Shi, Lei

Abstract While tissue-resident memory CD8+ T cells (TRM cells) provide superior frontline defense against pathogens, the molecular mechanisms governing their persistence and functional regulation remain poorly defined. Our study reveals that the costimulatory receptors CD27 and ICOS coordinately sustain PD-1high CD8+ TRM cell populations following resolution of acute influenza infection. These costimulatory signals serve as critical targets for PD-1/PD-L1 blockade, thereby facilitating the rejuvenation of PD-1high TRM cells and influencing the progression of fibrotic sequelae during the memory phase. Mechanistic dissection identifies the nuclear receptor Nur77 (NR4A1) as the convergent transcriptional hub downstream of CD27/ICOS, governing proliferative renewal and maintenance of PD-1high TRM cells. Therapeutic administration of a CD27 agonist not only amplified this TRM cell subset in late-stage memory but also conferred cross-protective immunity against heterosubtypic viral challenges. Clinically, the expression of CD27 and ICOS is enriched in CD8+ T cells within the lung tissues of patients with pulmonary fibrosis. Collectively, our findings establish the "CD27/ICOS-NR4A1-Proliferation" axis as a linchpin of PD-1/PD-L1-mediated TRM cell homeostasis, revealing druggable targets for intercepting infection-associated fibrotic progression.

(1) Background: Prostate cancer treatment efficacy is significantly influenced by androgen receptor (AR) signaling pathways. SLC22A3, a membrane transporter, has been linked to SNP rs9364554 risk loci for drug efficacy in prostate cancer. (2) Methods: We examined the location of SNP rs9364554 in the genome and utilized TCGA and other publicly available datasets to analyze the association of this SNP with SLC22A3 transcription levels. We verified onco-mining findings in prostate cancer cell lines using quantitative PCR and Western blots. Additionally, we employed electrophoretic mobility shift assay (EMSA) to detect the binding affinity of transcription factors to this SNP. The ChIP-Seq was used to analyze the enrichment of H3K27ac on the SLC22A3 promoter. (3) Results: In this study, we revealed that SNP rs9364554 resides in the SLC22A3 gene and affects its transcription. The downregulation of SLC22A3 is associated with drug resistance. More importantly, we found that this SNP has different binding affinities with transcription factors, specifically FOXA1 and AR, which significantly affects their regulation of SLC22A3 transcription. (4) Conclusions: Our findings highlight the potential of using this SNP as a biomarker for predicting chemotherapeutic outcomes and uncover possible mechanisms underlying drug resistance in advanced prostate cancers. More importantly, it provides a clinical foundation for targeting FOXA1 to enhance drug efficacy in prostate cancer patients.

Abstract Androgen receptor (AR) is a major survival factor for prostate cancer. Inflammation is implicated in many cancer types, including prostate cancer. Activation of MAP3K7 (also termed TAK1) and downstream IκB kinase β (IKKβ) by proinflammatory cytokines such as TNFα stimulates NF-κB survival pathways. Paradoxically, MAP3K7 is often deleted in human prostate cancer. Here, we demonstrate that AR protein expression is lower in inflammatory tumor areas compared with non-inflammatory tissues in patients with prostate cancer. Map3k7 knockout increased AR protein levels and activity in the mouse prostate, and MAP3K7 and AR protein levels were inversely correlated in prostate cancer patient specimens. TNFα treatment increased AR protein ubiquitination and proteasomal degradation. Mechanistically, activation of IKKβ by TNFα induced phosphorylation and TRCP1/2 E3 ligase–mediated polyubiquitination and degradation of AR protein. TNFα suppressed prostate cancer proliferation, which could be rescued by blockade of AR degradation. These findings reveal a previously unrecognized tumor suppressive function of the inflammation-activated MAP3K7–IKKβ axis in degrading AR protein. Moreover, they suggest that aberrant elevation of AR protein could be a prognostic biomarker and therapeutic target for MAP3K7-deficient prostate cancer. Significance: This study identifies that MAP3K7–IKKβ signaling plays a tumor-suppressive role in prostate cancer by degrading AR, revealing potential prognostic and therapeutic strategies for MAP3K7-deficient tumors.

Abstract Molecular mechanisms underlying intratumoral androgenesis and aberrant androgen receptor (AR) activation in prostate cancer remain poorly understood. Here we demonstrate that ectopic expression of the E3 ubiquitin ligase adaptor speckle-type poxvirus and zinc finger domain protein (SPOP) stabilizes 17βHSD4. SPOP bound a functional substrate-binding consensus (SBC) motif 315RATST319 in 17βHSD4 and promoted nondegradable K27- and K29-linked polyubiquitination of 17βHSD4. The effect of SPOP was antagonized by serum- and glucocorticoid kinase-3 (SGK3)-mediated phosphorylation of serine 318 (S318) in the SBC and S318 phosphorylation-dependent binding of SKP2 E3 ligase and subsequent K48-linked polyubiquitination and proteasomal degradation of 17βHSD4. Prostate cancer–associated SPOP mutations impaired the SPOP-17βHSD4 interaction, caused 17βHSD4 protein destruction in prostate cancer cells in culture and patient specimens, and increased testosterone production and prostate cancer cell growth in vitro and in mouse models. Thus, we have identified SPOP and SKP2 as two essential E3 ubiquitin ligases that exert opposite effects on 17βHSD4 protein degradation and intratumoral androgenesis in prostate cancer cells. We further demonstrate that SPOP mutations or SKP2 overexpression contribute to prostate cancer progression by decreasing 17βHSD4 expression and increasing intratumoral androgen synthesis. Significance: This study reveals a novel mechanism of aberrant AR activation in SPOP-mutated prostate cancer and uncovers putative biomarkers for effective treatment by AR-targeted therapies.