the antiproliferative activity and apoptosis caused by cisplatin in cultured cells. 36,37 Thus, the alkaloid decreases the cell viability when combined with cisplatin. 36,37 None of these effects were usually found when caffeine was used alone in cell culture assays, showing that they are really a result of the combination with cisplatin.…”

“…36,37 Thus, the alkaloid decreases the cell viability when combined with cisplatin. 36,37 None of these effects were usually found when caffeine was used alone in cell culture assays, showing that they are really a result of the combination with cisplatin. 37 Nevertheless, this opened up questions related to these findings concerning the real role of the cellular machinery in such a process and the physical chemistry of the interactions involved.…”