Oxidative stress in bladder cancer: an ally or an enemy?

Identification of tumor-antigen signatures and immune subtypes for mRNA vaccine selection in muscle-invasive bladder cancer

BACKGROUND

Muscle-invasive bladder cancer continues to lack reliable diagnostic and prognostic biomarkers. Recently, tumor vaccines targeting specific molecules have emerged as a promising treatment in inhibiting tumor progression, which was rekindled under the background of coronavirus disease-2019 pandemic. However, the application of mRNA vaccine targeting muscle-invasive bladder cancer-specific antigens remains limited, and there has been a lack of comprehensive studies or validations to identify suitable patient subgroups for vaccination. This study aims to explore novel muscle-invasive bladder cancer antigen signatures to identify patients most likely to benefit from vaccination.

METHODS

Gene expression profiles of muscle-invasive bladder cancer samples, along with corresponding clinical data, were retrieved from the Cancer Genome Atlas Program. The least absolute shrinkage and selection operator model was applied to develop signatures for stratifying muscle-invasive bladder cancer patients. Prognostic accuracy of each factor was assessed using receiver operating characteristic analysis. Tumor Immune Estimation Resource was employed to visualize the relationship between the proportion of antigen-presenting cells and the expression of selected genes. The CIBERSORT and WGCNA R packages were used to identify differences in immune infiltration levels across muscle-invasive bladder cancer subgroups. Additionally, the STRING database and Cytoscape were used to construct the protein-protein interaction network. CCK-8 and colony formation assays were employed in invitro experiments.

RESULTS

A total of 49 potential tumor antigens were identified. Using least absolute shrinkage and selection operator Cox regression, 14 tumor antigens were selected to develop a risk evaluation signature. The risk score signature can serve as a valuable tool for predicting the outcomes of muscle-invasive bladder cancer patients. Based on differential clinical, molecular, and immune-related gene profiles, muscle-invasive bladder cancer patients were classified into 2 subtypes: the immune "cold" subtype (immune score 1) and the immune "hot" subtype (immune score 2). The immune score signature, developed using a logistic score model, effectively distinguishes between patients more likely to belong to immune score 1 or 2. Notably, patients with a high risk score exhibited a higher proportion of immune score 2 compared to those with a low risk score. Additionally, the prognostic accuracy was significantly enhanced when the risk score and immune score were combined. Different tumor subtypes displayed distinct immune landscapes and signaling pathways. Moreover, novel tumor antigens associated with oxidative stress were identified.

CONCLUSION

The risk score and immune score signatures based on tumor antigens have identified potential effective neo-antigens for the development of mRNA vaccines targeting muscle-invasive bladder cancer. Patients with low risk score and immune score 1 subtype are more likely to benefit from mRNA vaccination. Additionally, this study highlights the critical role of oxidative stress in modulating the efficacy of the mRNA vaccine.

Redox System and Oxidative Stress-Targeted Therapeutic Approaches in Bladder Cancer

Bladder cancer (BCa) is the most common genitourinary malignancy, with a high global incidence and recurrence rate that is paired with an increasing caregiver burden and higher financial cost, in addition to increasing morbidity and mortality worldwide. Histologically, BCa is categorized into non-muscle invasive, muscle invasive, and metastatic BCa, on the basis of which the therapeutic strategy is determined. Despite all innovations and recent advances in BCa research, conventional therapies such as chemotherapy, immunotherapy, radiotherapy, and surgery fall short in the complete management of this important malignancy. Besides this worrying trend, the molecular basis of BCa development also remains poorly understood. Burgeoning evidence from experimental and clinical studies suggests that oxidative stress resulting from an imbalance between reactive oxygen species (ROS) generation and the body's antioxidant production plays an integral role in BCa development and progression. Hence, ROS-induced oxidative stress-related pathways are currently under investigation as potential therapeutic targets of BCa. This review focuses on our current understanding regarding ROS-associated pathways in BCa pathogenesis and progression, as well as on antioxidants as potential adjuvants to conventional BCa therapy.

The Association between NADPH Oxidase 2 (NOX2) and Drug Resistance in Cancer

NADPH oxidase, as a major source of intracellular reactive oxygen species (ROS), assumes an important role in the immune response and oxidative stress response of the body. NADPH oxidase 2 (NOX2) is the first and most representative member of the NADPH oxidase family, and its effects on the development of tumor cells are gaining more and more attention. Our previous study suggested that NCF4 polymorphism in p40phox, a key subunit of NOX2, affected the outcome of diffuse large B-cell lymphoma patients treated with rituximab. It hypothesized that NOX2-mediated ROS could enhance the cytotoxic effects of some anti-tumor drugs in favor of patients with tumors. Several reviews have summarized the role of NOX2 and its congeners-mediated ROS in anti-tumor therapy, but few studies focused on the relationship between the expression of NOX2 and anti-tumor drug resistance. In this article, we systematically introduced the NOX family, represented by NOX2, and a classification of the latest inhibitors and agonists of NOX2. It will help researchers to have a more rational and objective understanding of the dual role of NOX2 in tumor drug resistance and is expected to provide new ideas for oncology treatment and overcoming drug resistance in cancer.

Oxidative Stress Markers in Urine and Serum of Patients with Bladder Cancer

Oxidative stress is defined as an imbalanced state of the production of reactive oxygen species and antioxidant capacity that causes oxidative damage to biomolecules, leading to cell injury and finally death. Oxidative stress mediates the development and progression of several cancer diseases, including bladder cancer. The aim of our study was to determine markers of levels of the oxidative stress in serum and urine in the same patients in parallel in serum and urine. Furthermore, we tried to estimate the associations between oxidative stress markers and the type of cancer, its clinical stage and grade, as the well as correlations between serum and urinary markers in patients with bladder cancer. Sixty-one bladder cancer and 50 healthy volunteers as a control group were included. We determined the serum and urine levels of advanced oxidation protein products (AOPP), Amadori products, total antioxidant capacity, total oxidant status (TOS), oxidative status index (OSI), and malondialdehyde. We confirm that almost all markers are elevated in serum and urine from patients with bladder cancer than from healthy subjects. Moreover, we did not find differences in the level of oxidative stress markers and the type of tumor, its clinical stage, and grade. We noted correlations between serum and urinary biomarkers, in particular TOS and OSI. Our results clearly indicate the participation of oxidative stress in the development of bladder cancer.

The proteomic landscape shows oncologic relevance in cystitis glandularis

BACKGROUND

The relationship between cystitis glandularis (CG) and bladder malignancy remains unclear.

METHODS

We identified the oncologic significance of CG at the molecular level using liquid chromatography-tandem mass spectrometry-based proteomic analysis of 10 CG, 12 urothelial carcinoma (UC), and nine normal urothelium (NU) specimens. Differentially expressed proteins (DEPs) were identified based on an analysis of variance false discovery rate < 0.05, and their functional enrichment was analyzed using a network model, Gene Set Enrichment Analysis, and Gene Ontology annotation.

RESULTS

We identified 9,890 proteins across all samples and 1,139 DEPs among the three entities. A substantial number of DEPs overlapped in CG/NU, distinct from UC. Interestingly, we found that a subset of DEP clusters (n = 53, 5%) was differentially expressed in NU but similarly between CG and UC. This "UC-like signature" was enriched for reactive oxygen species (ROS) and energy metabolism, growth and DNA repair, transport, motility, epithelial-mesenchymal transition, and cell survival. Using the top 10 shortlisted DEPs, including SOD2, PRKCD, CYCS, and HCLS1, we identified functional elements related to ROS metabolism, development, and transport using network analysis. The abundance of these four molecules in UC/CG than in NU was consistent with the oncologic functions in CG.

CONCLUSIONS

Using a proteomic approach, we identified a predominantly non-neoplastic landscape of CG, which was closer to NU than to UC. We also confirmed a small subset of common DEPs in UC and CG, suggesting that altered ROS metabolism might imply potential cancerous risks in CG.

Harnessing ROS-Induced Oxidative Stress for Halting Colorectal Cancer via Thiazolidinedione-Based SOD Inhibitors

Based on the "canonical" view of reactive oxygen species' (ROS) contribution to carcinogenesis, ROS induce oxidative stress and promote various tumor progression events. However, tumor cells also need to defend themselves against oxidative damage. This "heresy" was supported by several recent studies underlining the role of cellular antioxidant capacity in promoting metastasis and resistance to chemotherapy. Accordingly, harnessing the ROS-induced oxidative stress via selective suppression of the cancer antioxidant defense machinery has been launched as an innovative anticancer strategy. Within this approach, pharmacological inhibition of superoxide dismutases (SODs), the first-line defense antioxidant enzymes for cancer cells, selectively kills tumor cells and circumvents their acquired resistance. Various SOD inhibitors have been introduced, of which some were tolerated in clinical trials. However, the hit SOD inhibitors belong to diverse chemical classes and lack comprehensive structure-activity relationships (SAR). Herein, we probe the potential of newly synthesized benzylidene thiazolidinedione derivatives to inhibit SOD in colorectal cancer with special emphasis on their effects on correlated antioxidant enzymes aldehyde dehydrogenase 1 (ALDH1) and glutathione peroxidase (GPx). This may possibly bring a new dawn for utilizing thiazolidinediones (TZDs) in cancer therapy through SOD inhibition mechanisms. The preliminary 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that all of the evaluated TZDs exhibited excellent safety profiles on normal human cells, recording an EC100 of up to 47.5-folds higher than that of doxorubicin. Compounds 3c, 6a, and 6e (IC50 = 4.4-4.7 μM) were superior to doxorubicin and other derivatives against Caco-2 colorectal cancer cells within their safe doses. The hit anticancer agents inhibited SOD (IC50 = 97.2-228.8 μM). Then, they were selected for further in-depth evaluation on the cellular level. The anticancer IC50 doses of 3c, 6a, and 6e diminished the antioxidant activities of SOD (by 29.7, 70.1, and 33.3%, respectively), ALDH1A (by 85.92, 95.84, and 86.48%, respectively), and GPX (by 50.17, 87.03, and 53.28%, respectively) in the treated Caco-2 cells, elevating the Caco-2 cellular content of ROS by 21.42, 7.863, and 8.986-folds, respectively. Docking simulations were conducted to display their possible binding modes and essential structural features. Also, their physicochemical parameters and pharmacokinetic profiles formulating drug-likeness were computed.

Potential Therapeutic Action of Autophagy in Gastric Cancer Managements: Novel Treatment Strategies and Pharmacological Interventions

Gastric cancer (GC), second most leading cause of cancer-associated mortality globally, is the cancer of gastrointestinal tract in which malignant cells form in lining of the stomach, resulting in indigestion, pain, and stomach discomfort. Autophagy is an intracellular system in which misfolded, aggregated, and damaged proteins, as well as organelles, are degraded by the lysosomal pathway, and avoiding abnormal accumulation of huge quantities of harmful cellular constituents. However, the exact molecular mechanism of autophagy-mediated GC management has not been clearly elucidated. Here, we emphasized the role of autophagy in the modulation and development of GC transformation in addition to underlying the molecular mechanisms of autophagy-mediated regulation of GC. Accumulating evidences have revealed that targeting autophagy by small molecule activators or inhibitors has become one of the greatest auspicious approaches for GC managements. Particularly, it has been verified that phytochemicals play an important role in treatment as well as prevention of GC. However, use of combination therapies of autophagy modulators in order to overcome the drug resistance through GC treatment will provide novel opportunities to develop promising GC therapeutic approaches. In addition, investigations of the pathophysiological mechanism of GC with potential challenges are urgently needed, as well as limitations of the modulation of autophagy-mediated therapeutic strategies. Therefore, in this review, we would like to deliver an existing standard molecular treatment strategy focusing on the relationship between chemotherapeutic drugs and autophagy, which will help to improve the current treatments of GC patients.

50-bp insertion/deletion polymorphism of the superoxide dismutase-1 is associated with bladder cancer risk in an Iranian population

Bladder cancer (BC) is considered the sixth prevalent malignancy in men and the ninth leading cause of malignancy-related worldwide. Superoxide dismutase (SOD) is an antioxidant enzyme in the defense system against oxidative stress. Hence, we aimed to investigate whether the 50 bp Insertion/Deletion(Ins/Del) polymorphism of the SOD1 associated with the risk of BC. The study was conducted on 158 BC patients and 153 age-matched healthy subjects. Genomic DNA from all individuals was screened for the 50-bp SOD1 promoter deletion using PCR assay. Our results demonstrated an association between SOD1 Ins/Del (45% vs. 32%) genotype and risk of BC and this genotype elevated the susceptibility to BC (OR = 1.80, 95% CI: (1.10-2.90), P = 0.01). In addition, the Del allele of the SOD1 variation was detected to be more prevalent in the BC patients with the frequency of 28% and 20% in cases and healthy groups, correspondingly (OR = 1.61, 95% CI: (1.10-2.36), P = 0.01). It seems that SOD1 50-bp Ins/Del genotype, as well as Del, allele, is associated with an increased risk of BC in an Iranian population. However, further investigations in more diverse populations are necessary to assess the value of the novel biomarkers as a risk stratification biomarker for BC.