Hypoxia-mediated stabilization of HIF1A in prostatic intraepithelial neoplasia promotes cell plasticity and malignant progression

Prostate cancer (PCa) is a leading cause of cancer-related deaths. The slow evolution of precancerous lesions to malignant tumors provides a broad time-frame for preventing PCa. To characterize prostatic intraepithelial neoplasia (PIN) progression, we conducted longitudinal studies on Pten(i)pe-/- mice which recapitulate prostate carcinogenesis in humans. We discovered that early PINs are hypoxic and that hypoxia-inducible factor 1 alpha (HIF1A) signaling is activated in luminal cells, which enhances malignant progression. Luminal HIF1A dampens immune surveillance and drives luminal plasticity leading to the emergence of cells with selective Transglutaminase 2 (TGM2) expression and impaired androgen signaling. Importantly, elevated TGM2 levels in PCa patients are associated with shortened progression-free survival after prostatectomy. Finally, we show that pharmacologically inhibiting HIF1A impairs cell proliferation and induces apoptosis in PINs. Therefore, our study demonstrates that HIF1A is a target for PCa prevention, and that TGM2 is a promising prognostic biomarker of early relapse after prostatectomy. The aim was to determine the HIF1A cistrome in mouse prostate adenocarcinoma cells. Myc-CaP cells were treated with DMOG (HIF1A stabilizer) at a concentration of 1.0 mM for 6h. 3 samples were analyzed: 1 replicate of DMOG-treated Myc-CaP cells with 50 µg of chromatin immunoprecipitated using 5 µg of HIF1A antibody; 1 replicate of DMOG-treated Myc-CaP cells with 50 µg of chromatin immunoprecipitated using 5 µg of rabbit IgG (negative control); 1 replicate of non-immunoprecipitated chromatin (control).

前列腺癌（Prostate Cancer, PCa）是癌症相关死亡的主要诱因之一。癌前病变向恶性肿瘤的缓慢演进过程，为前列腺癌的预防提供了充足的时间窗口。为解析前列腺上皮内瘤变（Prostatic Intraepithelial Neoplasia, PIN）的进展机制，我们对Pten(i)pe-/-小鼠开展了纵向研究——该小鼠模型可精准重现人类前列腺癌变的完整进程。本研究发现，早期PIN病灶处于缺氧微环境中，且缺氧诱导因子1α（Hypoxia-Inducible Factor 1 Alpha, HIF1A）信号通路在前列腺腔上皮细胞中被激活，该通路可显著促进恶性病变进展。腔上皮细胞中的HIF1A可抑制机体免疫监视功能，并驱动腔上皮细胞可塑性改变，最终促使仅表达谷氨酰胺转移酶2（Transglutaminase 2, TGM2）且雄激素信号通路受损的细胞亚群出现。值得注意的是，前列腺癌患者体内TGM2水平升高与前列腺切除术后无进展生存期缩短呈显著正相关。最后，本研究证实，通过药物靶向抑制HIF1A可削弱PIN病灶的细胞增殖能力，并诱导其发生细胞凋亡。综上，本研究表明HIF1A可作为前列腺癌预防的潜在治疗靶点，而TGM2则是前列腺切除术后早期复发的极具临床应用前景的预后生物标志物。本研究的核心目标为解析小鼠前列腺腺癌细胞中的HIF1A顺式调控组（cistrome）。实验设计如下：将Myc-CaP细胞用浓度为1.0 mM的DMOG（HIF1A稳定剂）处理6小时，随后共分析3份生物学重复样本：① 1份DMOG处理的Myc-CaP细胞样本，取50 μg染色质，使用5 μg HIF1A抗体进行染色质免疫沉淀；② 1份DMOG处理的Myc-CaP细胞对照样本，取50 μg染色质，使用5 μg兔IgG进行染色质免疫沉淀（阴性对照）；③ 1份未经免疫沉淀的染色质样本（总输入对照）。