Association between lysyl oxidase G473A polymorphism and ovarian cancer in the Han Chinese population

The Lysyl Oxidase G473A Polymorphism Exacerbates Oral Cancer Development in Humans and Mice

Oral cancer is primarily squamous-cell carcinoma with a 5-year survival rate of approximately 50%. Lysyl oxidase (LOX) participates in collagen and elastin maturation. The propeptide of LOX is released as an 18 kDa protein (LOX-PP) in the extracellular environment by procollagen C-proteinases and has tumor-inhibitory properties. A polymorphism in the propeptide region of LOX (rs1800449, G473A) results in a single amino acid substitution of Gln for Arg. Here we investigated the frequency of rs1800449 in OSCC employing TCGA database resources and determined the kinetics and severity of precancerous oral lesion development in wildtype and corresponding knockin mice after exposure to 4-nitroquinoline oxide (4 NQO) in drinking water. Data show that the OSCC is more common in humans carrying the variant compared to the wildtype. Knockin mice are more susceptible to lesion development. The immunohistochemistry of LOX in mouse tissues and in vitro studies point to a negative feedback pathway of wildtype LOX-PP on LOX expression that is deficient in knockin mice. Data further demonstrate modulations of T cell phenotype in knockin mice toward a more tumor-permissive condition. Data provide initial evidence for rs1800449 as an oral cancer susceptibility biomarker and point to opportunities to better understand the functional mechanism of LOX-PP cancer inhibitory activity.

Serum Lysyl Oxidase Levels and Lysyl Oxidase Gene Polymorphism in Ovarian Cancer Patients of Eastern Indian Population

(1) Background: Lysyl oxidase (LOX) plays a dual role in carcinogenesis and studies show a higher risk of cancer in LOX G473A variants. The present study evaluated the pattern of LOX G473A polymorphism (rs1800449) and serum LOX levels in ovarian cancer patients. (2) Methods: Serum LOX levels were estimated by enzyme linked immunosorbent assay (ELISA). A polymorphism of rs1800449 of LOX gene was detected by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Selected samples were sequenced for external validation. (3) Results: A majority of study participants were from low socio-economic status. Serum LOX level was significantly higher in ovarian cancer patients as compared to control. Serum LOX level in early-stage ovarian cancer was significantly lower as compared to advanced stage (FIGO stage III & IV). Wild type GG genotype was used as reference. Genotypes AA were associated with a significant risk of epithelial ovarian cancer (OR 3.208; p value- 0.033). A allele of rs1800449 polymorphism of LOX gene, the odds ratio was 1.866 (95% Confidence Interval 1.112–3.16) p value = 0.017 (4) Conclusions: A allele of rs1800449 polymorphism of LOX gene presents an increased risk of ovarian cancer in East Indian population. Serum LOX levels could be a potential biomarker for the diagnosis and prognosis of ovarian cancer.

Genetic polymorphism of lysyl oxidase, glutathione S-transferase M1, glutathione-S-transferase T1, and glutathione S-transferase P1 genes as risk factors for lung cancer in Egyptian patients

Lung cancer is a lethal malignancy and is affected by genetic polymorphisms that contribute to an individual's susceptibility to developing the disease. Several studies on lung cancer showed conflicting results. The aim of this study is to investigate whether individual or combined modifying effects of LOX G/A, GSTM1 active/null, GSTT1 active/null and GSTP1 Ile/Val polymorphisms are related to the risk of lung cancer in relation to smoking in the Egyptian population. This study is a hospital-based case control study that included 200 patients and 200 control subjects. Genotyping of the 4 studied genes was determined by Multiplex PCR for GSTM1 and GSTT1 and Taq man SNP assay for GSTP1 and LOX genes. The LOX G/A and GSTP1 Ile/Val in both homozygous and heterozygous variants, and the GSTM1 and GSTT1 null genotype showed significant association with lung cancer. Combination between gene polymorphism and smoking increased the risk of developing cancer by 2.7 fold in the LOX GA+AA variant, 1.9 fold in the GSTM1 null variant, 4.8 fold in the GSTT1 null variant and 4.3 fold in the GSTP1 Ile/Val+Val/Val variant. The genetic combination (LOX GA+AA/GSTT1 active, LOX GG/GSTT1 null, LOX GA+AA/GSTT1 null, LOX GA+AA/GSTP1 Ile/Ile, LOX GG/GSTP1 Ile/Val+Val/Val and LOX GA+AA/GSTP1 Ile/Val+Val/Val) led to a higher lung cancer risk, compared to the reference group. The LOX GA/AA, GSTM1 null, GSTT1 null and GSTP1 Ile/Val, Val/Val genotypes contributed to increased lung cancer susceptibility. To the best of our knowledge, this is the first study of LOX genotyping in the Egyptian population. The combination of genotypes increased the risk of cancer, indicating the importance of gene-gene interaction and giving a targeted preventive approach.

Influence of Lysyl oxidase Polymorphisms in Cancer Risk: An Updated Meta-analysis

Background: The aim of this study was to investigate associations between polymorphisms in the Lysyl oxidase (LOX) gene with susceptibility to cancer. The role of LOX in carcinogenesis prompted several association studies in various cancer types; however the outcomes of these studies have inconsistent. Thus, we performed a meta-analysis to obtain more precise estimates. Materials and Methods: A literature search yielded 14 articles from which we examined five cancer groups: breast, bone, lung, gastrointestinal, and gynecological cancers. For each cancer group, pooled odds ratios (ORs) and confidence intervals (95% CIs) were calculated using standard genetic models. High significance (p-value for association [p^a] < 0.00001), homogeneity (I² = 0%), and high precision of effects (CI difference [CID] <1.0 [upper CI - lower CI]) comprised the three criteria for strength of evidence. We used sensitivity analysis to assess robustness of the outcomes. Results: We generated 28 comparisons from which 13 were significant (p^a < 0.05), indicating increased risk, (OR >1.00) found in all cancer groups except breast (p^a = 0.10-0.91). Of the 13, three met all criteria (core) for strength of evidence (p^a < 0.00001, CIDs 0.49-0.56 and I² = 0%), found in dominant/codominant models of gynecological cancers (ORs 1.52-1.62, 95% CIs 1.26-1.88) and codominant model of lung cancer (OR 1.44, 95% CI 1.19-1.74). These three were deemed robust. Conclusion: Based on the three core outcomes, associations of LOX 473G/A with lung, ovarian, and cervical cancers indicate 1.4-1.6-fold increased risks, underpinned by robustness and high statistical power at the aggregate level.

Roles of Lysyl Oxidase Family Members in the Tumor Microenvironment and Progression of Liver Cancer

The lysyl oxidase (LOX) family members are secreted copper-dependent amine oxidases, comprised of five paralogues: LOX and LOX-like l-4 (LOXL1-4), which are characterized by catalytic activity contributing to the remodeling of the cross-linking of the structural extracellular matrix (ECM). ECM remodeling plays a key role in the angiogenesis surrounding tumors, whereby a corrupt tumor microenvironment (TME) takes shape. Primary liver cancer includes hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), ranked as the seventh most common cancer globally, with limited therapeutic options for advanced stages. In recent years, a growing body of evidence has revealed the key roles of LOX family members in the pathogenesis of liver cancer and the shaping of TME, indicating their notable potential as therapeutic targets. We herein review the clinical value and novel biological roles of LOX family members in tumor progression and the TME of liver cancers. In addition, we highlight recent insights into their mechanisms and their potential involvement in the development of target therapy for liver cancer.

Evolving roles of lysyl oxidase family in tumorigenesis and cancer therapy

The lysyl oxidase (LOX) family is comprised of LOX and four LOX-like proteins (LOXL1, LOXL2, LOXL3, and LOXL4), and mainly functions in the remodeling of extracellular matrix (ECM) and the cross-linking of collagen and elastic fibers. Recently, a growing body of research has demonstrated that LOX family is critically involved in the regulation of cancer cell proliferation, migration, invasion and metastasis. In this review, we discuss the roles of LOX family members in the development and progression of different types of human cancers. Furthermore, we also describe the potential inhibitors of LOX family proteins and highlight that LOX family might be an important therapeutic target for cancer therapy.

A polymorphism in the lysyl oxidase propeptide domain accelerates carcinogen-induced cancer

The propeptide (LOX-PP) domain of the lysyl oxidase proenzyme was shown to inhibit the transformed phenotype of breast, lung and pancreatic cells in culture and the formation of Her2/neu-driven breast cancer in a xenograft model. A single nucleotide polymorphism (SNP, rs1800449) positioned in a highly conserved region of LOX-PP results in an Arg158Gln substitution (humans). This arginine (Arg)→glutamine (Gln) substitution profoundly impaired the ability of LOX-PP to inhibit the invasive phenotype and xenograft tumor formation. To study the effect of the SNP in vivo, here we established a knock in (KI) mouse line (LOX-PPGln mice) expressing an Arg152Gln substitution corresponding to the human Arg158Gln polymorphism. Breast cancer was induced in wild-type (WT) and LOX-PPGln female mice beginning at 6 weeks of age by treatment with 7,12-dimethylbenz(a)anthracene (DMBA) in combination with progesterone. Time course analysis of tumor development demonstrated earlier tumor onset and shorter overall survival in LOX-PPGln versus WT mice. To further compare the tumor burden in WT and LOX-PPGln mice, inguinal mammary glands from both groups of mice were examined for microscopic lesion formation. LOX-PPGln glands contained more lesions (9.6 versus 6.9 lesions/#4 bilateral). In addition, more DMBA-treated LOX-PPGln mice had increased leukocyte infiltrations in their livers and were moribund compared with DMBA-treated WT mice. Thus, these data indicate that the Arg→Gln substitution in LOX-PP could be an important marker associated with a more aggressive cancer phenotype and that this KI model is ideal for further mechanistic studies regarding the tumor suppressor function of LOX-PP.

Functional importance of lysyl oxidase family propeptide regions

The lysyl oxidase family of proteins is primarily known for its critical role in catalyzing extracellular oxidative deamination of hydroxylysine and lysine residues in collagens, and lysine residues in elastin required for connective tissue structure and function. Lysyl oxidases have additional important biological functions in health and disease. While the enzyme domains are highly conserved, the propeptide regions are less uniform, and have biological activity, some of which are independent of their respective enzymes. This review summarizes what has been published regarding the functions of the propeptide regions of this family of proteins in the context of extracellular matrix biosynthesis, fibrosis and cancer biology. Although much has been learned, there is a need for greater attention to structure/function relationships and mechanisms to more fully understand these multifunctional proteins.

Impact of lysyl oxidase (G473A) polymorphism on diabetic foot ulcers

Lysyl oxidase (LOX) is an extra-cellular matrix-modifying enzyme that has been linked to cell proliferation, metastasis, angiogenesis and wound healing. This study was designed to examine the association of LOX gene polymorphism G473A, G>A, (rs1800449) located in exon 1 of the LOX gene in diabetic subjects with and without diabetic foot ulcers (DFU) and its impact of expression on DFU. Genotypic analysis of 906 samples showed a significant increase in the presence of 'A' allele in type 2 diabetes mellitus (T2DM) and DFU when compared to that of control subjects. Allele wise analysis showed a higher frequency of 'A' allele in the T2DM (36.23%, OR 1.069, P value 0.29) and DFU (41.69%, OR 1.195, P value 0.003) when compared to that of control subjects (33.17%). Interestingly, real time RT-PCR results showed significant increased transcript level of the LOX gene on the AA genotype of DFU when compared to that of the AA genotype of T2DM and control subjects. Our finding predicts that there is an association of LOX gene polymorphism (G473A) on diabetes and DFU patients when compared to that of healthy controls. Thus, this study merits further evaluation on a mechanistic approach of this gene.

The Extracellular Matrix in Epithelial Ovarian Cancer - A Piece of a Puzzle

Epithelial ovarian cancer is the fifth leading cause of cancer-related deaths in women and the most lethal gynecological malignancy. Extracellular matrix (ECM) is an integral component of both the normal and tumor microenvironment. ECM composition varies between tissues and is crucial for maintaining normal function and homeostasis. Dysregulation and aberrant deposition or loss of ECM components is implicated in ovarian cancer progression. The mechanisms by which tumor cells induce ECM remodeling to promote a malignant phenotype are yet to be elucidated. A thorough understanding of the role of the ECM in ovarian cancer is needed for the development of effective biomarkers and new therapies.

Association of the G473A polymorphism and expression of lysyl oxidase with breast cancer risk and survival in European women: a hospital-based case-control study

Background

Lysyl oxidase (LOX) is an extracellular enzyme essential for the covalent crosslinking of extracellular matrix proteins and may also have additional functions. LOX expression can be both up- and downregulated in cancer and is associated both with tumour suppression and metastasis progression. The G473A polymorphism (rs1800449) results in the Arg158Gln amino acid substitution in the LOX propeptide, compromises its tumour suppressive activity, and was associated with an increased breast cancer risk in a Chinese Han population. In the first hospital-based case-control study in European women, we aimed at investigating the association of LOX expression and the G473A polymorphism with breast cancer risk and survival in unselected and estrogen receptor (ER) negative patients.

Methodology/Principal Findings

The G473A polymorphism was genotyped in 386 breast cancer patients and 243 female controls. Moreover, LOX mRNA expression was quantified in the tumors of 105 patients by qRT-PCR. We found that the minor A-allele of this polymorphism is associated with a later age at breast cancer onset, a trend towards a decreased disease-free and metastasis-free survival, but not with an increased breast cancer risk. LOX mRNA expression was significantly elevated in tumours of patients older than 55 years, postmenopausal patients, estrogen receptor positive tumours, and p53 negative tumours, but was unaffected by G473A genotype in tumours and breast cancer cell lines. High LOX expression was associated with a poor disease-free and metastasis-free survival in ER negative but not ER positive patients. LOX expression was an independent prognostic parameter in multivariate analysis, whereas G473A genotype was not. A small, distinct subgroup of the ER negative patients was identified which exhibited a considerably elevated LOX expression and a very poor disease-free (p = 0.001) and metastasis-free survival (p = 0.0003).

Conclusions/Significance

This newly identified ER negative/LOX high subgroup may be a suitable collective for future individualized breast cancer diagnosis and therapy.

Lysyl oxidase rs1800449 polymorphism and cancer risk among Asians: evidence from a meta-analysis and a case-control study of colorectal cancer

Growing evidence has indicated that lysyl oxidase (LOX) G473A polymorphism (rs1800449) is associated with cancer risk among Asians. However, results of single center and small sample study lack enough power. We first investigated the effect of LOX G473A polymorphism on cancer risk among Asians by a meta-analysis, and then further validated this association by a case-control study of colorectal cancer (CRC) with LOX G473A polymorphism in a Chinese population. STATA 12.0 software was used for the meta-analysis. The relationships were evaluated by calculating the pooled odds ratios (ORs) and their 95 % confidence intervals (CIs). In a case-control study comprising 577 CRC patients and 696 controls, LOX G473A polymorphism was detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Logistic regression was used to evaluate genetic associations with the occurrence of CRC. The results of our meta-analysis, including seven case-control studies with a total of 2,377 cancer patients and 2,499 controls, suggested that LOX G473A polymorphism might be associated with an increased risk of cancer among Asians. In addition, results of a case-control study indicated that individuals with the AA or AG genotype had a significantly increased susceptibility to CRC occurrence, compared with individuals who had GG genotype. Overall, this meta-analysis and case-control study of CRC observed convincing association of LOX G473A polymorphism with cancer risk in Asians; our study would contribute to complete elucidation of carcinogenesis.

Lysyl oxidase genetic variants affect gene expression in cervical cancer

Lysyl oxidase (LOX) is a copper-dependent amine oxidase that plays important roles in the homeostasis of tumors. The aim of this study was to investigate the association between LOX polymorphisms and cervical cancer, and the effect of these polymorphisms on gene expression. We evaluated two polymorphisms of LOX, rs1800449G/A (G473A) and rs2278226C/G, in 262 cervical cancer cases and 298 healthy controls in the Chinese population. Results showed that the prevalence of rs1800449AA genotype was significantly increased in cases than in controls (p=0.004). Individuals who carried the rs1800449A allele had a 1.56-fold increased risk for cervical cancer than those with the rs1800449G allele (p=0.003). The rs2278226CG genotype also revealed a significantly higher proportion in cases (20.6%) than in controls (7.7%, p<0.001). Interestingly, when analyzing these two polymorphisms with the serum level of LOX, we identified that cervical cancer patients carrying the rs2278226CG genotype had a significantly elevated level of LOX than those with rs2278226CC wild type, whereas the same phenomenon was not observed in controls. The rs1800449 polymorphism did not affect the LOX serum level in either controls or patients. These results suggest that the polymorphisms in the LOX gene may be involved in the development of cervical cancer through various mechanisms.

Association of Lysyl oxidase (LOX) Polymorphisms with the Risk of Keratoconus in an Iranian Population

BACKGROUND

Keratoconus is a connective tissue-related eye disease with unknown etiology that causes the loss of visual acuity. Lysyl oxidase (LOX) is an amine oxidase that catalyzes the covalent cross-link of collagens and elastin in the extracellular environment, thus determining the mechanical properties of connective tissue. The current study aimed to investigate the possible associations between two LOX polymorphisms, rs1800449 and rs2288393, and susceptibility to keratoconus.

METHODS

A total of 262 Iranian subjects including 112 patients with keratoconus and 150 healthy individuals as controls were recruited. Genotyping for the LOX variants was performed using allele-specific PCR.

RESULTS

A significant difference was found between two groups regarding allelic and genotyping distribution of LOX polymorphism at position rs1800449 G>A. The frequency of AA and GA + AA genotypes were increased in patients compared to controls (17% versus 8% and 62.5% versus 50%, respectively), showing a statistically significant difference (OR = 2.827, 95% CI: 1.251-6.391, p = 0.012). The A allele was associated with an increased risk for keratoconus, with the frequency of 39.9% and 29% in patients and controls, respectively (OR = 1.614, 95% CI: 1.119-2.326, p = 0.011). Furthermore, the haplotype analysis revealed that the rs1800449G/rs2288393C is a protective factor against keratoconus (OR = 0.425, 95% CI = 0.296-0.609, p = 0.001). Conversely, the +473A/rs2288393C (OR = 3.703, 95% CI = 2.230-6.149, p = 0.001) and +473G/rs2288393G (OR = 15.48, 95% CI = 3.805-63.03, p = 0.001) haplotypes were identified as risk factors for keratoconus.

CONCLUSION

Our study demonstrated that the LOX rs1800449 genotypes (AA and GA + AA) and allele (A) appears to confer risk for susceptibility to keratoconus.

Comparative distribution of Lysyl Oxidase (G473A) and NQO1 (C609T) polymorphism among tea-garden workers (habitual chewers of betel quid) of Darjeeling district and Kolkata city of West Bengal

Context:

Chewing of processed arecanut products with tobacco and betel quid has been attributed to many oral pathological conditions. These products are very popular among the youngsters of lower economic groups. Genetic predisposition has been now identified as a major risk factor for increasing the susceptibility toward the disease among these chewers.

Aims:

Our study mainly aims to find out the predisposition of LOX (G473A) and NQO1 (C609T) polymorphisms and present a comparison between the population (habitually exposed to processed arecanut and smokeless tobacco products) of a metro-city Kolkata and the tea-garden workers of Darjeeling district of West Bengal.

Settings and Design:

Subjects for the study was recruited from various oral health check-up camps organized in the tea-gardens of Darjeeling district and Kolkata city.

Materials and Methods:

Genotyping analysis was done through a Polymerase Chain Reaction–Restriction Fragment Length Polymorphism (PCR-RFLP)-based approach.

Statistical Analysis Used:

A two-way contingency table analysis software (JAVASTAT: http://statpages.org/ctab2 × 2.html) using 95% confidence interval was used to study the distribution of genotypes among the populations. A P < 0.05 was considered to be significant.

Results:

The results indicates both the heterozygous and homozygous carriers of NQO1 C > T (609) was found to be significantly higher among the north Bengal tea-garden workers [OR 0.480 (0.280-0.82) P = 0.01; 0.218 (0.091–0.524) P = 0.0001], respectively. Interestingly CT (21% in both) and TT (8% and 7%, respectively) were found to be equally distributed in the two populations. For LOX G > A (473) a significantly higher number of Kolkata individuals were found to carry the heterozygous GA allele in individuals aged <30 years [OR 3.779 (1.684-6.547) P = 0.001]. However, none were carrier of heterozygous GA allele of Kolkata population as compared with 29% north Bengal tea-garden workers aged above 31 years.

Conclusions:

A close observation of occurrence of oral diseases over time among such a population will be helpful to identify risk genotypes responsible for betel quid-induced oral diseases.