K-ras-ERK1/2 down-regulates H2A.XY142ph through WSTF to promote the progress of gastric cancer

Signaling pathways and therapeutic interventions in gastric cancer

Gastric cancer (GC) ranks fifth in global cancer diagnosis and fourth in cancer-related death. Despite tremendous progress in diagnosis and therapeutic strategies and significant improvements in patient survival, the low malignancy stage is relatively asymptomatic and many GC cases are diagnosed at advanced stages, which leads to unsatisfactory prognosis and high recurrence rates. With the recent advances in genome analysis, biomarkers have been identified that have clinical importance for GC diagnosis, treatment, and prognosis. Modern molecular classifications have uncovered the vital roles that signaling pathways, including EGFR/HER2, p53, PI3K, immune checkpoint pathways, and cell adhesion signaling molecules, play in GC tumorigenesis, progression, metastasis, and therapeutic responsiveness. These biomarkers and molecular classifications open the way for more precise diagnoses and treatments for GC patients. Nevertheless, the relative significance, temporal activation, interaction with GC risk factors, and crosstalk between these signaling pathways in GC are not well understood. Here, we review the regulatory roles of signaling pathways in GC potential biomarkers, and therapeutic targets with an emphasis on recent discoveries. Current therapies, including signaling-based and immunotherapies exploited in the past decade, and the development of treatment for GC, particularly the challenges in developing precision medications, are discussed. These advances provide a direction for the integration of clinical, molecular, and genomic profiles to improve GC diagnosis and treatments.

Downregulation of Williams syndrome transcription factor (WSTF) suppresses glioblastoma cell growth and invasion by inhibiting PI3K/AKT signal pathway

Williams syndrome transcription factor (WSTF) participates in diverse cellular processes, including tumor cell proliferation and migration. However, the function of WSTF in glioblastoma (GBM) remains unknown. Data from the Gene Expression Profiling Interactive Analysis (GEPIA) and The Cancer Genome Atlas (TCGA) datasets showed that WSTF was upregulated in GBM tissues. Moreover, WSTF was also increased in the GBM cells. pcDNA-mediated over-expression of WSTF contributed to cell proliferation and invasion of GBM cells, while GBM cell proliferation and invasion were suppressed by shRNA-mediated silencing of WSTF. Additionally, GBM cell apoptosis was reduced by over-expression of WSTF accompanied by decrease in Bax and cleaved caspase-3, while promoted by silencing of WSTF with increase in Bax and cleaved caspase-3. Protein expression of AKT phosphorylation was enhanced by WSTF over-expression while reduced by WSTF silencing. Inhibitor of phosphatidylinositol 3 kinase attenuated WSTF over-expression-induced increase in GBM cell proliferation and invasion. In conclusion, WSTF contributed to GBM cell growth and invasion through activation of PI3K/AKT pathway.

The emerging role of ISWI chromatin remodeling complexes in cancer

Disordered chromatin remodeling regulation has emerged as an essential driving factor for cancers. Imitation switch (ISWI) family are evolutionarily conserved ATP-dependent chromatin remodeling complexes, which are essential for cellular survival and function through multiple genetic and epigenetic mechanisms. Omics sequencing and a growing number of basic and clinical studies found that ISWI family members displayed widespread gene expression and genetic status abnormalities in human cancer. Their aberrant expression is closely linked to patient outcome and drug response. Functional or componential alteration in ISWI-containing complexes is critical for tumor initiation and development. Furthermore, ISWI-non-coding RNA regulatory networks and some non-coding RNAs derived from exons of ISWI member genes play important roles in tumor progression. Therefore, unveiling the transcriptional regulation mechanism underlying ISWI family sparked a booming interest in finding ISWI-based therapies in cancer. This review aims at describing the current state-of-the-art in the role of ISWI subunits and complexes in tumorigenesis, tumor progression, immunity and drug response, and presenting deep insight into the physiological and pathological implications of the ISWI transcription machinery in cancers.

AKT inhibits the phosphorylation level of H2A at Tyr57 via CK2α to promote the progression of gastric cancer

Background

Histone H2A and its variants have an important effect on DNA damage repair and cancer development. Protein kinase B (AKT) can regulate various cellular functions and play critical roles in the progression of different cancers. However, the interaction mechanism of H2A with AKT in gastric cancer (GC) has not been reported. A series of experiments were carried out in the present study to investigate this issue.

Methods

Firstly, we used western blot and immunoprecipitation assays to determine the correlation between AKT and H2A, then detected the relationship between AKT and protein kinase CK2α that can phosphorylate H2A at Tyr57 site (H2A^Y57), and next examined the interaction among AKT, CK2α, and H2A in SNU-16 cells. Subsequently, the effect of these molecules on the cellular proliferation, migration, and invasion was measured by Cell Counting Kit-8 (CCK-8), wound healing, and transwell invasion assays.

Results

Our study preliminarily found that AKT was negatively correlated with H2A phosphorylation at the Tyr 57 site (H2A^Y57p). It was revealed that AKT mediated the phosphorylation of CK2α at the T13 site, which decreased the affinity of CK2α with its substrate histone H2A and inhibited the level of H2A^Y57p in GC cells. Furthermore, AKT-mediated CK2α phosphorylation promoted the proliferation, migration, and invasion of SNU-16 cells possibly through downregulating H2A^Y57p level.

Conclusions

These findings contribute to understanding the interactions among AKT, CK2α, and H2A in GC, and provide the potential biomarkers for the diagnosis and treatment of GC.

Williams syndrome transcription factor promotes proliferation and invasion of cervical cancer cells by regulating PI3K/Akt signaling pathway

OBJECTIVE

This study aimed to investigate the expression of Williams Syndrome transcription factor (WSTF) in cervical cancer (CC) tissues and cells, the effect on the proliferation, migration, invasion, and the molecular mechanism of WSTF in CC cells to find a new biomarker.

MATERIALS AND METHODS

The expression of WSTF in tissues was detected by real-time quantitative polymerase chain reaction (RT-qPCR) and/or immunohistochemistry. Human CC cell lines and human normal cervical epithelial cell lines were detected by RT-qPCR. Lentivirus-mediated gene transfected in Siha/CaSki cells. The transfection efficiency of lentivirus was observed by a fluorescence microscope, RT-qPCR, and western blot. After transfection, the proliferation of Siha/CaSki cells was detected by CCK-8 assay and colony formation assay. The migration and invasion of Siha/CaSki cells were detected by transwell assay and wound healing assay. Western blot assay were used to detect the expression of WSTF and PI3K/Akt-related proteins in Siha/CaSki cells.

RESULTS

The expression of WSTF in CC tissues was higher than that in adjacent tissues (p < 0.05). The expression of WSTF in CC cells was higher than that in normal cervical epithelial cells (p < 0.01). Downregulation of WSTF expression could inhibit the proliferation, migration, and invasion of CC cells (p < 0.01). WSTF overexpression activates PI3K/Akt signaling pathway (p < 0.01).

CONCLUSION

WSTF is highly expressed in CC tissues and cells, and downregulation of WSTF can inhibit the proliferation, invasion, and migration of CC cells by activating the PI3K/Akt signaling pathway. WSTF is a very promising new biomarker for CC.

LncRNA PROX1-AS1 Facilitates Gastric Cancer Progression via miR-877-5p/PD-L1 Axis

Introduction

Growing evidences imply that multiple long non-coding RNAs (lncRNAs) play a significant role in the treatment of cancer. Therefore, it is of great significance to discover new biomarkers or therapeutic targets of gastric cancer (GC). However, the potential molecular mechanism of lncPROX1-AS1 in GC remains unknown. The objective of current study is to investigate the effect of PROX1-AS1 in GC.

Methods

Thus, we detect that PROX1-AS1 is over-expressed in tissues and cell lines of GC using qRT-PCR analysis. CCK-8, colony formation, flow cytometry, wounding healing and transwell analyses were performed to explore the effect of PROX1-AS1 on GC malignant behaviors.

Results

It is further disclosed that silencing of PROX1-AS1 represses cell proliferation, migration, and invasion, whereas promotes cell apoptosis in GC. Bioinformatics analysis suggests that miR-877-5p is negatively regulated by PROX1-AS1 and ectopic of miR-877-5p alleviates the malignant behaviors of GC. Subsequently, miR-877-5p suppresses the activity of PD-L1-3ʹ UTR. At last, rescue assays demonstrated that the GC progression is suppressed by sh-PROX1-AS1 and facilitated on account of miR-877-5p inhibitors and then is retrieved by sh-PD-L1.

Discussion

Our findings reveal that PROX1-AS1 exerts its role via miR-877-5p/PD-L1 axis in the GC progression, suggesting that PROX1-AS1 may represent a new therapeutic target for the diagnosis and treatment of GC patients.

A comprehensive review on the role of protein tyrosine phosphatases in gastric cancer development and progression

The main post-translational reversible modulation of proteins is phosphorylation and dephosphorylation, catalyzed by protein kinases (PKs) and protein phosphatases (PPs) which is crucial for homeostasis. Imbalance in this crosstalk can be related to diseases, including cancer. Plenty of evidence indicates that protein tyrosine phosphatases (PTPs) can act as tumor suppressors and tumor promoters. In gastric cancer (GC), there is a lack of understanding of the molecular aspects behind the tumoral onset and progression. Here we describe several members of the PTP family related to gastric carcinogenesis. We discuss the associated molecular mechanisms which support the down or up modulation of different PTPs. We emphasize the Helicobacter pylori (H. pylori) virulence which is in part associated with the activation of PTP receptors. We also explore the involvement of intracellular redox state in response to H. pylori infection. In addition, some PTP members are under influence by genetic mutations, epigenetics mechanisms, and miRNA modulation. The understanding of multiple aspects of PTPs in GC may provide new targets and perspectives on drug development.

High expression of the CKIP-1 gene might promote apoptosis through downregulation of the Ras/ERK signalling pathway in the intestinal type of gastric cancer

Objective

To investigate the effect of the casein kinase 2 interacting protein 1 (CKIP-1) on the apoptosis of the intestinal type of gastric cancer (GC).

Methods

The levels of CKIP-1 protein and the rates of apoptosis were measured in tissue samples of the intestinal type of GC and human GC cell lines. The rate of apoptosis and the protein levels of B cell lymphoma-2 (Bcl-2), Bcl-2 associated X protein (Bax), cleaved cysteinyl aspartate specific protease 3 (cleaved caspase-3), cleaved caspase-9, rat sarcoma (Ras), extracellular signal-regulated kinase 1 and 2 (ERK1/2) and phosphorylated extracellular signal-regulated kinase 1 and 2 (p-ERK1/2) were analysed in SGC7901 cells expressing CKIP-1 short hairpin RNA (shRNA; knockdown) and SGC7901 cells overexpressing CKIP-1.

Results

The levels of CKIP-1 protein were significantly lower in the intestinal type of GC tissues compared with the samples of intestinal metaplasia. Both the levels of CKIP-1 protein and the levels of apoptosis decreased gradually with decreasing cell differentiation in the intestinal type of GC tissue and cell lines; and they were positively correlated. In the CKIP-1 shRNA group, the rate of apoptosis and the levels of Bax, cleaved caspase-3 and cleaved caspase-9 were decreased; and the levels of Bcl-2, Ras and the ratio of p-ERK/ERK were increased, compared with the control group. Opposite results were observed in the CKIP-1 overexpression group.

Conclusion

High levels of CKIP-1 protein may promote apoptosis in the intestinal type of GC, possibly via the downregulation of the Ras/ERK signalling pathway.

Akt regulates RSK2 to alter phosphorylation level of H2A.X in breast cancer

Histone H2AX (H2A.X) is a variant of the histone H2A family. Phosphorylation of H2A.X is a marker of DNA strand breaks and the presence or absence of H2A.X is closely related to tumor susceptibility and drug resistance. The present study found that the activity of the serine/threonine kinase Akt was negatively associated with H2A.X phosphorylated at the Ser16 site (H2A.X S16ph), but the mechanism of the inverse relationship remains elusive. The aim of the present study was to elucidate the mechanism of action between Akt and H2A.X S16ph and the exact role of this mechanism. Western blot analysis was performed to detect the regulatory association between p-Akt and H2A.X S16ph/p-RSK2, and immunoprecipitation and chromatin immunoprecipitation were performed to prove that Akt, RSK2 and H2A.X combine and interact in human breast cancer cells. The changes of cellular proliferation and migration induced by the interaction of Akt, RSK2 and H2A.X was determined by MTT, soft agar colony formation and cell migration experiments. The effect of interaction of Akt, RSK2 and H2A.X on cancer-promoting genes, such as PSAT-1 was determined via reverse transcription-quantitative PCR analysis. The current study indicated that the serine/threonine kinase ribosomal S6 kinase 2 (RSK2) as a kinase of H2A.X could be phosphorylated by Akt at Ser19 site. Moreover, Akt positively regulated the phosphorylation of RSK2 to inhibit phosphorylation of H2A.X, thereby affecting the affinity between RSK2 and substrate histone, promoting the survival and migration of breast cancer cells. In conclusion, Akt-mediated phosphorylation of RSK2 regulated the phosphorylation of H2A.X, thereby promoting oncogenic activity. This finding provides new insights to understand the pathogenesis and treatment mechanisms of breast cancer.

A Novel 10-Gene Signature Predicts Poor Prognosis in Low Grade Glioma

AIM

Low grade glioma (LGG) is a lethal brain cancer with relatively poor prognosis in young adults. Thus, this study was performed to develop novel molecular biomarkers to effectively predict the prognosis of LGG patients and finally guide treatment decisions.

METHODS

survival-related genes were determined by Kaplan-Meier survival analysis and multivariate Cox regression analysis using the expression and clinical data of 506 LGG patients from The Cancer Genome Atlas (TCGA) database and independently validated in a Chinese Glioma Genome Atlas (CGGA) dataset. A prognostic risk score was established based on a linear combination of 10 gene expression levels using the regression coefficients of the multivariate Cox regression models. GSEA was performed to analyze the altered signaling pathways between the high and low risk groups stratified by median risk score.

RESULTS

We identified a total of 1489 genes significantly correlated with patients' prognosis in LGG. The top 5 protective genes were DISP2, CKMT1B, AQP7, GPR162 and CHGB, the top 5 risk genes were SP1, EYA3, ZSCAN20, ITPRIPL1 and ZNF217 in LGG. The risk score was predictive of poor overall survival and relapse-free survival in LGG patients. Pathways of small cell lung cancer, pathways in cancer, chronic myeloid leukemia, colorectal cancer were the top 4 most enriched pathways in the high risk group. SP1, EYA3, ZSCAN20, ITPRIPL1, ZNF217 and GPR162 were significantly up-regulated, while DISP2, CKMT1B, AQP7 were down-regulated in 523 LGG tissues as compared to 1141 normal brain controls.

CONCLUSIONS

The 10-gene signature may become novel prognostic and diagnostic biomarkers to considerably improve the prognostic prediction in LGG.

The role of non-H. pylori bacteria in the development of gastric cancer

There is a complex ecosystem of bacteria and other microorganisms inside and outside the human body, which play an intricate role in maintaining health. In recent years, many researches focused on the relationship between microorganisms and cancer. Studies have identified that numerous microbes are presented in human stomach, which are closely linked to the development of gastric cancer (GC). Helicobacter pylori (H. pylori) is the mostly well-studied bacterial pathogen in the stomach, which account for the vast majority of GC. However, recent studies have found that microflora dysbiosis was occurred in mucosa of GC patients, and evidences have potentially proved that microbes other than H. pylori are also contribute to the development of GC, while the overall knowledge is still limited. In this review, we summarized the role of gastric flora in GC, especially the possible role of non-H. pylori bacteria in the development of GC. These knowledges and awareness may open doors for new therapeutic strategies of GC.

MAP Kinases Pathways in Gastric Cancer

Gastric cancer (GC) is turning out today to be one of the most important welfare issues for both Asian and European countries. Indeed, while the vast majority of the disease burden is located in China and in Pacific and East Asia, GC in European countries still account for about 100,000 deaths per year. With this review article, we aim to focus the attention on one of the most complex cellular pathways involved in GC proliferation, invasion, migration, and metastasis: the MAP kinases. Such large kinases family is to date constantly studied, since their discovery more than 30 years ago, due to the important role that it plays in the regulation of physiological and pathological processes. Interactions with other cellular proteins as well as miRNAs and lncRNAs may modulate their expression influencing the cellular biological features. Here, we summarize the most important and recent studies involving MAPK in GC. At the same time, we need to underly that, differently from cancers arising from other tissues, where MAPK pathways seems to be a gold target for anticancer therapies, GC seems to be unique in any aspect. Our aim is to review the current knowledge in MAPK pathways alterations leading to GC, including H. pylori MAPK-triggering to derail from gastric normal epithelium to GC and to encourage researches involved in MAPK signal transduction, that seems to definitely sustain GC development.