Shuangshuang Wu

Down-regulation of ALKBH2 increases cisplatin sensitivity in H1299 lung cancer cells.

Aim:To elucidate the combined effect of alkylated DNA repair protein alkB homolog 2 (ALKBH2)-targeting gene therapy and cisplatin (cDDP) chemotherapy on the non-small cell lung cancer (NSCLC) H1299 cell line.Methods:ALKBH2 was down-regulated in H1299 cells by lentivirus-mediated RNA interference (RNAi). Changes in ALKBH2 expression were determined using real-time RT-PCR and Western blotting. Cell viability was evaluated using MTT assay. DNA synthesis in proliferating cells was determined using BrdU incorporation assay. Cell apoptosis was determined using flow cytometry.Results:Lentivirus-mediated ALKBH2 silencing alone did not induce apoptosis or attenuate the growth potential of H1299 cells within five days post-infection. Combined treatment modalities with lentivirus-mediated ALKBH2 down-regulation and cDDP (333 μmol/L) were significantly more potent in inhibiting cell growth and inducing apoptosis than mono-chemotherapy.Conclusion:Combined treatment modalities of ALKBH2 knockdown and cDDP chemotherapy have the potential to improve the efficacy in the treatment of NSCLC.

A functional variant in miR-155 regulation region contributes to lung cancer risk and survival

Emerging evidence suggested that upregulation of miR-155 could serve as a promising marker for the diagnosis and prognosis of non-small cell lung cancer (NSCLC). In the present study, we genotyped rs767649 (A > T) located in miR-155 regulation region in 1341 cases and 1982 controls, and analyzed the associations of rs767649 with NSCLC risk and survival. Consequently, rs767649 exhibited the significant associations with the risk (adjusted OR = 1.12, 95% CI = 1.01–1.24, P = 0.031) and prognosis of NSCLC (adjusted HR = 1.17, 95% CI = 1.03–1.32, P = 0.014). Meanwhile, rs767649 specifically interacted with radio-chemotherapy (Pint = 0.013), and patients with both the rs767649-TT genotype and radio-chemotherapy had the highest hazard ratio (adjusted HR = 1.65, 95% CI = 1.26–2.16, P < 0.001). Furthermore, using functional assays and The Cancer Genome Atlas (TCGA) Lung Adenocarcinoma (LUAD) dataset, we found that rs767649 variant allele could increase the transcriptional activity of miR-155, which in turn facilitated tumor growth and metastasis by inhibiting HBP1, TJP1, SMAD5 and PRKAR1A expression. Our findings suggested that rs767649 A > T might contribute to the increased risk and poor prognosis of NSCLC, highlighting the importance of rs767649 in the prevention and therapy of NSCLC.

Hepatitis B virus subgenotype C2- and B2-associated mutation patterns may be responsible for liver cirrhosis and hepatocellular carcinoma, respectively

The objective of this study was to examine hepatitis B virus (HBV) subgenotypes and mutations in enhancer II, basal core promoter, and precore regions of HBV in relation to risks of liver cirrhosis (LC) and hepatocellular carcinoma (HCC) in Southeast China. A case-control study was performed, including chronic hepatitis B (CHB; n=125), LC (n=120), and HCC (n=136). HBV was genotyped by multiplex polymerase chain reaction and subgenotyped by restriction fragment length polymorphism. HBV mutations were measured by DNA sequencing. HBV genotype C (68.2%) predominated and genotype B (30.2%) was the second most common. Of these, C2 (67.5%) was the most prevalent subgenotype, and B2 (30.2%) ranked second. Thirteen mutations with a frequency >5% were detected. Seven mutation patterns (C1653T, G1719T, G1730C, T1753C, A1762T, G1764A, and G1799C) were associated with C2, and four patterns (C1810T, A1846T, G1862T, and G1896A) were associated with B2. Six patterns (C1653T, G1730C, T1753C, A1762T, G1764A, and G1799C) were obviously associated with LC, and 10 patterns (C1653T, G1730C, T1753C, A1762T, G1764A, G1799C, C1810T, A1846T, G1862T, and G1896A) were significantly associated with HCC compared with CHB. Four patterns (C1810T, A1846T, G1862T, and G1896A) were significantly associated with HCC compared with LC. Multivariate regression analyses showed that HBV subgenotype C2 and C2-associated mutation patterns (C1653T, T1753C, A1762T, and G1764A) were independent risk factors for LC when CHB was the control, and that B2-associated mutation patterns (C1810T, A1846T, G1862T, and G1896A) were independent risk factors for HCC when LC was the control.

Quantitative assessment of polymorphisms in H19 lncRNA and cancer risk: a meta-analysis of 13,392 cases and 18,893 controls

H19 refers to a long non-coding RNA (lncRNA) that functions as an oncogenic molecule in different cancer cells. Genetic variants of H19 may affect the activity of certain regulatory factors, which subsequently regulate the aberrant expression of H19. This feedback loop might be one of the underlying mechanisms influencing tumour susceptibility and prognosis. Although there have been several recent studies that examined possible links between polymorphisms in H19 and cancer risk, the results have been inconclusive. Thus, we performed a meta-analysis to estimate the associations between H19 polymorphisms (rs2107425, rs2839698 and rs217727) and cancer risk. Ten studies comprising 13,392 cases and 18,893 controls were included in the study. Overall, the variant T allele of rs2107425 correlated with a significantly decreased risk of developing cancer (dominant model: OR = 0.86; 95% CI = 0.76–0.98). In addition, a marginally significant association between the rs2839698 and cancer risk was observed (dominant model: OR = 1.09; 95% CI = 0.99–1.20). After stratification for ethnicity, it became apparent that Asians with the variant A allele of rs2839698 exhibited a significantly higher risk of developing cancer (dominant model: OR = 1.11; 95% CI = 1.01–1.23). Interestingly, the rs2839698 variant was also significant associated with an increased risk of cancers of the digestive system (dominant model: OR = 1.23; 95% CI = 1.08–1.41). These findings provided evidence that H19 rs2107425 may modify general cancer susceptibility, while rs2839698 may modify cancer susceptibility based on ethnicity and type. Further experimental studies to evaluate the limits of this hypothesis are warranted, and future functional studies are required to clarify the possible mechanisms.

Genetic Variations in Key MicroRNAs are Associated With the Survival of Nonsmall Cell Lung Cancer.

AbstractMicroRNAs (miRNAs) are a class of small, noncoding RNA molecules involved in carcinogenesis. It has been identified that genetic variations in miRNAs contribute to cancer risk, prognosis, and survival. In the present study, we investigated whether single nucleotide polymorphisms (SNPs) of several key miRNAs (miR-184, miR-218, and miR-124) were associated with the prognosis of nonsmall cell lung cancer (NSCLC) in a clinical cohort study including 1001 cases. Cox proportional hazards regression models were used to estimate the hazard ratios (HRs) and their 95% confidence intervals (CIs). We found that 5 SNPs were associated with NSCLC survival (rs919968, rs3775815, rs4867902, and rs6122390 in an additive model: adjusted HR = 1.15, 95% CI = 1.02–1.29; adjusted HR = 0.78, 95% CI = 0.67–0.91, adjusted HR = 1.24, 95% CI = 1.09–1.41; adjusted HR = 1.21, 95% CI = 1.07–1.36, respectively; rs298206 in a dominant model: HR = 1.25, 95% CI = 1.05–1.49). Even after the Bonferroni correction, 3 SNPs remained significant (adjusted P = 0.010, 0.010, and 0.032 for rs3775815, rs4867902, and rs6122390, respectively). Additionally, the combined analysis of these 5 SNPs showed a significant locus-dosage effect between number of unfavorable alleles (rs919968-A, rs3775815-C, rs4867902-G, rs6122390-A, and rs298206-T) and death risk of NSCLC (P for trend < 0.001). A statistically significant multiplicative interaction was found between the genotypes of rs4867902 and surgical operation status (Pint = 0.013). These findings indicated that genetic variations in miRNAs (miR-184, miR-218, and miR-124) might be prognostic markers for NSCLC patients.

The miR-608 rs4919510 polymorphism may modify cancer susceptibility based on type

Previous meta-analysis has not shown different effects of miR-608 rs4919510 polymorphism in specific cancer types and reported no significant association between rs4919510 and cancer risk among Chinese. However, more recent findings have been inconsistent. Therefore, we performed an updated meta-analysis to examine whether this polymorphism is associated with cancer risk based on ethnicity and type. A total of 18 case-control studies, comprising 12,517 cases and 15,624 controls, were included in our study. Surprisingly, in contrast with previous meta-analysis, a significant association between the rs4919510 polymorphism and cancer risk was observed in Chinese (CG vs CC: odds ratio = 1.11; 95% confidence interval = 1.04–1.19). In further stratified analyses based on cancer type, rs4919510 was significantly associated with an increased risk of papillary thyroid cancer (CG vs CC: odds ratio = 1.25; 95% confidence interval = 1.01–1.54) and exhibited borderline significant associations with increased risk of gastric cancer (GG vs CC: odds ratio = 1.27; 95% confidence interval = 1.00–1.62) and lung cancer (CG vs CC: odds ratio = 1.14; 95% confidence interval = 0.99–1.32), but a decreased risk of colorectal cancer (GG vs CC: odds ratio = 0.74; 95% confidence interval = 0.60–0.91). Moreover, the RegulomeDB database indicated that rs4919510 may affect the expression of two nearby genes (SEMA4G and MRPL43), and the Cancer Genome Atlas database revealed that the expression level of SEMA4G was significantly lower in colorectal cancer and lung cancer tissues than that in adjacent non-tumour tissues, while the expression level of SEMA4G was significantly higher in gastric cancer tissues than that in adjacent non-tumour tissues. These findings provide evidence that the miR-608 rs4919510 polymorphism may modify cancer susceptibility in a type-specific manner. Furthermore, SEMA4G may function as an oncogene or tumour suppressor to regulate tumour development in a type-specific manner. Further studies with experimental evaluations are warranted.

The rs2609255 polymorphism in the FAM13A gene is reproducibly associated with silicosis susceptibility in a Chinese population

BACKGROUND Two recent genome-wide association studies (GWASs) reported that the FAM13A gene at the 4q22 locus associated with pulmonary fibrosis (defined by rs2609255) overlapping with COPD (defined by rs6837671). We hypothesized that single-nucleotide polymorphisms (SNPs) related to lung disease (especially pulmonary fibrosis) identified in this region are also associated with the risk of silicosis. METHODS To test this hypothesis, we genotyped these two SNPs (rs2609255 and rs6837671) in a case-control study including 177 silicosis cases and 204 controls with silica dust exposure years similar to the levels for cases in a Chinese population. RESULTS We found that rs2609255 was significantly associated with increased silicosis risk (dominant model: OR = 1.71; 95% CI = 1.01-2.92; P = 0.047). Additionally, eQTL analysis based on the GTEx database indicated that the rs2609255 polymorphism may alter the expression level of FAM13A in lung tissues (P = 1.8 × 10-4). Furthermore, interaction analyses showed that rs2609255 interacts multiplicatively with years of silica dust exposure to contribute to silicosis risk (interaction P = 0.040). CONCLUSIONS These results indicate that rs2609255 may modify silicosis susceptibility in the Chinese population.

RAGE may act as a tumour suppressor to regulate lung cancer development

Although the correlation of the RAGE rs2070600 polymorphism and cancer risk has been confirmed, detailed studies with functional and experimental evaluations are lacking. In this study, we first aimed to examine whether this polymorphism is associated with cancer risk based on the latest published data, and consistent with previous meta-analyses, a significant association between the rs2070600 polymorphism and cancer risk was observed (A versus G: OR = 1.25; 95% CI = 1.12-1.40). In additional stratified analyses based on cancer type, rs2070600 was significantly associated with an increased risk of lung cancer (A versus G: OR = 1.20; 95% CI = 1.09-1.33). Moreover, TCGA database showed that the expression level of RAGE was significantly lower in lung cancer tumour tissues than in adjacent non-tumour tissues, which was validated in the GEO database. Additionally, eQTL analysis indicated that the rs2070600 polymorphism may modify the expression level of RAGE in lung squamous cell carcinoma tissues (P = 0.09). Finally, we performed functional experiments in lung cancer cells and preliminarily demonstrated that RAGE may act as a tumour suppressor in lung cancer development. These findings provide evidence that the variant A allele of rs2070600 may decrease the expression of the tumour suppressor gene RAGE, thereby increasing lung cancer risk.

Depleted aldehyde dehydrogenase 1A1 (ALDH1A1) reverses cisplatin resistance of human lung adenocarcinoma cell A549/DDP

Cisplatin is the standard first‐line chemotherapeutic agent for the treatment of non‐small cell lung cancer (NSCLC). However, resistance to chemotherapy has been a major obstacle in the management of NSCLC. Aldehyde dehydrogenase 1A1 (ALDH1A1) overexpression has been observed in a variety of cancers, including lung cancer. The purpose of this study was to investigate the effect of ALDH1A1 expression on cisplatin resistance and explore the mechanism responsible.

Per2 participates in AKT-mediated drug resistance in A549/DDP lung adenocarcinoma cells

Period2 (Per2) is a key mammalian circadian clock protein, and additionally has a tumor suppressive function. The present study aimed to investigate its role in drug resistance in A549/cisplatin (DDP) lung adenocarcinoma cells. Per2 knockdown and overexpression in A549/DDP cells were used to compare cell proliferation (by MTT assay), apoptosis (active-caspase 3 western blot) and clone forming assay. The activation of AKT/mechanistic target of rapamycin (mTOR) was investigated by a western blot assay. The Per2 expression level was decreased in A549/DDP cells compared with A549 cells. Per2 knockdown by short hairpin RNA protects A549/DDP cells from apoptosis, and promotes proliferation and migration. Per2 knockdown results in increased activation of the phosphoinositide 3-kinase (PI3K)/AKT/mTOR signaling pathway. Overexpression of Per2 in A549/DDP cells may reduce the activity of the PI3K/AKT/mTOR signaling pathway, and promote apoptosis of A549 cells. The results of the present study suggest that Per2 participates in AKT-mediated drug resistance in A549/DDP lung adenocarcinoma cells.