Knockdown of GRHL3 inhibits activities and induces cell cycle arrest and apoptosis of human colorectal cancer cells

A large-scale cancer-specific protein-DNA interaction network

Cancer development and progression are generally associated with gene dysregulation, often resulting from changes in the transcription factor (TF) sequence or expression. Identifying key TFs involved in cancer gene regulation provides a framework for potential new therapeutics. This study presents a large-scale cancer gene TF-DNA interaction network, as well as an extensive promoter clone resource for future studies. Highly connected TFs bind to promoters of genes associated with either good or poor cancer prognosis, suggesting that strategies aimed at shifting gene expression balance between these two prognostic groups may be inherently complex. However, we identified potential for oncogene-targeted therapeutics, with half of the tested oncogenes being potentially repressed by influencing specific activators or bifunctional TFs. Finally, we investigate the role of intrinsically disordered regions within the key cancer-related TF ESR1 in DNA binding and transcriptional activity, and found that these regions can have complex trade-offs in TF function. Altogether, our study broadens our knowledge of the TFs involved in cancer gene regulation and provides a valuable resource for future studies and therapeutics.

lncRNA SNHG4 modulates colorectal cancer cell cycle and cell proliferation through regulating miR-590-3p/CDK1 axis

Colorectal cancer (CRC) is a prevalent malignancy worldwide. The development of genome sequencing technology has allowed the discovery that epigenetic regulation might play a critical role in CRC tumorigenesis. In the present study, we found that the long noncoding RNA (lncRNA) SNHG4 was dramatically increased in CRC tissue samples and cell lines based on both publicly available and experimental data. SNHG4 knockdown suppressed the viability and colony formation capacity of CRC cells. The expression of CDK1 was considerably increased in CRC tissue samples and cells and had a positive correlation with the expression of SNHG4 in CRC. SNHG4 silencing not only caused S phase cell cycle arrest but also significantly downregulated the CDK1, cyclin B1, and cyclin A2 protein levels in CRC cells. miR-590-3p simultaneously bound to SNHG4 and CDK1. miR-590-3p functioned to inhibit CDK1 expression. miR-590-3p overexpression exerted the same effects on the CRC cell phenotype as SNHG4 knockdown. The effects of si-SNHG4 on CRC cells were significantly reversed by anti-miR-590-3p, indicating that SNHG4 relieved the miR-590-3p-induced inhibition of CDK1 by acting as a competing endogenous RNA (ceRNA). In vivo, SNHG4 silencing inhibited subcutaneously transplanted tumor growth and decreased cell cycle marker levels, whereas miR-590-3p inhibition exerted the opposite effects. The in vivo effects of SNHG4 silencing were also reversed by miR-590-3p inhibition. The SNHG4/miR-590-3p/CDK1 axis influences the cell cycle to modulate CRC cell proliferation and subcutaneously transplanted tumor growth. Further application of this axis still requires analysis using more animal models and clinical investigations.

Grainyhead-Like 3 Influences Migration and Invasion of Urothelial Carcinoma Cells

Invasive urothelial carcinomas of the bladder (UCB) characteristically show a loss of differentiation markers. The transcription factor Grainyhead-like 3 (GRHL3) plays an important role in the development and differentiation of normal urothelium. The contribution to UCB progression is still elusive. Differential expression of GRHL3 was assessed in normal human urothelium and in non-invasive and invasive bladder cancer cell lines. The contribution of GRHL3 to cell proliferation, viability and invasion in UCB cell lines was determined by gain- and loss-of-function assays in vitro and in an organ culture model using de-epithelialized porcine bladders. GRHL3 expression was detectable in normal human urothelial cells and showed significantly higher mRNA and protein levels in well-differentiated, non-invasive RT4 urothelial carcinoma cells compared to moderately differentiated RT112 cells. GRHL3 expression was absent in anaplastic and invasive T24 cells. Ectopic de novo expression of GRHL3 in T24 cells significantly impaired their migration and invasion properties in vitro and in organ culture. Its downregulation improved the invasive capacity of RT4 cells. The results indicate that GRHL3 may play a role in progression and metastasis in UCB. In addition, this work demonstrates that de-epithelialized porcine bladder organ culture can be a useful, standardized tool to assess the invasive capacity of cancer cells.

Porphyromonas gingivalis Promotes the Proliferation and Migration of Esophageal Squamous Cell Carcinoma through the miR-194/GRHL3/PTEN/Akt Axis

Recent studies have revealed that Porphyromonas gingivalis is closely related to the occurrence and progression of esophageal squamous cell carcinoma (ESCC). However, the underlying mechanism of P. gingivalis in ESCC has not been well elucidated. To explore the mechanism of P. gingivalis infection in ESCC, cellular proliferation, invasion, and migration models of KYSE-30 and KYSE-150 cells infected by P. gingivalis at a multiplicity of infection (MOI) of 10 were established. The results showed that P. gingivalis infection could drastically increase the proliferation, invasion, and migration ability of ESCC. Furthermore, the results of high-throughput sequencing showed that miR-194 was considerably upregulated in infected cells compared with control cells, which was further verified by qRT-PCR. The inhibition or overexpression of miR-194 had a significant effect on KYSE-30 and KYSE-150 cell migration and invasion. Additionally, the levels of GRHL3 and PTEN were decreased in P. gingivalis-infected esophageal cancer cells compared with uninfected esophageal cancer cells. Furthermore, dual-luciferase experiments confirmed that GRHL3 is a direct target of miR-194. In addition, the GRHL3-related pathway was investigated, and the levels of GRHL3 and PTEN were downregulated while the level of p-Akt was upregulated after P. gingivalis infection. Taken together, these findings indicated that P. gingivalis might promote ESCC proliferation and migration via the miR-194/GRHL3/PTEN/Akt signaling axis.

Grainyhead-Like Genes Family May Act as Novel Biomarkers in Colon Cancer

OBJECTIVE

The Grainyhead-like (GRHL) genes family were reported to participate in the development of a number of diseases. This study was designed to investigate the role of GRHL genes family in colon cancer (CC).

METHODS

In this study, the transcriptional levels of GRHL genes family in patients with CC from GEPIA were explored. Meanwhile, the immunohistochemical data of the GRHL genes family were also obtained in the HPA database. Additionally, we re-identified the mRNA of these genes via real-time PCR. Furthermore, the association between the levels of GRHL genes and stage plot as well as survival condition including overall survival and disease-free survival of patients with CC was analyzed. Finally, by transfecting with specific-siRNA, clone formation assay was performed to observe the role of GRHL genes family in the proliferation of SW480 human colon cancer cells.

RESULTS

We found that the mRNA and protein levels of GRHL1, GRHL2 and GRHL3 were significantly higher in CC tissues than in normal colon tissues. Additionally, GRHL1, GRHL2 and GRHL3 were significantly associated with the stages of CC. The Kaplan-Meier plotter showed that the low levels of GRHL1, GRHL2 and GRHL3 conferred a better overall survival of patients with CC while the high levels of GRHL1 and GRHL3 were associated with poor disease-free survival. Knockdown of GRHL1, GRHL2 and GRH L3 siHgnificantly inhibited the ability of colony formation of human colon cancer cells.

CONCLUSION

Our study demonstrated that GRHL genes are involved in the prognosis and survival in patients with CC, the inhibition of which may suppress the proliferation of colon cancer cells.

Grainyhead-like transcription factors in cancer - Focus on recent developments

The role of grainyhead-like transcription factors in cancer has been widely investigated by the scientific community. However, some of its aspects do not seem to be adequately appreciated, and these are the topic of our article. In addition to their well-documented role as tumor suppressors, in many cases the grainyhead-like proteins perform tumor-promoting functions, which make them potential drug targets. However, it is difficult to directly target transcription factors, which is why we recommend an alternative approach. The transcriptional transactivation activity of grainyhead-like transcription factors is regulated by phosphorylation, and protein kinases are much more feasible drug targets. Studying the phosphorylation of grainyhead-like proteins may thus allow to identify protein kinases regulating the activity of these factors, and design inhibitors of these kinases to indirectly regulate the activity of grainyhead-like transcription factors. There are many somatic mutations in the GRHL genes that occur during cancer development. These mutations are widely distributed across the GRHL loci, and these mutations are very rare. For this reason, they are unlikely to become targets of future therapies, nevertheless some of them may be driver mutations and studying them may provide important novel information about the regulation of functioning of the GRHL genes and proteins. Analogous information may be obtained by studying single nucleotide polymorphisms in GRHL genes that are associated with disease risk. Such polymorphisms may also prove useful in identifying individuals with an increased risk of a particular disease.

Impact statement

In the present article, we focus on relatively little appreciated aspects of involvement of the grainyhead-like (GRHL) transcription factors in cancer. These aspects are nevertheless very important for the functioning of GRHL proteins, as well as for cancer development. Some of the GRHL factors perform tumor-promoting functions in certain types of cancer, which makes them potential drug targets. Much information is available about somatic cancer mutations in the GRHL genes, yet there are very few analyses of these mutations in the scientific literature. The activity of GRHL transcription factors is controlled by phosphorylation, and we suggest that regulating their phosphorylation with specific protein kinases provides an alternative approach to modify the activity of GRHL proteins. Some single nucleotide polymorphisms (SNPs) in the GRHL genes are associated with disease risk. Studying such SNPs may yield new information about the functioning of GRHL genes and proteins, and may also allow to identify people with an increased risk of a particular disease.