Cytotoxic and Radiosensitizing Effects of Folic Acid-Conjugated Gold Nanoparticles and Doxorubicin on Colorectal Cancer Cells.

Purpose: Radiotherapy is one of the most important therapeutic options used to treat cancers. Radiation effects can be improved using nanoparticles and chemotherapeutic drugs as radiosensitizing agents. The aim of the present study was to evaluate the effects of folic acid-conjugated gold nanoparticles (GNP-F) in combination with doxorubicin (DOX) and x-Ray irradiation in colorectal cancer (CRC) cell line (HT-29). Methods: The cell viability assay (WST-1) was performed to study the cytotoxic effects of different concentrations of DOX and GNP-F after 24 and 48 hours treatments. Then, the effects of the GNP-F, X-Ray irradiation, and DOX drug in single and combined treatments were examined after 24 and 48 hours treatment with effective doses. Likewise, the caspase 3 gene expression ratio and the caspase 3 activity were assessed after 48 h treatment. Moreover, the malondialdehyde (MDA) level was determined in treated and untreated cells. Results: When GNP-F (at a concentration of 70 µM) was combined with X-ray irradiation (2 Gy) and DOX drug, induced more cytotoxic effects compared to the control group. The results of cell viability assay showed that GNP-F + X-Ray in combination with a low concentration of DOX (0.25 × IC50) enhanced the cytotoxic effects of cells compared to related single treatments. Caspase 3 gene expression ratio and caspase 3 activity increased in double and triple combination treatments in comparison with the single groups. Moreover, the MDA level increased in triple combination compared to the single treatments. Conclusion: Our findings confirmed the potential anti-cancer effects of the GNP-F and DOX in combination with X-Ray irradiation in CRC cells.

Effects of Radiotherapy in Combination With Irinotecan and 17-AAG on Bcl-2 and Caspase 3 Gene Expression in Colorectal Cancer Cells.

Introduction: In this study, the cytotoxic and anti-cancer effects of Irinotecan as a conventional chemotherapeutic agent compared to 17-(allyl amino)-17-demethoxygeldanamycin (17-AAG) as possible radiosensitizers in the HCT-116 cell line were investigated. Methods: HCT-116 cells were treated with various concentrations of irinotecan and 17-AAG and also irradiated with a 2-Gy of X-ray radiation. Then, the cell viability was examined by a water-soluble tetrazolium-1 assay after 24 hours. For single therapies and double and triple combination cases, IC50, 0.5×IC50 and 0.25×IC50 concentrations of each drug were selected respectively for a terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) assay and other tests. In treated and untreated cells, the caspase 3 and Bcl-2 gene expression ratios were evaluated by the real-time PCR method. Likewise, caspase 3 activity was detected with a colorimetric assay. Results: In all combined treatments, including 17-AAG- radiation, irinotecan - radiation, irinotecan -17-AAG, and irinotecan-17-AAG-radiation, decreased cellular viability and increased TUNEL positive cells were presented versus the control group (P < 0.05). There were increased TUNEL positive cells in the triple combination, in concentrations of 0.25×IC50 of each drug, in comparison with single and double agent treatments. Moreover, in triple combination, the caspase 3 mRNA level and caspase 3 activity increased versus related single treatments. Likewise, in the irinotecan-17-AAG-radiation combined treatment and the 17-AAG-radiation double treatment, the Bcl-2 gene expression level decreased in comparison with single therapies. Conclusion: It can be indicated that the combination of chemo-radiotherapy versus single treatments has significant anti-cancer effects.

Anti-cancer effects of chemotherapeutic agent; 17-AAG, in combined with gold nanoparticles and irradiation in human colorectal cancer cells.

OBJECTIVE: The present study evaluated the anti-cancer effects of irradiation (Ir) alone, Ir after heat shock protein 90 inhibitor; 17-allylamino-17-demethoxygeldanamycin (17-AAG) and gold nanoparticle (GNP) treatments in human colorectal cancer cell line (HCT-116), with the targeting of related mechanisms. METHODS: Water-soluble tetrazolium salt-1 assay was utilized to study the cytotoxic effects of 17-AAG, GNP, Ir in single and combination cases on the cell viability of HCT-116 cells. The cells were examined with DNA fragmentation electrophoresis and evaluated for apoptosis induction. Caspase-3 expression as a critical apoptosis element in protein level was detected by western blotting. RESULTS: Treatment with 17-AAG in a dose dependent manner for 24 h inhibited the cellular viability of HCT-116 cells. GNP at a dose of 70 µM had the lowest cytotoxic effects and was thus selected for combination treatment studies. Based on the results, GNP at a dose of 70 µM did not have a significant effect on cellular viability of HCT-116. In contrast, the evaluation of double and triple combinations, GNP with Ir (2 Gy of 6 MV X-ray radiation) and 17-AAG in double combinations induced significant cytotoxicity. Both DNA damage pattern and caspase-3 protein upregulation were present in Ir,GNP/17-AAG,GNP and Ir,17-AAG combinations compared to single treatments. Furthermore, in the three combination of GNP,Ir,17-AAG, radiosensitization effects (increased caspase-3 expression) occurred with a minimum concentration of 17-AAG. CONCLUSION: According to the results of this study, 17-AAG as chemotherapeutic agent in combination with Ir and GNP exerts noticeable anti-cancer effects, inhibited cell viability, and increased apoptosis occurrence by upregulating caspase-3 expression. It is suggested that these combinations should be more evaluated as a promising candidate for colorectal cancer treatment. Graphical abstract Anti-cancer effects of chemotherapeutic agent; 17-AAG, in combined with gold nanoparticles and irradiation in human colorectal cancer cells.