Docetaxel Enhances Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand-Mediated Apoptosis in Prostate Cancer Cells via Epigenetic Gene Regulation by Enhancer of Zeste Homolog 2

3-Deazaneplanocin A (DZNep): A Drug That Deserves a Second Look

The emerging data compiled during the past five years on 3-deazaneplanocin (DZNep) provide compelling evidence to reevaluate this drug as a better alternative over the specific catalytic inhibitors of histone methyl transferases (HTMs). The indirect mechanism of DZNep via inhibition of AdoHcy-ase, once considered a liability due to possible side effects, has now shown to be rather beneficial as additional pathways targeted by DZNep are important contributors to its superior anticancer properties. Furthermore, DZNep has demonstrated the ability to induce proteasomal degradation of its target and reduce toxicity in combination with well-established antitumor therapies in animal models. In addition, DZNep has shown important effects in suppressing fibrosis and inflammation in liver, kidney, peritoneum, and airways. Finally, inhibition of mRNA m6A methylation by DZNep suppresses the synthesis of the viral genome in SARS-Cov-2 infection and promises to have important therapeutic value when combined with its potent antiviral efficacy and anti-inflammatory effects.

TRIAL-based combination therapies in cancers

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) shows promising therapeutic potential in cancer treatment as it is able to trigger extrinsic apoptotic pathways by binding to the cognate death receptor, causing broad-spectrum apoptosis in cancer cells with negligible toxicity to normal cells. However, the majority of cancers display resistance to TRAIL, limiting its clinical utility. Overcoming resistance to TRAIL therapies remains a challenge in the development of effective anti-cancer strategies. To address the limitations of TRAIL therapy, a viable alternative approach involves combining TRAIL with more potent drugs compared to monotherapy. This combination strategy aims to induce synergistic effects or sensitize drug-resistant cancer cells. This review provides an overview of relevant modalities of TRAIL combination therapy, highlighting different drug classes. The findings demonstrate that combining TRAIL with other agents can effectively counteract resistance observed with TRAIL therapies in cancer. These findings lay a foundation for future advancements in TRAIL-based therapies for treating various cancers.

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.

Up-Regulation of PSMA Expression In Vitro as Potential Application in Prostate Cancer Therapy

Possibilities to improve the therapeutic efficacy of Lu-177-PSMA-617 radionuclide therapy by modulation of target expression are being investigated. Knowledge on regulatory factors that promote prostate cancer (PCa) progression may contribute to targeting prostate cancer more effectively. We aimed at the stimulation of PCa cell lines using the substances 5-aza-2'-deoxycitidine (5-aza-dC) and valproic acid (VPA) to achieve increased prostate-specific membrane antigen (PSMA) expression. PC3, PC3-PSMA, and LNCaP cells were incubated with varying concentrations of 5-aza-dC and VPA to investigate the cell-bound activity of Lu-177-PSMA-617. Stimulation effects on both the genetically modified cell line PC3-PSMA and the endogenously PSMA-expressing LNCaP cells were demonstrated by increased cellular uptake of the radioligand. For PC3-PSMA cells, the fraction of cell-bound radioactivity was enhanced by about 20-fold compared to that of the unstimulated cells. Our study reveals an increased radioligand uptake mediated by stimulation for both PC3-PSMA and LNCaP cell lines. In perspective of an enhanced PSMA expression, the present study might contribute to advanced radionuclide therapy approaches that improve the therapeutic efficacy, as well as combined treatment options.