Effect of XPD and TP53 Gene Polymorphisms on the Risk of Platinum-Based Chemotherapy Induced Toxicity in Bangladeshi Lung Cancer Patients.

BACKGROUND: Platinum-based drugs, including cisplatin and carboplatin, are the most active and extensively used agents for treating lung cancer. Genetic polymorphisms of DNA repair gene XPD and tumor suppressor gene TP53 are connected with alterations in enzyme activity. They may help explain interindividual differences in toxicity outcomes after platinum-based chemotherapy for lung cancer. Therefore, this study aimed to investigate XPD Lys751Gln and TP53 Arg72Pro polymorphisms on the risk of platinum-based chemotherapy-induced toxicity in lung cancer patients in the Bangladeshi population. PATIENTS AND METHODS: Study subjects comprised of 180 platinum-based chemotherapy treated histologically confirmed lung cancer patients. Genetic polymorphisms of XPD were ascertained by Polymerase Chain Reaction-based Restriction Fragment Length Polymorphism (PCR-RFLP), while TP53 genotypes were analyzed using the multiplex PCR-based method. Toxicity was assessed based on the Common Terminology Criteria for Adverse Events (CTCAE v5.0). RESULTS: From the results, there was no significant association observed between grade 1-2 or grade 3-4 platinum-based chemotherapy induced toxicities like anemia and XPD codon 751 (Lys/Gln: OR=1.40, 95% CI=0.75-2.64, p>0.05; Gln/Gln: OR=1.07, 95% CI=0.45-2.52, p>0.05 and Lys/Gln+Gln/Gln: OR=1.31, 95% CI=0.73-2.38, p>0.05) or TP53 codon 72 genetic polymorphisms (Arg/Pro: OR=0.64, 95% CI=0.34-1.17, p>0.05; Pro/Pro: OR=0.46, 95% CI=0.15-1.42, p>0.05 and Arg/Pro+Pro/Pro: OR=0.62, 95% CI=0.34-1.15, p>0.05). Similar results were found between neutropenia, leukopenia, thrombocytopenia and gastrointestinal toxicities and XPD Lys751Gln or TP53 Arg72Pro genetic polymorphisms. CONCLUSION: These findings indicated that no significant association was found between either XPD codon 751 or TP53 codon 72 genetic polymorphisms and platinum-based chemotherapy-related toxicities in Bangladeshi lung cancer patients.

Influence of Morinda citrifolia (Noni) on Expression of DNA Repair Genes in Cervical Cancer Cells.

BACKGROUND: Previous studies have suggested that Morinda citrifolia (Noni) has potential to reduce cancer risk. OBJECTIVE: The purpose of this study was to investigate the effect of Noni, cisplatin, and their combination on DNA repair genes in the SiHa cervical cancer cell line. MATERIALS AND METHODS: SiHa cells were cultured and treated with 10% Noni, 10 µg/dl cisplatin or their combination for 24 hours. Post culturing, the cells were pelleted, RNA extracted, and processed for investigating DNA repair genes by real time PCR. RESULTS: The expression of nucleotide excision repair genes ERCC1, ERCC2, and ERCC4 and base excision repair gene XRCC1 was increased 4 fold, 8.9 fold, 4 fold, and 5.5 fold, respectively, on treatment with Noni as compared to untreated controls (p<0.05). In contrast, expression was found to be decreased 22 fold, 13 fold, 16 fold, and 23 fold on treatment with cisplatin (p<0.05). However, the combination of Noni and cisplatin led to an increase of 2 fold, 1.6 fold, 3 fold, 1.2 fold, respectively (p<0.05). CONCLUSIONS: Noni enhanced the expression of DNA repair genes by itself and in combination with cisplatin. However, high expression of DNA repair genes at mRNA level only signifies efficient DNA transcription of the above mentioned genes; further investigations are needed to evaluate the DNA repair protein expression.

Comparative toxicity of arsenite metabolites in wild type CHO cells and in cells deficient in excision repair cross-complementing 1 and 2.

Arsenic (As) has been shown to alter one or more DNA repair processes. Excision repair cross-complementing 1 and 2 (ERCC1 and ERCC2) have shown to be associated with arsenic-induced toxicity and carcinogenicity. In this study, we investigated cytotoxic effects of various As metabolites in relation to two nucleotide excision repair genes: ERCC1 and ERCC2. Various arsenate (pentavalent) and arsenite (trivalent) metabolites were tested in ERCC1, ERCC2 deficient and wild type cells. Our results showed that in the selected concentration range pentavalent As metabolites; iAs(V), MMA(V) and DMA(V) were not cytotoxic, unlike the trivalent As metabolites; iAs(III), MMA(III) and DMA(III). The measured LC(50) demonstrated a significant difference (p<0.01) for iAs(III) between the three cell lines, while MMA(III) and DMA(III) are more cytotoxic to all three cell lines. UV5 (ERCC2 deficient) cells also showed a lower resistance to iAs(III) in comparison to AA8 (wild type) and UV20 (ERCC2 deficient) cells. This might be explained through the generation of hydrogen peroxide (H(2)O(2)), which is generated by increase of intracellular Ca(2+) level. Generation of H(2)O(2) in UV5 cells after incubation with iAs(III) is significantly higher than AA8 and UV20 cells (p<0.01). In conclusion, absence of ERCC2 leads to a increased generation of H(2)O(2) by iAs(III) in UV5 cells, which is in contrast to AA8 and UV20 cells.