The significance of lymphatic space invasion and its association with vascular endothelial growth factor-C expression in ovarian cancer

SAR131675 exhibits anticancer activity on human ovarian cancer cells through inhibition of VEGFR-3/ERK1/2/AKT signaling pathway

Vascular endothelial growth factor receptor-3 (VEGFR-3) is known to participate in tumorigenesis and lymphangiogenesis, and as such, has the potential to serve as a molecular target for cancer therapy. SAR131675 is a highly selective VEGFR-3 antagonist that has an inhibitive effect on lymphatic cell growth. However, the anticancer effects and underlying mechanisms of SAR131675 in ovarian cancer remain poorly understood. In this study, we investigated the pathological role of VEGFR-3, and the effects of SAR131675 on proliferation, cell cycle, migration, and apoptosis in ovarian cancer cells. Our results showed that the mRNA and protein of VEGFR-3 were expressed in OVCAR3 and SKOV3 ovarian cancer cells, and this receptor was activated following stimulation with 50 ng/ml VEGF-C Cys156Ser (VEGF-CS), a selective ligand for VEGFR-3. Enhancing VEGFR-3 phosphorylation by treatment of ovarian cancer cells with VEGF-CS resulted in increased levels of phosphorylated extracellular signal-regulated kinases 1/2 (ERK1/2) and AKT. Moreover, our data demonstrated that SAR131675 inhibited VEGF-CS-mediated proliferation, colony formation, and migration of cancer cells in a dose-dependent manner. In addition, inhibition of VEGFR-3 activation with SAR131675 significantly increased cell cycle arrest and promoted apoptosis in both OVCAR3 and SKOV3 cells. Mechanistically, SAR131675 effectively suppressed the VEGF-CS-induced phosphorylation of VEGFR-3 and its downstream effectors including activated ERK1/2 and AKT in ovarian cancer cells. Our results reveal an anticancer activity of SAR131675 on the growth and migration of ovarian cancer cells, which may be through inhibiting VEGFR-3/ERK1/2/AKT pathway. SAR131675 may serve as an effective targeted drug for ovarian cancer.

Macrophages Promote Ovarian Cancer-Mesothelial Cell Adhesion by Upregulation of ITGA2 and VEGFC in Mesothelial Cells

Ovarian cancer is a metastatic disease that frequently exhibits extensive peritoneal dissemination. Recent studies have revealed that noncancerous cells inside the tumor microenvironment, such as macrophages and mesothelial cells, may play a role in ovarian cancer metastasis. In this study, we found that human ovarian cancer cells (A2780 and SKOV3) adhered more to human mesothelial Met5A cells stimulated by macrophages (M-Met5A) in comparison to unstimulated control Met5A cells. The mRNA sequencing revealed that 94 adhesion-related genes, including FMN1, ITGA2, COL13A1, VEGFC, and NRG1, were markedly upregulated in M-Met5A cells. Knockdown of ITGA2 and VEGFC in M-Met5A cells significantly inhibited the adhesion of ovarian cancer cells. Inhibition of the JNK and Akt signaling pathways suppressed ITGA2 and VEGFC expression in M-Met5A cells as well as ovarian cancer-mesothelial cell adhesion. Furthermore, increased production of CC chemokine ligand 2 (CCL2) and CCL5 by macrophages elevated ovarian cancer-mesothelial cell adhesion. These findings imply that macrophages may play a significant role in ovarian cancer-mesothelial cell adhesion by inducing the mesothelial expression of adhesion-related genes via the JNK and Akt pathways.

Ovarian Tumor Microenvironment Signaling: Convergence on the Rac1 GTPase

The tumor microenvironment for epithelial ovarian cancer is complex and rich in bioactive molecules that modulate cell-cell interactions and stimulate numerous signal transduction cascades. These signals ultimately modulate all aspects of tumor behavior including progression, metastasis and therapeutic response. Many of the signaling pathways converge on the small GTPase Ras-related C3 botulinum toxin substrate (Rac)1. In addition to regulating actin cytoskeleton remodeling necessary for tumor cell adhesion, migration and invasion, Rac1 through its downstream effectors, regulates cancer cell survival, tumor angiogenesis, phenotypic plasticity, quiescence, and resistance to therapeutics. In this review we discuss evidence for Rac1 activation within the ovarian tumor microenvironment, mechanisms of Rac1 dysregulation as they apply to ovarian cancer, and the potential benefits of targeting aberrant Rac1 activity in this disease. The potential for Rac1 contribution to extraperitoneal dissemination of ovarian cancer is addressed.

VEGF-C expression attributes the risk for lymphatic metastases to ovarian cancer patients

Background

Peritoneal dissemination and retroperitoneal lymph node involvement are main routes for progression of epithelial ovarian cancer (EOC). Vascular endothelial growth factor (VEGF) mediated angiogenesis has been identified as an important mechanism promoting tumour progression.

Methods

Tumour tissue of 100 patients with EOC was analysed for protein expression of vascular endothelial growth factor (VEGF)-A, -C, -D by Western Blot analysis. Expression patterns in patients with ‘extensive intraperitoneal’ metastases (pT3c pN1 and pT3b-pT3c pN0, n=80) were compared to patients with ‘predominantly retroperitoneal’ metastases (pT1a-pT3b, pN1, n=20). Overall and progression-free survival was analysed by Kaplan-Meier method.

Results

While no significant differences in expression levels among the different modes of metastases were noted for VEGF-A and -D, VEGF-C expression was significantly higher in the group of predominantly retroperitoneal metastases compared to the group with extensive intraperitoneal metastases. Patients with high VEGF-C expression had a significantly worse overall survival compared to patients with low expression levels.

Conclusions

Retroperitoneal tumour progression in EOC patients is associated with high VEGF-C expression. VEGF-C may serve as a molecular marker to identify patients with assumed high risk for lymphatic metastases, who might benefit from specific treatment strategies.

Expression analysis and clinical significance of eIF4E, VEGF-C, E-cadherin and MMP-2 in colorectal adenocarcinoma

The underlying mechanisms of colorectal carcinoma (CRC) metastasis remain to be elucidated. The aim of this study is to investigate clinical significance and the expression of eIF4E, VEGF-C, MMP-2, and E-cadherin in the CRC metastasis. We investigated their expressions in 108 patients, analyzed the relationships between their expressions in CRC and evaluated the relationships between their expressions and clinical pathogenic parameters. Furthermore, their roles in patient survival and in CRC metastasis were also investigated. We found that eIF4E, VEGF-C and MMP-2 were up-regulated in CRC, and their expression frequencies (EFs) were higher in cancerous tissues than in adjacent normal tissues. The EF of E-cadherin is lower in cancerous tissues than in adjacent normal tissues. Totally, their EFs were not associated with sex and age of patient, however, their EFs were associated with tumor differentiation, the depth of invasion, lymph node metastasis and tumor stages. Furthermore, eIF4E, VEGF-C, and MMP-2 shortened and E-cadherin prolonged survival in patient-derived CRC xenografts. Similarly, eIF4E, VEGF-C, and MMP-2 promoted and E-cadherin suppressed the lung metastasis of CRC cells. In addition, knockdown of eIF4E inhibited migration of CRC cells, downregulated VEGF-C, MMP-2 and upregulated E-cadherin. In conclusion, eIF4E promoted CRC metastasis via up-regulating the expression of VEGF-C, MMP-2 and suppressing E-cadherin.

Pharmacological Review on Asiatic Acid and Its Derivatives: A Potential Compound

Natural triterpenes represent a group of pharmacologically active and structurally diverse organic compounds. The focus on these phytochemicals has been enormous in the past few years, worldwide. Asiatic acid (AA), a naturally occurring pentacyclic triterpenoid, is found mainly in the traditional medicinal herb Centella asiatica. Triterpenoid saponins, which are the primary constituents of C. asiatica, are commonly believed to be responsible for their extensive therapeutic actions. Published research work has described the molecular mechanisms underlying the various biological activities of AA and its derivatives, which vary for each chronic disease. However, a compilation of the various pharmacological properties of AA has not yet been done. Herein, we describe in detail the pharmacological properties of AA and its derivatives that inhibit multiple pathways of intracellular signaling molecules and transcription factors that are involved in the various stages of chronic diseases. Furthermore, the pharmacological activities of AA were compared with two natural compounds: curcumin and resveratrol. This review summarizes the research on AA and its derivatives and helps to provide future directions in the area of drug development.

Transcriptional factor OCT4 promotes esophageal cancer metastasis by inducing epithelial-mesenchymal transition through VEGF-C/VEGFR-3 signaling pathway

The octamer-binding transcription factor 4 (OCT4) can promote cancer proliferation and metastasis. Esophageal carcinoma (ECC) harbors different quantities of OCT4-positive cancer cells. These cells are highly malignant and prone to metastasis; however, the mechanism remains unknown. In this study, we found that OCT4 enhances vascular endothelial growth factor C (VEGF-C) promoter activity to promote VEGF-C expression and activates VEGF receptor 3 (VEGFR-3) in ECC cells, thereby inducing cancer cell epithelial-mesenchymal transition (EMT). Studies using xenograft models showed that OCT4 promoted xenograft growth and intraperitoneal implantation metastasis of ECC cells. Downregulation of OCT4 expression could inhibit cancer metastasis. OCT4- and VEGF-C-positive ECC presented more malignant biological behaviors and the corresponding patients exhibited a poor prognosis. The study confirmed that the OCT4/VEGF-C/VEGFR-3/EMT signaling plays a role in the progression of ECC. Understanding of how OCT4 regulates EMT and how ECC metastasis occurs will provide useful targets for the biological treatment of ECC.