Pyroptosis-Related Patterns Predict Tumor Immune Landscape and Immunotherapy Response in Bladder Cancer

IMP2 drives chemoresistance by repressing cisplatin-induced apoptosis and ferroptosis via activation of IPO4 and SLC7A11 under hypoxia in bladder cancer

BACKGROUND

Cisplatin resistance is the leading cause of mortality in muscle-invasive bladder cancer (MIBC) cases. Previous evidence suggests that abnormal epitranscriptome modifications are associated with reduced chemotherapy responses. However, the exact underlying mechanism remains largely unknown.

METHODS

Insulin-like growth factor-2 mRNA-binding protein 2 (IMP2) was identified by clustered regularly interspaced short palindromic repeats (CRISPR) data screening, single-cell RNA-sequencing and sample analysis. To evaluate the regulatory role of IMP2, functional studies were conducted both in vitro and in vivo. To elucidate the underlying mechanisms, various techniques including immunofluorescence, fluorescent in situ hybridization, RNA pull-down, coimmunoprecipitation, and RNA immunoprecipitation were used.

RESULTS

Our study revealed that IMP2 was overexpressed in chemoresistant MIBC and lung metastasis tissues. IMP2 inhibition markedly enhanced the sensitivity of BC cells to cisplatin both in vitro and in vivo. Mechanistically, IMP2 enhanced the mRNA stability of IPO4 and SLC7A11 in a m6A-dependent manner, augmenting the nuclear translocation of C/EBPδ to activate PRKDC-mediated DNA damage repair in response to cisplatin. Moreover, IMP2 upregulated SLC7A11 levels and suppressed cisplatin-induced ferroptosis. Combining ferroptosis and apoptosis inhibitors completely reversed cisplatin resistance caused by IMP2 overexpression. LINC00941, which was induced by HIF-1α-mediated transcriptional activation, specifically bound IMP2 and protects it from degradation.

CONCLUSIONS

This work demonstrated a novel mechanism involving the IMP2-IPO4/SLC7A11 pathway as a promising treatment target for cisplatin-resistant bladder cancer.

Analysis of cell death-related genes to evaluate the prognostic and immunotherapeutic value in bladder cancer

To enhance therapeutic approaches, we created a distinctive pattern utilizing the cell demise indicator (CDI) to predict the effectiveness of immunotherapy in individuals with bladder carcinoma (BLCA). Hub prognostic CDIs were identified from the TCGA database using differential gene expression and survival analysis, encompassing 763 genes across 13 death modes. The subtype assessment was employed to evaluate the impact of these genes on the prognosis and immunotherapeutic outcomes in patients with BLCA. The LASSO regression method was used to identify significant CDIs, while Cox regression and nomogram analyses were conducted to explore the impact of CDIs on prognosis. CHMP4C and GSDMB were selected as the hub genes for the following research. Subsequently, These two central genes underwent further investigation to explore their association with immunotherapy, followed by an analysis of their potential regulatory network. Subtype analysis showed that these CDIs were significantly associated with the prognosis and immunotherapy of BLCA patients. The regulatory network in BLCA was evaluated through the establishment of the lncRNA XIST/NEAT1-CDIs-miR-146a-5p/miR-429 axis. Immunohistochemical analysis revealed a significant up-regulation of CHMP4C in bladder cancer tissues, which was strongly associated with an unfavorable prognosis for BLCA patients. Moreover, our findings provide compelling evidence that CHMP4C plays a pivotal role in promoting BLCA progression through the activation of the epithelial-mesenchymal transition (EMT) pathway. These findings highlight the negative impact of CHMP4C on BLCA patient prognosis, while also providing insights into the oncogenic mechanisms and immunotherapy in which CHMP4C may be involved.

A prognostic model based on necroptosis-related genes for prognosis and therapy in bladder cancer

Bladder cancer, one of the most prevalent malignant cancers, has high rate of recurrence and metastasis. Owing to genomic instability and high-level heterogeneity of bladder cancer, chemotherapy and immunotherapy drugs sensitivity and lack of prognostic markers, the prognosis of bladder cancer is unclear. Necroptosis is a programmed modality of necrotic cell death in a caspase-independent form. Despite the fact that necroptosis plays a critical role in tumor growth, cancer metastasis, and cancer patient prognosis, necroptosis-related gene sets have rarely been studied in bladder cancer. As a result, the development of new necroptosis-related prognostic indicators for bladder cancer patients is critical. Herein, we assessed the necroptosis landscape of bladder cancer patients from The Cancer Genome Atlas database and classified them into two unique necroptosis-related patterns, using the consensus clustering. Then, using five prognosis-related genes, we constructed a prognostic model (risk score), which contained 5 genes (ANXA1, DOK7, FKBP10, MAP1B and SPOCD1). And a nomogram model was also developed to offer the clinic with a more useful prognostic indicator. We found that risk score was significantly associated with clinicopathological characteristics, TIME, and tumor mutation burden in patients with bladder cancer. Moreover, risk score was a valid guide for immunotherapy, chemotherapy, and targeted drugs. In our study, DOK7 was chosen to further verify our prognosis model, and functional assays indicated that knockdown the expression of DOK7 could prompt bladder cancer proliferation and migration. Our work demonstrated the potential role of prognostic model based on necroptosis genes in the prognosis, immune landscape and response efficacy of immunotherapy of bladder cancer.

Cell origin and genome profile difference of penoscrotum invasive extramammary Paget disease compared with its in situ counterpart

Penoscrotum extramammary Paget disease (pEMPD) is a rare cutaneous carcinoma with an unknown cell origin. pEMPD always presents as a tumor in situ with an indolent process, whereas some progress into invasive forms with more aggressive behavior. The in situ and invasive cases display different morphologies and biological behavior, and thus far, a relationship between these two components has not been demonstrated. Immunohistochemistry was used to disclose the immunotype of pEMPD, and the results revealed that invasive/in situ pEMPD possessed with some identical immunophenotypes such as CK7, P63, and CK10, which inferred the clonal relatedness. The variable expressions of GCDFP-15 and carcino embryonic antigen hinted that tumor cell origin might be an epidermal sweat gland in epiderma. In our cohort, invasive pEMPD presented increased expression of androgen receptor and decreased MUC5CA expression, and these two changes might bring to the shift of invasive phenotype. To better understanding the relationship between these distinct tumor forms, we performed whole exome sequencing testing to evaluate overlapping genomic alterations of six paired invasive/in situ pEMPDs. The results showed that missense mutation was the predominant mutation type, and C>T transition accounted for 65.1% in all SNP mutation. Among the top 20 differential genes obtained from the six paired invasive/in situ pEMPD analysis, MUC4 (one missense, one in frame del, and one multi-hit), AHNAK2 (two missense and one multi-hit), DOT1L (two missense and one multi-hit), and FRG1 (two missense and one-multi hit) mutations were most enriched in invasive pEMPDs, which postulated that these genes may play roles in the disease progression.