Human leukocyte antigen (HLA)-G gene polymorphism in patients with non-small cell lung cancer

HLA-G/sHLA-G and HLA-G-Bearing Extracellular Vesicles in Cancers: Potential Role as Biomarkers

As a non-classic major histocompatibility complex (MHC) class I molecule, human leukocyte antigen G (HLA-G) is expressed in fetal-maternal interface and immunoprivileged site only in healthy condition, and in pathological conditions such as cancer, it can be de novo expressed. It is now widely accepted that HLA-G is a key molecule in the process of immune escape of cancer cells, which is ubiquitously expressed in the tumor environment. This raises the possibility that it may play an adverse role in tumor immunity. The expression level of HLA-G has been demonstrated to be highly correlated with clinical parameters in many tumors, and its potential significance in the diagnosis and prognosis of cancer has been postulated. However, because HLA-G itself has up to seven different subtypes, and for some subtypes, detected antibodies are few or absent, it is hard to evaluate the actual expression of HLA-G in tumors. In the present work, we described (a) the structure and three main forms of HLA-G, (b) summarized the mechanism of HLA-G in the immune escape of tumor cells, (c) discussed the potential role of HLA-G as a tumor marker, and reviewed (d) the methods for detecting and quantifying HLA-G.

HLA-G and single nucleotide polymorphism (SNP) associations with cancer in African populations: Implications in personal medicine

The immune system plays an important role in protecting the body against malignancy. During cancer immunoediting, the immune system can recognize and keep checking the tumor cells by down-expression of some self-molecules or by increasing expression of some novel molecules. However, the microenvironment created in the course of cancer development hampers the immune ability to recognize and destroy the transforming cells. Human Leukocyte Antigen G (HLA-G) is emerging as immune checkpoint molecule produced more by cancer cells to weaken the immune response against them. HLA-G is a non-classical HLA class I molecule which is normally expressed in immune privileged tissues as a soluble or membrane-bound protein. HLA-G locus is highly polymorphic in the non-coding 3′ untranslated region (UTR) and in the 5′ upstream regulatory region (5′ URR). HLA-G expression is controlled by polymorphisms located in these regions, and several association studies between these polymorphic sites and disease predisposition, response to therapy, and/or HLA-G protein expression have been reported. Various polymorphisms are demonstrated to modulate its expression and this is increasingly finding more significance in cancer biology. This review focuses on the relevance of the HLA-G gene and its polymorphisms in cancer development. We highlight population genetics of HLA-G as evidence to espouse the need and importance of exploring potential utility of HLA-G in cancer diagnosis, prognosis and immunotherapy in the currently understudied African population.

Long non-coding RNA ATB promotes human non-small cell lung cancer proliferation and metastasis by suppressing miR-141-3p

Long noncoding RNA activated by transforming growth factor-β (lncRNA-ATB) plays a critical role in progression of several cancers. In this study, lncRNA-ATB was significantly up-regulated in NSCLC tissues and cell lines, and high lncRNA-ATB expression indicated poor prognosis. Knockdown of lncRNA-ATB suppressed NSCLC cell growth, colony formation, migration, invasion and reversed epithelial-mesenchymal transition. In vivo study showed that silencing lncRNA-ATB inhibited tumor growth. Further mechanism studies demonstrated that lncRNA-ATB was a target of miR-141-3p. MiR-141-3p expression was negatively related to lncRNA-ATB expression in NSCLC tissues. These results suggested that inhibiting lncRNA-ATB might be an approach for NSCLC treatment.

Implication of Soluble HLA-G and HLA-G +3142G/C Polymorphism in Breast Cancer Patients Receiving Adjuvant Therapy in Tanzania

BACKGROUND

During cancer growth, immunosuppressive microenvironment is created that enables tumour cells to evade an eliminative immune response and hence manage to grow into malignancy. HLA-G, existing as either membrane-bound (mHLA-G) or soluble (sHLA-G) molecule is thought to be immunosuppressive and produced more by tumor cells. The +3142G/C polymorphism in HLA-G gene affects its expression, and G allele is considered to be a protective mutant allele associated with less expression of HLA-G. The implication of HLA-G in cancer development has been reported in different cancers and populations. But, its implication in most African populations has not yet been investigated. The aim of this study was to determine the possible associations of soluble HLA-G and HLA-G +3142G/C SNP with breast cancer.

MATERIALS AND METHODS

75 breast cancer patients and 84 normal controls were recruited in this study. The genotyping of HLA-G +3142G/C polymorphism was determined by LightSNiP typing assay using quantitative Real-Time PCR and sHLA-G levels were determined by ELISA.

RESULTS

The sHLA-G levels were significantly lower in breast cancer patients than in controls (p<0.001). Also, they were significantly lower in mastectomized patients compared to non-mastectomized patients (p=0.018). The ROC analysis revealed a significant ability of sHLA-G to differentiate breast cancer patients versus normal controls (AUC=0.697, 95% CI= 0.619-0.767, p<0.001) and identify mastectomized patients (AUC=0.667, 95% CI= 0.549 to 0.772, p=0.041). The assessment of +3142G/C polymorphism revealed a relatively similar distribution of frequencies of genotypes and alleles between breast cancer patients and normal controls (p>0.05) and was neither associated with sHLA-G levels.

CONCLUSION

While the +3142G/C SNP was found not to be relevant to breast cancer, the changes of sHLA-G levels in response to medical interventions such as mastectomy may be translated into its potential prognostic utility for breast cancer. More studies are needed to provide clear evidence of sHLA-G as a diagnostic and prognostic marker of breast cancer in Tanzania.
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MiR-940 inhibits TGF-β-induced epithelial-mesenchymal transition and cell invasion by targeting Snail in non-small cell lung cancer

Increased evidence reveals that miR-940 inhibits the migration and invasion of cancer cells. Considering transforming growth factor β (TGF-β) signaling is crucial to cellular epithelial-mesenchymal transition (EMT) process and metastasis of cancer, it is in urgent to explore whether and how miR-940 plays an essential role in regulating TGF-β-induced EMT in lung cancer progression. In the present study, we observed a reciprocal expression with down-regulated miR-940 and up-regulated Snail mRNA in non-small-cell lung cancer (NSCLC) tissues. we further found that the expression of miR-940 was decreased in NSCLC tissues with lymph node metastasis, advanced TNM stages and poor cell differentiation, in which, on the contrary, the expression of Snail was increased. Overexpression of miR-940 significantly inhibited Snail mRNA and protein expression in A549 and H226 cells. Mechanistically, Snail mRNA was identified as target of miR-940. In addition, miR-940 repressed TGF-β-induced EMT and further hampered the cell migration and invasion. Finally, siRNA-mediated knockdown of Snail copied the phenotype of miR-940 overexpression in A549 and H226 cells. Taken together, our study reveals that miR-940 can suppress TGF-β-induced EMT and cell invasion by targeting Snail 3'-UTR mRNA in NSCLC.

Association between AKT rs2494752 single nucleotide polymorphism and the risk of metastasis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common types of human tumors, which is characterized by high morbidity and mortality rates. AKT1 transcriptional activity is implicated in HCC initiation and development. In the present study, the effects of rs2494752 single nucleotide polymorphism (SNP) on AKT1 transcriptional activity in the progression of HCC cells were investigated. A case-control study was analyzed in 1,056 HCC patients and 1,080 healthy individuals using the PCR assay method. Results indicated AKT1 expression levels were up-regulated in HCC tissue compared to adjacent normal tissues. Furthermore, a higher frequency of AKT rs2494752 AG and AA genotypes were observed in HCC cases (P=0.0046). Gene polymorphism identified C and T alleles were frequency in HCC patients compared to healthy individuals. Individuals harboring AKT rs2494752 AG/AA genotype had a vital increased susceptibility to HCC in the dominant model (P=0.0028). In addition, AKT1 rs2494752 GG genotype showed an increasing of AKT1 promoter activity determined by the luciferase assay. Furthermore, it was demonstrated that AKT1 rs2494752 GG and C polymorphism was more aggressive than other AKT1 rs2494752 cancer cells. Moreover, AKT1 rs2494752 GG markedly increased rates of response to NCT chemotherapy. Additionally, results revealed that AKT1 rs2494752 GG and C increased the risk factors of HCC. In conclusion, these results indicate that AKT1 rs2494752 polymorphisms may be regarded as a candidate gene in assessing the susceptibility, metastasis and responses to chemotherapy in the progression of hepatocellular carcinoma.

Prognostic role of snail in lung cancer: Protocol for a systematic review

BACKGROUND

Increasing studies were performed to explore the prognostic value of snail in lung cancer (LC), however, with inconsistent results. Hence, this systematic review is aimed to evaluate the prognostic role of snail in patients with LC.

METHODS

A comprehensive literature search in the PubMed, Embase, the Cochrane Library, and Web of Science databases will be conducted to identify eligible studies. Language is limited as English. We will employ hazard ratios (HRs) and 95% confidence intervals (95% CIs) to estimate the correlations between snail expression and overall survival (OS), progression-free survival (PFS), recurrence-free survival (RFS), disease-free survival (DFS), and clinicopathological features. Meta-analysis will be performed using STATA 14.0 software.

RESULTS

This study will provide a high-quality synthesis of current evidence of the correlations between snail expression and OS, PFS/RFS/DFS, and clinicopathological features.

CONCLUSION

The study will provide updated evidence to assess whether the expression of snail is in association with poor prognosis in patients with LC.

ETHICS AND DISSEMINATION

It is not necessary for ethical approval because individuals cannot be identified. The protocol will be disseminated in a peer-reviewed journal or presented at a relevant conference.

PROSPERO REGISTRATION NUMBER

This systematic review protocol has been registered in the PROSPERO network (No. CRD42018095191).

Human Leukocyte Antigen G Polymorphism and Expression Are Associated with an Increased Risk of Non-Small-Cell Lung Cancer and Advanced Disease Stage

Human leukocyte antigen (HLA)-G acts as negative regulator of the immune responses and its expression may enable tumor cells to escape immunosurveillance. The purpose of this study was to investigate the influence of HLA-G allelic variants and serum soluble HLA-G (sHLA-G) levels on risk of non-small-cell lung cancer (NSCLC). We analyzed 191 Caucasian adults with NSCLC and 191 healthy subjects recruited between January 2009 and March 2014 in Ariana (Tunisia). Serum sHLA-G levels were measured by immunoassay and HLA-G alleles were determined using a direct DNA sequencing procedures. The heterozygous genotypes of HLA-G 010101 and -G 010401 were associated with increased risks of both NSCLC and advanced disease stages. In contrast, the heterozygous genotypes of HLA-G 0105N and -G 0106 were associated with decreased risks of NSCC and clinical disease stage IV, respectively. Serum sHLA-G levels were significantly higher in patients with NSCLC and particularly in those with advanced disease stages compared to healthy subjects. The area under the receiver-operating characteristic (ROC) curves was 0.82 for controls vs patients. Given 100% specificity, the highest sensitivity achieved to detect NSCLC was 52.8% at a cutoff value of 24.9 U/ml. Patients with the sHLA-G above median level (≥ 50 U/ml) had a significantly shorter survival time. This study demonstrates that HLA-G allelic variants are independent risk factors for NSCLC. Serum sHLA-G levels in NSCLC patients could be useful biomarkers for the diagnostic and prognosis of NSCLC.