orlistat and Adenocarcinoma

Colon cancer is a highly anabolic entity with upregulation of glycolysis, glutaminolysis, and de novo synthesis of fatty acids, which also induces a hypercatabolic state in the patient. The blockade of either cancer anabolism or host catabolism has been previously proven to be a successful anticancer experimental treatment. However, it is still unclear whether the simultaneous blockade of both metabolic counterparts can limit malignant survival and the energetic consequences of such an approach. In this chapter, by using the CT26.WT murine colon adenocarcinoma cell line as a model of study, we provide a method to simultaneously perform a pharmacological blockade of tumor anabolism and host catabolism, as a feasible therapeutic approach to treat cancer, and to limit its energetic supply.

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Colonic Neoplasms; Diazooxonorleucine; Drug Screening Assays, Antitumor; Fatty Acid Synthase, Type I; Fatty Acids; Female; Glutaminase; Glutamine; Glycolysis; Hexokinase; Indazoles; Mice; Mice, Inbred BALB C; Molecular Targeted Therapy; Orlistat; Smegmamorpha

Fatty acid synthase (FASN) expression is elevated in several cancers, and this over-expression is associated with poor prognosis. Inhibitors of FASN, such as orlistat, reportedly show antitumor effects against cancers that over-express FASN, making FASN a promising therapeutic target. However, large variations in FASN expression levels in individual tumors have been observed, and methods to predict FASN-targeted therapy outcome before treatment are required to avoid unnecessary treatment. In addition, how FASN inhibition affects tumor progression remains unclear. Here, we showed the method to predict FASN-targeted therapy outcome using radiolabeled acetate uptake and presented mechanisms of FASN inhibition with human prostate cancer cell lines, to provide the treatment strategy of FASN-targeted therapy. We revealed that tumor uptake of radiolabeled acetate reflected the FASN expression levels and sensitivity to FASN-targeted therapy with orlistat in vitro and in vivo. FASN-targeted therapy was noticeably effective against tumors with high FASN expression, which was indicated by high acetate uptake. To examine mechanisms, we established FASN knockdown prostate cancer cells by transduction of short-hairpin RNA against FASN and investigated the characteristics by analyses on morphology and cell behavior and microarray-based gene expression profiling. FASN inhibition not only suppressed cell proliferation but prevented pseudopodia formation and suppressed cell adhesion, migration, and invasion. FASN inhibition also suppressed genes involved in production of intracellular second messenger arachidonic acid and androgen hormones, both of which promote tumor progression. Collectively, our data demonstrated that uptake of radiolabeled acetate is a useful predictor of FASN-targeted therapy outcome. This suggests that [1-(11)C]acetate positron emission tomography (PET) could be a powerful tool to accomplish personalized FASN-targeted therapy by non-invasive visualization of tumor acetate uptake and selection of responsive tumors. FASN-targeted therapy could be an effective treatment to suppress multiple steps related to tumor progression in prostate cancers selected by [1-(11)C]acetate PET.

Topics: Acetic Acid; Adenocarcinoma; Animals; Antineoplastic Agents; Biological Transport; Carbon Radioisotopes; Cell Adhesion; Cell Line, Tumor; Cell Movement; Cell Proliferation; Enzyme Inhibitors; Fatty Acid Synthase, Type I; Gene Expression; Gene Expression Profiling; Humans; Lactones; Male; Mice; Mice, Inbred NOD; Molecular Targeted Therapy; Neoplasms, Experimental; Orlistat; Prostatic Neoplasms; RNA, Small Interfering