Continuous versus intermittent docetaxel for metastatic castration resistant prostate cancer

Anticancer Effect by Combined Treatment of Artemisia annua L. Polyphenols and Docetaxel in DU145 Prostate Cancer Cells and HCT116 Colorectal Cancer Cells

Docetaxel (DTX), a semi-synthetic analogue of paclitaxel (taxol), is known to exert potent anticancer activity in various cancer cells by suppressing normal microtubule dynamics. In this study, we examined how the anticancer effect of DTX is regulated by polyphenols extracted from Korean Artemisia annua L. (pKAL) in DU145 prostate cancer cells (mutant p53) and HCT116 colorectal cancer cells (wild-type p53). Here, we show that the anticancer effect of DTX was enhanced more significantly by pKAL in HCT116 cells than in DU145 cells via phase-contrast microscopy, CCK-8 assay, Western blot, and flow cytometric analysis of annexin V/propidium iodide-stained cells. Notably, mutant p53 was slightly downregulated by single treatment of pKAL or DTX in DU145 cells, whereas wild-type p53 was significantly upregulated by pKAL or DTX in HCT116 cells. Moreover, the enhanced anticancer effect of DTX by pKAL in HCT116 cells was significantly associated with the suppression of DTX-induced p53 upregulation, increase of DTX-induced phospho-p38, and decrease of DTX-regulated cyclin A, cyclin B1, AKT, caspase-8, PARP1, GM130, NF-κB p65, and LDHA, leading to the increased apoptotic cell death and plasma membrane permeability. Our results suggest that pKAL could effectively improve the anticancer effect of DTX-containing chemotherapy used to treat various cancers expressing wild-type p53.

Effect of different molecular weight and terminal group PLGA on docetaxel nanoparticles: Characterization and cytotoxic activity of castration-resistant prostate cancer cells

The choice of polymer and its compatibility with drug used determine the fate of nanoparticle in therapy. There has been limited sources about effect of resomer differentiation in nanoparticle related with physical and chemical properties and also biological activities of product. Therefore, we aimed to formulate docetaxel loaded polylactic-co-glycolic acid nanoparticles with different molecular weights (Resomer 502 and 504) and terminal groups (Resomer 502H and 504H) and to investigate the effect of these resomers on nanoparticle character, prostate cancer and healthy cells. Docetaxel loaded PLGA nanoparticles were prepared by single emulsion solvent evaporation method. Surface characterizations were carried out by zeta sizer and scanning electron microscopy. Encapsulation efficiency, in vitro drug release profiles and cytotoxic activity were determined. Main effect on the surface morphology of nanoparticles was the molecular weight of the polymer. In groups with acid terminal function have higher encapsulation and reaction efficiency. In all formulations, in vitro release was observed after 334 hours at pH 7.4 and 240 hours at pH 5.6. Also, the groups with high molecular weight showed selective cytotoxicity. These resomers especially RG 504 and RG 504H have potential to be used as a low-dose and high-efficiency extended-release drug delivery system in the treatment of prostate cancer.

Maintenance versus discontinuation of androgen deprivation therapy during continuous or intermittent docetaxel administration in castration-resistant prostate cancer patients: A multicentre, randomised Phase III study by the Piemonte Oncology Network

BACKGROUND

This study was designed to demonstrate the non-inferiority (NI) in overall survival (OS) of suspension of androgen deprivation therapy (ADT) versus maintenance and intermittent versus continuous docetaxel administration in metastatic castration-resistant prostate cancer (mCRPC) patients.

PATIENTS AND METHODS

mCRPC patients were randomised to first-line docetaxel with maintenance or suspension of ADT. Patients attaining a prostate-specific antigen (PSA) response after four chemotherapy cycles underwent second randomisation to receive continuous or intermittent docetaxel therapy. Six hundred patients were to be randomised to achieve 80% statistical power to demonstrate an NI hazard ratio (HR) of 1.25 of interruption versus maintenance of ADT.

RESULTS

The trial was prematurely closed when 198 participants were randomised. OS was similar in patients who continued (N = 96) versus those who interrupted (n = 102) ADT during docetaxel therapy (HR 0.98, 95% confidence interval [CI] 0.72-1.33] and those on a continuous (N = 35) versus an intermittent (N = 42) docetaxel schedule (HR 0.86, 95% CI 0.55-1.43). No difference in radiological progression-free survival, PSA response, or toxicity was observed between the study arms. The actual NI hazard margins of OS in Arms A and B patients were 1.33 and 1.43, respectively.

CONCLUSIONS

This trial enrolled one-third of the planned patients; this main weakness dramatically limits the interpretation of the results. ADT discontinuation and switching to an intermittent schedule did not seem to affect docetaxel efficacy. The absence of testosterone recovery in the majority of patients could have been a contributory factor. In men with mCRPC, ADT discontinuation should only be done with regular biochemical and clinical monitoring, with the option of quickly restarting ADT at disease progression.

Novel thiazolidine derivatives as potent selective pro-apoptotic agents

A series of 2-arylthiazolidine-4-carboxylic acid amide derivatives were synthesized and their cytotoxic activity against three cancer cell lines (PC-3, SKOV3 and MDA-MB231) was evaluated. Various structural modifications were tried including modifications of the length of the amide chain and modifications of the 2-aryl part using disubstituted phenyl and thiophene derivatives. The structure activity relationship was evaluated based on the in vitro biological evaluation against the above mentioned three cancer cell lines. The most selective compounds towards cancer cells were further evaluated against DLD-1, NCI-H520, Du145, MCF-7 and NCI-N87 cancer cells. The dodecyl amide having the 4-bromothienyl as the 2-aryl, compound 2e, exhibited the highest selectivity for cancer cells vs non-tumor cells. Mechanistic studies of the anticancer effect of compound 2e in prostate cancer PC-3 and colorectal cancer DLD-1 cells revealed that 2e could prevent the cell cycle in the G0/G1 phase by up-regulating the expression of p21 and reducing the expression of CDK2 and cyclin E. It increased the pro-apoptotic protein Bax and cleaved caspase 3, and down-regulated the expression of anti-apoptotic protein Bcl-2 to induce apoptosis. In addition, 2e also downregulated AKT, N-cadherin, and vimentin proteins expression giving indication that 2e inhibit the PI3K/AKT pathway to regulate cell cycle arrest and induce apoptosis, and can regulate the expression of epithelial-mesenchymal transition-related proteins.

Maintenance Long-Term Multiple Cycles Treatment with Docetaxel in Metastatic Castration-Resistant Prostate Cancer: A Report of Three Cases

Prostate cancer (PCa) is one of the most common types of malignancy, most patients with PCa will eventually progress to metastatic castration-resistant prostate cancer (mCRPC), which has a poor prognosis. Since 2004, chemotherapy has been approved by the FDA as the first-line treatment for mCRPC, and docetaxel-based regimens have been shown to improve both the patients’ symptoms and overall survival (OS). 10 cycles of docetaxel therapy are usually given to patients with mCPRC, but there is still no consensus on the optimal number of treatment cycles. Here, we present three cases of mCRPC patients that received maintenance long-term multiple-cycles docetaxel treatment. We believe that this new treatment strategy may benefit carefully selected mCRPC patients and provide several key advantages such as maximum exposure to drugs, improvements in drug efficacy, and reduce the risk of developing drug resistance.

Preclinical Evaluation of a Cabazitaxel Prodrug Using Nanoparticle Delivery for the Treatment of Taxane-Resistant Malignancies

Taxane-based chemotherapeutics are clinically available as frontline treatment regimens for cervical cancer. However, drug resistance and life-threatening toxicity impair the clinical efficacy of taxanes, so more effective and less toxic therapeutic modalities are urgently needed. Cabazitaxel has attracted increasing interest due to its potential to circumvent the drug resistance by taxanes. We previously showed that tethering docosahexaenoic acid (DHA) to cabazitaxel enabled the prodrug to self-assemble into nanoparticles in water. Despite this encouraging finding, the DHA-cabazitaxel conjugate formulation requires further optimization to enhance nanoparticle retention and tumor delivery. We here integrated this conjugate into amphiphilic poly(ethylene glycol)-block-poly(_D,L-lactic acid) copolymers to assemble dCTX NPs The nanoparticle abrogated P-glycoprotein-mediated resistance in cancer cells. In a docetaxel-resistant cervical tumor xenograft-bearing mouse model, the efficacy was augmented by the nanotherapy when compared with solution-based free drugs (i.e., docetaxel and cabazitaxel). Dose intensification of dCTX NPs markedly suppressed the tumor growth in this model. Detailed studies revealed that systemic toxicity was alleviated, and MTD of dCTX NPs was at least 3 times higher than that of free cabazitaxel in animals, which may enable dose increases for clinical studies. In conclusion, the new formulation addresses essential requirements in terms of the stability, safety, and translational capacity for initiating early-phase clinical trials.