Creatine supplementation and resistance training to preserve muscle mass and attenuate cancer progression (CREATINE-52): a protocol for a double-blind randomized controlled trial.

BACKGROUND: Muscle mass is important for metastatic prostate cancer survival and quality of life (QoL). The backbone of treatment for men with metastatic castration sensitive prostate cancer (mCSPC) is androgen deprivation therapy (ADT) with an androgen signaling inhibitor. ADT is an effective cancer treatment, but it facilitates significant declines in muscle mass and adverse health outcomes important to mCSPC survivors, such as fatigue, and reductions in physical function, independence, insulin sensitivity, and QoL. In non-metastatic CSPC survivors, resistance training (RT) preserves muscle mass and improves these related health outcomes, but the biggest barrier to RT in CSPC survivors of all stages is fatigue. Creatine monohydrate supplementation coupled with RT (Cr + RT) may address this barrier since creatine plays a critical role in energy metabolism. Cr + RT in cancer-free older adults and other clinical populations improves muscle mass and related health outcomes. Evidence also suggests that creatine supplementation can complement cancer treatment. Thus, Cr + RT is a strategy that addresses gaps in survivorship needs of people with mCSPC. The purpose of this parallel, double-blind randomized controlled trial is to test the effects of 52-weeks of Cr + RT compared with placebo (PLA) and RT (PLA + RT) on muscle mass, other related health outcomes, and markers of cancer progression. METHODS: We will carry out this trial with our team's established, effective, home-based, telehealth RT program in 200 mCSPC survivors receiving ADT, and evaluate outcomes at baseline, 24-, and 52-weeks. RT will occur twice weekly with elastic resistance bands, and an established creatine supplementation protocol will be used for supplementation delivery. Our approach addresses a major facilitator to RT in mCSPC survivors, a home-based RT program, while utilizing a supervised model for safety. DISCUSSION: Findings will improve delivery of comprehensive survivorship care by providing a multicomponent, patient-centered lifestyle strategy to preserve muscle mass, improve health outcomes, and complement cancer treatment (NCT06112990).

MIR145 Core Promoter Methylation in Pretreatment Cell-Free DNA: A Liquid Biopsy Tool for Muscle-Invasive Bladder Cancer Treatment Outcome.

PURPOSE: The lack of personalized management of bladder cancer (BlCa) results in patients' lifelong post-treatment monitoring with invasive interventions, underlying the urgent need for tailored and minimally invasive health care services. On the basis of our previous findings on miR-143/145 cluster methylation in bladder tumors, we evaluated its clinical significance in pretreatment cell-free DNA (cfDNA) of patients with BlCa. MATERIALS AND METHODS: Methylation analysis was performed in our screening cohort (120 patients with BlCa; 20 age-matched healthy donors) by bisulfite-based pyrosequencing. Tumor recurrence/progression for patients with non-muscle-invasive bladder cancer, and progression and mortality for patients with muscle-invasive bladder cancer (MIBC) were used as clinical end point events in survival analysis. Bootstrap analysis was applied for internal validation of Cox regression models and decision curve analysis for assessment of clinical benefit on disease prognosis. RESULTS: Decreased methylation of MIR145 core promoter in pretreatment cfDNA was associated with short-term disease progression (multivariate Cox: hazard ratio [HR], 2.027 [95% CI, 1.157 to 3.551]; P = .010) and poor overall survival (multivariate Cox: HR, 2.098 [95% CI, 1.154 to 3.817]; P = .009) of patients with MIBC after radical cystectomy (RC). Multivariate models incorporating MIR145 promoter methylation in cfDNA with tumor stage clearly ameliorated patients' risk stratification, highlighting superior clinical benefit in MIBC prognostication. CONCLUSION: Reduced pretreatment cfDNA methylation of MIR145 core promoter was markedly correlated with increased risk for short-term progression and worse survival of patients with MIBC after RC and adjuvant therapy, supporting modern personalized and minimally invasive prognosis. Methylation profiling of MIR145 core promoter in pretreatment cfDNA could serve as a minimally invasive and independent predictor of MIBC treatment outcome and emerge as a promising marker for blood-based test in BlCa.

[Current and Future Status of Muscle Pathology: The Position of Muscle Pathology Diagnosis in the Future].

Many muscle disease names are mostly based on muscle pathology findings. Naturally, muscle pathology is important in the diagnosis of muscle diseases. Moreover, in recent years, extensive genetic analysis and autoantibody testing for myositis have been applied clinically, although muscle biopsies are less performed. However, muscle pathology should be proactively considered when a single gene presents multiple phenotypes, when variants of unknown pathological significance are detected, or in cases of autoimmune myositis that may be misdiagnosed as muscular dystrophy.

Challenges and technical aspects in the management of muscle invasive bladder cancer as retrograde radical cystectomy with ileal conduit.

Objective: To evaluate long-term outcomes in patients homogenously treated with radical cystectomy and ileal conduit for muscle invasive bladder cancer. METHODS: The retrospective study was conducted at the Urology Department of Pakistan Kidney and Liver Institute and Research Centre, Lahore, Pakistan, and comprised data from December 25, 2017, to January 16, 2023, related to patients who underwent radical cystectomy with ileal conduit with or without neo-adjuvant and adjuvant radiation, chemotherapy, or immunotherapy for papillary urothelial carcinom of the bladder. Clinical trajectory, histopathological characteristics and long-term clinical outcomes were noted. Data was analysed using SPSS 20. RESULTS: In our study of 40 patients with muscle invasive bladder cancer, males predominated (32, 80%), with a median age of 57.4 years (IQR: 29-80). Diagnosis was early in 5 (12.5%) patients with varying haematuria durations, while 34 (85%) patients had a smoking history. Comorbidities included hypertension in 17 (42.5%) patients, diabetes in 1 (2.5%) patient, both hypertension and diabetes in 9 (22.5%) patients and a combination of hypertension, diabetes, and ischaemic heart disease in 3 (7.5%) patients. Transurethral resection was performed once in 13 (32.5%) patients and multiple times in 27 (67.5%) patients. Additionally, 5 (12.5%) patients received immunotherapy, 11 (27.5%) patients underwent non-adjuvant radiation, and 14 (35%) patients received non-adjuvant chemotherapy. Papillary urothelial carcinoma was the predominant histological subtype among 37 (92.5%) patients. Patients receiving chemotherapy had significantly better overall survival (p=0.02). No significant differences were noted in recurrence or survival by therapy modality (p>0.05). These findings highlight the significance of early diagnosis, tailored treatments, and comorbidity management in muscle invasive bladder cancer patients. Age stratification revealed significant survival differences across groups (χ²=10.923, df=3, p= 0.012). Analysis by complications did not show age-related survival variations (χ² =3.978, df = 3, p=0.264). Conclusion: Achieving excellent long-term survival in MIBC patients requires a multidisciplinary approach, emphasizing early diagnosis, tailored treatment, and adherence to guidelines and protocols.

Patient metabolic profile defined by liver and muscle 18F-FDG PET avidity is independently associated with overall survival in gastric cancer.

BACKGROUND: PET-CT-based patient metabolic profiling is a novel concept to incorporate patient-specific metabolism into gastric cancer care. METHODS: Staging PET-CTs, demographics, and clinicopathologic variables of gastric cancer patients were obtained from a prospectively maintained institutional database. PET-CT avidity was measured in tumor, liver, spleen, four paired muscles, and two paired fat areas in each patient. The liver to rectus femoris (LRF) ratio was defined as the ratio of SUVmean of liver to the average SUVmean of the bilateral rectus femoris muscles. Kaplan-Meier and Cox-proportional hazards models were used to identify the impact of LRF ratio on OS. RESULTS: Two hundred and one patients with distal gastroesophageal (48%) or gastric (52%) adenocarcinoma were included. Median age was 65 years, and 146 (73%) were male. On univariate analysis, rectus femoris PET-CT avidity and LRF ratio were significantly associated with overall survival (p < 0.05). LRF ratio was significantly higher in males, early-stage cancer, patients with an ECOG 0 or 1 performance status, patients with albumin > 3.5 mg/dL, and those with moderately differentiated tumor histology. In multivariable regression, gastric cancer stage, albumin, and LRF ratio were significant independent predictors of overall survival (LRF ratio HR = 0.73 (0.56-0.96); p = 0.024). Survival curves showed that the prognostic impact of LRF was associated with metastatic gastric cancer (p = 0.009). CONCLUSIONS: Elevated LRF ratio, a patient-specific PET-CT-based metabolic parameter, was independently associated with an improvement in OS in patients with metastatic gastric cancer. With prospective validation, LRF ratio may be a useful, host-specific metabolic parameter for prognostication in gastric cancer.

Integrating molecular subtype and CD8+ T cells infiltration to predict treatment response and survival in muscle-invasive bladder cancer.

BACKGROUND: Luminal and Basal are the primary intrinsic subtypes of muscle-invasive bladder cancer (MIBC). The presence of CD8+ T cells infiltration holds significant immunological relevance, potentially influencing the efficacy of antitumor responses. This study aims to synergize the influence of molecular subtypes and CD8+ T cells infiltration in MIBC. METHODS: This study included 889 patients with MIBC from Zhongshan Hospital, The Cancer Genome Atlas, IMvigor210 and NCT03179943 cohorts. We classified the patients into four distinct groups, based on the interplay of molecular subtypes and CD8+ T cells and probed into the clinical implications of these subgroups in MIBC. RESULTS: Among patients with Luminal-CD8+Thigh tumors, the confluence of elevated tumor mutational burden and PD-L1 expression correlated with a heightened potential for positive responses to immunotherapy. In contrast, patients featured by Luminal-CD8+Tlow displayed a proclivity for deriving clinical advantages from innovative targeted interventions. The Basal-CD8+Tlow subgroup exhibited the least favorable three-year overall survival outcome, whereas their Basal-CD8+Thigh counterparts exhibited a heightened responsiveness to chemotherapy. CONCLUSIONS: We emphasized the significant role of immune-molecular subtypes in shaping therapeutic approaches for MIBC. This insight establishes a foundation to refine the process of selecting subtype-specific treatments, thereby advancing personalized interventions for patients.

The role of neoadjuvant chemotherapy for patients with variant histology muscle invasive bladder cancer undergoing robotic cystectomy: Data from the International Robotic Cystectomy Consortium.

OBJECTIVE: To assess the role of neoadjuvant chemotherapy (NAC) before robot-assisted radical cystectomy (RARC) for patients with variant histology (VH) muscle-invasive bladder cancer (MIBC). METHODS: Retrospective review of 988 patients who underwent RARC (2004-2023) for MIBC. Primary outcomes included the utilization of NAC among this cohort of patients, frequency of downstaging, and discordance between preoperative and final pathology in terms of the presence of VH. Secondary outcomes included disease-specific (DSS), recurrence-free (RFS), and overall survival (OS). RESULTS: A total of 349 (35%) had VH on transurethral resection or at RARC. The 4 most common VH subgroups were squamous (n = 94), adenocarcinoma (n = 64), micropapillary (n = 34), and sarcomatoid (n = 21). There was no difference in OS (log-rank: P = 0.43 for adenocarcinoma, P = 0.12 for micropapillary, P = 0.55 for sarcomatoid, P = 0.29 for squamous), RFS (log-rank: P = 0.25 for adenocarcinoma, P = 0.35 for micropapillary, P = 0.83 for sarcomatoid, P = 0.79 for squamous), or DSS (log-rank P = 0.91 for adenocarcinoma, P = 0.15 for micropapillary, 0.28 for sarcomatoid, P = 0.92 for squamous) among any of the VH based on receipt of NAC. Patients with squamous histology who received NAC were more likely to be downstaged on final pathology compared to those who did not (P < 0.01). CONCLUSION: Our data showed no significant difference in OS, RFS, or DSS for patients with VH MIBC cancer who received NAC before RARC. Patients with the squamous variant who received NAC had more pathologic downstaging compared to those who did not. The role of NAC among patients with VH is yet to be defined. Results were limited by small number in each individual group and lack of exact proportion of VH.

POLQ identifies a better response subset to immunotherapy in muscle-invasive bladder cancer with high PD-L1.

BACKGROUND: Though programmed cell death-ligand 1 (PD-L1) has been used in predicting the efficacy of immune checkpoint blockade (ICB), it is insufficient as a single biomarker. As a key effector of an intrinsically mutagenic microhomology-mediated end joining (MMEJ) pathway, DNA polymerase theta (POLQ) was overexpressed in various malignancies, whose expression might have an influence on genomic stability, therefore altering the sensitivity to chemotherapy and immunotherapy. METHODS: A total of 1304 patients with muscle-invasive bladder cancer (MIBC) from six independent cohorts were included in this study. The Zhongshan Hospital (ZSHS) cohort (n = 134), The Cancer Genome Atlas (TCGA) cohort (n = 391), and the Neo-cohort (n = 148) were included for the investigation of chemotherapeutic response. The IMvigor210 cohort (n = 234) and the UNC-108 cohort (n = 89) were used for the assessment of immunotherapeutic response. In addition, the relationship between POLQ and the immune microenvironment was assessed, and GSE32894 (n = 308) was used only for the evaluation of the immune microenvironment. RESULTS: We identified POLQhigh PD-L1high patients could benefit more from immunotherapy and platinum-based chemotherapy. Further analysis revealed that high POLQ expression was linked to chromosome instability and higher tumor mutational burden (TMB), which might elicit the production of neoantigens. Further, high POLQ expression was associated with an active tumor immune microenvironment with abundant infiltration of immune effector cells and molecules. CONCLUSIONS: The study demonstrated that high POLQ expression was correlated with chromosome instability and antitumor immune microenvironment in MIBC, and the combination of POLQ and PD-L1 could be used as a superior companion biomarker for predicting the efficacy of immunotherapy.

[A case of Stiff-person syndrome with muscle tonicity of the extremities and neck after use of Dulvalumab for lung adenocarcinoma].

A 74-year-old woman taking dulvalumab for lung adenocarcinoma developed muscle tonicity in the extremities and trunk. Painful paroxysmal muscle spasms with profuse sweating were frequently observed, and surface electromyography showed simultaneous contraction of the active and antagonist muscles. Blood tests were strongly positive for anti-amphiphysin antibodies, and stiff-person syndrome (SPS) was diagnosed. Intravenous immunoglobulin therapy and clonazepam were initiated, and the paroxysmal painful muscle spasms disappeared. As the primary tumor was under control, and the onset occurred approximately six weeks after the resumption of immune checkpoint inhibitors, we considered SPS to be an immune-related adverse event. Although extremely rare, it should be considered a neuromuscular disease that can occur in association with immune checkpoint inhibitors.

Giant Intrathoracic Desmoid Tumor - a Case Report.

Desmoid tumors are soft tissue neoplasms arising from fascial and muscle-aponeurotic structure. These tumors are locally aggressive and have a high recurrence rate, even after complete resection. We present the case of a female with a giant intrathoracic desmoid tumor. She underwent complete surgical resection with no disease recurrence. Desmoid tumors' natural history is not well defined and is often enigmatic, making these tumors difficult to manage. Currently, for intrathoracic desmoid tumors, medical treatment is the recommended approach, nevertheless, surgery can be considered in selected patients.

Injury to the Muscle Layer and Risk of Non-cardiac Chest Pain after Endoscopic Submucosal Dissection for Esophageal Cancer.

BACKGROUND AND AIMS: Non-cardiac chest pain (NCCP) is a frequent complication of endoscopic submucosal dissection (ESD) for early-stage esophageal cancer. However, little is known about relationships between ESD findings and NCCP. This study aims to evaluate the risk factors for NCCP, including ESD findings related to injury to the muscle layer. METHODS: We enrolled a total of 296 lesions from 270 patients with esophageal squamous cell carcinoma (ESCC), who underwent ESD in our center. The grade of injury to the muscle layer caused by ESD was categorized as follows: grade 0: no exposure of muscularis propria; grade 1: muscularis propria exposure and/or whitish color change by the electrocoagulation; grade 2: torn muscularis propria with whitish color change by the electrocoagulation; and grade 3, esophageal perforation. The risk factors for NCCP, including ESD findings, were analyzed by univariate and multivariate analyses. RESULTS: NCCP occurred in 89 patients (33.0%) after esophageal ESD. Multivariate analysis demonstrated that younger age [odds ratio (OR) 0.95, 95% confidence interval (95%CI) 0.92-0.98, p=0.003), postoperative fever (>= 38°C) (OR=25.9, 95%CI: 2.89-232.10, p=0.004), ESD findings (grade 1: OR=3.99, 95%CI: 1.63-9.75, p=0.003 and grade 2: OR=3.18, 95%CI: 1.54-6.57, p=0.002) were independently associated with the incidence of post ESD NCCP. CONCLUSIONS: ESD findings relate to slight Injury to the muscle layer, such as muscularis propria exposure and whitish color change by the electrocoagulation were identified as risk factor for post ESD NCCP. We should therefore perform esophageal ESD carefully to avoid injuring the muscle layers.

DaBlaCa-17: nationwide observational study in Denmark on survival before and after implementation of neoadjuvant chemotherapy prior to cystectomy for muscle-invasive bladder cancer.

OBJECTIVE: To investigate the impact of neoadjuvant chemotherapy implementation with gemcitabine-cisplatin on survival outcomes for patients with muscle-invasive bladder cancer in Denmark. MATERIALS AND METHODS: Data were collected on all patients in Denmark undergoing radical cystectomy who were potential candidates for neoadjuvant chemotherapy from 2010 to 2015 (n = 851). A cohort before the implementation of neoadjuvant chemotherapy (Cohort 2010-12) was compared with a cohort after implementation (Cohort 2013-15). Patients in Cohort 2013-15 receiving neoadjuvant chemotherapy (+NAC, n = 213) were compared with patients in Cohort 2013-15 not receiving neoadjuvant chemotherapy (-NAC, n = 139). Pathological results after radical cystectomy and oncological outcomes were compared between the study cohorts. Overall survival, disease-free survival, and disease-specific survival were compared with Kaplan-Meier plots and with univariable and multivariable Cox regression. Kaplan-Meier estimates of overall survival were also performed separately for treating hospital and for pathological stage. RESULTS: Pathological T0 (pT0) was more frequent in patients who received neoadjuvant chemotherapy: 34% versus 18% when comparing Cohort 2013-15 with Cohort 2010-12 (p < 0.001), and 46% versus 16% in +NAC compared with -NAC (p < 0.001). Overall survival, disease-free survival, and disease-specific survival at 5 years after cystectomy were not improved in Cohort 2013-15 compared with Cohort 2010-12 with adjusted hazard ratios of 1.11 (95% confidence interval [CI]: 0.87-1.43), 1.02 (95% CI: 0.81-1.29), and 1.06 (95% CI: 0.80-1.41), respectively. CONCLUSIONS: This observational study found no improved survival in a national cohort of patients with muscle-invasive bladder cancer undergoing radical cystectomy after implementation of NAC. However, reservations should be made regarding the study design and the true effect of NAC on survival outcomes.

Novel Biomarkers for Limb Girdle Muscular Dystrophy (LGMD).

OBJECTIVE: To identify novel biomarkers as an alternative diagnostic tool for limb girdle muscular dystrophy (LGMD). BACKGROUND: LGMD encompasses a group of muscular dystrophies characterized by proximal muscles weakness, elevated CK levels and dystrophic findings on muscle biopsy. Heterozygous CAPN3 mutations are associated with autosomal dominant LGMD-4, while biallelic mutations can cause autosomal recessive LGMD-1. Diagnosis is currently often based on invasive methods requiring muscle biopsy or blood tests. In most cases Western blotting (WB) analysis from muscle biopsy is essential for a diagnosis, as muscle samples are currently the only known tissues to express the full-length CAPN3 isoform. METHODS: We analyzed CAPN3 in a cohort including 60 LGMD patients. Selected patients underwent a complete neurological examination, electromyography, muscle biopsy, and skin biopsies for primary fibroblasts isolation. The amount of CAPN3 was evaluated by WB analysis in muscle and skin tissues. The total RNA isolated from muscle, fibroblast and urine was processed, and cDNA was used for qualitative analysis. The expression of CAPN3 was investigated by qRT-PCR. The CAPN3 3D structure has been visualized and analyzed using PyMOL. RESULTS: Among our patients, seven different CAPN3 mutations were detected, of which two were novel. After sequencing CAPN3 transcripts from fibroblast and urine, we detected different CAPN3 isoforms surprisingly including the full-length transcript. We found comparable protein levels from fibroblasts and muscle tissue; in particular, patients harboring a novel CAPN3 mutation showed a 30% reduction in protein compared to controls from both tissues. CONCLUSIONS: Our findings showed for the first time the presence of the CAPN3 full-length transcript in urine and skin samples. Moreover, we demonstrated surprisingly comparable CAPN3 protein levels between muscle and skin samples, thus allowing us to hypothesize the use of skin biopsy and probably of urine samples as an alternative less invasive method to assess the amount of CAPN3 when molecular diagnosis turns out to be inconclusive.

Comparative survival analysis of bladder preservation therapy versus radical cystectomy in muscle-invasive bladder cancer.

BACKGROUND: Bladder preservation therapy is an alternative to radical cystectomy in patients with muscle-invasive bladder cancer (MIBC). The purpose of this study is to compare survival outcomes between bladder preservation therapy and radical cystectomy in MIBC patients using an Asian nationwide cancer registry database. METHODS: From the Taiwan Cancer Registry database and the Taiwan National Health Insurance Research Database, we identified bladder cancer patients from 2008 to 2018. The patients with urothelial carcinoma and clinical stage T2-T4aN0-1 M0 were included. Propensity score matching by age, gender, clinical stage, cT classification, and Charlson Comorbidity Index score was used between those receiving bladder preservation therapy or radical cystectomy. Overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS) were compared using the Kaplan-Meier method. Multivariate Cox regression models were used to determine the predictive factors of OS, CSS, and DFS. RESULTS: Following the propensity score matching, 393 MIBC patients were analyzed, 131 (33.3%) receiving bladder preservation therapy and 262 (66.7%) receiving radical cystectomy. After 5 years of the follow-up period the overall duration was with a median of 15.6 months. The treatment groups did not differ significantly in OS, CSS, and DFS (p = 0.2681, 0.7208, and 0.3616, respectively). In multivariable Cox regression models, bladder preservation therapy remained non-inferior to radical cystectomy in OS (adjusted hazard ratio [aHR] 1.08; 95% confidence interval [CI], 0.77-1.50; p = 0.6689), CSS (aHR, 1.06; 95% CI, 0.72-1.57; p = 0.7728), and DFS (aHR, 0.76; 95% CI, 0.46-1.27; p = 0.2929). Additionally, among patients ≥80 years, the use of bladder preservation therapy compared with radical cystectomy resulted in an equivalent OS, CSS and DSS. CONCLUSION: In Asian populations, bladder preservation therapy yielded similar survival outcomes as radical cystectomy in MIBC patients. Based on the results, it is evident that a multidisciplinary approach and shared decision-making are recommended for bladder cancer treatment.

Association of preoperative muscle-adipose index measured by computed tomography with survival in patients with esophageal squamous cell carcinoma.

BACKGROUND: Conventional nutritional metrics are closely associated with the prognosis of patients with radically resected esophageal squamous cell carcinoma (ESCC). Nevertheless, the prognostic implications of muscle and adipose tissue composite indexes in ESCC remain unknown. METHODS: We retrospectively analyzed clinicopathological data of 304 patients who underwent resected ESCC. To obtain measurements of the muscle and adipose indexes, preoperative computed tomography (CT) images were used to quantify skeletal-muscle adipose tissue. The diagnostic threshold for muscle-adipose imbalance was determined using X-tile software and used to analyze the association between the muscle-adipose index (MAI) and survival. Instantaneous risk of recurrence was assessed using a hazard function. We constructed a nomogram based on the MAI and other clinical characteristics and established a novel predictive model with independent prognostic factors. The prognostic capabilities of these nomograms were evaluated using calibration curves, receiver operating characteristic (ROC) curves, and decision-curve analysis (DCA). RESULTS: The overall survival (OS) and disease-free survival (DFS) rates in the muscle-adipose-balanced group were significantly better than those in the muscle-adipose-imbalanced group. Multivariate analyses revealed that the MAI, prognostic nutritional index (PNI), tumor stage, and tumor differentiation were independent prognostic factors for OS and DFS in patients with resected ESCC (P < 0.05). The nuclear density curve indicated a lower risk of recurrence for patients in the muscle-adipose-balanced group than that for their imbalanced counterparts. Conversely, the nuclear density curve for PNI was confounded. Postoperative radiotherapy- (RT) benefit analysis demonstrated that patients with ESCC in the muscle-adipose-balanced group could benefit from adjuvant RT. CONCLUSION: This study confirmed that preoperative MAI could serve as a useful independent prognostic factor in patients with resected ESCC. A nomogram based on the MAI and other clinical characteristics could provide individualized survival prediction for patients receiving radical resection. Timely and appropriate nutritional supplements may improve treatment efficacy.

Tumorigenesis of basal muscle invasive bladder cancer was mediated by PTEN protein degradation resulting from SNHG1 upregulation.

BACKGROUND: Phosphatase and tensin homolog deleted on chromosome ten (PTEN) serves as a powerful tumor suppressor, and has been found to be downregulated in human bladder cancer (BC) tissues. Despite this observation, the mechanisms contributing to PTEN's downregulation have remained elusive. METHODS: We established targeted genes' knockdown or overexpressed cell lines to explore the mechanism how it drove the malignant transformation of urothelial cells or promoted anchorageindependent growth of human basal muscle invasive BC (BMIBC) cells. The mice model was used to validate the conclusion in vivo. The important findings were also extended to human studies. RESULTS: In this study, we discovered that mice exposed to N-butyl-N-(4-hydroxybu-tyl)nitrosamine (BBN), a specific bladder chemical carcinogen, exhibited primary BMIBC accompanied by a pronounced reduction in PTEN protein expression in vivo. Utilizing a lncRNA deep sequencing high-throughput platform, along with gain- and loss-of-function analyses, we identified small nucleolar RNA host gene 1 (SNHG1) as a critical lncRNA that might drive the formation of primary BMIBCs in BBN-treated mice. Cell culture results further demonstrated that BBN exposure significantly induced SNHG1 in normal human bladder urothelial cell UROtsa. Notably, the ectopic expression of SNHG1 alone was sufficient to induce malignant transformation in human urothelial cells, while SNHG1 knockdown effectively inhibited anchorage-independent growth of human BMIBCs. Our detailed investigation revealed that SNHG1 overexpression led to PTEN protein degradation through its direct interaction with HUR. This interaction reduced HUR binding to ubiquitin-specific peptidase 8 (USP8) mRNA, causing degradation of USP8 mRNA and a subsequent decrease in USP8 protein expression. The downregulation of USP8, in turn, increased PTEN polyubiquitination and degradation, culminating in cell malignant transformation and BMIBC anchorageindependent growth. In vivo studies confirmed the downregulation of PTEN and USP8, as well as their positive correlations in both BBN-treated mouse bladder urothelium and tumor tissues of bladder cancer in nude mice. CONCLUSIONS: Our findings, for the first time, demonstrate that overexpressed SNHG1 competes with USP8 for binding to HUR. This competition attenuates USP8 mRNA stability and protein expression, leading to PTEN protein degradation, consequently, this process drives urothelial cell malignant transformation and fosters BMIBC growth and primary BMIBC formation.