ABSTRACT
High stage and recurrent ovarian clear cell carcinoma (OCC) are associated with poor prognosis and resistance to chemotherapy. A distinguishing histological feature of OCC is abundant cytoplasmic stores of glucose, in the form of glycogen, that can be mobilized for cellular metabolism. Here, we report the effect on preclinical models of OCC of disrupting glycogen utilization using the glucose analogue 2-deoxy-D-glucose (2DG). At concentrations significantly lower than previously reported for other cancers, 2DG markedly improves the efficacy in vitro of carboplatin chemotherapy against chemo-sensitive TOV21G and chemo-resistant OVTOKO OCC cell lines, and this is accompanied by the depletion of glycogen. Of note, 2DG doses-of more than 10-fold lower than previously reported for other cancers-significantly improve the efficacy of carboplatin against cell line and patient-derived xenograft models in mice that mimic the chemo-responsiveness of OCC. These findings are encouraging, in that 2DG doses, which are substantially lower than previously reported to cause adverse events in cancer patients, can safely and significantly improve the efficacy of carboplatin against OCC. Our results thus justify clinical trials to evaluate whether low dose 2DG improves the efficacy of carboplatin in OCC patients.
ABSTRACT
Elevated CUB-domain containing protein 1 (CDCP1) is predictive of colorectal cancer (CRC) recurrence and poor patient survival. While CDCP1 expression identifies stem cell populations that mediate lung metastasis, mechanisms underlying the role of this cell surface receptor in CRC have not been defined. We sought to identify CDCP1 regulated processes in CRC using stem cell populations, enriched from primary cells and cell lines, in extensive in vitro and in vivo assays. These experiments, demonstrating that CDCP1 is functionally important in CRC tumor initiation, growth and metastasis, identified CDCP1 as a positive regulator of Wnt signaling. Detailed cell fractionation, immunoprecipitation, microscopy, and immunohistochemical analyses demonstrated that CDCP1 promotes translocation of the key regulators of Wnt signaling, ß-catenin, and E-cadherin, to the nucleus. Of functional importance, disruption of CDCP1 reduces nuclear localized, chromatin-associated ß-catenin and nuclear localized E-cadherin, increases sequestration of these proteins in cell membranes, disrupts regulation of CRC promoting genes, and reduces CRC tumor burden. Thus, disruption of CDCP1 perturbs pro-cancerous Wnt signaling including nuclear localization of ß-catenin and E-cadherin.
