BLCA is the most common malignant tumor of the urinary system and one of the 10 most common cancers(Bray et al., 2018). The high recurrence rate and low prognosis of advanced BLCA make treatment a challenge. This study analyzed and predicted BLCA patient prognosis and related target genes based on their clinical characteristics. Findings should inform the development of more individualized and targeted treatment options for this disease.
Several recent studies have identified new methods for predicting BLCA patient prognosis. For example, miR-133 downregulation was shown to predict the progression and poor prognosis of patients with urothelial carcinoma of the bladder(Zhao et al., 2013), and let-7c, miR-100, and miR-145 expression were associated with the EMT score and abundance of macrophages in tumor tissue(Feng et al., 2019). In addition, stromal lymphocytic infiltrate (SLI) was shown to be a reliable marker of poor BLCA patient prognosis and positively correlated with histological grade, tumor stage, and lymph node status(Furuya et al., 2019). The presence of CD163 + and CD103 + macrophages also predicted the poor prognosis of patients with primary T1 high-grade bladder urothelial carcinoma(Yang et al., 2019;Jin et al., 2022). However, the predictors identified to date remain insufficient for reliable BLCA prognosis and precision treatment.
To determine more reliable prognosis markers, survival analysis using clinical information and the RNA matrix of BLCA patients was conducted to screen for prognosis-related genes and compare them with programmed necroptosis-related genes to identify genes that overlapped. Different molecular subtypes were obtained using consensus clustering analysis of the combined overlapping gene expression matrix along with clinical information. Immunological analysis of the molecular subgroups was also performed to determine the TIME and immune status of the different subtypes. Furthermore, differential analysis of gene expression matrices of the molecular subtypes was performed to find and screen out DEGs and functional analysis was used to identify the underlying mechanisms. Finally, Lasso and multifactorial Cox regression analyses were used to build a prognostic risk model and screen out representative genes. A pan-cancer analysis of the screened genes was then used to characterize the potential mechanisms of their gene targets on other cancer prognoses and to evaluate the efficacy of the risk model.
Lasso regression analysis was used to screen three genes, TRPC6, ATAD3A, and ANXA1, for prognostic relevance based on their role in necroptosis, which was shown to be closely associated with tumor development. TRPC6, a member of the TRPC family, can affect breast cancer proliferation and migration through Ca2+-dependent signaling, while inhibition of TRPC6 reduces proliferation and invasion of non-small cell lung cancer cells(Yang et al., 2017). LncRNA TUG1 promotes cell growth and migration in colorectal cancer through the TUG1-miR-145-5p-TRPC6 pathway(Wang et al., 2021). Helicobacter pylori can promote gastric cancer migration and invasion by upregulating TRPC6 through Wnt/β-catenin signaling(Song et al., 2019).
The AAA structural domain of ATAD3A, a nuclear-encoded mitochondrial enzyme, is involved in cell death processes. Transcriptional upregulation and increased protein stability are potential mechanisms for elevated ATAD3A in cancer(Teng et al., 2019). ATAD3A also mediates the activation of RAS-independent mitochondrial ERK1/2 signaling, which facilitates the development of head and neck cancer. ANXA1 acts as a damage-associated molecular pattern-linked molecule that promotes necroptosis(Lang et al., 2022). By binding to and stabilizing EphA2, ANXA1 induces the growth and metastasis of nasopharyngeal carcinoma. Transcriptome analysis was used to confirm ANXA1 as a prognostic and immune microenvironmental marker for glioma(Feng et al., 2020). ANXA1-containing extracellular vesicles also regulate macrophage polarization in the TIME and promote the development and metastasis of pancreatic cancer. And the typical immunostaining graphs of three genes in BLCA tumor tissue were provided by the human protein atlas (HPA) database (Supplementary Figure S5)(Novizio et al., 2021).
The current study used pan-cancer analysis to determine the prognosis-related expression of these three representative genes in other tumors. Specifically, the R “survival” package was used to build a risk regression model and analyze the prognostic relationship between gene expression and specific cancers by using the Log rank test. It was observed that TRPC6 prognosed poor outcomes when highly expressed in tumor models such as glioma (TCGA-GBMLGG), stomach and esophageal carcinoma (TCGA-STES), kidney renal papillary cell carcinoma (TCGA-KIRP), stomach adenocarcinoma (TCGA-STAD), bladder urothelial carcinoma (TCGA-BLCA), mesothelioma (TCGA-MESO) and acute lymphoblastic leukemia (TARGET-ALL-R), and when expressed at low levels in tumor models such as uterine corpus endometrial carcinoma (TCGA-UCEC) and kidney renal clear cell carcinoma (TCGA-KIRC)(Supplementary Figure S6). ANXA1 prognosed poor outcomes when highly expressed in tumor models such as glioma (TCGA-GBMLGG), brain lower-grade glioma (TCGA-LGG), glioblastoma multiforme (TCGA-GBM), bladder urothelial carcinoma (TCGA-BLCA), uveal melanoma (TCGA-UVM), pancreatic adenocarcinoma (TCGA-PAAD), and acute lymphoblastic leukemia (TARGET-ALL-R), and when expressed at low levels in tumor models such as skin cutaneous melanoma (TCGA-SKCM) (Supplementary Figure S7). ATAD3A prognosed poor outcomes when highly expressed in tumor models such as glioma (TCGA-GBMLGG), brain lower-grade glioma (TCGA-LGG), sarcoma (TCGA-SARC), liver hepatocellular carcinoma (TCGA-LIHC), skin cutaneous melanoma (TCGA-SKCM), bladder urothelial carcinoma (TCGA-BLCA), mesothelioma (TCGA-MESO), acute myeloid leukemia (TCGA-LAML), TARGET-ALL, adrenocortical carcinoma (TCGA-ACC), and kidney chromophobe (TCGA-KICH) and when expressed in low levels in tumor models such as kidney renal papillary cell carcinoma (TCGA-KIRP) (Supplementary Figure S8).
In sum, this study established a model and identified relevant genes that can predict BLCA patient prognosis. Findings should contribute to the development of targeted BLCA treatments and help inform more precise treatment decisions.