[Frontiers In Bioscience, Elite, 9, 235-245, March 1, 2017]

Combinatorial effect of curcumin with docetaxel modulates apoptotic and cell survival molecules in prostate cancer

Saswati Banerjee1, Santosh K. Singh1, Indrajit Chowdhury2, James W. Lillard Jr1, Rajesh Singh1

1Department of Microbiology, Biochemistry and Immunology, 2Department of Obstetrics and Gynecology; Morehouse School of Medicine, 720 Westview drive, SW, Atlanta- 30310 USA

FIGURES

Figure 1. Curcumin enhances the anti-proliferative effect of docetaxel on DU145 and PC3 cells. (i) Cells were grown on 96 well plates and treated with sequential doses of either curcumin (A, B) or docetaxel (C, D) for 48 hours. Thereafter, viability was measured by MTT assay for DU145 (A, C) and PC3 (B, D) after 48 hours. (ii) Cells were treated with either 10 nM docetaxel and 20 μM curcumin or combination of 10 nM docetaxel and 20 μM curcumin. Cell viability was measured by MTT assay after 48 hours of treatment for DU145 (E-I); PC3 (J-N). Images were captured at 100x magnification. Data are represented as a mean ± standard error of the mean of at least three independent experiments and are analyzed by unpaired t-test. ** and * indicate p value≤0.01 and 0.05, respectively.

Figure 2. Curcumin enhances the docetaxel-mediated apoptosis in (A) DU145 and (B) PC3. Cells were treated either with docetaxel (10 nM) or curcumin (20 μM) or a combination of docetaxel and curcumin. Apoptosis was evaluated using Annexin V-APC and PI staining followed by flow cytometry analysis. Percentage of early and late apoptotic cells and the necrotic cells are shown as numbers in bold in the flow cytometry chart. Q1 and Q2 (Annexin (+)/(PI (+) represents necrotic and late apoptotic cells. Q3 (Annexin (-) /(PI (-) and Q4 (Annexin (+)/(PI (-) represent viable cells and early apoptotic cells respectively. Data are representative of three independent experiments.

Figure 3. Curcumin enhances the docetaxel-mediated apoptosis in (A) DU145 and (B) PC3 cells. Cells were treated with 10 nM docetaxel and 20 μM curcumin or a combination of 10 nM docetaxel and 20 μM curcumin. TUNEL assay was done after 48h of treatment. The TUNNEL (red staining) indicates the fragmented nuclei of the apoptotic cell. DAPI (blue staining) indicates intact nuclei. The images were captured at 200x magnification. Data are representative of three independent experiments.

Figure 4. Curcumin decreases the expression of the proliferative markers and enhances the expression of pro- and anti-apoptotic markers in docetaxel-treated (A) DU145 and (B) PC3 cells. Cells were treated with curcumin and docetaxel, or the combination of curcumin and docetaxel for 48h. The expressions of proliferative, anti- and pro-apoptotic markers were analyzed by western blots. Equal amounts of protein were loaded and separated by 1D gel electrophoresis. GAPDH and β-Actin were used as an internal control. The immunoblots are shown in the left panel and the densitometry of the proteins in right panel. Data are representative of three independent experiments. Data are represented as a mean ± standard error of the mean of three independent experiments and analyzed by unpaired t-test. ** and * indicate p value≤0.01 and 0.05, respectively.

Figure 5. Curcumin with docetaxel down-regulates the expression of RTKs, oncogenic kinases, tumor suppressor protein and inflammatory marker in (A) DU145 and (B) PC3. Cells were treated with curcumin and docetaxel or the combination of curcumin and docetaxel for 48h. The expressions of markers were monitored by western blot analysis. Equal amount of protein was loaded; GAPDH and β-Actin were used as internal control. The immunoblots are shown in the left panel, and the densitometry of the proteins are shown in right panel. Data are representative of three independent experiments. Data are represented as a mean ± standard error of the mean of three independent experiments and analyzed by unpaired t-test. ** and * indicate p value≤0.01 and 0.05, respectively.