The association between COX-2 polymorphisms and hematologic toxicity in patients with advanced non-small-cell lung cancer treated with platinum-based chemotherapy

Impact of genetic factors on platinum-induced gastrointestinal toxicity

Severe gastrointestinal (GI) toxicity is a common side effect after platinum-based chemotherapy. The incidence and severity of GI toxicity vary among patients with the same chemotherapy. Genetic factors involved in platinum transport, metabolism, detoxification, DNA repair, cell cycle control, and apoptosis pathways may account for the interindividual difference in GI toxicity. The influence of gene polymorphisms in the platinum pathway on GI toxicity has been extensively analyzed. Variations in study sample size, ethnicity, design, treatment schedule, dosing, endpoint definition, and assessment of toxicity make it difficult to precisely interpret the results. Hence, we conducted a review to summarize the most recent pharmacogenomics studies of GI toxicity in platinum-based chemotherapy and identify the most promising avenues for further research.

COX-2 promotes metastasis and predicts prognosis in gastric cancer via regulating mTOR

Aim: Gastric cancer (GC) is one of the most common malignant tumors in the world. It is important to find accurate and reliable biomarkers in order to decrease whole morbidity and mortality. Results: We examined the expression of COX-2 and mTOR on GC tissue microarrays by immunohistochemistry. Multivariate COX regression analysis showed that the expression of COX-2 or mTOR was an independent factor in the prognosis of GC patients. In addition, COX-2 and mTOR have a potentially synergistic effect on predicting the prognosis of GC. Conclusion: The combined expression of COX-2 and mTOR could serve as efficient prognostic indicators and COX-2 could suppress GC metastasis via regulating mTOR.

Correlation of TET2 SNP rs2454206 with improved survival in children with acute myeloid leukemia featuring intermediate-risk cytogenetics

Single nucleotide polymorphisms (SNPs) may influence the disease course and outcome of hematologic neoplasms. SNP rs2454206 is common in the TET2 gene, which plays a role in epigenetic regulation of myelopoiesis. Few investigations examined the role of TET2 SNP rs2454206 in acute myeloid leukemia (AML) and none of those studies was performed in Chinese populations. Here, we report the prevalence and clinical relevance of TET2 SNP rs2454206 in 254 Chinese patients with childhood AML. Our data demonstrate that TET2 SNP rs2454206^AG/GG is associated with improved overall survival and event-free survival in AML patients with intermediate-risk cytogenetics features. The prognostic impact of TET2 SNP rs2454206^AG/GG was independent of other common AML risk factors, such as age, white blood cell count, and FLT3-ITD. No difference in TET2 expression levels in AML with TET2 SNP rs2454206^AA and TET2 SNP rs2454206^AG/GG was detected, indicating that TET2 SNP rs2454206 status does not affect TET2 expression in pediatric AML.

The VEGFR2, COX-2 and MMP-2 polymorphisms are associated with clinical outcome of patients with inoperable non-small cell lung cancer

Certain common inherited variations in genes involved in tumor angiogenesis, progression and metastasis may contribute to cancer therapy outcome and prognosis by altering the gene expression and protein activity. In this report, we examined the effect of functional polymorphisms in MMP-1, MMP-2, MMP-3, VEGF, VEGFR2, FGFR4 and COX-2 genes on overall (OS) and progression-free survival (PFS) of 350 Caucasian patients with inoperable non-small cell lung cancer (NSCLC). The results of multivariate analysis indicated that VEGFR2 -906C and COX-2 -1195G alleles were strongly associated with poor OS and PFS (p = 0.002 and 0.015, respectively, for OS; p = 0.009 and 0.015, respectively, for PFS), while MMP-2 -1306 T allele carriers had significantly reduced PFS (p = 0.010). Moreover, an increased risk of death and progression was significantly associated with the number of adverse alleles for VEGFR2/COX-2 (p = 0.0005 for OS and 0.0006 for PFS in >1 adverse allele carriers) and VEGFR2/COX-2/MMP-2 combinations (p = 0.0003 for OS and 0.0001 for PFS in patients with >2 adverse alleles). Finally, VEGFR2 TC/CC, COX-2 AG/GG and MMP-2 CT/TT genotypes as well as "at risk" allele combinations were identified as independent predictors of unfavorable OS and PFS in the group. In conclusion, the data suggest that selected VEGFR2, COX-2 and MMP-2 polymorphisms may be potential prognostic markers in unresectable NSCLC treated with radiotherapy with or without chemotherapy, although further validation studies are warranted to confirm our observations.

Genome-wide association study of myelosuppression in non-small-cell lung cancer patients with platinum-based chemotherapy

Platinum-induced myelosuppression severely impedes successful chemotherapy in non-small-cell lung cancer (NSCLC) patients. Hence, it is clinically important to identify the patients who are at high risk for severe toxicity to certain chemotherapy. We first carried out a genome-wide scan of 906 703 single-nucleotide polymorphisms (SNPs) to identify genetic variants associated with platinum-induced myelosuppression risk in 333 NSCLC patients with chemotherapy. Then, we replicated 24 SNPs that had P<1 × 10(-4) in another independent cohort of 876 NSCLC patients. With P<0.05 as the criterion of statistical significance, we found that rs13014982 at 2q24.3 and rs9909179 at 17p12 exhibited consistently significant associations with myelosuppression risk in both the genome-wide association studies (GWAS) scan and the replication stage (rs13014982: odds ratio (OR)=0.55, 95% confidence intervals (CIs): 0.41-0.74, P=7.29 × 10(-5) for GWAS scan and OR=0.77, 95% CI: 0.65-0.93, P=0.006 for replication stage; rs9909179: OR=0.51, 95% CI: 0.37-0.70, P=4.60 × 10(-5) for GWAS scan and OR=0.82, 95% CI: 0.68-0.99, P=0.040 for replication stage; both in additive model). In combined samples of genome-wide scan and replication samples, the minor alleles of rs13014982 and rs9909179 remained significant associations with the decreased risk of myelosuppression (rs13014982: OR=0.71, 95% CI: 0.61-0.83, P =1.36 × 10(-5); rs9909179: OR=0.76, 95% CI: 0.65-0.89, P=0.001). Rs13014982 at 2q24.3 and rs9909179 at 17p12 might be independent susceptibility markers for platinum-induced myelosuppression risk in NSCLC patients.

TGF-β Suppresses COX-2 Expression by Tristetraprolin-Mediated RNA Destabilization in A549 Human Lung Cancer Cells

PURPOSE

Overexpression of cyclooxygenase 2 (COX-2) is thought to promote survival of transformed cells. Transforming growth factor β (TGF-β) exerts anti-proliferative effects on a broad range of epithelial cells. In the current study, we investigated whether TGF-β can regulate COX-2 expression in A549 human lung adenocarcinoma cells, which are TGF-β-responsive and overexpress COX-2.

MATERIALS AND METHODS

Western blotting, Northern blotting, and mRNA stability assays were performed to demonstrate that COX-2 protein and mRNA expression were suppressed by TGF-β. We also evaluated the effects of tristetraprolin (TTP) on COX-2 mRNA using RNA interference.

RESULTS

We demonstrated that COX-2 mRNA and protein expression were both significantly suppressed by TGF-β. An actinomycin D chase experiment demonstrated that COX-2 mRNA was more rapidly degraded in the presence of TGF-β, suggesting that TGF-β-induced inhibition of COX-2 expression is achieved via decreased mRNA stability. We also found that TGF-β rapidly and transiently induced the expression of TTP, a well-known mRNA destabilizing factor, before suppression of COX-2 mRNA expression was observed. Using RNA interference, we confirmed that increased TTP levels play a pivotal role in the destabilization of COX-2 mRNA by TGF-β. Furthermore, we showed that Smad3 is essential to TTP-dependent down-regulation of COX-2 expression in response to TGF-β.

CONCLUSION

The results of this study show that TGF-β down-regulated COX-2 expression via mRNA destabilization mediated by Smad3/TTP in A549 cells.

Prognostic value of cyclooxygenase-2 gene polymorphisms in advanced non-small cell lung cancer patients treated with first-line platinum-based chemotherapy

AIM

Cyclooxygenase-2 (COX-2) plays an important role in cell apoptosis, angiogenesis and tumor invasion, and over-expression of COX-2 is associated with tumor development and occurrence. The aim of this study is to investigate the association between COX-2 polymorphisms and clinical outcomes in advanced non-small cell lung cancer (NSCLC) patients treated with first-line platinum-based chemotherapy.

METHODS

A total of 190 patients with IIIB or IV NSCLC who received platinum-based chemotherapy were recruited in this study. Four functional COX-2 polymorphisms, including rs689465, rs689466, rs3218625 and rs20417, were genotyped by PCR-based restriction fragment length polymorphism methods. Kaplan-Meier methods were used to compare survival by different genotypes. Cox proportional hazard models were used to identify independently significant variables.

RESULTS

The rs689465 AA genotype was significantly associated with longer overall survival (OS) (13.0 months vs 8.8 months, P = 0.019 for log-rank test; hazard ratio [HR] 0.624; 95% confidence internal [CI] 0.418-0.931) and progression-free survival (5.3 months vs 4.0 months, P = 0.018 for log-rank test; HR 0.627; 95% CI 0.421-0.934) compared with AG or GG genotype, especially in patients with adenocarcinoma (P = 0.002), performance status of 1 (P = 0.009) and stage IV disease (P = 0.012), and treated with gemcitabine-based chemotherapy (P = 0.012). Multivariate regression analysis showed that COX-2 rs689465 polymorphism had a significantly independent prognostic value for OS (P = 0.017, HR = 1.637, 95% CI = 1.093-2.453).

CONCLUSION

Our study suggested that rs689465 polymorphism could be a prognostic biomarker for advanced NSCLC patients treated with first-line platinum-based chemotherapy.