fk-866 and Lung-Neoplasms

Despite advances in clinical therapy, metastasis remains the leading cause of death in breast cancer patients. Mutations in mitochondrial DNA, including those affecting complex I and oxidative phosphorylation, are found in breast tumors and could facilitate metastasis. This study identifies mitochondrial complex I as critical for defining an aggressive phenotype in breast cancer cells. Specific enhancement of mitochondrial complex I activity inhibited tumor growth and metastasis through regulation of the tumor cell NAD+/NADH redox balance, mTORC1 activity, and autophagy. Conversely, nonlethal reduction of NAD+ levels by interfering with nicotinamide phosphoribosyltransferase expression rendered tumor cells more aggressive and increased metastasis. The results translate into a new therapeutic strategy: enhancement of the NAD+/NADH balance through treatment with NAD+ precursors inhibited metastasis in xenograft models, increased animal survival, and strongly interfered with oncogene-driven breast cancer progression in the MMTV-PyMT mouse model. Thus, aberration in mitochondrial complex I NADH dehydrogenase activity can profoundly enhance the aggressiveness of human breast cancer cells, while therapeutic normalization of the NAD+/NADH balance can inhibit metastasis and prevent disease progression.

Topics: Acrylamides; Animals; Autophagy; Autophagy-Related Protein 5; Brain Neoplasms; Cell Line, Tumor; Cell Proliferation; Cytokines; Disease Progression; Electron Transport Complex I; Female; Gene Knockdown Techniques; Humans; Lung Neoplasms; Mammary Neoplasms, Experimental; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Inbred BALB C; Mice, SCID; Microtubule-Associated Proteins; Mitochondria; Multiprotein Complexes; NAD; Neoplasm Transplantation; Niacin; Niacinamide; Nicotinamide Phosphoribosyltransferase; Piperidines; Protein Transport; Proteins; Recombinant Proteins; Saccharomyces cerevisiae Proteins; TOR Serine-Threonine Kinases

Non-small cell lung cancer (NSCLC) often has an epidermal growth factor receptor (EGFR) gene mutation. Growth of EGFR-gene-mutated NSCLC depends predominantly on EGFR signaling and requires a large amount of intracellular ATP to activate EGFR signal transduction. Nicotinamide phosphoribosyltransferase (NAMPT) is a rate-limiting enzyme in nicotinamide adenine dinucleotide biosynthesis, and it regulates intracellular ATP levels in mammalian cells. The effect of NAMPT inhibition on NSCLC has not been completely understood.. We aimed to clarify the hypothesis that NAMPT inhibition suppresses growth of EGFR-gene-mutated NSCLC through reduction of intracellular ATP levels, using NAMPT-siRNA transfection and NAMPT inhibitor FK866. We used four lung adenocarcinoma cell lines, including H358 (Wild type EGFR), LC2 (EGFR), PC9 (EGFR), and H1975 (EGFR), and evaluated the effect of FK866 on these cells and its mechanisms, using cell proliferation, Western blot, ATP, and apoptosis assay.. We found that (1) H358, LC2, and H1975 cell lines highly expressed NAMPT-mRNA; (2) NAMPT-specific siRNA and FK866 suppressed proliferation of these NSCLCs; (3) FK866 reduced intracellular ATP levels in H1975 cells; (4) FK866 dephosphorylated EGFR signal proteins, including EGFR, Akt, Map kinase kinase 1/2, and extracellular signal-regulated kinase 1/2 (ERK 1/2); (5) FK866 induced apoptosis of H1975 cells; and (6) FK866 suppressed growth of H1975 xenograft tumors and attenuated expression of phospho-ERK 1/2 in the tumors in a tumor-bearing mouse model.. These findings indicate that NAMPT is a potent therapeutic target in the treatment of EGFR-gene-mutated NSCLC.

Topics: Acrylamides; Adenocarcinoma; Adenosine Triphosphate; Animals; Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Line, Tumor; Cell Proliferation; ErbB Receptors; Female; Humans; Lung Neoplasms; MAP Kinase Kinase 1; MAP Kinase Kinase 2; Mice; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Nicotinamide Phosphoribosyltransferase; Piperidines; RNA, Messenger; RNA, Small Interfering; Signal Transduction

Malignant cells display increased demands for energy production and DNA repair. Nicotinamide adenine dinucleotide (NAD) is required for both processes and is also continuously degraded by cellular enzymes. Nicotinamide phosphoribosyltransferase (Nampt) is a crucial factor in the resynthesis of NAD, and thus in cancer cell survival. Here, we establish the cytotoxic mechanism of action of the small molecule inhibitor CHS-828 to result from impaired synthesis of NAD. Initially, we detected cross-resistance in cells between CHS-828 and a known inhibitor of Nampt, FK866, a compound of a structurally different class. We then showed that nicotinamide protects against CHS-828-mediated cytotoxicity. Finally, we observed that treatment with CHS-828 depletes cellular NAD levels in sensitive cancer cells. In conclusion, these results strongly suggest that, like FK866, CHS-828 kills cancer cells by depleting NAD.

Topics: Acrylamides; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cyanides; Dose-Response Relationship, Drug; Guanidines; Humans; Lung Neoplasms; NAD; Piperidines; Signal Transduction