Ke Ji

The Kiss‑1/Kiss‑1R complex as a negative regulator of cell motility and cancer metastasis (Review)

Metastasis is a complex multistep process that involves the impairment of cell-cell adhesion in the neoplastic epithelium, invasion into adjacent tissues and the dissemination of cancer cells through the lymphatic and haematogenous routes. The inhibition of the metastatic process at an early stage has become a hot topic in cancer research. The Kiss-1 gene, initially described as a suppressor of metastasis in malignant melanoma, encodes the Kiss-1 protein which can be processed to other peptides, e.g., Kisspeptin-10, Kisspeptin-13, Kisspeptin-14 and Kisspeptin-54. These peptides are endogenous ligands of the Kiss‑1 receptor (Kiss-1R), a G protein-coupled receptor (GPR) also known as hOT7T175, AXOR12 or GPR54. The Kiss-1 gene has been suggested as a suppressor of metastasis in a various types of cancer, including gastric cancer, oesophageal carcinoma, pancreatic, ovarian, bladder and prostate cancer, through the regulation of cellular migration and invasion. In the current review, we summarise the current understanding of the role of Kiss‑1 and Kiss‑1R in cancer and cancer metastasis.

Implication of metastasis suppressor gene, Kiss-1 and its receptor Kiss-1R in colorectal cancer

BackgroundKiss-1 and Kiss-1R have been suggested as a novel pair of metastasis suppressors for several human solid tumours, however, their role in colorectal cancer remains largely unknown. Therefore, the aim of this study was to investigate the role and signal transduction of Kiss-1 and Kiss-1R in colorectal cancer.MethodsRibozyme transgenes were used to knockdown high expression of Kiss-1 and Kiss-1R in HT115 and HRT18 cells. The stabilized transfected cells were then used to deduce the influence of Kiss-1 and Kiss-1R on the function of colorectal cancer cells by in vitro assays and ECIS assay. The effect of Kiss-1 on MMPs related to tumour metastasis was also deleted by zymography. The mRNA and protein expression of Kiss-1 and Kiss-1R, and their correlation to the clinical outcome in human colorectal cancer were investigated using real-time PCR and IHC respectively.ResultsKnocking down Kiss-1 resulted in increased invasion and migration of colorectal cancer cells. Kisspeptin-10 decreased cellular migration of colorectal cancer cells and required ERK signaling as shown during the ECIS based analyses. Reduction of MMP-9 was caused by Kisspeptin-10 and ERK inhibitor, shown by zymography. In human colorectal cancer tissues, the mRNA expression level of Kiss-1 had a negative correlation with Dukes staging, TNM staging, tumour size and lymph node involvement. Reduction of Kiss-1R was also linked to poor prognosis for the patients.ConclusionsThe present study has presented evidence that Kiss-1 may be a putative metastasis suppressor molecule in human colorectal cancer.

WISP-2 in human gastric cancer and its potential metastatic suppressor role in gastric cancer cells mediated by JNK and PLC-γ pathways

Background:It has recently been shown that WISP proteins (Wnt-inducted secreted proteins), a group of intra- and extra-cellular regulatory proteins, have been implicated in the initiation and progression of a variety of tumour types including colorectal and breast cancer. However, the role of WISP proteins in gastric cancer (GC) cells and their clinical implications have not yet been elucidated.Methods:The expression of WISP molecules in a cohort of GC patients was analysed using real-time quantitative PCR and immunohistochemistry. The expression of a panel of recognised epithelial–mesenchymal transition (EMT) markers was quantified using Q-PCR in paired tumour and normal tissues. WISP-2 knockdown (kd) sublines using ribozyme transgenes were created in the GC cell lines AGS and HGC27. Subsequently, several biological functions, including cell growth, adhesion, migration and invasion, were studied. Potential pathways for the interaction of EMT, extracellular matrix and MMP were evaluated.Results:Overexpression of WISP-2 was detected in GC and significantly correlated with early tumour node-metastasis staging, differentiation status and positively correlated with overall survival and disease-free survival of the patients. WISP-2 expression was inversely correlated with that of Twist and Slug in paired samples. Kd of WISP-2 expression promoted the proliferation, migration and invasion of GC cells. WISP-2 suppressed GC cell metastasis through reversing EMT and suppressing the expression and activity of MMP9 and MMP2 via JNK and ERK. Cell motility analysis indicated that WISP-2 kd contributed to GC cells’ motility and can be attenuated by PLC-γ and JNK small inhibitors.Conclusions:Increased expression of WISP-2 in GC is positively correlated with favourable clinical features and the survival of patients with GC and is a negative regulator of growth, migration and invasion in GC cells. These findings suggest that WISP-2 is a potential tumour suppressor in GC.

Wnt1 inducible signalling pathway protein-2 (WISP‑2/CCN5): Roles and regulation in human cancers (Review)

Wnt1 inducible signalling pathway protein-2 (WISP‑2), also known as CCN5, CT58, CTGF-L, CTGF-3, HICP and Cop1, is one of the 3 WNT1 inducible proteins that belongs to the CCN family. This family of members has been shown to play multiple roles in a number of pathophysiological processes, including cell proliferation, adhesion, wound healing, extracellular matrix regulation, epithelial-mesenchymal transition, angiogenesis, fibrosis, skeletal development and embryo implantation. Recent results suggest that WISP-2 is relevant to tumorigenesis and malignant transformation, particularly in breast cancer, colorectal cancer and hepatocarcinoma. Notably, its roles in cancer appear to vary depending on cell/tumour type and the microenvironment. The striking difference in the structure of WISP-2 in comparison with the other 2 family members may contribute to its difference in functions, which leads to the hypothesis that WISP-2 may act as a dominant-negative regulator of other CCN family members. In the present review, we summarise the roles, regulation and underlying mechanism of WISP-2 in human cancers.

Inhibition of sphingosine-1-phosphate phosphatase 1 promotes cancer cells migration in gastric cancer: Clinical implications Corrigendum in /10.3892/or.2018.6269

Sphingosine-1-phosphate (S1P) plays an important role in regulating many biological processes. Sphingosine-1-phosphate phosphatase 1 (SGPP1) can dephosphorylate S1P into sphingosine and tip the balance of sphingosine-S1P. Increased levels of sphingosine leads to a decrease in the ability of cell invasion as well as an increase in the ability of cell apoptosis. However, little is known regarding the effects of SGPP1 in gastric cancer. The present study examined the function of SGPP1 on gastric cancer cell lines as well as its clinical relevance in gastric cancer progression. Using immunohistochemistry and RT-qPCR techniques, the clinical significance of SGPP1 expression was analyzed in 288 paraffin-embedded gastric tissue specimens and 219 fresh gastric tissues, respectively. Transgenes encoding ribozymes to specifically target human SGPP1 (pEF-SGPP1) was constructed. Human gastric cancer cell lines (AGS and HGC27) were transfected with pEF-SGPP1 transgene and examined by functional analysis. SGPP1 was downregulated in gastric cancer tissues, compared with adjacent normal gastric tissues (p=0.034). SGPP1 mRNA levels in gastric cancer tissues were significantly decreased when compared with their adjacent non-cancerous tissues (p<0.001). Weakly expressed SGPP1 was positively correlated with the lymph node metastasis (p=0.005) and distant metastasis (p=0.031). Kaplan-Meier survival curves revealed that patients with SGPP1 positive expression had a significant increase in overall survival (OS) (p=0.034) and progression-free survival (PFS) (p=0.041). Multivariate analysis indicated the expression of SGPP1 was an independent prognostic factor in gastric cancer patients (p=0.041). In vitro experiments showed that knockdown of SGPP1 resulted in an increase in the invasion (2-fold) and migration (5-fold) of AGS and HGC27. The two gastric cancer cells transfected with pEF-SGPP1 exhibited a slower rate of growth with less adhesion. Thus, our findings provided evidence that SGPP1 may serve as a prognostic biomarker for patients with advanced gastric cancers.

Antitumour effects of Yangzheng Xiaoji in human osteosarcoma: The pivotal role of focal adhesion kinase signalling

The present study examined, in vitro and in vivo, the potential antitumour effects of Yangzheng Xiaoji (YZXJ), a traditional Chinese medical formula used in cancer treatment, on osteosarcoma, a tumour type recently found to be sensitive to YZXJ. The human osteosarcoma cell line MG63 was used in cell-matrix adhesion and cell growth assays. The same cell line was used in an in vivo tumour model by establishing subcutaneous osteosarcoma xenografts. Oral and intraperitoneal routes were used to deliver the YZXJ extract. The effect of YZXJ on the activation of focal adhesion kinase (FAK) and paxillin was evaluated by immunofluorescence methods. It was found that YZXJ exhibited a significant inhibitory effect on cell-matrix adhesion as demonstrated by a cell-based assay and electric cell-substrate impedance sensing (ECIS) analysis. The effect was observed together with a reduction in phospho-FAK and phospho-paxillin in the cells when treated with YZXJ. In the in vivo tumour model, YZXJ was found to significantly inhibit the growth of osteosarcoma with a sustained effect observed when YZXJ was delivered intraperitoneally. YZXJ sensitized cells to the effect of FAK inhibitor in vitro and in vivo. It is concluded that Yangzheng Xiaoji plays a significant role in cell-matrix adhesion and tumour growth, likely by inhibiting the activation of the FAK pathway. The therapeutic role of Yangzheng Xiaoji in osteosarcoma warrants further investigation.

Potential implication of IL-24 in lymphangiogenesis of human breast cancer

Lymphangiogenesis is involved in the dissemination of malignant cells from solid tumours to regional lymph nodes and possibly to various distant sites. Lymphangiogenesis is regulated by vascular endothelial growth factor (VEGF)-C and VEGF-D. Interleukin (IL)-24 is known as a cytokine with potent antitumour and tumour-suppressive activity which functions through its receptor (IL-22R). Expression of IL-24 has been shown to be reduced in breast cancer, and the reduced expression is associated with lymphatic metastases and a poor prognosis. However, the involvement of IL-24 in lymphangiogenesis during lymphatic metastasis remains unclear. The aim of the present study was to determine whether there is an association between IL-24, IL-22R and lymphangiogenic factors and markers in breast cancer. Analysis of IL-24, IL-22R and lymphangiogenic factors in malignant breast tissue samples (n=127) revealed a correlation between increased expression of lymphangiogenic markers (podoplanin, Prox-1 and LYVE-1) and reduced levels of IL-24 and IL-22R. Samples stained with a high degree of positivity for lymphangiogenic factors and markers whereas staining for IL-24 was weak. In vitro assays showed that the average perimeter length of microtubules formed by endothelial cells treated with IL-24 was significantly reduced compared to the control. The growth of endothelial cells was significantly reduced when exposed to a high concentration of IL-24 (250 ng/ml). Treatment of HECV cells with IL-24 resulted in significantly reduced expression of VEGF-C (P<0.05) and VEGF-D (P<0.001). In conclusion, reduced expression of IL-24 and IL-22R in breast cancer is correlated with increased expression of specific lymphangiogenic markers. IL-24 suppressed in vitro growth and microtubule formation of endothelial cells. IL-24 may downregulate the expression of lymphangiogenic markers and factors although further research is required. This suggests that IL-24 plays a profound role in suppressing tumour lymphangiogenesis, thereby, reducing the likelihood of cancer metastasis via the lymphatic route.

Death-associated protein-3, DAP-3, correlates with preoperative chemotherapy effectiveness and prognosis of gastric cancer patients following perioperative chemotherapy and radical gastrectomy

Background:DAP3 is a member of the death-associated protein (DAP) family and is characterised by proapoptotic function. It is involved in both exogenous and endogenous apoptotic pathways. In our previous studies, apoptotic level was found to be correlated with the effectiveness of preoperative chemotherapy. The effectiveness of preoperative chemotherapy was also associated with the overall effectiveness of the combined therapy and prognosis. The present study aimed to investigate the role of DAP3 in the evaluation of preoperative chemotherapy effectiveness and its ability to predict prognosis in gastric cancer.Methods:Quantitative PCR and immunohistochemistry staining were performed in 87 patients who received combined therapy. Knockdown of DAP3 was conducted in gastric cancer cell lines to investigate its impact on cell growth, migration, adhesion and invasion. Tolerance to chemotherapy agents was determined by assessing apoptosis and caspase-3.Results:Higher DAP3 expression in gastric tumours was correlated with better prognosis. Knockdown of DAP3 expression promoted cell migration and enhanced resistance to chemotherapy by inhibiting apoptosis.Conclusion:DAP3 is a potential molecular marker for response to preoperative chemotherapy and for predicting prognosis in gastric cancer patients treated with neoadjuvant chemotherapy and gastrectomy.

Application of Electric Cell-Substrate Impedance Sensing in Evaluation of Traditional Medicine on the Cellular Functions of Gastric and Colorectal Cancer Cells

Evaluation of the impact of traditional medicine on cancer cells has been challenging, for many reasons including challenges to obtain suitable cell models and reliable and predictive methods. This brief chapter explores the use electric cell-substrate sensing (ECIS) in evaluation of the effect of traditional Chinese medicine Yanzheng Xiaoji, commonly used in patients with cancer in China including gastrointestinal malignancies, on the cellular functions of gastric and colonic cancer cells. This study has shown that the extract from the formula had a substantial inhibitory effect on the adhesion and migration of gastric cancer cells (HGC27) and colorectal cancer cells (RKO). These effects were achieved at concentrations without affecting cell growth. It is concluded therefore that ECIS is a useful tool in evaluation of the effect of traditional medicine on cancer cells.

Association of Wnt1-inducible signaling pathway protein-1 with the proliferation, migration and invasion in gastric cancer cells

Wnt1-inducible signaling pathway protein-1 is a cysteine-rich protein that belongs to the CCN family, which has been implicated in mediating the occurrence and progression through distinct molecular mechanisms in several tumor types. However, the association of Wnt1-inducible signaling pathway protein-1 with gastric cancer and the related molecular mechanisms remain to be elucidated. Therefore, this study aimed to clarify the biological role of Wnt1-inducible signaling pathway protein-1 in the proliferation, migration, and invasion in gastric cancer cells and further investigated the associated molecular mechanism on these biological functions. We first detected the expression level of Wnt1-inducible signaling pathway protein-1 in gastric cancer, and the reverse transcription polymerase chain reaction have shown that Wnt1-inducible signaling pathway protein-1 expression levels were upregulated in gastric cancer tissues. The expression of Wnt1-inducible signaling pathway protein-1 in gastric cancer cell lines was also detected by quantitative real-time polymerase chain reaction and Western blotting. Furthermore, two gastric cancer cell lines with high expression of Wnt1-inducible signaling pathway protein-1 were selected to explore the biological function of Wnt1-inducible signaling pathway protein-1 in gastric cancer. Function assays indicated that knockdown of Wnt1-inducible signaling pathway protein-1 suppressed cell proliferation, migration, and invasion in BGC-823 and AGS gastric cancer cells. Further investigation of mechanisms suggested that cyclinD1 was identified as one of Wnt1-inducible signaling pathway protein-1 related genes to accelerate proliferation in gastric cancer cells. In addition, one pathway of Wnt1-inducible signaling pathway protein-1 induced migration and invasion was mainly through the enhancement of epithelial-to-mesenchymal transition progression. Taken together, our findings presented the first evidence that Wnt1-inducible signaling pathway protein-1 was upregulated in gastric cancer and acted as an oncogene by promoting proliferation, migration, and invasion in gastric cancer cells.