gw-5074 and Colorectal-Neoplasms

Despite new agent development and short-term benefits in patients with colorectal cancer (CRC), metastatic CRC cure rates have not improved due to high rates of 5-fluorouracil (5-FU)/leucovorin/oxaliplatin (FOLFOX)-resistance and a clinical therapeutic plateau. At the same time, this treatment regime leads to significant toxicity, cost, and patient inconvenience. Drug-resistance is linked to CRC stem cells, which are associated with the epidermal-to-mesenchymal transition (EMT) pathway. Thus, to optimally treat CRC, a therapy that can target the cell survival and EMT pathways in both CRC bulk and stem cell populations is critical. We recently identified a novel small molecule NSC30049 (7a) that is effective alone, and in combination potentiates 5-FU-mediated growth inhibition of CRC bulk, FOLFOX-resistant, and CRC stem cells both in vitro and in vivo models. In the present study, we report the synthesis and anti-CRC evaluation of several stable and effective 7a analogs. ASR352 (7b) was identified as one of the equipotent 7a analogs that inhibited the growth of CRC bulk cells, sensitized FOLFOX-resistant cells, and reduced the sphere formation capacity of CRC stem cells. It appears that the complex mechanism of cytotoxicity for 7b includes abrogation of 5-FU-induced the S phase, reduction of the phosphorylation of Chk1 at S317P, S345P and S296P, increased γH2AX staining, activation of caspase 3/PARP1 cleavage, and enhancement of Bax/Bcl2 ratio. Further 7b-mediated reduced phosphorylation of Chk1 was an indirect effect, since it did not inhibit Chk1 activity in an in vitro kinase assay. Our findings suggest that 7b as a single agent, or in combination with 5-FU can be developed as a therapeutic agent in CRC bulk, FOLFOX-resistant, and CRC stem cell populations for unmanageable metastatic CRC conditions.

Topics: Adamantane; Antineoplastic Agents; Aza Compounds; Cell Proliferation; Cell Survival; Colorectal Neoplasms; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Drug Screening Assays, Antitumor; Fluorouracil; HCT116 Cells; HT29 Cells; Humans; Molecular Structure; Oxaliplatin; Stem Cells; Structure-Activity Relationship; Tumor Cells, Cultured

Colorectal cancer (CRC) remains one of the leading causes of cancer-related death. Novel therapeutics are urgently needed, especially for tumours with activating mutations in. Colonosphere cultures were established from human tumour specimens obtained from patients who underwent colon or liver resection for primary or metastatic adenocarcinoma. The role of RAF1 was tested by generating knockdowns (KDs) using three independent shRNA constructs or by using RAF1-kinase inhibitor GW5074. Clone-initiating and tumour-initiating capacities were assessed by single-cell cloning and injecting CRC cells into immune-deficient mice. Expression of tight junction (TJ) proteins, localisation of polarity proteins and activation of MEK-ERK pathway was analysed by western blot, immunohistochemistry and immunofluorescence.. KD or pharmacological inhibition of RAF1 significantly decreased clone-forming and tumour-forming capacity of all CRC cultures tested, including. RAF1 plays a critical role in maintaining the transformed phenotype of CRC cells, including those with mutated

Topics: Adenocarcinoma; Animals; Cell Differentiation; Cell Polarity; Colorectal Neoplasms; Gene Expression; Gene Knockdown Techniques; Humans; Indoles; MAP Kinase Kinase Kinases; Mice; Neoplasm Transplantation; Phenols; Phosphorylation; Primary Cell Culture; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-raf; RNA, Small Interfering; Tight Junctions; Tumor Cells, Cultured