calixarenes and Carcinoma--Squamous-Cell

To investigate the in vitro effects of inhibiting galectin-1 using the small-molecule inhibitor OTX008 on oral squamous cell carcinoma (OSCC) cell lines and the role of the MAPK pathway.. One normal oral keratinocyte (NOK) and three OSCC cell lines were cultured in vitro and the expression of galectin-1 protein by each quantified using ELISA. Cell lines were treated with galectin-1 (50, 100 and 150 ng/mL) or OTX008 (12.5, 25, 50 and 100 μg/mL) and cell viability assayed (n = 3). OSCC cell lines with and without 25 μg/mL OTX008 (n = 3) treatment for 48 h, were analysed using qRT. All cell lines were found to express galectin-1 protein. Exogenous galectin-1 significantly reduced cell viability in one OSCC cell line over time while the others were only minimally affected. OTX008 treatment reduced cell viability in a dose and time-dependent manner in all cell lines and this was associated with significant regulation of FOS gene expression in the OSCC cell lines.. OTX008 decreased the viability of OSCC and NOK cells in a dose-dependent manner. The significant regulation of FOS suggests OTX008 causes early induction of the MAPK pathway via the immediate response gene FOS as a subunit of the AP-1 complex.

Topics: Calixarenes; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Galectin 1; Gene Expression Regulation, Neoplastic; Head and Neck Neoplasms; Humans; MAP Kinase Signaling System; Mouth Neoplasms; Squamous Cell Carcinoma of Head and Neck; Transcription Factor AP-1

Galectin-1 is a hypoxia-regulated protein and a prognostic marker in head and neck squamous cell carcinomas (HNSCC). Here we assessed the ability of non-peptidic galectin-1 inhibitor OTX008 to improve tumor oxygenation levels via tumor vessel normalization as well as tumor growth inhibition in two human HNSCC tumor models, the human laryngeal squamous carcinoma SQ20B and the human epithelial type 2 HEp-2. Tumor-bearing mice were treated with OTX008, Anginex, or Avastin and oxygen levels were determined by fiber-optics and molecular marker pimonidazole binding. Immuno-fluorescence was used to determine vessel normalization status. Continued OTX008 treatment caused a transient reoxygenation in SQ20B tumors peaking on day 14, while a steady increase in tumor oxygenation was observed over 21 days in the HEp-2 model. A >50% decrease in immunohistochemical staining for tumor hypoxia verified the oxygenation data measured using a partial pressure of oxygen (pO₂) probe. Additionally, OTX008 induced tumor vessel normalization as tumor pericyte coverage increased by approximately 40% without inducing any toxicity. Moreover, OTX008 inhibited tumor growth as effectively as Anginex and Avastin, except in the HEp-2 model where Avastin was found to suspend tumor growth. Galectin-1 inhibitor OTX008 transiently increased overall tumor oxygenation via vessel normalization to various degrees in both HNSCC models. These findings suggest that targeting galectin-1-e.g., by OTX008-may be an effective approach to treat cancer patients as stand-alone therapy or in combination with other standards of care.

Topics: Angiogenesis Inhibitors; Animals; Bevacizumab; Calixarenes; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Galectin 1; Head and Neck Neoplasms; Humans; Mice; Oxygen; Peptides; Squamous Cell Carcinoma of Head and Neck; Xenograft Model Antitumor Assays