👤 Slawomir Wolczynski

Breast cancer (BC) is the most prevalent malignancy among women worldwide. Growing evidence highlights the crucial role of circular RNAs (circRNAs) in BC carcinogenesis; however, their underlying mechanisms remain largely unknown. In this study, we identify circCLASP1, which is significantly upregulated in BC tissues (n = 65) and serum samples (n = 61). Its expression correlates with lymph node metastasis, ki67 expression, and tumor size. Receiver operation characteristic (ROC) curve analysis reveals area under the curve (AUC) values of 0.8196 (BC tissues) and 0.8902 (BC serum), respectively. Functionally, circCLASP1 knockdown significantly suppresses BC cell proliferation, migration, and invasion. Mechanistically, circCLASP1 prevents the ubiquitin-mediated degradation of GLI1 protein by facilitating its interaction with CCT2, thereby stabilizing GLI1. Moreover, circCLASP1 enhances the nuclear accumulation of GLI1, leading to increased SNAIL expression and thereby upregulating the expression of CCL2 and CCL5, which in turn promotes macrophage M2 polarization, ultimately resulting in BC progression and subsequent lung metastasis. Further analysis reveals that U2AF2 regulates circCLASP1 biogenesis. Collectively, these findings demonstrate that circCLASP1 promotes BC progression and an immunosuppressive microenvironment via the CCT2/GLI1/SNAIL axis, highlighting its potential as a prognostic biomarker and therapeutic target for BC. Show less

Mutations in the X-linked androgen receptor (AR) gene cause complete androgen insensitivity syndrome (CAIS). CAIS may cause congenital sexual development disorder, which frequently develops into testicular tumors. Here, we describe a novel splice-site intron 1 mutation in AR leading to improper splicing and AR protein absence in CAIS gonads. We characterized a patient's postpubertal gonadal steroidogenic enzyme expression profile. Localization of both CYP11A1 and CYP17A1 enzymes was restricted to both Leydig tumor cells and adjacent to tumor gonadal tissues. Sertoli cells of the CAIS gonad showed abundant HSD17B3 protein, which is an adult Leydig cell marker that enables the conversion of androstenedione to testosterone. Such HSD17B3 expression is typical for fetal-type Sertoli cells in rodents. The postpubertal CAIS gonad of our patient was completely devoid of androgen signaling pathway activity. Plausibly, the postpubertal Leydig cells consisted of two distinct cell populations: postpubertal fetal-type Leydig cells that persisted as androgen-independent cells and immature adult Leydig cells that failed to differentiate. Taken together, in this CAIS postpubertal testis, both Leydig and fetal-type Sertoli cells participated in testosterone production. Our results indicate the importance of molecular analysis as well as the characterization of steroidogenic enzyme profiling in the CAIS patient's gonad. Show less