ABSTRACT
BACKGROUND: Several studies have highlighted hyperthermia's ability to enhance the effectiveness of radiation and chemotherapy in various in vitro and in vivo cancer models. MATERIALS AND METHODS: In vivo murine models of malignant melanoma and colon carcinoma were utilized for demonstrating hyperthermia's therapeutic effectiveness by examining levels of caspase 3, COX-2 and phospho-H2A.X (Ser139) as endpoints of apoptosis, proliferation and DNA damage respectively. RESULTS: Hyperthermia induced in vitro cytotoxicity in malignant melanoma (B16-F10) and colon carcinoma (CT26) cell lines. In addition, it reduced post-in vitro proliferation and suppression of tumor growth by inducing the expression of caspase-3 and phospho-H2A.X (Ser139) while reducing the expression of COX-2 in both murine cancer models. CONCLUSION: Hyperthermia can exert therapeutic effectiveness against melanoma and colon carcinoma by inhibiting a number of critical cellular cascades including apoptosis, proliferation and DNA damage.
Subject(s)
Colonic Neoplasms/therapy , Hyperthermia, Induced , Melanoma, Experimental/therapy , Melanoma/therapy , Animals , Apoptosis/radiation effects , Carcinoma/pathology , Carcinoma/therapy , Caspase 3/genetics , Cell Line, Tumor , Cell Proliferation/genetics , Colonic Neoplasms/pathology , Cyclooxygenase 2/genetics , DNA Damage/genetics , Disease Models, Animal , Gene Expression Regulation, Neoplastic/genetics , Histones/genetics , Humans , Melanoma/pathology , Melanoma, Experimental/genetics , MiceABSTRACT
Plant-derived bioactive compounds attract considerable interest as potential chemopreventive anticancer agents. We analyzed the volatile dietary phytochemicals (terpenes) present in mastic oil extracted from the resin of Pistacia lentiscus var. chia and comparatively investigated their effects on colon carcinoma proliferation, a) in vitro against colon cancer cell lines and b) in vivo on tumor growth in mice following oral administration. Mastic oil inhibited - more effectively than its major constituents- proliferation of colon cancer cells in vitro, attenuated migration and downregulated transcriptional expression of survivin (BIRC5a). When administered orally, mastic oil inhibited the growth of colon carcinoma tumors in mice. A reduced expression of Ki-67 and survivin in tumor tissues accompanied the observed effects. Notably, only mastic oil -which is comprised of 67.7% α-pinene and 18.8% myrcene- induced a statistically significant anti-tumor effect in mice but not α-pinene, myrcene or a combination thereof. Thus, mastic oil, as a combination of terpenes, exerts growth inhibitory effects against colon carcinoma, suggesting a nutraceutical potential in the fight against colon cancer. To our knowledge, this is the first report showing that orally administered mastic oil induces tumor-suppressing effects against experimental colon cancer.