Galectin-3 rs4652 A>C polymorphism is associated with the risk of gastric carcinoma and P-glycoprotein expression level

The <i>LGALS1</i> gene polymorphism is not associated with galectin-1 levels in tumor tissue and blood of colon cancer patients

Background: Galectin-1 plays an important role in the pathogenesis of colorectal cancer (CRC). The blood and tumoral levels of galectin-1 could be dependent on the polymorphism of the promotor region of LGALS1 gene. Aim: To analyze an association between galectin-1 levels in tumor tissue and plasma and the genotype of the rs4820293 and rs4820294 polymorphisms of the LGALS1 gene in CRC patients. Materials and methods: The study included a total of 70 inpatients with pathologically verified CRC (International Classification of Diseases 10th Revision codes C18-C20, 39 men and 31 women, mean age 65.4 ± 5.7 years), who were receiving treatment in the Tomsk Regional Oncology Center and Cancer Research Institute of the Tomsk National Research Medical Center from 2020 to 2022. The control group consisted of 70 healthy volunteers (34 men and 36 women, mean age 62.3 ± 7.2 years). Venous blood samples were taken from all study participants and tumor tissue samples were obtained from the CRC patients. Galectin-1 expression in the tumor tissue was assessed by immunohistochemistry and plasma galectin-1 levels by enzyme-linked immunosorbent assay. The LGALS1 gene polymorphisms rs4820293 and rs4820294 were identified by restriction fragment length polymorphism analysis. Results: The distributions of genotype and allele frequencies of polymorphic variants rs4820293 and rs4820294 of the LGALS1 gene in the CRC patients and in the healthy donors were comparable (p 0.05). Calculation of odds ratios did not confirm any association between LGALS1 gene polymorphisms and CRC. However, the rs4820294 polymorphism had a strong association with regional metastasis and tumor differentiation grade (Cramer's V above 0.4, p 0.001). The plasma galectin-1 levels in the CRC patients with the AA genotype of the rs4820294 polymorphism were higher than in the healthy carriers (17.42 versus 12.92 ng/ml, p = 0.040). However, there were no significant differences in the content of galectin-1+ cells in the tumor and galectin-1 in plasma of the CRC patients depending on the genotype of the LGALS1 gene polymorphisms (p 0.05). Conclusion: The LGALS1 gene polymorphism is not associated with CRC, but in the carriers of the rs4820294 variant is related to clinical and morphological parameters of the tumor process. The intratumoral expression and blood levels of galectin-1 in CRC patients are not dependent on the genotype of rs4820293 and rs4820294 polymorphisms of the LGALS1 gene.

Polymorphism Pro64His within galectin-3 has functional consequences at proteome level in thyroid cells

Introduction

The single nucleotide polymorphism (SNP) rs4644 at codon 64 of galectin-3 (gal-3, gene name: LGALS3), specifying the variant proline (P64) to histidine (H64), is known to affect the protein's functions and has been associated with the risk of several types of cancer, including differentiated thyroid carcinoma (DTC).

Materials and methods

To deepen our understanding of the biological effects of this SNP, we analyzed the proteome of two isogenic cell lines (NC-P64 vs. NA-H64) derived from the immortalized non-malignant thyrocyte cell line Nthy-Ori, generated through the CRISPR-Cas9 technique to differ by rs4644 genotype. We compared the proteome of these cells to detect differentially expressed proteins and studied their proteome in relation to their transcriptome.

Results

Firstly, we found, consistently with previous studies, that gal-3-H64 could be detected as a monomer, homodimer, and heterodimer composed of one cleaved and one uncleaved monomer, whereas gal-3-P64 could be found only as a monomer or uncleaved homodimer. Moreover, results indicate that rs4644 influences the expression of several proteins, predominantly upregulated in NA-H64 cells. Overall, the differential protein expression could be attributed to the altered mRNA expression, suggesting that rs4644 shapes the function of gal-3 as a transcriptional co-regulator. However, this SNP also appeared to affect post-transcriptional regulatory mechanisms for proteins whose expression was oppositely regulated compared to mRNA expression. It is conceivable that the rs4644-dependent activities of gal-3 could be ascribed to the different modalities of self-dimerization.

Conclusion

Our study provided further evidence that rs4644 could affect the gal-3 functions through several routes, which could be at the base of differential susceptibility to diseases, as reported in case-control association studies.

The role of galectin-3 and its genetic variants in tumor risk and survival of patients with surgically resected early-stage non-small cell lung cancer

Background

The aim of this study was to investigate the possible relationship between galectin-3 gene variants, serum level, gene expression level, and the risks and survivals of resectable non-small cell lung cancer patients.

Methods

The rs4644 and rs4652 variants of galectin-3 were genotyped by TaqMan single nucleotide polymorphism assay using genomic deoxyribonucleic acid isolated from the peripheral blood of 65 (54 males, 11 females; mean age: 60.1±11.9 years; range, 34 to 83 years) with Stage IA-IIIA non-small cell lung cancer who underwent primary surgical treatment and 95 healthy individuals (48 males, 47 females; mean age: 53.9±13.5 years; range, 32 to 87 years) between March 2017 and September 2018. Circulating galectin-3 levels in serum samples of the patient and control groups were assessed by enzyme-linked immunosorbent assay. Messenger ribonucleic acid expression of galectin-3 in tumor and surrounding tissues of the patient group was examined by real-time quantitative polymerase chain reaction. Both predictive and prognostic significance of the results were analyzed.

Results

The presence of angiolymphatic invasion was significant in the patients with rs4652 AA genotype (p=0.04). Serum galectin-3 levels were significantly higher in the patients than the controls (p<0.0001). The patients with rs4644 CA/CC (p<0.0001 and p<0.0001) and rs4652 AA/AC (p=0.001 and p<0.0001) genotypes had higher serum galectin-3 levels than their corresponding controls. Serum galectin-3 levels increased in the presence of vascular invasion in patients with both rs4644 AC (p=0.03) and rs4652 AC (p=0.019) genotypes. The receiver operating characteristic curve suggested serum galectin-3 level as a strong predictive marker for the patient group with a cut-off value of 17.089 ng/mL (area under the curve: 0.910±0.04; 95% confidence interval: 0.832-0.988; p<0.001). Univariate analysis revealed the association of lower serum galectin-3 levels with better survival (p=0.048). Multivariate survival analysis showed that only high serum galectin-3 levels tended to be related to survival of the patients (hazard ratio: 5.106; 95% confidence interval: 0.956-27.267; p=0.056).

Conclusion

The presence of galectin-3 gene variants may lead to histopathological differences among patients with non-small cell lung cancer. Serum galectin-3 level may be a valuable diagnostic biomarker and be associated with survival of these patients.

Galectins in Intra- and Extracellular Vesicles

Carbohydrate-binding galectins are expressed in various tissues of multicellular organisms. They are involved in autophagy, cell migration, immune response, inflammation, intracellular transport, and signaling. In recent years, novel roles of galectin-interaction with membrane components have been characterized, which lead to the formation of vesicles with diverse functions. These vesicles are part of intracellular transport pathways, belong to the cellular degradation machinery, or can be released for cell-to-cell communication. Several characteristics of galectins in the lumen or at the membrane of newly formed vesicular structures are discussed in this review and illustrate the need to fully elucidate their contributions at the molecular and structural level.

The Impact of Natural Selection on the Evolution and Function of Placentally Expressed Galectins

Immunity genes have repeatedly experienced natural selection during mammalian evolution. Galectins are carbohydrate-binding proteins that regulate diverse immune responses, including maternal-fetal immune tolerance in placental pregnancy. Seven human galectins, four conserved across vertebrates and three specific to primates, are involved in placental development. To comprehensively study the molecular evolution of these galectins, both across mammals and within humans, we conducted a series of between- and within-species evolutionary analyses. By examining patterns of sequence evolution between species, we found that primate-specific galectins showed uniformly high substitution rates, whereas two of the four other galectins experienced accelerated evolution in primates. By examining human population genomic variation, we found that galectin genes and variants, including variants previously linked to immune diseases, showed signatures of recent positive selection in specific human populations. By examining one nonsynonymous variant in Galectin-8 previously associated with autoimmune diseases, we further discovered that it is tightly linked to three other nonsynonymous variants; surprisingly, the global frequency of this four-variant haplotype is ∼50%. To begin understanding the impact of this major haplotype on Galectin-8 protein structure, we modeled its 3D protein structure and found that it differed substantially from the reference protein structure. These results suggest that placentally expressed galectins experienced both ancient and more recent selection in a lineage- and population-specific manner. Furthermore, our discovery that the major Galectin-8 haplotype is structurally distinct from and more commonly found than the reference haplotype illustrates the significance of understanding the evolutionary processes that sculpted variants associated with human genetic disease.