Effects of docetaxel on metastatic prostate (DU-145) carcinoma cells cultured as 2D monolayers and 3D multicellular tumor spheroids.

Docetaxel (DTX) is one of the chemotherapeutic drugs indicated as a first-line treatment against metastatic prostate cancer (mPCa). This study aimed to compare the impact of DTX on mPCa (DU-145) tumor cells cultured as 2D monolayers and 3D multicellular tumor spheroids (MCTS) in vitro. The cells were treated with DTX (1-96 µM) at 24, 48, or 72 hr in cell viability assays (resazurin, phosphatase acid, and lactate dehydrogenase). Cell death was assessed with fluorescent markers and proliferation by clonogenic assay (2D) and morphology, volume, and integrity assay (3D). The cell invasion was determined using transwell (2D) and extracellular matrix (ECM) (3D). Results showed that DTX decreased cell viability in both culture models. In 2D, the IC50 (72 hr) values were 11.06 µM and 14.23 µM for resazurin and phosphatase assays, respectively. In MCTS, the IC50 values for the same assays were 114.9 µM and 163.7 µM, approximately 10-fold higher than in the 2D model. The % of viable cells decreased, while the apoptotic cell number was elevated compared to the control in 2D. In 3D spheroids, only DTX 24 µM induced apoptosis. DTX (≥24 µM at 216 hr) lowered the volume, and DTX 96 µM completely disintegrated the MCTS. DTX reduced the invasion of mPCa cells to matrigel (2D) and migration from MCTS to the ECM. Data demonstrated significant differences in drug response between 2D and 3D cell culture models using mPCa DU-145 tumor cells. MCTS resembles the early stages of solid tumors in vivo and needs to be considered in conjunction with 2D cultures when searching for new therapeutic targets.

Flavonoid brachydin B decreases viability, proliferation, and migration in human metastatic prostate (DU145) cells grown in 2D and 3D culture models.

Brachydin B (BrB) is a unique dimeric flavonoid extracted from Fridericia platyphylla (Cham.) LG Lohmann with different biological activities. However, the antitumoral potential of this flavonoid is unclear. In our study, we evaluated the effects of the BrB flavonoid on cell viability (MTT, resazurin, and lactate dehydrogenase assays), proliferation (protein dosage and clonogenic assay), and migration/invasion (3D ECM gel, wound-healing, and transwell assays) of metastatic prostate (DU145) cells cultured both as traditional 2D monolayers and 3D tumor spheroids in vitro. The results showed that the BrB flavonoid promotes cytotoxic effects from ≥1.50 µM after 24 h of treatment in DU145 cells in monolayers. In 3D prostate tumor spheroids, BrB also induced cytotoxic effects at higher concentrations after longer treatment (48, 72, and 168 h). Furthermore, BrB treatment is associated with reduced DU145 clonogenicity in 2D cultures, as well as decreased area/volume of 3D tumor spheroids. Finally, BrB (6 µM) reduced cell migration/invasion in 2D monolayers and promoted antimigratory effects in DU145 tumor spheroids (≥30 µM). In conclusion, the antitumoral and antimigratory effects observed in DU145 cells cultured in 2D and 3D models are promising results for future studies with BrB using in vivo models and confirm this molecule as a candidate for metastatic prostate cancer therapy.