Role of KAI1/CD82 polymorphisms in colon cancer risk in Han Chinese population

Investigations of a Possible Role of SNPs in KAI1 Gene on Its Down-Regulation in Breast Cancer

Objective:

KAI1 (CD82) is a metastasis suppressor gene known to be down-regulated in carcinomas of breast, prostate and many other organs. The mechanism of KAI1 down-regulation is complex and not well understood. Here, we investigate the role of 8 SNPs (not previously studied) in KAI1 gene that could influence its expression in tumor tissue samples of breast cancer patients from the Eastern province of Saudi Arabia.

Methods:

Single nucleotide polymorphisms (SNPs) in KAI1 gene were selected from the NCBI website (dbSNP) and were then filtered for those SNPs causing stop codon mutations (rs139889503 and rs150533529) or nonsynonymous mutation in the 5’-UTR (rs11541048, rs77359459, rs115500759, rs182579675, rs200238062, and rs372733853). SNPs genotyping was performed using TaqMan SNP Genotyping Assay and the results were correlated with KAI1 protein expression profile by immunohistochemistry (IHC) on formalin-fixed paraffin-embedded (FFPE) samples of breast cancer and control none-neoplastic tissues.

Results:

KAI1 expression by IHC was observed in all none-neoplastic breast tissue samples and only in 35% out of the 59 breast cancer tissue samples. None of the samples was homozygous for the stop codon allele A in the SNP rs139889503 or allele T in the SNP rs150533529. The SNPs in the 5-UTR, rs11541048, rs115500759, and rs182579675, were only present in the homozygous state for the G and C alleles respectively in both cancer and control samples. The other SNPs in the 5’-UTR (rs77359459, rs200238062, and rs372733853) had no significant difference in the allele distribution between KAI1 expressing or none-expressing tissue samples.

Conclusion:

Our findings showed no significant effect of the studied SNPs on down-regulation of KAI1 expression.

Long noncoding RNA LINC01234 promoted cell proliferation and invasion via miR-1284/TRAF6 axis in colorectal cancer

Colorectal cancer is one of the most common and leading malignancies globally. Long noncoding RNAs (lncRNAs) function as potentially critical regulator in colorectal cancer. LINC01234, a novel lncRNA in tumor biology, regulates the progression of various tumors. However, the tumorigenic mechanism of LINC01234 in colorectal cancer is still unclear. This study was performed with the aim to prospectively investigate clinical significance, effect, and mechanism of lncRNA LINC01234 in colorectal cancer. First, we found that LINC01234, localized in the cytoplasm, was increased in both colorectal cancer cell lines and tissues. Subsequent functional assays suggested LINC01234 knockdown suppressed cell proliferation, migration, and invasion of colorectal cancer cells, while blocked cell cycle and induced cell apoptosis. Moreover, we identified that miR-1284 was target of LINC01234, we further demonstrated a negative correlation with LINC01234 in colorectal cancer tissues and cells. Furthermore, miR-1284 targeted and suppressed tumor necrosis factor receptor-associated factor 6 (TRAF6). Loss-of-function assay revealed that LINC01234 silencing suppressed colorectal cancer progression through inhibition of miR-1284. In vivo subcutaneous xenotransplanted tumor model indicated LINC01234 knockdown inhibited in vivo tumorigenic ability of colorectal cancer via downregulation of TRAF6. Collectively, this study clarified the biological significance of LINC01234/miR-1284/TRAF6 axis in colorectal cancer progression, providing insights into LINC01234 as novel potential therapeutic target for colorectal cancer therapeutic from bench to clinic.

Anti-miR-362-3p Inhibits Migration and Invasion of Human Gastric Cancer Cells by Its Target CD82

AIM

This study was to investigate the effects and mechanisms of miR-362-3p on regulation of gastric cancer (GC) cell metastasis potential.

METHODS

We detected miR-362-3p level in GC and adjacent normal tissues and investigated the relationship with clinicopathological factors. Next, we analyzed the level of miR-362-3p expression and CD82 in different differentiated GC cells compared with a normal gastric mucosa cell by RT-PCR and Western blot. Dual-luciferase reporter assay and Western blot confirmed a direct interaction between miR-362-3p and CD82 3'UTR. After miR-362-3p and CD82 were silenced in GC cells, we compared the transfected GC cells migration and invasion capacity by transwell assay. In addition, we detected the effects on cells angiogenesis by tube formation assay. Western blot was used to detect the impact of CD82 and miR-362-3p on epithelial-to-mesenchymal transition markers in treated GC cells.

RESULTS

Level of miR-362-3p expression was much higher in GC cells than in normal gastric mucosa cell, and miR-362-3p expression negatively correlated with CD82 mRNA expression in these cell lines. Furthermore, miR-362-3p expression induced [corrected] GC cell metastasis capacity by suppression of CD82 expression. Level of miR-362-3p may mediate E-cadherin, N-cadherin, and vimentin expression in GC cells.

CONCLUSION

This study illuminated that downregulation of miR-362-3p along with the upregulation of CD82 in GC cells resulted in the inhibition of GC migration and invasion. Thus, our results suggested that miR-362-3p or CD82 can be exploited as a new potential target for control of GC in the future.

A functional variant at miR-520a binding site in PIK3CA alters susceptibility to colorectal cancer in a Chinese Han population

An increasing body of evidence has indicated that polymorphisms in the miRNA binding site of target gene can alter the ability of miRNAs to bind their target genes and modulate the risk of cancer. We aimed to investigate the association between a miR-520a binding site polymorphism rs141178472 in the PIK3CA 3′-UTR and the risk of colorectal cancer (CRC) in a Chinese Han population. The polymorphism rs141178472 was analyzed in a case-control study, including 386 CRC patients and 394 age- and sex-matched controls; the relationship between the polymorphism and the risk of colorectal cancer was examined. Individuals carrying the rs141178472 CC genotype or C allele had an increased risk of developing CRC (CC versus TT, OR (95% CI): 1.716 (1.084–2.716), P = 0.022; C versus T, OR (95% CI): 1.258 (1.021–1.551), P = 0.033). Furthermore, the expression of PIK3CA was detected in the peripheral blood mononucleated cell of CRC patients, suggesting that mRNA levels of PIK3CA might be associated with SNP rs141178472. These findings provide evidence that a miR-520a binding site polymorphism rs141178472 in the PIK3CA 3′-UTR may play a role in the etiology of CRC.

Clinical significance of KAI1/CD82 protein expression in nasopharyngeal carcinoma

The aim of this study was to investigate KAI1/CD82 protein expression in human nasopharyngeal carcinoma (NPC) cell lines and human NPC tissues. Immunohistochemistry and western blot analysis were used to detect the localization and expression levels of the KAI1/CD82 protein in five human NPC cell lines. Immunohistochemistry was also conducted to detect the expression of the KAI1/CD82 protein in 70 NPC tissues and 30 non-neoplastic nasopharyngeal tissues. The levels of KAI1/CD82 protein expression were found to decrease as the metastatic potential of cells increased. The expression rate of KAI1/CD82 protein in the NPC tissues (44.3%) was significantly lower than that in the non-neoplastic nasopharyngeal tissues (70.0%) (P<0.05). KAI1/CD82 protein expression in the NPC tissues was not associated with clinical parameters, including gender, age, histological type and T stage, and the positive expression of KAI1/CD82 decreased with increased N staging. The level of KAI1/CD82 protein expression was increased in different human NPC cell lines. The KAI1/CD82 gene was highly expressed in cells with low metastatic potential, while low expression was observed in cells with a high metastatic potential. In addition, the KAI1/CD82 gene was expressed at low levels in nasopharyngeal carcinoma tissues, while high expression was identified in non-neoplastic nasopharyngeal tissues, and was associated with lymph node metastasis. These results indicated that the KAI1/CD82 gene may be involved in the occurrence, development and metastasis of nasopharyngeal carcinoma.

Association between EZH2 polymorphisms and colorectal cancer risk in Han Chinese population

The aim of this study is to investigate the associations between EZH2 gene polymorphisms and colorectal cancer (CRC) risk. We undertook a case-control study to analyze three EZH2 polymorphisms (148505302C>T, 2110+6A>C and 626-394T>C) in an Han Chinese population, by extraction of genomic DNA from the peripheral blood of 512 patients with CRC and 546 control participants, and performed EZH2 genotyping using DNA sequencing. The obtained results indicated that overall, no statistically significant association was observed in 2,110+6A>C. Nevertheless, 148505302C>T genotype demonstrated a protective effect in CRCs (P=0.014; odds ratio (OR) 0.777, CI 95%:0.647-0.933). Furthermore, 148505302 T allele CRC was more significantly common in patients with tumor size of <4 cm than C allele CRC and in cases of good differentiation and lower advanced pathological stage. However, 626-394T>C genotype was at increased risk of CRCs (P<0.001; odds ratio (OR) 1.457, CI 95%:1.160-1.829). Moreover, 626-394C/C genotype CRCs were more significantly common in patients with tumor size of >4 cm than T allele CRC and in cases of poor differentiation and lower advanced pathological stage. In conclusion, polymorphism in 626-394T>C was observed to be associated with susceptibility of CRC. However, 148505302C>T polymorphism indicated to play a protective role in susceptibility to CRC. Nevertheless, further investigation with a larger sample size is needed to support our results.