The development of androgen-independent growth in advanced carcinoma of the prostate (CaP) is associated with poor prognosis and few therapeutic options. Chemotherapeutic drugs offer the afflicted patient palliative benefits, but these are short-lived because of the chemoresistant nature of hormone-refractory prostate cancer. Given the high percentage of CaP patients with mutations in the PTEN tumor suppressor gene, we sought to determine the involvement of the phosphatidylinositol 3'-kinase (PI3K) cascade in the development of CaP drug resistance. PTEN-negative PC3 cells were observed to have increased resistance to both doxorubicin and paclitaxel when compared with PTEN-positive DU145 cells. Furthermore, modulation of PI3K activity with the use of constitutively active and dominant-negative inhibitors was found to affect the ability to CaP cells to respond to chemotoxic treatments. Additionally, inhibition of PI3K with a small molecular weight inhibitor (LY294002) was able to potentiate the antineoplastic activity of both doxorubicin and paclitaxel in CaP cells. Interestingly, multidrug resistance protein-1 (MRP-1) expression, but not MDR-1 (p-glycoprotein), was observed to be induced as a consequence of PI3K activation in these cell types. Inhibition of MRP-1 expression via siRNA was observed to synergistically sensitize CaP cells to chemotoxic drugs while having no appreciable effect on cell growth in the absence of these compounds. Taken together, these data suggest that PI3K activation can lead to the development of chemoresistant cells in prostatic carcinomas through the up-regulation of MRP-1. Thus, inhibition of PI3K activity with concomitant administration of chemotoxic compounds may prove beneficial in preventing the development of drug resistance in patients with hormone-refractory prostate cancer.

https://cancerres.aacrjournals.org/content/canres/64/22/8397.full.pdf

Phosphatidylinositol 3'-kinase activation leads to multidrug resistance protein-1 expression and subsequent chemoresistance in advanced prostate cancer cells.

Chemotherapy for prostate cancer

Current strategies in the management of hormone refractory prostate cancer.

Background
To assess the outcome of neoadjuvant chemohormonal therapy comprising complete androgen blockade followed by treatment with docetaxel and estramustine phosphate before radical prostatectomy in Japanese patients with a high risk of localized prostate cancer (PCa)

/pdf/short-term-clinicopathological-outcome-of-neoadjuvant-1zssywr8ol.pdf

Short-term clinicopathological outcome of neoadjuvant chemohormonal therapy comprising complete androgen blockade, followed by treatment with docetaxel and estramustine phosphate before radical prostatectomy in Japanese patients with high-risk localized prostate cancer

Mutations “ciblables” dans les cancers de la prostate métastatiques Fruit de la collaboration entre de grandes institutions américaines et européennes, un groupe de chercheurs international (1) a analysé, par séquençage systémique de l’exome entier et du transcriptome, les échantillons de 150 patients atteints d’un cancer de la prostate résistant à la castration métastatique (CPRCm). Près de 90 % des hommes testés présentaient au moins 1 mutation permettant de prédire une réponse ou une résistance à des thérapies connues. Des mutations au niveau du récepteur des androgènes (RA) ont été notées chez près du tiers des patients (63 %). Les autres anomalies génomiques retrouvées le plus fréquemment concernaient les gènes de fusion ETS, TP53 et PTEN (40 à 60 % des cas) avec, par rapport aux cancers de la prostate primaires, un enrichissement des altérations du RA et de TP53. De nouvelles altérations ont été identifiées : PI3K3CA/B, R-spondin , BRAF/RAF1, APC, β-caténine, ZBTB16/PLZF. Mais la découverte sans doute la plus importante est le fait, encore une fois par rapport aux tumeurs primaires, que de nombreux patients (23 %) présentaient des mutations des gènes de la réparation de l’ADN, comme BRCA2, BRCA1 et ATM, ouvrant des perspectives thérapeutiques particulières. Ces patients pourraient répondre à des inhibiteurs de PARP, comme l’olaparib (2) .

Cancer de la prostate

Weekly docetaxel and estramustine in patients with hormone-refractory prostate cancer.

Autosomal-recessive congenital ichthyosis (ARCI) is a heterogeneous group of ichthyoses presenting at birth. Self-improving congenital ichthyosis (SICI) is a subtype of ARCI and is diagnosed when skin condition improves remarkably (within years) after birth. So far, there are sparse data on SICI and quality of life (QoL) in this ARCI subtype. This study aims to further delineate the clinical spectrum of SICI as a rather unique subtype of ARCI.This prospective study included 78 patients (median age: 15 years) with ARCI who were subdivided in SICI (n = 18) and non-SICI patients (nSICI, n = 60) by their ARCI phenotype.Quality of life (QoL) was assessed using the (Children's) Dermatology Life Quality Index. Statistical analysis was performed with chi-squared and t-Tests.The genetically confirmed SICI patients presented causative mutations in the following genes: ALOXE3 (8/16; 50.0%), ALOX12B (6/16; 37.5%), PNPLA1 (1/16; 6.3%) and CYP4F22 (1/16; 6.3%). Hypo-/anhidrosis and insufficient vitamin D levels (<30 ng/mL) were often seen in SICI patients. Brachydactyly (a shortening of the 4th and 5th fingers) was statistically more frequent in SICI (P = 0.023) than in nSICI patients. A kink of the ear's helix was seen in half of the SICI patients and tends to occur more frequently in patients with ALOX12B mutations (P = 0.005). QoL was less impaired in patients under the age of 16, regardless of ARCI type.SICI is an underestimated, milder clinical variant of ARCI including distinct features such as brachydactyly and kinking of the ears. Clinical experts should be aware of these features when seeing neonates with a collodion membrane. SICI patients should be regularly checked for clinical parameters such as hypo-/anhidrosis or vitamin D levels and monitored for changes in quality of life. 

Quality of life and clinical characteristics of self‐improving congenital ichthyosis within the disease spectrum of autosomal‐recessive congenital ichthyosis

L Hake

Papers

Weekly docetaxel and estramustine in patients with hormone-refractory prostate cancer.

Quality of life and clinical characteristics of self‐improving congenital ichthyosis within the disease spectrum of autosomal‐recessive congenital ichthyosis