fumarates and Neoplasm-Metastasis

Hepatocellular carcinoma (HCC) is among the leading causes of cancer-related mortality worldwide. Our previous study identified a novel alternative splicing variant of prenyl diphosphate synthase subunit 2 (PDSS2) in HCC characterized by a deletion of exon 2, named PDSS2-Del2, which is devoid of the tumor-suppressive function of full-length PDSS2 (PDSS2-FL). To better understand the clinical significance of PDSS2-Del2, we performed a BaseScope™ assay on an HCC tissue microarray and found that positive staining for PDSS2-Del2 predicted a worse overall survival in patients with HCC (P = 0.02). PDSS2-Del2 levels correlated significantly with microvessel counts in HCC tumor tissues. Importantly, PDSS2-Del2 overexpression functionally promoted HCC metastasis, as demonstrated by in vitro and in vivo migration assays. In vivo assays also demonstrated that PDSS2-Del2 increased angiogenesis in xenografts. Furthermore, we discovered that elevated PDSS2-Del2 expression in HCC tumor cells decreased fumarate levels and activated the canonical nuclear factor-κB pathway. The epithelial-to-mesenchymal transition (EMT) and WNT/β-catenin signaling pathways were also activated by overexpression. Dimethyl fumarate (DMF), a fumaric acid ester, effectively reduced the metastasis induced by PDSS2-Del2 as observed with in vivo spleen-liver metastasis animal experiments. DMF is a prescribed oral therapy for multiple sclerosis and it might be a potential treatment for metastasis of patients with HCC. Early clinical trials are needed to validate its potential in this context.

Topics: Adult; Aged; Alkyl and Aryl Transferases; Animals; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Movement; Dietary Supplements; Epithelial-Mesenchymal Transition; Female; Fumarates; Humans; Liver Neoplasms; Male; Mice, Inbred BALB C; Mice, Nude; Microvessels; Middle Aged; Neoplasm Metastasis; Neovascularization, Pathologic; NF-kappa B; Survival Analysis; Wnt Signaling Pathway; Young Adult

Despite emergence of new systemic therapies, metastatic melanoma remains a challenging and often fatal form of skin cancer. The renin-angiotensin system (RAS) is a major physiological regulatory pathway controlling salt-water equilibrium, intravascular volume and blood pressure. Biological effects of the RAS are mediated by the vasoactive hormone angiotensin II (AngII) via two receptor subtypes, AT1R (encoded by AGTR1) and AT2R (encoded by AGTR2). We report decreasing expression and increasing CpG island methylation of AGTR1 in metastatic versus primary melanoma and detection in serum of methylated genomic DNA from the AGTR1 CpG island in metastatic melanoma implying that AGTR1 encodes a tumour suppressor function in melanoma. Consistent with this hypothesis, antagonism of AT1R using losartan or shRNA-mediated knockdown in melanoma cell lines expressing AGTR1 resulted in acquisition of the ability to proliferate in serum-free conditions. Conversely, ectopic expression of AGTR1 in cell lines lacking endogenous expression inhibits proliferation irrespective of the presence of AngII implying a ligand-independent suppressor function for AT1R. Treatment of melanoma cell lines expressing endogenous AT2R with either AngII or the AT2R-selective agonist Y6AII induces proliferation in serum-free conditions whereas the AT2R-specific antagonists PD123319 and EMA401 inhibit melanoma growth and angiogenesis and potentiate inhibitors of BRAF and MEK in cells with BRAF V600 mutations. Our results demonstrate that the RAS has both oncogenic and tumour suppressor functions in melanoma. Pharmacological inhibition of AT2R may provide therapeutic opportunities in melanomas expressing this receptor and AGTR1 CpG island methylation in serum may serve as a novel biomarker of metastatic melanoma.

Topics: Amides; Angiotensin II; Angiotensin-Converting Enzyme Inhibitors; Animals; Antihypertensive Agents; Cell Line, Tumor; Cell Proliferation; Cells, Cultured; DNA Methylation; Embryo, Nonmammalian; Fumarates; Humans; Imidazoles; Melanoma; Molecular Targeted Therapy; Neoplasm Metastasis; Pyridines; Receptor, Angiotensin, Type 1; Receptor, Angiotensin, Type 2; Renin-Angiotensin System; Xenograft Model Antitumor Assays; Zebrafish

Accumulation of intermediate metabolites of the tricarboxylic acid (TCA) cycle in tumor cells can cause epithelial-to-mesenchymal transition (EMT), although the exact mechanisms remain elusive. Recent studies show that the oncometabolite fumarate, which accumulates in fumarate hydratase-deficient renal cancers, confers tumor aggressiveness by causing epigenetic changes in the antimetastatic miRNA cluster mir-200ba429. This may have important implications for the use of fumarates in the clinic.

Topics: Animals; Citric Acid Cycle; Epigenesis, Genetic; Epithelial-Mesenchymal Transition; Fumarates; Humans; MicroRNAs; Neoplasm Metastasis; Neoplasms

Dimethylfumarate (DMF) inhibits signals transmitted by Rel proteins and is used for the treatment of inflammatory skin diseases such as psoriasis, but potential effects of DMF on tumor progression have yet not been analyzed. We show that DMF reduced melanoma growth and metastasis in severe combined immunodeficient mouse models. To identify targets of DMF action, we analyzed mRNA expression in DMF-treated melanomas by gene chip arrays. Using BiblioSphere software for data analysis, significantly regulated genes were mapped to Gene Ontology terms cell death, cell growth, and cell cycle. Indeed, we found that DMF inhibited proliferation of human melanoma cells A375 and M24met in vitro. The cell cycle was arrested at the G(2)-M boundary. Moreover, DMF was proapoptotic, as shown by cell cycle analysis and by Annexin V and Apo2.7 staining. These results were confirmed in vivo. DMF reduced proliferation rates of tumor cells as assessed by Ki-67 immunostaining and increased apoptosis as assessed by terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling staining. In conclusion, DMF is antiproliferative and proapoptotic and reduces melanoma growth and metastasis in animal models.

Topics: Animals; Cell Cycle; Cell Division; Cell Line, Tumor; Dimethyl Fumarate; Female; Fumarates; Humans; Lymphatic Metastasis; Melanoma; Mice; Mice, Inbred C57BL; Neoplasm Metastasis; Radiation-Sensitizing Agents; Transplantation, Heterologous

Topics: Alanine Transaminase; Alkaline Phosphatase; Arginine; Aspartate Aminotransferases; Bilirubin; Biopsy; Blood Proteins; Cholesterol; Chronic Disease; Clinical Enzyme Tests; Creatine Kinase; Fumarates; Hepatitis; Hepatitis A; Humans; L-Lactate Dehydrogenase; Liver; Liver Diseases; Liver Neoplasms; Lyases; Methods; Neoplasm Metastasis; Succinates