Hongzhuan Yin

Overexpression of integrin-linked kinase (ILK) promotes migration and invasion of colorectal cancer cells by inducing epithelial-mesenchymal transition via NF-κB signaling.

Integrin-linked kinase (ILK), a ubiquitously expressed and evolutionally conserved serine/threonine kinase, has been shown to be aberrantly overexpressed and activated in diversified types of human malignancies, including colorectal cancer (CRC). However, the potential role of ILK in cancer cell migration and invasion remains to be elucidated. In this study, we introduced the human ILK gene into a low ILK-expressing human CRC cell line SW480. Cell migration and invasion were evaluated by the wound healing assay and transwell invasion assay, respectively. The epithelial-mesenchymal transition (EMT)-related proteins were detected by Western blot analysis or immunofluorescence. We found that enforced overexpression of ILK in SW480 cells dramatically promoted their migratory and invasive ability in vitro. Furthermore, SW480 cells stably overexpressing ILK underwent EMT, as indicated by mesenchymal morphology, decreased expression of E-cadherin, and increased expression of vimentin, Snail, and Slug. Finally, the nuclear factor (NF)-κB inhibitor BAY 11-7028 or NF-κB p65 small interfering RNA significantly restored the reduced E-cadherin level in ILK-overexpressing cells, suggesting that ILK-mediated down-regulation of E-cadherin is dependent on NF-κB activation. Overall, our study demonstrates a pivotal role of ILK in EMT and metastasis, and suggests novel therapeutic opportunities for the treatment of CRC.

High Expression of Polo-Like Kinase 1 Is Associated with Early Development of Hepatocellular Carcinoma

Polo-like kinase 1 (PLK1), one of serine/threonine-protein kinase, has been demonstrated to play pivotal roles in malignant transformation. Here we illustrated the clinicopathological significance of PLK1 expression in hepatocellular carcinoma (HCC) in more detail. Immunohistochemistry was performed to detect the expression of PLK1 in 67 HCC patients as well as corresponding noncancerous liver tissues. In addition, the correlation of PLK1 expression with clinicopathological factors or prognosis of HCC was analyzed. Results showed that the expression of PLK1 was increased significantly in HCC tissues than that of corresponding normal liver tissues. The correlation between PLK1 and HCC cell differentiation or capsule invasion was also revealed. We found that PLK1 inhibition promoted cell arrest in G2/M phase of cell cycle and cell apoptosis. Our results also indicated that the potential mechanisms of PLK1 inhibition regulating cell growth involved enhancing expression of caspase3, caspase8, and Bax and decreasing expression of Bcl-2. Furthermore, we also found that PLK1 downregulation inducing inhibition of cell growth was associated with enhancing expression of p53. Thus, we presume that the status of PLK1 expression might be an independent prognostic factor for HCC and targeting PLK1 might be a useful strategy for diagnosis and treatment of human HCC.

Mutation spectrum in human colorectal cancers and potential functional relevance

BackgroundSomatic variants, which occur in the genome of all cells, are well accepted to play a critical role in cancer development, as their accumulation in genes could affect cell proliferations and cell cycle.MethodsIn order to understand the role of somatic mutations in human colorectal cancers, we characterized the mutation spectrum in two colorectal tumor tissues and their matched normal tissues, by analyzing deep-sequenced transcriptome data.ResultsWe found a higher mutation rate of somatic variants in tumor tissues in comparison with normal tissues, but no trend was observed for mutation properties. By applying a series of stringent filters, we identified 418 genes with tumor specific disruptive somatic variants. Of these genes, three genes in mucin protein family (MUC2, MUC4, and MU12) are of particular interests. It has been reported that the expression of mucin proteins was correlated with the progression of colorectal cancer therefore somatic variants within those genes can interrupt their normal expression and thus contribute to the tumorigenesis.ConclusionsOur findings provide evidence of the utility of RNA-Seq in mutation screening in cancer studies, and suggest a list of candidate genes for future colorectal cancer diagnosis and treatment.

Knockdown of protein phosphatase magnesium-dependent 1 (PPM1D) through lentivirus-mediated RNA silencing inhibits colorectal carcinoma cell proliferation.

Colorectal cancer is one of the most common cancers in the world. Protein phosphatase magnesium-dependent 1δ (PPM1D) is aberrantly upregulated in many human carcinoma cells, and recent research has suggested that it could be a potential therapeutic target of cancer. However, the function of PPM1D in colorectal carcinoma cells is not well studied. To investigate the function of PPM1D in colorectal carcinoma, we used lentivirus-based RNA silencing to knock down the expression of PPM1D in RKO cells. We found that the lentivirus-mediated RNAi system efficiently decreased the expression level of endogenous PPM1D. Inhibiting PPM1D expression efficiently inhibited the proliferation and colony formation of RKO cells. Moreover, we found that PPM1D silencing led to G0/G1 cell-cycle arrest and the accumulation of cells at the sub-G1 phase. Furthermore, we found that PPM1D knockdown reduced the expression level of cyclinB1, inhibited ERK phosphorylation and activated the AKT signaling pathway. We found that PPM1D plays a crucial role in colorectal carcinoma cell proliferation and colony formation. Our work provides strong evidence suggesting that PPM1D is a potential therapeutic target of human colorectal cancers. Lentivirus-mediated PPM1D silencing is a promising gene therapeutic method to treat colorectal cancers.

The function of BTG3 in colorectal cancer cells and its possible signaling pathway

PurposeB-cell translocation gene 3 (BTG3) has been identified as a candidate driver gene for various cancers, but its specific role in colorectal cancer (CRC) is poorly understood. We aimed to investigate the relationship between expression of BTG3 and clinicopathological features and prognosis, as well as to explore the effects and the role of a possible BTG3 molecular mechanism on aggressive colorectal cancer behavior.MethodsBTG3 expression was assessed by immunohistochemistry (IHC) on specimens from 140 patients with CRC. The association of BTG3 expression with clinicopathological features was examined. To confirm the biological role of BTG3 in CRC, two CRC cell lines expressing BTG3 were used and BTG3 expression was knocked down by shRNA. CCK-8, cell cycle, apoptosis, migration, and invasion assays were performed. The influence of BTG3 knockdown was further investigated by genomic microarray to uncover the potential molecular mechanisms underlying BTG3-mediated CRC development and progression.ResultsBTG3 was downregulated in colorectal cancer tissues and positively correlated with pathological classification (p = 0.037), depth of invasion (p = 0.016), distant metastasis (p = 0.024), TNM stage (p = 0.007), and overall survival (OS) and disease-free survival (DFS). BTG3 knockdown promoted cell proliferation, migration, invasion, relieved G2 arrest, and inhibited apoptosis in HCT116 and LoVo cells. A genomic microarray analysis showed that numerous tumor-associated signaling pathways and oncogenes were altered by BTG3 knockdown. At the mRNA level, nine genes referred to the extracellular-regulated kinase/mitogen-activated protein kinase pathway were differentially expressed. Western blotting revealed that BTG3 knockdown upregulated PAK2, RPS6KA5, YWHAB, and signal transducer and activator of transcription (STAT)3 protein levels, but downregulated RAP1A, DUSP6, and STAT1 protein expression, which was consistent with the genomic microarray data.ConclusionsBTG3 expression might contribute to CRC carcinogenesis. BTG3 knockdown might strengthen the aggressive colorectal cancer behavior.

Naringenin induces laxative effects by upregulating the expression levels of c-Kit and SCF, as well as those of aquaporin 3 in mice with loperamide-induced constipation

Constipation is a common affliction which causes discomfort and affects the quality of life of affected individuals. Naringenin (NAR), a natural flavonoid widely found in citrus fruits and tomatoes, has been reported to exhibit various pharmacological effects, such as anti-inflammatory, anti-atherogenic, anti-mutagenic, hepatoprotective and anticancer effects. Increasing evidence has indicated that NAR has potential for use in the treatment of constipation. Thus, the aim of this study was to evaluate the laxative effects of NAR in mice with loperamide-induced (Lop-induced) constipation. The data indicated that NAR relieved Lop-induced constipation in mice based on the changes of fecal parameters (numbers, weight and water content), the intestinal charcoal transit ratio and the histological alteration. ELISA revealed that NAR regulated the production levels of gastrointestinal metabolic components, such as motilin (MTL), gastrin (Gas), endothelin (ET), substance P (SP), acetylcholinesterase (AChE) and vasoactive intestinal peptide (VIP) in serum. The expression levels of enteric nerve-related factors, glial cell line-derived neurotrophic factor (GDNF), transient receptor potential vanilloid 1 (TRPV1), nitric oxide synthase (NOS), c-Kit, stem cell factor (SCF) and aquaporin 3 (AQP3) were examined by western blot analysis and RT-PCR analysis. The results of this study suggest that NAR relieves Lop-induced constipation by increasing the levels of interstitial cells of Cajal markers (c-Kit and SCF), as well as AQP3. Thus, NAR may be effective as a candidate in patients suffering from lifestyle-induced constipation.

Expression profile analyses of human HCT-116 colon cancer cell line before and after serum induction.

Multi-exon genes may generate distinct isoforms in different conditions and exhibit versatile properties. Here we investigated the isoform-specific gene expression and the gene expression changes of without and with serum-induced human HCT-116 colon cancer cell lines. For these analyses, 4 transcriptome sequencing datasets were used and 2 replicates for each condition. We observed that ~73% of those expressed genes in four samples generated only one isoform, while ~27% encoded at least two isoforms. Our results show that human gene expression can exhibit great flexibility in alternative splicing. Those expressed genes generated ~1.4 isoforms for each gene across four samples on average. In addition, most of these expressed genes were expressed at moderate or low levels. We found that these four samples have similar patterns of their gene expression distributions. Furthermore, we also conducted the differential expression analysis between without and with serum-induced two conditions of these four samples. We detected that 123 genes were differentially expressed and 110 of them were up-regulated. Among those differentially expressed genes, we found intriguing phenomena that a portion of them could be clustered into different functional groups and some oncogenes and proto-oncogenes are differentially expressed.