BACKGROUND: Enzalutamide, a second-generation androgen receptor (AR) pathway inhibitor, is widely used in the treatment of castration-resistant prostate cancer. However, after a period of enzalutamide treatment, patients inevitably develop drug resistance. In this study, we characterized leucine-rich repeated G-protein-coupled receptor 5 (LGR5) and explored its potential therapeutic value in prostate cancer. METHODS: A total of 142 pairs of tumor and adjacent formalin-fixed paraf-fin-embedded tissue samples from patients with prostate cancer were collected from the Pathology Department at Sun Yat-sen Memorial Hos-pital. LGR5 was screened by sequencing data of enzalutamide-resistant cell lines combined with sequencing data of lesions with different Gleason scores from the same patients. The biological function of LGR5 and its effect on enzalutamide resistance were investigated in vitro and in vivo . Glutathione-S-transferase (GST) pull-down, coimmunoprecipitation, Western blotting, and immunofluorescence assays were used to explore the specific binding mechanism of LGR5 and related pathway changes. RESULTS: LGR5 was significantly upregulated in prostate cancer and negatively correlated with poor patient prognosis. Overexpression of LGR5 promoted the malignant progression of prostate cancer and reduced sensitivity to enzalutamide in vitro and in vivo . LGR5 promoted the phosphorylation of glycogen synthase kinase-3β (GSK-3β) by binding heat shock protein 90,000 alpha B1 (HSP90AB1) and mediated the activation of the Wingless/integrated (WNT)/β-catenin signaling pathway. The increased β-catenin in the cytoplasm entered the nucleus and bound to the nuclear AR, promoting the transcription level of AR, which led to the enhanced tolerance of prostate cancer to enzalutamide. Reducing HSP90AB1 binding to LGR5 significantly enhanced sensitivity to enzalutamide. CONCLUSIONS LGR5 directly binds to HSP90AB1 and mediates GSK-3β phosphorylation, promoting AR expression by regulating the WNT/β-catenin signaling pathway, thereby conferring resistance to enzalutamide treatment in prostate cancer.
Male ; Humans ; Phenylthiohydantoin/pharmacology* ; Benzamides ; Receptors, G-Protein-Coupled/genetics* ; Nitriles ; Cell Line, Tumor ; HSP90 Heat-Shock Proteins/metabolism* ; Drug Resistance, Neoplasm/genetics* ; Prostatic Neoplasms/drug therapy* ; beta Catenin/metabolism* ; Receptors, Androgen/genetics* ; Animals ; Mice ; Wnt Signaling Pathway/physiology*

AIM: To study the suppressive effect of c hu ankezhi (CKZ) injection, a Chinese medicine, on murine allergic contact dermatit is (type IV hypersensitivity). METHODS: Mice were divided into 6 groups according to different medicine treatments: CKZ high, middle, low dose ( CKZⅠ,Ⅱ,Ⅲ) groups, dexamethasone(DEX), benadryl and saline groups. Murine alle rgic contact dermatitis was induced by intraperitoneal injection of 2, 4-dinitro fluorobenzene. Different medicines were administrated at 2 h before sensitizatio n on day 0 and day 1, day 2, 2 h before elicitation and 6 h after on day 5. The six experimental groups were compared according to left ear thickness difference (S1), left ear weight difference (S2), body weight difference (S3) and dermal i nflammatory infiltration cell number. RESULTS: Compared with saline group, the left ear swelling and d ermal inflammatory infiltration cell number were significantly reduced in CKZⅠ, Ⅱ,Ⅲ and DEX groups (P