8-Cl-cAMP is a novel agent able to inhibit the growth of a wide variety of cancer cell types in vitro and in vivo by interfering with the protein kinase A type I (PKAI), a protein directly involved in mitogenic signalling and neoplastic transformation. In a recent phase I study conducted in cancer patients we have demonstrated that 8-Cl-cAMP, at doses devoid of toxicity, may achieve plasma concentrations in a range previously shown effective for cancer cell growth inhibition. In the present study we have investigated the effect of 8-Cl-cAMP in association with cytotoxic drugs acting by different mechanisms of action on the growth of LS174T and GEO human colon cancer cells. We here demonstrate that 8-Cl-cAMP administered after the cytotoxic drugs does not interfere with their growth inhibitory effect but rather is additive with most of them. Moreover, a synergistic effect was observed when 8-Cl-cAMP was administered after cisplatin or paclitaxel. The sequence of treatment seems to be important since pretreatment with 8-Cl-cAMP interferes with the effect of the cytoxic drugs. These results demonstrate that 8-Cl-cAMP is not only able to induce cell growth inhibition when used alone but also exhibit the capacity to enhance the efficacy of different cytotoxic drugs.
8-Chloro-cAMP enhances the growth inhibitory effect of cytotoxic drugs in human colon cancer cells
PEPE, Stefano;
1996-01-01
Abstract
8-Cl-cAMP is a novel agent able to inhibit the growth of a wide variety of cancer cell types in vitro and in vivo by interfering with the protein kinase A type I (PKAI), a protein directly involved in mitogenic signalling and neoplastic transformation. In a recent phase I study conducted in cancer patients we have demonstrated that 8-Cl-cAMP, at doses devoid of toxicity, may achieve plasma concentrations in a range previously shown effective for cancer cell growth inhibition. In the present study we have investigated the effect of 8-Cl-cAMP in association with cytotoxic drugs acting by different mechanisms of action on the growth of LS174T and GEO human colon cancer cells. We here demonstrate that 8-Cl-cAMP administered after the cytotoxic drugs does not interfere with their growth inhibitory effect but rather is additive with most of them. Moreover, a synergistic effect was observed when 8-Cl-cAMP was administered after cisplatin or paclitaxel. The sequence of treatment seems to be important since pretreatment with 8-Cl-cAMP interferes with the effect of the cytoxic drugs. These results demonstrate that 8-Cl-cAMP is not only able to induce cell growth inhibition when used alone but also exhibit the capacity to enhance the efficacy of different cytotoxic drugs.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
