Words of wisdom. Re: Activity of cabazitaxel in castration-resistant prostate cancer progressing after docetaxel and next-generation endocrine agents

Integrated Therapeutic Targeting of the Prostate Tumor Microenvironment

Prostate cancer is a common and deadly cancer among men. The heterogeneity that characterizes prostate tumors contributes to clinical challenges in the diagnosis, prognosis, and treatment of this malignancy. While localized prostate cancer can be treated with surgery or radiotherapy, metastatic disease to the lymph nodes and the bone requires aggressive treatment with androgen deprivation treatment (ADT). Unfortunately, this often eventually progresses to metastatic castration-resistant prostate cancer (mCRPC). Advanced prostate cancer treatment today involves 1st- and 2nd-line taxane chemotherapy and 2nd-generation antiandrogens. The process of epithelial mesenchymal transition (EMT), during which epithelial cells lose their adhesions and their polarity, is a critical contributor to prostate cancer metastasis. In this article, we aim to integrate the current understanding of mechanisms dictating the dynamics of phenotypic EMT, with apoptosis outcomes in prostate tumors in response to antiandrogen and taxane chemotherapy for the treatment of advanced disease. Novel insights into the signaling mechanisms that target the functional interface between apoptosis and EMT will be considered in the context of potential clinical markers of tumor prognosis, as well as for effective therapeutic targeting of α- and β- adrenergic signaling (by novel and existing chemotherapeutic agents and antiandrogens). Interfering with EMT and apoptosis simultaneously toward eradicating the tumor mass is of major significance in combating the lethal disease and increasing patient survival.

Revisiting nomenclature for the description of prostate cancer androgen-responsiveness

Ever since the Noble prize-winning findings of Huggins and Hodges, the androgen receptor (AR) has been the main target for treatment of advanced prostate cancer (CaP). Today, second- and even third-line androgen deprivation strategies, which have been designed rationally to interfere with the AR signaling that re-emerges under conditions of androgen deprivation and is at least in part responsible for disease recurrence, are effective in impeding progression of advanced CaP. The therapeutic success of these novel agents in CaP that has failed initial androgen deprivation therapy (ADT) and subsequent chemotherapy is prompting studies to explore their use earlier in the course of CaP progression. Repositioning of these drugs, along with alterations in the timing, sequencing and/or combination of traditional or novel ADTs, either alone or in combination with radiation or chemo- or immuno-therapies are expected to broaden significantly the scope of treatment options for CaP. Despite the rapidly changing and continuously innovating landscape of CaP therapies that target AR activity, the terminology that is used to describe CaP androgen status has not evolved. Currently available nomenclature falls short in capturing the sustained androgen-responsiveness of mostCaPs after ADT, does not distinguish readily between CaP's responsiveness to androgens and other steroid hormones, and does not specify the treatment condition(s) under which CaP recurs. A novel vocabulary is introduced to solve these limitations and to facilitate optimal communication among physicians, scientists and CaP patients.