As there is currently no effective therapy for patients with prostate cancer (PCa) bone metastasis, it was stringent to explore the relevant treatment strategies. Actually, the interaction between cancer cells and bone microenvironment plays important role in prostate cancer bone metastasis, especially the Sonic hedgehog protein (SHH) signaling in the bone microenvironment. The SHH promotes osteoblast maturation and osteoblast then secretes RANKL to induce osteoclastogenesis. Herein, this study develops bone-targeting calcium phosphate lipid hybrid nanoparticles (NPs) loaded with docetaxel (DTXL) and SHH siRNA for PCa bone metastasis treatment. For bone targeting purposes, the nanoplatform was modified with alendronate (ALN). (DTXL + siRNA)@NPs-ALN NPs effectively change the bone microenvironment by inhibiting the SHH paracrine and autocrine signaling, enhancing the anti-tumor effects of DTXL. Besides showing good in vitro cellular uptake, the NPs-ALN also inhibited tumor growth both in vitro and in vivo by inducing apoptosis, cell cycle arrest, and autophagy. This DDS comprised of (DTXL + siRNA)-loaded NPs provides an excellent strategy to treat PCa bone metastasis.

Prostate cancer (PCa) is one of the most common cancers with increasing rates of incidence. Bone metastasis and drug resistance are the most serious threat faced by patients following a delayed diagnosis of cancer, which might lead to treatment failure and death. The theoretical model of cancer stem cells (CSCs) explains the diverse molecular characteristics of cancer as well as its relapse, metastasis and drug resistance. Prostate cancer involves heterogeneous cells community, including prostate cancer stem cells as an important component. These subtypes of cancer cells are usually monoclonal, expressing specific biomarkers and exhibiting self-renewal and differentiation capacity. Therefore, therapies that target CSCs might be more effective in overcome drug resistance and metastasis. Thus, anti-CSCs therapies differ from the traditional anti-proliferative approach. We focus here on reviewing the effects of prostate CSCs on bone metastasis and resistance to traditional treatment in PCa, and report new clinical strategies that address CSC-based tumorigenesis.