Hypoxia and its Modification in Bladder Cancer: Current and Future Perspectives

Hypoxia-mediated attenuation of EGLN2 inhibition of the NF-κB signaling pathway leads to the formation of a loop between HIF-1α and MUC1-C promoting chemoresistance in bladder cancer

The expression pattern of MUC1-C in tumors is closely linked to tumor progression; however, its specific mechanism remains unclear. The expression of MUC1-C in cancer and adjacent normal tissues was detected using immunohistochemistry and Western blot. The IC50 of cells to gemcitabine was determined using the CCK8 assay. The effects of hypoxia and MUC1-C on the behavioral and metabolic characteristics of bladder cancer cells were investigated. Gene expression was assessed through Western blot and polymerase chain reaction. The relationship between the genes was analyzed by co-immunoprecipitation, immunofluorescence and Western blot. Finally, the role of the EGLN2 and NF-κB signaling pathways in the interaction between MUC1-C and hypoxia-inducible factor-1α (HIF-1α) was investigated. MUC1-C expression is significantly higher in bladder cancer tissues than in adjacent normal tissues, particularly in large-volume tumors, and is closely correlated with clinical features such as tumor grade. Tumor volume-mediated hypoxia resulted in increased expression of MUC1-C and HIF-1α in bladder cancer cells. Under stimulation of hypoxia, the inhibitory effect of EGLN2 on the NF-κB signaling pathway was weakened, allowing NF-κB to promote the positive feedback formation of MUC1-C and HIF-1α. Simultaneously, EGLN2-mediated degradation of HIF-1α was reduced. This ultimately led to elevated HIF-1α-mediated downstream gene expression, promoting increased glucose uptake and glycolysis, and ultimately resulting in heightened chemotherapy resistance and malignancy.

Vasohibin-1 Expression Can Predict Pathological Complete Remission of Advanced Bladder Cancer with Neoadjuvant Chemotherapy

BACKGROUND AND PURPOSE

Neoadjuvant chemotherapy (NAC) is a well-established standard practice in invasive bladder cancer (BCa), however patient selection remains challenging. High expression of vasohibin-1 (VASH1), an endogenous regulator of angiogenesis, has been reported in high-grade and advanced BCa; however, its prognostic value for chemotherapy outcomes remains unexplored. In this study, we sought to identify biomarkers of chemotherapy response focusing on the relationship between angiogenesis and tissue hypoxia.

METHODS

Forty Japanese patients with BCa who underwent NAC and radical cystectomy were included in the present analysis. We compared the immunohistochemical expression of CD34, VASH1, and carbonic anhydrase 9 (CA9) between patients who achieved tumor clearance at operation (ypT0) and those with residual disease after cystectomy.

RESULTS

There were 19 patients in the ypT0 group, while the remaining 21 patients had residual tumors at operation. Patients in the ypT0 group had high microvessel density (p = 0.031), high VASH1 density (p < 0.001), and stronger CA9 staining (p = 0.046) than their counterparts. Multivariate analysis identified microvessel and VASH1 density as independent predictive factors for pathological ypT0 disease (p = 0.043 and 0.002, respectively). The 5-year recurrence-free survival rate was higher in the high VASH1 density group than in the low VASH1 density group (66.3% vs. 33.3%, p = 0.036).

CONCLUSION

VASH1 density is a potential therapeutic biomarker for chemotherapy response in BCa.

Molecular profiling of a bladder cancer with very high tumour mutational burden

The increasing incidence of urothelial bladder cancer is a notable global concern, as evidenced by the epidemiological data in terms of frequency, distribution, as well as mortality rates. Although numerous molecular alterations have been linked to the occurrence and progression of bladder cancer, currently there is a limited knowledge on the molecular signature able of accurately predicting clinical outcomes. In this report, we present a case of a pT3b high-grade infiltrating urothelial carcinoma with areas of squamous differentiation characterized by very high tumor mutational burden (TMB), with up-regulations of immune checkpoints. The high TMB, along with elevated expressions of PD-L1, PD-L2, and PD1, underscores the rationale for developing a personalized immunotherapy focused on the use of immune-checkpoint inhibitors. Additionally, molecular analysis revealed somatic mutations in several other cancer-related genes, including TP53, TP63 and NOTCH3. Mutations of TP53 and TP63 genes provide mechanistic insights on the molecular mechanisms underlying disease development and progression. Notably, the above-mentioned mutations and the elevated hypoxia score make the targeting of p53 and/or hypoxia related pathways a plausible personalized medicine option for this bladder cancer, particularly in combination with immunotherapy. Our data suggest a requirement for molecular profiling in bladder cancer to possibly select appropriate immune-checkpoint therapy.

TFRC, associated with hypoxia and immune, is a prognostic factor and potential therapeutic target for bladder cancer

BACKGROUND

Bladder cancer is a common malignancy of the urinary system, and the survival rate and recurrence rate of patients with muscular aggressive (MIBC) bladder cancer are not ideal. Hypoxia is a pathological process in which cells acquire special characteristics to adapt to anoxic environment, which can directly affect the proliferation, invasion and immune response of bladder cancer cells. Understanding the exact effects of hypoxia and immune-related genes in BLCA is helpful for early assessment of the prognosis of BLCA. However, the prognostic model of BLCA based on hypoxia and immune-related genes has not been reported.

PURPOSE

Hypoxia and immune cell have important role in the prognosis of bladder cancer (BLCA). The aim of this study was to investigate whether hypoxia and immune related genes could be a novel tools to predict the overall survival and immunotherapy of BLCA patients.

METHODS

First, we downloaded transcriptomic data and clinical information of BLCA patients from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. A combined hypoxia and immune signature was then constructed on the basis of the training cohort via least absolute shrinkage and selection operator (LASSO) analysis and validated in test cohort. Afterwards, Kaplan-Meier curves, univariate and multivariate Cox and subgroup analysis were employed to assess the accuracy of our signature. Immune cell infiltration, checkpoint and the Tumor Immune Dysfunction and Exclusion (TIDE) algorithm were used to investigate the immune environment and immunotherapy of BLCA patients. Furthermore, we confirmed the role of TFRC in bladder cancer cell lines T24 and UMUC-3 through cell experiments.

RESULTS

A combined hypoxia and immune signature containing 8 genes were successfully established. High-risk group in both training and test cohorts had significantly poorer OS than low-risk group. Univariate and multivariate Cox analysis indicated our signature could be regarded as an independent prognostic factor. Different checkpoint was differently expressed between two groups, including CTLA4, HAVCR2, LAG3, PD-L1 and PDCD1. TIDE analysis indicated high-risk patients had poor response to immunotherapy and easier to have immune escape. The drug sensitivity analysis showed that high-risk group patients were more potentially sensitive to many drugs. Meanwhile, TFRC could inhibit the proliferation and invasion ability of T24 and UMUC-3 cells.

CONCLUSION

A combined hypoxia and immune-related gene could be a novel predictive model for OS and immunotherapy estimation of BLCA patients and TFRC could be used as a potential therapeutic target in the future.

Innate Lymphoid Cells in Bladder Cancer: From Mechanisms of Action to Immune Therapies

Bladder tumors have a high mutational burden and tend to be responsive to immune therapies; however, response rates remain modest. To date, immunotherapy in bladder cancer has largely focused on enhancing T-cell immune responses in the bladder tumor microenvironment. It is anticipated that other immune cells, including innate lymphoid cells (ILC), which play an important role in bladder oncogenesis and tumor suppression, could be targeted to improve response to existing therapies. ILCs are classified into five groups: natural killer cells, ILC1s, ILC2s, ILC3s, and lymphoid tissue inducer cells. ILCs are pleiotropic and play dual and sometimes paradoxical roles in cancer development and progression. Here, a comprehensive discussion of the current knowledge and recent advancements in understanding the role of ILCs in bladder cancer is provided. We discuss the multifaceted roles that ILCs play in bladder immune surveillance, tumor protection, and immunopathology of bladder cancer. This review provides a rationale for targeting ILCs in bladder cancer, which is relevant for other solid tumors.

Inhibiting stanniocalcin 2 reduces sunitinib resistance of Caki-1 renal cancer cells under hypoxia condition

Background

Our previous study has suggested that blocking stanniocalcin 2 (STC2) could reduce sunitinib resistance in clear cell renal cell carcinoma (ccRCC) under normoxia. The hypoxia is a particularly important environment for RCC occurrence and development, as well as sunitinib resistance. The authors proposed that STC2 also plays important roles in RCC sunitinib resistance under hypoxia conditions.

Methods

The ccRCC Caki-1 cells were treated within the hypoxia conditions. Real-time quantitative PCR and Western blotting were applied to detect the STC2 expression in ccRCC Caki-1 cells. STC2-neutralizing antibodies, STC2 siRNA, and the recombinant human STC2 (rhSTC2) were used to identify targeting regulation on STC2 in modulating sunitinib resistance, proliferation, epithelial-mesenchymal transition (EMT), migration, and invasion. In addition, autophagy flux and the lysosomal acidic environment were investigated by Western blotting and fluorescence staining, and the accumulation of sunitinib in cells was observed with the addition of STC2-neutralizing antibodies and autophagy modulators.

Results

Under hypoxia conditions, sunitinib disrupted the lysosomal acidic environment and accumulated in Caki-1 cells. Hypoxia-induced the STC2 mRNA and protein levels in Caki-1 cells. STC2-neutralizing antibodies and STC2 siRNA effectively aggravated sunitinib-reduced cell viability and proliferation, which were reversed by rhSTC2. In addition, sunitinib promoted EMT, migration, and invasion, which were reduced by STC2-neutralizing antibodies.

Conclusion

Inhibiting STC2 could reduce the sunitinib resistance of ccRCC cells under hypoxia conditions.

Construction of a Prognostic Model Based on Methylation-Related Genes in Patients with Colon Adenocarcinoma

Purpose

Colon adenocarcinoma (COAD) is the second leading cause of death in the world, and the new incidence rate ranks third among all cancers. Abnormal DNA methylation is related to the occurrence and development of tumors. In this study, we aimed to identify genes associated with abnormal methylation in COAD.

Methods

COAD transcriptome data, methylation data and clinical information were downloaded from the TCGA database and GEO database. The differentially expressed genes (DEGs) and methylated genes (DMGs) were analyzed and identified in COAD. PCA analysis was applied to divide COAD into subtypes, and the survival and immune cell infiltration of each subtype were evaluated. Cox and LASSO analyses were performed to construct COAD risk model. GSEA was used to evaluate the enrichment pathways. The Kaplan-Meier was used to analyze the difference in survival. ROC curve was plotted to evaluate the accuracy of the model, and GSE17536 was used to verify the accuracy of the risk model. The risk model is combined with the clinicopathological characteristics of COAD patients to perform multivariate Cox regression analysis to obtain independent risk factors and draw nomograms.

Results

In total, 4564 DEGs and 1093 DMGs were screened, among which 298 were found to be overlapping genes. For 220 of these overlapping genes, the methylation was significantly negatively correlated to expression levels. An optimal signature from 4 methylated biomarkers was identified to construct the prognostic model.

Conclusion

Our study identified 4 methylated biomarkers in the COAD. Then, we constructed the risk model to provide a theoretical basis and reference value for the research and treatment of COAD.

Enhancing the anti-tumor response by combining DNA damage repair inhibitors in the treatment of solid tumors

The anti-cancer efficacy of anti-malignancy therapies is related to DNA damage. However, DNA damage-response mechanisms can repair DNA damage, failing anti-tumor therapy. The resistance to chemotherapy, radiotherapy, and immunotherapy remains a clinical challenge. Thus, new strategies to overcome these therapeutic resistance mechanisms are needed. DNA damage repair inhibitors (DDRis) continue to be investigated, with polyadenosine diphosphate ribose polymerase inhibitors being the most studied inhibitors. Evidence of their clinical benefits and therapeutic potential in preclinical studies is growing. In addition to their potential as a monotherapy, DDRis may play an important synergistic role with other anti-cancer therapies or in reversing acquired treatment resistance. Here we review the impact of DDRis on solid tumors and the potential value of combinations of different treatment modalities with DDRis for solid tumors.

Recruitment mechanisms and therapeutic implications of tumor-associated macrophages in the glioma microenvironment

As one of the main components of the glioma immune microenvironment, glioma-associated macrophages (GAMs) have increasingly drawn research interest. Primarily comprised of resident microglias and peripherally derived mononuclear macrophages, GAMs are influential in a variety of activities such as tumor cell resistance to chemotherapy and radiotherapy as well as facilitation of glioma pathogenesis. In addition to in-depth research of GAM polarization, study of mechanisms relevant in tumor microenvironment recruitment has gradually increased. Suppression of GAMs at their source is likely to produce superior therapeutic outcomes. Here, we summarize the origin and recruitment mechanism of GAMs, as well as the therapeutic implications of GAM inhibition, to facilitate future glioma-related research and formulation of more effective treatment strategies.

A prognosis marker MUC1 correlates with metabolism and drug resistance in bladder cancer: a bioinformatics research

Background

MUC1 is a type I transmembrane protein that plays an important role in tumor cell signal transduction. Although current studies have shown that MUC1 is upregulated in bladder cancer (BC), the specific mechanism is still unclear.

Methods

We performed expression analysis, gene set enrichment analysis, survival analysis, immune infiltration analysis, drug sensitivity analysis, and metabolism-related gene expression analysis on TCGA-BLCA, GES31684 and GSE13507.

Results

The expression of MUC1 in the tumor and lymphatic metastasis positive samples was significantly increased. Genes related to MUC1 expression were significantly enriched in immune response, ribosomes, exosomes, and energy metabolism. The results of the immune infiltration analysis showed that M1 macrophages in BC with high MUC1 expression were significantly decreased. Expression of MUC1 increases drug resistance in BC patients. In addition, MUC1 increases glycolysis, glucose uptake, and lactate production by inducing metabolic reprogramming.

Conclusion

MUC1 has a significant effect on the metabolism and immune cell infiltration of BC, which may be the cause of increased drug resistance, and can be used as a molecular target for the diagnosis and treatment of BC.

Identifying a hypoxia related score to predict the prognosis of bladder cancer: a study with The Cancer Genome Atlas (TCGA) database

Background

Recurrence is common in bladder cancer, with a hypoxic tumor microenvironment (TME) playing a role in genetic instability and prognosis of bladder cancer. However, we still lack practical hypoxia related model for predicting the prognosis of bladder cancer. In this study, we identified new prognosis-related hypoxia genes and established a new hypoxia score related signature.

Methods

The Gene Set Variation Analysis (GSVA) algorithm was utilized to calculate the hypoxia score of bladder cancer cases found on the The Cancer Genome Atlas (TCGA) database on the gene expression profiles. The cases were first divided into low- and high-hypoxia score groups and then differentially expressed genes (DEGs) expression analysis was conducted. Hypoxia-related genes were identified using weighted gene co-expression network analysis (WGCNA). We then conducted a protein-protein interaction (PPI) network and carried out functional enrichment analysis of the genes that overlapped between DEGs and hypoxia-related genes. LASSO Cox regression analysis was used to establish a hypoxia-related prognostic signature, which was validated using the GSE69795 dataset downloaded from GEO database.

Results

Results from Kaplan-Meier analysis showed that patients with a high hypoxia score had significantly poor overall survival compared to patients with low hypoxia score. We selected 270 DEGs between low- and high-hypoxia score groups, while WGCNA analysis identified 1,313 genes as hypoxia-related genes. A total of 170 genes overlapped between DEGs and hypoxia-related genes. LASSO algorithms identified 29 genes associated with bladder cancer prognosis, which were used to construct a novel 29-gene signature model. The prognostic risk model performed well, since the receiver operating characteristic (ROC) curve showed an accuracy of 0.802 (95% CI: 0.759–0.844), and Cox proportional hazards regression analysis proved the model an independent predictor with hazard ratio (HR) =1.789 (95% CI: 1.585–2.019) (P<0.001). The low-risk score patients had remarkably longer overall survival than patients with a higher score (survival rate 71.06% vs. 23.66%) in the The Cancer Genome Atlas (TCGA) cohort (P<0.0001) and in the dataset GSE69795 (P=0.0079).

Conclusions

We established a novel 29-gene hypoxia-related signature model to predict the prognosis of bladder cancer cases. This model and identified hypoxia-related genes may further been used as biomarkers, assisting the evaluation of prognosis of bladder cancer cases and decision making in clinical practice.