The functional IGFBP7 promoter -418G>A polymorphism and risk of head and neck cancer

Genetic Associations With an Amyotrophic Lateral Sclerosis Reversal Phenotype

BACKGROUND AND OBJECTIVES

The term "ALS Reversal" describes patients who initially meet diagnostic criteria for amyotrophic lateral sclerosis (ALS) or had clinical features most consistent with progressive muscular atrophy (PMA) but subsequently demonstrated substantial and sustained clinical improvement. The objective of this genome-wide association study (GWAS) was to identify correlates of this unusual clinical phenotype.

METHODS

Participants were recruited from a previously created database of individuals with the ALS Reversal phenotype. Whole-genome sequencing (WGS) data were compared with ethnicity-matched patients with typically progressive ALS enrolled through the CReATe Consortium's Phenotype-Genotype-Biomarker (PGB) study. These results were replicated using an independent ethnically matched WGS data set from Target ALS. Significant results were further explored with available databases of genetic regulatory markers and expression quantitative trait loci (eQTL) analysis.

RESULTS

WGS from 22 participants with documented ALS Reversals was compared with the PGB primary cohort (n = 103) and the Target ALS validation cohort (n = 140). Two genetic loci met predefined criteria for statistical significance (two-sided permutation p ≤ 0.01) and remained plausible after fine-mapping. The lead single nucleotide variant (SNV) from the first locus was rs4242007 (primary cohort GWAS OR = 12.0, 95% CI 4.1 to 34.6), which is in an IGFBP7 intron and is in near-perfect linkage disequilibrium with a SNV in the IGFBP7 promoter region. Both SNVs are associated with decreased frontal cortex IGFBP7 expression in eQTL data sets. Notably, 3 Reversals, but none of the typically progressive individuals (n = 243), were homozygous for rs4242007. The importance of the second locus, located near GRIP1, is uncertain given the absence of an associated effect on nearby gene transcription.

DISCUSSION

We found a significant association between the Reversal phenotype and an IGFBP7 noncoding SNV that is associated with IGFBP7 expression. This is biologically relevant as IGFBP7 is a reported inhibitor of the insulin growth factor-1 (IGF-1) receptor that activates the possibly neuroprotective IGF-1 signaling pathway. This finding is limited by small sample size but suggests that there may be merit in further exploration of IGF-1 pathway signaling as a therapeutic mechanism for ALS.

TRIAL REGISTRATION INFORMATION

This study was registered with ClinicalTrials.gov (NCT03464903) on March 14, 2018. The first participant was enrolled on June 22, 2018.

Placenta and appetite genes GDF15 and IGFBP7 are associated with hyperemesis gravidarum

Hyperemesis gravidarum (HG), severe nausea and vomiting of pregnancy, occurs in 0.3-2% of pregnancies and is associated with maternal and fetal morbidity. The cause of HG remains unknown, but familial aggregation and results of twin studies suggest that understanding the genetic contribution is essential for comprehending the disease etiology. Here, we conduct a genome-wide association study (GWAS) for binary (HG) and ordinal (severity of nausea and vomiting) phenotypes of pregnancy complications. Two loci, chr19p13.11 and chr4q12, are genome-wide significant (p < 5 × 10-8) in both association scans and are replicated in an independent cohort. The genes implicated at these two loci are GDF15 and IGFBP7 respectively, both known to be involved in placentation, appetite, and cachexia. While proving the casual roles of GDF15 and IGFBP7 in nausea and vomiting of pregnancy requires further study, this GWAS provides insights into the genetic risk factors contributing to the disease.

IGFBP7 functions as a potential lymphangiogenesis inducer in non-small cell lung carcinoma

Lymphangiogenesis is not only involved in the processes of embryonic development, tissue repair and chronic inflammation, but also in tumor lymphatic metastasis. Metastatic tumor cells spreading through lymphatic vessels occur in non-small cell lung carcinoma (NSCLC), with regional lymph node metastasis often being the most important prognostic factor for carcinoma patients. Recent research has identified a range of lymphangiogenic growth factors that could conceivably play a great role in promoting tumor lymphangiogenesis and lymphatic metastasis. The most extensively accepted signaling pathways promoting lymphangiogenesis in tumors include the secreted lymphangiogenic proteins: vascular endothelial growth factor-C (VEGF-C) and VEGF-D, and their cognate receptor on lymphatic endothelium VEGF receptor-3 (VEGFR-3). Targeting VEGF pathway strategy sometimes failed to decrease tumor metastasis in vivo experiments and clinical trials. It is unclear whether the tumor cells induced the lymphangiogenesis process, while VEGF pathway could not completely illustrate the mechanism of tumor cell lymphatic metastasis. To explore the novel tumor lymphangiogenesis targets, we screened 181 candidate genes between high lymphatic vascular density (LVD) and low LVD in lung adenocarcinomas using Human Genome U133 Plus 2.0 Microarray. Insulin-like growth factor binding protein 7 (IGFBP7) was proven to be associated with metastatic clinicopathological features and high LVD. Furthermore, by assessing the capability of lymphatic endothelial cell forming lymphatic vessel-like structures in vitro, it appears to enhance lymphangiogenesis.

Serum IGFBP7 levels associate with insulin resistance and the risk of metabolic syndrome in a Chinese population

Metabolic syndrome (MetS), one of the major public health concerns, is regarded as the “common soil” of incidence of common chronic diseases and may increase the risk of type 2 diabetes. The predominant underlying mechanism of MetS is insulin resistance (IR). Additionally, previous studies have indicated that IGFBP7 has high affinity of binding with insulin and might induce IR. The objective of this study was to firstly evaluate the associations of serum IGFBP7 levels with IR and MetS with a relatively large sample and population based design. In a population based MetS case-control study, HOMA-IR was used to evaluate the insulin sensitivity and serum IGFBP7 levels were determined with chemiluminescence–linked immunoassay. As a result, the subjects of MetS and IR had higher serum levels of IGFBP7 than control healthy subjects. High serum IGFBP7 levels increased the risk of MetS and IR. Serum IGFBP7 levels were also found to be significantly correlated with metabolic-associated parameters of Waist-to-hip ratio (WHR), HDL and LDL. These findings suggest that serum IGFBP7 levels are associated with IR and MetS, providing new insight into the mechanism of IR and Mets. IGFBP7 may be a potential interventional target for IR and Mets.

Insulin-like growth factor binding protein-related protein 1 and cancer

Insulin-like growth factor binding protein-related protein 1 (IGFBP-rP1) belongs to the IGFBP family whose members have a conserved structural homology. It has a low affinity for IGFs and a high affinity for insulin, suggesting that IGFBP-rP1 may have a biological function distinct from other members of the family. IGFBP-rP1 is ubiquitously expressed in normal human tissues and has diverse biological functions, regulating cell proliferation, apoptosis and senescence; it may also have a key role in vascular biology. Increasing evidence suggests that IGFBP-rP1 acts as a tumor suppressor. It elicits its biological effects by both insulin/IGF-dependent and -independent mechanisms. This paper provides a brief overview of the structure and regulation of IGFBP-rP1 and its various biological functions in cancer, as well as the underlying molecular mechanisms.

Risk genes in head and neck cancer: a systematic review and meta-analysis of last 5 years

The aim of this work was to identify risk genes related to the development and progression of squamous cell carcinoma head and neck (SCCHN) and do a meta-analysis of available estimates. Eligible gene/polymorphism studies were identified by electronic searches. Individual participant data of 8540 patients with HNC and 9844 controls from 19 genetic studies were analyzed, yielding adjusted (tobacco, gender, age and alcohol) odds ratios (OR) and 95% confidence intervals (CIs) comparing cases with controls. A meta-analysis was done on the studies that applied fixed and random models. People have an increase of polymorphism expression related to inflammation (NFKB1-294-ATTG, TNFα308-A2A2/A2A1, and TNFβ252- B2B2/B2B1) or carcinogenic metabolism (GSTM1 null, and CYP1A1 m1/m1), representative of malignancy development. Furthermore, the increased expression of genes associated with the stabilization and repair of the cellular (OGG1-Asp267Asn, Ser279Gly Ile253Phe, 1578A>T, 1582C>T Ala399Glu (1542C>A) 1582insG 1543_1544delCT), and genes associated with the regulation of proliferation, apoptosis or tumor survival (miRNA499-CT/CC, CRYABC802G-CG/GG) are considered as risk factors. In this scheme, only the polymorphisms of ADH7A92G-GG and DEC1606-T/C genes are protective against malignancy transformation. The TP53, GSTM1 and CYPA1genes have been evaluated in more than one study and analyzed for homogeneity in each genotype. The meta-analysis showed no significant association between different allelic variants of Arg72Pro rs1042522 and SCCHN risk. In a model of tumorigenesis, an increased risk of SCCHN is associated with DNA repair and DNA stabilization genes. In addition, the polymorphisms involved in inflammation and carcinogenic metabolism processes represent an increased risk of SCCHN.

Functional single nucleotide polymorphisms of the RASSF3 gene and susceptibility to squamous cell carcinoma of the head and neck

BACKGROUND

RASSF3 suppresses tumour formation through uncertain mechanisms, but it is an important gene of p53-dependent apoptosis. RASSF3 depletion impairs DNA repair after DNA damage, leading to polyploidy. The authors hypothesised that potential functional single-nucleotide polymorphisms (SNPs) of RASSF3 are associated with risk of squamous cell carcinoma of the head and neck (SCCHN).

METHODS

The authors used a functional SNP approach to evaluate the associations between common (minor allele frequency⩾0.05), putative functional variants in RASSF3 and risk of SCCHN. Four selected such functional SNPs (rs6581580 T>G, rs7313765 G>A, rs12311754 G>C and rs1147098 T>C) in RASSF3 were identified and genotyped in 1087 patients and 1090 cancer-free controls in a non-Hispanic white population.

RESULTS

The authors found that two SNPs were significantly associated with SCCHN risk. Carriers of the variant rs6581580G and rs7313765A alleles were at a reduced SCCHN risk, compared with the corresponding common homozygotes [adjusted odds ratio (OR)=0.75 and 0.73 and 95% confidence interval (CI)=0.62-0.91 and 0.60-0.88, respectively, for dominant models; and Ptrend=0.012 and 0.041, respectively, for additive models], particularly for non-oropharyngeal tumours (adjusted OR=0.68 and 0.60 and 95% CI=0.53-0.86 and 0.47-0.77, respectively, for dominant models). In the genotype-phenotype correlation analysis of peripheral blood mononuclear cells from 102 cancer-free controls, the rs6581580 GG genotype was associated with significantly increased expression levels of RASSF3 mRNA (P=0.038), compared with the TT genotype. Additional functional experiments further showed that variant G allele of rs6581580 had a significantly stronger binding affinity to the nuclear protein extracts than the T allele.

CONCLUSION

Taken together, these findings indicate that the RASSF3 promoter rs6581580 T>G SNP is potentially functional, modulating susceptibility to SCCHN among non-Hispanic whites. Larger replication studies are needed to confirm our findings.

Polymorphisms of XPG/ERCC5 and risk of squamous cell carcinoma of the head and neck

OBJECTIVES

Xeroderma pigmentosum group G (XPG) protein is essential for the nucleotide excision repair system, and genetic variations in XPG/ERCC5 that affect DNA repair capacity may contribute to the risk of tobacco-induced cancers, including squamous cell carcinoma of the head and neck (SCCHN). We investigated the association between XPG/ERCC5 polymorphisms and risk of SCCHN.

METHODS

We genotyped 12 tagging and potentially functional single nucleotide polymorphisms (SNPs) of XPG/ERCC5 in a case-control study of 1059 non-Hispanic white patients with SCCHN and 1066 cancer-free age- and sex-matched controls, and evaluated their associations with the risk of SCCHN.

RESULTS

Multivariate logistic regression showed that only an intronic tagging SNP (rs4150351A/C) of XPG/ERCC5 was associated with a decreased risk of SCCHN (adjusted odds ratio=0.76, 95% confidence interval=0.62-0.92 for AC vs. AA; adjusted odds ratio=0.81, 95% confidence interval=0.67-0.98 for AC/CC vs. AA), but this association was nonsignificant after corrections by the permutation test (empirical P=0.105). In the genotype-phenotype correlation analysis using peripheral lymphocytes from 44 patients with SCCHN, we found that rs4150351 AC/CC was associated with a statistically significant increase in the XPG/ERCC5 mRNA expression.

CONCLUSION

These findings suggest that genetic variation in XPG/ERCC5 may not affect the risk of SCCHN, although rs4150351 C variant genotypes were associated with an increased expression of XPG/ERCC5 mRNA and nonsignificantly decreased risk of SCCHN. Larger population-based and additional functional studies are warranted to validate our findings.

Combined effects of E2F1 and E2F2 polymorphisms on risk and early onset of squamous cell carcinoma of the head and neck

Deregulated expression of most members of the E2F family has been detected in many human cancers. We examined the association of common single nucleotide polymorphisms (SNPs) of E2F transcription factors 1 and 2 (E2F1 and E2F2) with risk of squamous cell carcinoma of the head and neck (SCCHN) in 1,096 SCCHN patients and 1,090 cancer-free controls. We genotyped 10 selected SNPs in E2F1 and E2F2, including those at the near 5'-untranslated region (UTR), microRNA (miRNA)-binding sites at the near 3'-UTR and tagSNPs according to bioinformatics analysis. Although none of the selected SNPs alone was significantly associated with risk of SCCHN, there was a statistically significantly increased risk of SCCHN associated with the combined risk genotypes (i.e., rs3213182 AA, rs3213183 GG, rs3213180 GG, rs321318121 GG, rs2742976 GT+TT, rs6667575 GA+AA, rs3218203 CC, rs3218148 AA, rs3218211 CC, and rs3218123 GT+TT). Compared with those with 0-4 risk genotypes, an increased risk was observed for those who carried 5-8 risk genotypes (adjusted OR = 1.04; 95% CI = 0.86-1.26) and 9-10 risk genotypes (adjusted OR = 1.62; 95% CI = 1.14-2.30) in a dose-response manner (P = 0.045). Furthermore, the joint effect was more pronounced among patients with oropharyngeal cancer, younger adults (≤57 yr old), men, non-smokers, non-drinkers, and individuals with family history of cancer in first-degree relatives. Additionally, we also observed that those with 5-10 risk genotypes had an earlier SCCHN onset than those with 0-4 risk genotypes, particularly for non-smokers and/or non-drinkers. We concluded that E2F1 and E2F2 genetic variants may jointly play important roles in head and neck carcinogenesis.

Association between novel PLCE1 variants identified in published esophageal cancer genome-wide association studies and risk of squamous cell carcinoma of the head and neck

BACKGROUND

Phospholipase C epsilon 1 (PLCE1) (an effector of Ras) belonging to the phospholipase family plays crucial roles in carcinogenesis and progression of several cancers, including squamous cell carcinoma of the head and neck (SCCHN). A single nucleotide polymorphism (SNP, rs2274223) in PLCE1 has been identified as a novel susceptibility locus in genome-wide association studies (GWAS) of esophageal squamous cell carcinoma (ESCC) and gastric cardia adenocarcinoma (GCA) that share similar risk factors with SCCHN. Therefore, we investigated the association between potentially functional SNPs in PLCE1 and susceptibility to SCCHN.

METHODS

We genotyped three potentially functional SNPs (rs2274223A/G, rs3203713A/G and rs11599672T/G) of PLCE1 in 1,098 SCCHN patients and 1,090 controls matched by age and sex in a non-Hispanic white population.

RESULTS

Although none of three SNPs was alone significantly associated with overall risk of SCCHN, their combined effects of risk alleles (rs2274223G, rs3203713G and rs11599672G) were found to be associated with risk of SCCHN in a locus-dose effect manner (Ptrend=0.046), particularly for non-oropharyngeal tumors (Ptrend=0.017); specifically, rs2274223 was associated with a significantly increased risk (AG vs. AA: adjusted OR=1.29, 95% CI=1.01-1.64; AG/GG vs. AA: adjusted OR=1.30, 95% CI=1.03-1.64), while rs11599672 was associated with a significantly decreased risk (GG vs. TT: adjusted OR=0.54, 95% CI=0.34-0.86; TG/GG vs. TT: adjusted OR=0.76, 95% CI=0.61-0.95).

CONCLUSIONS

Our findings suggest that PLCE1 variants may have an effect on risk of SCCHN associated with tobacco and alcohol exposure, particularly for those tumors arising at non-oropharyngeal sites. These findings, although need to be validated by larger studies, are consistent with those in esophageal and gastric cancers.