Jiachun Lu

The fragile-site associated tumor suppressor (FATS, formerly known as C10orf90), a regulator of p53-p21 pathway has been involved in the onset of breast cancer. Recent data support the idea that the crosstalk between FATS and p53 may be of physiological importance for reproduction during evolution. The aim of the current study was to test the hypothesis that FATS genetic polymorphism can influence the risk of breast cancer. We conducted population-based studies in two independent cohorts comprising 1 532 cases and 1 573 controls in Tianjin of North China, and 804 cases and 835 controls in Guangzhou of South China, coupled with functional validation methods, to investigate the role of FATS genetic variant in breast cancer risk. We identified a functional variant rs11245007 (905C > T, 262D/N) in fragile-site gene FATS that modulates p53 activation. FATS-262 N exhibited stronger E3 activity to polyubiquitinate p53 than did FATS-262D, leading to the stronger transcriptional activity of p53 and more pronounced stabilization of p53 protein and its activation in response to DNA damage. Case–control studies found that CT or TT genotype was significantly associated with a protective effect on breast cancer risk in women with parity ≥ 3, which was not affected by family history. Our findings suggest the role of FATS-p53 signaling cascade in suppressing pregnancy-related carcinogenesis and potential application of FATS genotyping in breast cancer prevention.

Lung inflammation and epithelial to mesenchymal transition (EMT) are two pathogenic features for the two contextual diseases: chronic obstructive pulmonary disease (COPD) and lung cancer. VEGFR1 (or FLT1) plays a certain role in promoting tumour growth, inflammation and EMT. To simultaneously test the association between the single nucleotide polymorphisms (SNPs) in VEGFR1 and risk of COPD and lung cancer would reveal genetic mechanisms shared by these two diseases and joint aetiology. We conducted a two-population hospital-based case–control study. Three potential functional SNPs (rs664393, rs7326277 and rs9554314) were genotyped in southern Chinese and validated in eastern Chinese to explore their associations with COPD risk in 1511 COPD patients and 1677 normal lung function controls, and with lung cancer risk in 1559 lung cancer cases and 1679 cancer-free controls. We also detected the function of the promising SNP. Individuals carrying the rs7326277C (CT+CC) variant genotypes of VEGFR1 had a significant decrease in risk of both COPD (OR = 0.78; 95% CI = 0.68–0.90) and lung cancer (OR = 0.79; 95% CI = 0.64–0.98), compared with those carrying the rs7326277TT genotype. Functional assays further showed that the rs7326277C genotypes had lower transcriptional activity and caused decreased VEGFR expression, compared with the rs7326277TT genotype. However, no significant association was observed for the other two SNPs (rs664393 and rs9554314) and either COPD or lung cancer risk. Our data suggested that the rs7326277C variant of VEGFR1 could reduce both COPD and lung cancer risk by lowering VEGFR1 mRNA expression; the SNP might be a common susceptible locus for both COPD and lung cancer.

Protein phosphatase-2A (PP2A) is one of the major cellular serine-threonine phosphatases and functions as a tumor suppressor that negatively regulates the activity of some oncogenic kinases. Recent studies have reported that PP2A expression was suppressed during lung carcinogenesis, we there hypothesized that the single nucleotide polymorphisms (SNPs) in PP2A subunit genes may affect PP2A function and thus contribute to lung cancer susceptibility. In a two-stage case-control study with a total of 1559 lung cancer patients and 1679 controls, we genotyped eight putative functional SNPs and one identified functional SNP (i.e., rs11453459) in seven major PP2A subunits (i.e., PPP2R1A, PPP2R1B, PPP2CA, PPP2R2A, PPP2R2B, PPP2R5C, PPP2R5E) in southern and eastern Chinese. We found that rs11453459G (-G/GG) variant genotypes of PPP2R1A and the rs1255722AA variant genotype of PPP2R5E conferred increased risks of lung cancer (rs11453459, -G/GG vs. –: OR = 1.31, 95% CI = 1.13–1.51; rs1255722, AA vs. AG/GG: OR = 1.27, 95% CI = 1.07–1.51). After combined the two variants, the number of the adverse genotypes was positively associated with lung cancer risk in a dose-response manner (P_trend = 5.63×10⁻⁶). Further functional assay showed that lung cancer tissues carrying rs1255722AA variant genotype had a significantly lower mRNA level of PPP2R5E compared with tissues carrying GG/GA genotypes. However, such effect was not observed for the other SNPs and other combinations. Our findings suggested that the two functional variants in PPP2R1A and PPP2R5E and their combination are associated with lung cancer risk in Chinese, which may be valuable biomarkers to predict risk of lung cancer.

Mitogen-activated protein kinase-activated protein kinase 2 (MAPKAPK2) is recognized as oncogenic and simulative role on tumorigenesis by virtue of abnormal expression in cancer including nasopharyngeal carcinoma (NPC). We hypothesized that the copy number variation (CNV)-30450, which duplicates the MAPKAPK2 promoter, may affect MAPKAPK2 expression and be associated with NPC risk. In two independent case–control panels of southern and eastern Chinese with a total of 1590 NPC patients and 1979 cancer-free controls, we investigated the association between CNV-30450 and NPC risk by genotyping the CNV-30450 with the TaqMan assay, and tested its biological effect. Consistent findings were observed in the two populations, that the increased copy number of CNV-30450 was associated with increased risk of NPC (3/4-copy versus 2-copy: odds ratio = 1.28, 95% confidence interval = 1.10–1.49), in which lies a biological mechanism that the adverse genotypes enhanced the promoter activity of MAPKAPK2 and elevated MAPKAPK2 expression. Moreover, the CNV-30450 adverse genotypes significantly interacted with Epstein–Barr virus (EBV) infection on increasing NPC risk (P = 0.035), and the genotype–phenotype correlation was only significant in EBV-positive cases (P = 0.037) but not in EBV-negative ones (P = 0.366). These data suggest that the functional CNV-30450 in the MAPKAPK2 promoter elevates the NPC risk with a modulation by EBV infection, which may be an indicator of susceptibility to NPC.

Mitogen/extracellular signal-regulated kinase-5 (MEK5)/extracellular signal-regulated protein kinase-5 (ERK5) pathway plays a pro-oncogenic role in tumourigenesis by anticell apoptosis, promoting cell proliferation and differentiation in response to extracellular stimuli. As overexpressed MEK5/ERK5 is involved in the development of lung cancer, we hypothesised that the single nucleotide polymorphisms (SNPs) in MEK5 and ERK5 genes may influence gene expression and thus be associated with lung cancer risk. Five putative functional polymorphisms (rs3743353T>C, rs7172582C>T and rs2278076A>G of MEK5 and rs3866958G>T and rs2233083C>T of ERK5) were genotyped in two independent case–control studies with a total of 1559 lung cancer patients and 1679 controls in southern and eastern Chinese population. We found the rs3866958G>T of ERK5 was significantly associated with lung cancer risk, while other SNPs were not. Compared with the rs3866958TG/TT genotypes, the GG genotype conferred an increased risk of lung cancer (odds ratio = 1.30, 95% confidence interval = 1.12–1.51, P = 5.0×10⁻⁴), and this effect was more pronounced in smokers, accompanying with a significant interaction with smoking (P_interaction = 0.013). The GG genotype also had significant higher mRNA levels of ERK5 in lung cancer tissues than TG/TT genotypes (P = 1.0×10⁻⁴); the luciferase reporter with the G allele showed significant higher transcription activities than the T allele, especially after the treatment with tobacco extract in vitro. Our data indicated that the functional polymorphism rs3866958G>T in ERK5 was associated with an increased lung cancer risk in smokers by virtue of the positive interaction with smoking on promoting the ERK5 expression, which might be a valuable indicator for predicting lung cancer risk in smokers.

CD133 is a pivotal marker of cancer stem cells (CSCs), which is involved in tumorigenesis and cancer progression. Recent studies have identified CD133 to be a prognostic factor for cancer rested with its expression and genetic variants. Here, we hypothesized that the single nuclear polymorphisms (SNPs) in CD133 may be associated with lung cancer risk and prognosis. Based on three independent case–control analyses with a total of 2332 lung cancer cases and 2457 controls, the gene-based association analysis with 13 polymorphisms of CD133 suggested that CD133 is a susceptible gene for lung cancer ( P = 0.043) and that the SNP rs2240688A>C in the 3′-untranslated region of CD133 is the most significant associated SNP with the risk of lung cancer ( P = 0.020); further analysis showed that the rs2240688C variant genotypes (CA+CC) harbored a decreased risk of lung cancer (odds ratio = 0.80; 95% confidence interval (CI) = 0.72–0.90) and conferred a favorable survival for lung cancer patients (median survival time: 15 months) compared with AA genotype (median survival time: 11 months, log-rank test: P = 3.31 × 10 ^–6 ; Cox model: hazards ratio = 0.81, 95% CI = 0.70–0.94). Functional assays revealed that the rs2240688A to rs2240688C transition gained a new binding of the microRNA hsa-miR-135a/b and decreased the CD133 expression. Our data suggest that the functional polymorphism rs2240688A>C in CD133 is associated with lung cancer risk and survival. This SNP may be a functional biomarker to predict risk and prognosis of lung cancer.

WW domain-containing oxidoreductase (WWOX) is a tumor suppressor that has been reported to lose function due to genetic alterations in several cancers. WWOX maps to the common chromosomal fragile site FRA16D and several copy number variations (CNVs) were found within this gene. In this study, we investigated the association between the CNVs of WWOX and lung cancer risk in four independent case–control studies, which are on 2942 lung cancer cases and 3074 cancer-free controls of southern, eastern and northern Chinese. A common CNV-67048 was genotyped by the Taqman real-time PCR, and its biological effect was accessed with protein expression and sequencing assays. We found that in comparison with the common 2-copy genotype, the carriers of loss variant genotypes (1-copy or 0-copy) had a significantly increased risk of lung cancer (adjusted OR = 1.39, 95% CI = 1.24–1.55, P = 9.01×10⁻⁹) in a dose–response manner (P_trend = 1.12 × 10⁻¹⁰), and the WWOX protein expressions in lung cancer tissues were significantly lower (P = 0.036), accompanying a higher rate of exons absence (P = 0.021) in subjects with loss genotypes of CNV-67048. Our data suggest that the loss genotypes of CNV-67048 in WWOX predispose their carriers to lung cancer; this might be related with altered WWOX gene expression and exons absence in them.

Lung inflammation is the major pathogenetic feature for both chronic obstructive pulmonary disease (COPD) and lung cancer. The nuclear factor-kappa B (NFκB) and its inhibitor (IκB) play crucial roles in inflammatory. Here, we tested the hypothesis that single nucleotide polymorphisms (SNPs) in NFκB/IκB confer consistent risks for COPD and lung cancer. Four putative functional SNPs (NFκB1: −94del>insATTG; NFκB2: −2966G>A; IκBα: −826C>T, 2758G>A) were analyzed in southern and validated in eastern Chineses to test their associations with COPD risk in 1,511 COPD patients and 1,677 normal lung function controls, as well as lung cancer risk in 1,559 lung cancer cases and 1,679 cancer-free controls. We found that the −94ins ATTG variants (ins/del + ins/ins) in NFκB1 conferred an increased risk of COPD (OR 1.27, 95 % CI 1.06–1.52) and promoted COPD progression by accelerating annual FEV1 decline (P = 0.015). The 2758AA variant in IκBα had an increased risk of lung cancer (OR 1.53, 95 % CI 1.30–1.80) by decreasing IκBα expression due to the modulation of microRNA hsa-miR-449a but not hsa-miR-34b. Furthermore, both adverse genotypes exerted effect on increasing lung cancer risk in individuals with pre-existing COPD, while the −94del>insATTG did not in those without pre-existing COPD. However, no significant association with COPD or lung cancer was observed for −2966G>A and −826C>T. Our data suggested a common susceptible mechanism of inflammation in lung induced by genetic variants in NFκB1 (−94del>ins ATTG) or IκBα (2758G>A) to predict risk of COPD or lung cancer.

Essential meiotic endonuclease 1 homolog 1 (EME1) is a key DNA repair protein that participates in the recognition and repair of DNA double-strand breaks. Deficiency of the EME1 gene can lead to spontaneous genomic instability and thus contribute to tumorgenesis. We hypothesized that the exon variants of EME1 confer genetic susceptibility to breast cancer. In a case-control study of 748 breast cancer patients and 778 normal controls, we analyzed the association between two exon variants of EME1 (i.e.,Ile350Thr: rs12450550T > C and Glu69Asp: rs3760413T > G) and breast cancer risk. We found that compared to the common Ile/Ile genotype, the Thr variant genotypes (Thr/Ile + Thr/Thr) conferred a 1.47-fold increased risk of breast cancer (OR=1.47, 95% CI=1.13-1.92). The variant Ile350Thr was also associated with early onset of breast cancer (r = -0.116, P = 0.002). The mean age of onset was 44.4 years for Thr/Thr genotype carriers and 46.5 years for Thr/Ile genotype carriers, which was significantly lower than that (49.4 years) for Ile/Ile genotype carriers (P = 0.006). Moreover, no significant association was observed between the Glu69Asp variant and breast cancer risk. Our findings suggest that the EME1 variant Ile350Thr contributes to an increased risk and early onset of breast cancer.

Recently, several genome-wide association studies (GWAS) have identified many susceptible single nucleotide polymorphisms (SNPs) for chronic obstructive pulmonary disease (COPD) and lung cancer which are two closely related diseases. Among those SNPs, some of them are shared by both the diseases, reflecting there is possible genetic similarity between the diseases. Here we tested the hypothesis that whether those shared SNPs are common predictor for risks or prognosis of COPD and lung cancer. Two SNPs (rs6495309 and rs1051730) located in nicotinic acetylcholine receptor alpha 3 (CHRNA3) gene were genotyped in 1511 patients with COPD, 1559 lung cancer cases and 1677 controls in southern and eastern Chinese populations. We found that the rs6495309CC and rs6495309CT/CC variant genotypes were associated with increased risks of COPD (OR = 1.32, 95% C.I. = 1.14–1.54) and lung cancer (OR = 1.57; 95% CI = 1.31–1.87), respectively. The rs6495309CC genotype contributed to more rapid decline of annual Forced expiratory volume in one second (FEV1) in both COPD cases and controls (PA. The data show a statistical association and suggest biological plausibility that the rs6495309T>C polymorphism contributed to increased risks and poor prognosis of both COPD and lung cancer.