5-(4-amino-1-propan-2-yl-3-pyrazolo[3-4-d]pyrimidinyl)-1-3-benzoxazol-2-amine and Colorectal-Neoplasms

Glycolysis and the pentose phosphate pathway (PPP) are preferentially activated in cancer cells. Accumulating evidence indicated the significance of the altered glucose metabolism in cancer, but the implication for oncotherapy remains unclear. Here we report that the synthesis of glycolytic and PPP enzymes is almost ubiquitously augmented in colorectal carcinoma (CRC) specimens. The mammalian target of rapamycin (mTOR) inhibitor INK128 (300 nM) and phytochemical Avemar (1 mg/ml) inhibited the synthesis of PPP enzymes in CRC cell lines. INK128 (150-600 nM) and resveratrol (75-300 μM) inhibited aerobic glycolysis in the cell lines. INK128 (300 nM) and Avemar (1 mg/ml) decreased the NADPH/NADP(+) ratio as well as the GSH/GSSG ratio in the cell lines. Finally, per os administration of INK128 (0.8 mg/kg) or Avemar (1 g/kg) suppressed tumor growth and delayed tumor formation by transplantable CRC specimens derived from patients. Taken together, pharmacological inhibition of the mTOR-PPP axis is a promising therapeutic strategy against CRCs.

Topics: Administration, Oral; Animals; Antineoplastic Agents; Benzoxazoles; Blotting, Western; Cell Line, Tumor; Colorectal Neoplasms; Female; Glucose; Glutathione Disulfide; Glycolysis; Humans; Japan; Lactic Acid; Mice; Mice, Nude; Pentose Phosphate Pathway; Plant Extracts; Pyrimidines; Receptors, Peptide; Resveratrol; Stilbenes; TOR Serine-Threonine Kinases; Transplantation, Heterologous; Treatment Outcome

The colorectal cancer is the leading contributor of cancer-related mortality. Mammalian target of rapamycin (mTOR), existing in 2 complexes (mTORC1/2), is frequently dysregulated and constitutively activated in colorectal cancers. It represents an important drug target. Here we found that INK-128, the novel ATP-competitive kinase inhibitor of mTOR, blocked both mTORC1 and mTORC2 activation in colorectal cancer cells (both primary and transformed cells). The immunoprecipitation results showed that the assembly of mTORC1 (mTOR-Raptor association) and mTORC2 (mTOR-Rictor-Sin1 association) was also disrupted by INK-128. INK-128 inhibited colorectal cancer cell growth and survival, and induced both apoptotic and non-apoptotic cancer cell death. Further, INK-128 showed no effect on Erk/MAPK activation, while MEK/Erk inhibition by MEK-162 enhanced INK-128-induced cytotoxicity in colorectal cancer cells. Meanwhile, INK-128 downregulated Fascin1 (FSCN1)/E-Cadherin expressions and inhibited HT-29 cell in vitro migration. In vivo, daily INK-128 oral administration inhibited HT-29 xenograft growth in mice, which was further enhanced by MEK-162 administration. Finally, we found that INK-128 sensitized 5-fluorouracil-(5-FU)-mediated anti-HT-29 activity in vivo and in vitro. Thus, our preclinical studies strongly suggest that INK-128 might be investigated for colorectal cancer treatment in clinical trials.

Topics: Animals; Antineoplastic Agents; Apoptosis; Benzoxazoles; Cadherins; Carrier Proteins; Cell Line, Tumor; Cell Movement; Colorectal Neoplasms; Disease Models, Animal; Drug Evaluation, Preclinical; Drug Synergism; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases; Fluorouracil; HT29 Cells; Humans; Male; Mechanistic Target of Rapamycin Complex 1; Mechanistic Target of Rapamycin Complex 2; Mice; Microfilament Proteins; Multiprotein Complexes; Protein Kinase Inhibitors; Pyrimidines; TOR Serine-Threonine Kinases; Xenograft Model Antitumor Assays