Prostate cancer-derived extracellular vesicles metabolic biomarkers: Emerging roles for diagnosis and prognosis.

Prostate cancer (PCa) is a global health concern, ranking as the most common cancer among men in Western countries. Traditional diagnostic methods are invasive with adverse effects on patients. Due to the heterogeneous nature of PCa and their multifocality, tissue biopsies often yield false-negative results. To address these challenges, researchers are exploring innovative approaches, particularly in the realms of proteomics and metabolomics, to identify more reliable biomarkers and improve PCa diagnosis. Liquid biopsy (LB) has emerged as a promising non-invasive strategy for PCa early detection, biopsy selection, active surveillance for low-risk cases, and post-treatment and progression monitoring. Extracellular vesicles (EVs) are lipid-bilayer nanovesicles released by all cell types and play an important role in intercellular communication. EVs have garnered attention as a valuable biomarker resource in LB for PCa-specific biomarkers, enhancing diagnosis, prognostication, and treatment guidance. Metabolomics provides insight into the body's metabolic response to both internal and external stimuli, offering quantitative measurements of biochemical alterations. It excels at detecting non-genetic influences, aiding in the discovery of more accurate cancer biomarkers for early detection and disease progression monitoring. This review delves into the potential of EVs as a resource for LB in PCa across various clinical applications. It also explores cancer-related metabolic biomarkers, both within and outside EVs in PCa, and summarises previous metabolomic findings in PCa diagnosis and risk assessment. Finally, the article addresses the challenges and future directions in the evolving field of EV-based metabolomic analysis, offering a comprehensive overview of its potential in advancing PCa management.

Proteomic Identification of Small Extracellular Vesicle Proteins LAMB1 and Histone H4 for Prostate Cancer Diagnosis and Risk Stratification.

Diagnosis and stratification of prostate cancer (PCa) patients using the prostate-specific antigen (PSA) test is challenging. Extracellular vesicles (EVs), as a new star of liquid biopsy, has attracted interest to complement inaccurate PSA screening and invasiveness of tissue biopsy. In this study, a panel of potential small EV (sEV) protein biomarkers is identified from PCa cell lines using label-free LC-MS/MS proteomics. These biomarkers underwent further validation with plasma and urine samples from different PCa stages through parallel reaction monitoring-based targeted proteomics, western blotting, and ELISA. Additionally, a tissue microarray containing cancerous and noncancerous tissues is screened to provide additional evidence of selected sEV proteins associated with cancer origin. Results indicate that sEV protein LAMB1 is highly expressed in human plasma of metastatic PCa patients compared with localised PCa patients and control subjects, while sEV protein Histone H4 is highly expressed in human urine of high-risk PCa patients compared to low-risk PCa patients and control subjects. These two sEV proteins demonstrate higher specificity and sensitivity than the PSA test and show promise for metastatic PCa diagnosis, progression monitoring, and risk stratification.

68Ga-PSMA-PET/CT in addition to mpMRI in men undergoing biopsy during active surveillance for low- to intermediate-risk prostate cancer: study protocol for a prospective cross-sectional study.

Background: In active surveillance there is significant interest in whether imaging modalities such as multiparametric magnetic resonance imaging (mpMRI) or 68Gallium prostate-specific membrane antigen positron emission tomography/computerized tomography (68Ga-PSMA-PET/CT) can improve the detection of progression to clinically significant prostate cancer (csPCa) and thus reduce the frequency of prostate biopsies and associated morbidity. Recent studies have demonstrated the value of mpMRI in active surveillance; however, mpMRI does miss a proportion of disease progression and thus alone cannot replace biopsy. To date, prostate-specific membrane antigen positron emission tomography (PSMA-PET) has shown additive value to mpMRI in its ability to detect prostate cancer (PCa) in the primary diagnostic setting. Our objective is to evaluate the diagnostic utility of PSMA-PET to detect progression to csPCa in active surveillance patients. Methods: We will perform a prospective, cross-sectional, partially blinded, multicentre clinical trial evaluating the additive value of PSMA-PET with mpMRI against saturation transperineal template prostate biopsy. Two hundred and twenty-five men will be recruited who have newly diagnosed PCa which is suitable for active surveillance. Following enrolment, patients will undergo a PSMA-PET and mpMRI within 3 months of a repeat 12-month confirmatory biopsy. Patients who remain on active surveillance after confirmatory biopsy will then be planned to have a further mpMRI and PSMA-PET prior to a repeat biopsy in 3-4 years. The primary outcome is to assess the ability of PSMA-PET to detect or exclude significant malignancy on repeat biopsy. Secondary outcomes include (I) assess the comparative diagnostic accuracies of mpMRI and PSMA-PET alone [sensitivity/specificity/negative predictive value (NPV)/positive predictive value (PPV)] to detect progression on biopsy based on predefined histologic criteria for progression; (II) comparison of index lesion identification by template biopsies vs. MRI targeted lesions vs. PSMA targeted lesions; (III) evaluation of concordance of lesions identified on final histopathology and each imaging modality (PSMA-PET and/or mpMRI) in the subset of patients proceeding to RP. Discussion: The results of this trial will define the role of PSMA-PET in active surveillance and potentially reduce the number of biopsies needed to detect progression to csPCa. Trial Registration: The current trial was registered with the ANZCTR on the 3/2/2022 with the trial ID ACTRN12622000188730, it is accessible at https://www.anzctr.org.au/.

Experimental and Theoretical Exploration of the Kinetics and Thermodynamics of the Nucleophile-Induced Fragmentation of Ylidenenorbornadiene Carboxylates.

Ylidenenorbornadienes (YNDs), prepared by [4 + 2] cycloadditions between fulvenes and acetylene carboxylates, react with thiol nucleophiles to yield mixtures of four to eight diastereomers depending on the symmetry of the YND substrate. The mixtures of diastereomers fragment via a retro-[4 + 2] cycloaddition with a large variation in rate, with half-lives ranging from 16 to 11,000 min at 80 °C. The diastereomer-enriched samples of propane thiol adducts [YND-propanethiol (PTs)] were isolated and identified by nuclear Overhauser effect spectroscopy (NOESY) correlations. Simulated kinetics were used to extrapolate the rate constants of individual diastereomers from the observed rate data, and it correlated well with rate constants measured directly and from isolated diastereomer-enriched samples. The individual diastereomers of a model system fragment at differing rates with half-lives ranging from 5 to 44 min in CDCl3. Density functional theory calculations were performed to investigate the mechanism of fragmentation and support an asynchronous retro-[4 + 2] cycloaddition transition state. The computations generally correlated well with the observed free energies of activation for four diastereomers of the model system as a whole, within 2.6 kcal/mol. However, the observed order of the fragmentation rates across the set of diastereomers deviated from the computational results. YNDs display wide variability in the rate of fragmentation, dependent on the stereoelectronics of the ylidene substituents. A Hammett study showed that the electron-rich aromatic rings attached to the ylidene bridge increase the fragmentation rate, while electron-deficient systems slow fragmentation rates.

Differentiation of renal masses with multi-parametric MRI: the de Silva St George classification scheme.

PURPOSE: To develop a system for multi-parametric MRI to differentiate benign from malignant solid renal masses and assess its accuracy compared to the gold standard of histopathological diagnosis. METHODS: This is a retrospective analysis of patients who underwent 3 Tesla mpMRI for further assessment of small renal tumours with specific scanning and reporting protocol incorporating T2 HASTE signal intensity, contrast enhancement ratios, apparent diffusion coefficient and presence of microscopic/macroscopic fat. All MRIs were reported prior to comparison with histopathologic diagnosis and a reporting scheme was developed. 2 × 2 contingency table analysis (sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV)), Fisher Exact test were used to assess the association between suspicion of malignancy on mpMRI and histopathology, and descriptive statistics were performed. RESULTS: 67 patients were included over a 5-year period with a total of 75 renal masses. 70 masses were confirmed on histopathology (five had pathognomonic findings for angiomyolipomas; biopsy was therefore considered unethical, so these were included without histopathology). Three patients were excluded due to a non-diagnostic result, non-standardised imaging and one found to be an organising haematoma rather than a mass. Therefore 72 cases were included in analysis (in 64 patients, with seven patients having multiple tumours). Unless otherwise specified, all further statistics refer to individual tumours rather than patients. 52 (72.2%) were deemed 'suspicious or malignant' and 20 (27.8%) were deemed 'benign' on mpMRI. 51 cases (70.8%) had renal cell carcinoma confirmed. The sensitivity, NPV, specificity and PPV for MRI for detecting malignancy were 96.1%, 90%, 85.7% and 94.2% respectively, Fisher's exact test demonstrated p < 0.0001 for the association between suspicion of malignancy on MRI and histopathology. CONCLUSION: The de Silva St George classification scheme performed well in differentiating benign from malignant solid renal masses, and may be useful in predicting the likelihood of malignancy to determine the need for biopsy/excision. Further validation is required before this reporting system can  be recommended for clinical use.

Ylidenenorbornadiene Carboxylates: Experimental Kinetic Analysis of a Nucleophile-Induced Fragmentation Reaction.

Ylidenenorbornadienes (YNDs), prepared by [4 + 2] cycloadditions between fulvenes and acetylene carboxylates, react with beta-mercaptoethanol to yield a mixture of four diastereomers. These four diastereomers fragment via a retro-[4 + 2] cycloaddition at differing rates. A simulated kinetics approach extrapolated the rate constants of the diastereomers from the observed rate data. YNDs display wide variability in rate of fragmentation, dependent on the stereoelectronics of the ylidene substituents. A substrate containing one carboxylic ester proved exceptionally stable to fragmentation.

The diagnostic utility of diffusion weighted MRI imaging and ADC ratio to distinguish benign from malignant renal masses: sorting the kittens from the tigers.

BACKGROUND: MRI is playing an increasing role in risk stratification and non-invasive diagnosis of the undifferentiated small renal mass. This study was designed to assess the reliability of MRI in diagnostic evaluation of renal masses, specifically characterising lesions with diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) values. METHODS: This is a retrospective analysis of patients undergoing MRI as part of their clinical workup for a renal mass suspicious for renal cell carcinoma (RCC) on CT or ultrasound followed by biopsy and/or surgical excision. All cases were conducted on 3 Tesla MRI, with conventional breath-held sequences, DWI and dynamic contrast enhanced phases. Tumour regions of interest were evaluated on ADC maps and compared with T2 weighted and post-contrast images. RESULTS: Of the 66 renal tumours included, 33 (50.0%) were Clear Cell RCC, 11 (16.7%) were Oncocytoma, nine (13.6%) were Angiomyolipoma (AML), nine (13.6%) were Papillary RCC and four (6.1%) were Chromophobe RCC. Oncocytoma had the largest ADC values, significantly larger than AMLs and all RCC subtypes (p < 0.001). The average ADC value was also significantly larger in Clear Cell RCCs compared to AMLs, and other RCC subtypes (p < 0.001). CONCLUSIONS: MRI with DWI/ADC imaging may aid the differentiation of oncocytomas from RCCs and stratify RCC subtypes, Further studies are required to validate these findings. TRIAL REGISTRATION: Not applicable/retrospective study.

Bladder perforation: A rare complication of retention management.

A healthy 25 year old woman presented with acute urinary retention following alcohol ingestion. A 14 french foley catheter drained over 1 L of haematuria immediately. Due to worsening and persistent abdominal pain, CT and ultrasound imaging was performed, demonstrating only a small amount of free fluid. Diagnostic laparoscopy revealed an intraperitoneal bladder perforation with the foley catheter visible. The bladder defect was repaired and she recovered well. This is a rare case of likely iatrogenic bladder perforation from simple catheterisation without predisposing comorbidities, highlighting the importance of correct technique and awareness of potential complications.

Quality Assessment and Comparison of Plasma-Derived Extracellular Vesicles Separated by Three Commercial Kits for Prostate Cancer Diagnosis.

INTRODUCTION: Current standard biomarkers in clinic are not specific enough for prostate cancer (PCa) diagnosis. Extracellular vesicles (EVs) are nano-scale vesicles released by most mammalian cells. EVs are promising biomarker source for PCa liquid biopsy due to its minimal invasive approach, rich information and improved accuracy compared to the clinical standard prostate-specific antigen (PSA). However, current EV separation methods cannot separate pure EVs and the quality characteristics from these methods remain largely unknown. In this study, we evaluated the quality characteristics of human plasma-derived EVs by comparing three clinical suitable separation kits. METHODS: We combined EV separation by commercial kits with magnetic beads capture and flow cytometry analysis, and compared three kits including ExoQuick Ultra based on precipitation and qEV35 and qEV70 based on size exclusion chromatography (SEC). RESULTS: Our results indicated that two SEC kits provided higher EV purity and lower protein contamination compared to ExoQuick Ultra precipitation and that qEV35 demonstrated a higher EV yield but lower EV purity compared to qEV70. Particle number correlated very well particularly with CD9/81/63 positive EVs for all three kits, which confirms that particle number can be used as the estimate for EV amount. At last, we found that several EV metrics including total EVs and PSA-specific EVs could not differentiate PCa patients from health controls. CONCLUSION: We provided a systematic workflow for the comparison of three separation kits as well as a general analysis process in clinical laboratories for EV-based cancer diagnosis. Better EV-associated cancer biomarkers need to be explored in the future study with a larger cohort.

Chemical shift imaging in the identification of those renal tumours that contain microscopic fat and the utility of multiparametric MRI in their differentiation.

INTRODUCTION: The aim of this study was to assess the qualitative and MRI findings of renal tumours, to determine which lesions contain microscopic fat, one of the potential differentiating factors between tumour types. METHODS: 73 patients who underwent 3 Tesla MRI including chemical shift imaging, with subsequent biopsy or excision for histopathological diagnosis, were included in the study. The images were reviewed for a decrease in signal intensity (SI) on the opposed phase compared with the in-phase gradient echo T1 images, indicating the presence of microscopic fat. The chemical shift index was then calculated as a percentage of SI change and compared with the pathological diagnosis. RESULTS: In total, 38 (52%) of lesions demonstrated a decrease in SI, consistent with microscopic fat. Microscopic fat was found in 28 (80%) clear cell renal cell carcinomas (RCCs), 6 (66.7%) angiomyolipomas, 2 (20%) papillary RCCs, 1 (20%) chromophobe RCC and 1 (9.1%) oncocytoma. Pairwise comparison of means indicated that the amount of microscopic fat was significantly larger only for angiomyolipomas compared with clear cell RCCs (P < 0.001) and other renal lesions (P < 0.001). CONCLUSIONS: A decrease in SI on opposed phase compared with in-phase chemical shift imaging favours the diagnosis of either clear cell RCC or an angiomyolipoma. When combined with other parameters in mpMRI, this may aid differentiation of benign from malignant tumours and differentiation of aggressive from indolent RCC subtypes. This may be of value where biopsy is non-diagnostic, not feasible due to location or in high-risk patients.

Towards real time in-vivo rectal dosimetry during trans-rectal ultrasound based high dose rate prostate brachytherapy using MOSkin dosimeters.

PURPOSE: To compare the dose measured by MOSkin dosimeters coupled to a trans-rectal ultrasound (TRUS) probe to the dose predicted by the brachytherapy treatment planning system (BTPS) during high dose rate (HDR) prostate brachytherapy (pBT), and to examine the feasibility of performing real-time catheter-by-catheter analysis of in-vivo rectal dosimetry during TRUS based HDR pBT. METHOD: Four MOSkin dosimeters were coupled to a TRUS probe during 20 TRUS-based HDR pBT treatment fractions. The measured MOSkin doses were retrospectively compared to those predicted by the BTPS for the total treatment fraction, as well as on a per catheter basis. RESULTS: The average relative percentage difference between MOSkin measured and BTPS predicted doses for a total treatment fraction was 0.3% ± 11.6% (k = 1), with a maximum of 23.2% and a minimum of -29.0%. The average relative percentage difference per catheter was +2.5% ± 16.9% (k = 1). The majority (64%) of per catheter MOSkin measured doses agreed with the treatment planning system within the calculated uncertainty budget of 12.3%. CONCLUSION: The results of the study agreed well with previously published data, despite differences in clinical workflows. To improve the redundancy to potential dosimeter errors, a minimum of 4 MOSkin dosimeters should be used when performing real-time in-vivo rectal dosimetry for HDR pBT, and error thresholds should be based off the total combined uncertainty estimate of measurement. 'Real time' error thresholds can be more confidently applied in the future through enhanced integration between IVD systems with both the imaging device and the BTPS/afterloader.

What not to expect when you're expecting - Postpartum proximal ureteric rupture: A case report.

INTRODUCTION: Spontaneous ureteric rupture is an extremely rare cause of acute abdominal pain in the intrapartum and postpartum period. We present the case of a right ureteric rupture diagnosed immediately postpartum. CASE: A 23-year-old woman in her second pregnancy (who had had a previous caesarean section) developed acute-onset right-flank pain 12 h after vaginal delivery. A contrast computerized tomography scan suggested a ureteric injury; ureteroscopy diagnosed a proximal ureteric rupture and a stent was placed. DISCUSSION: This case outlines an extremely rare cause of abdominal pain in the peripartum. There can be serious complications, including urinoma, abscess and sepsis, and therefore the diagnosis should not be delayed.

Extracellular vesicles: the next generation of biomarkers for liquid biopsy-based prostate cancer diagnosis.

Prostate cancer (PCa) is a leading cause of cancer death for males in western countries. The current gold standard for PCa diagnosis - template needle biopsies - often does not convey a true representation of the molecular profile given sampling error and complex tumour heterogeneity. Presently available biomarker blood tests have limited accuracy. There is a growing demand for novel diagnostic approaches to reduce both the number of men with an abnormal PSA/ DRE who undergo invasive biopsy and the number of cores collected per biopsy. 'Liquid biopsy' is a minimally invasive biofluid-based approach that has the potential to provide information and improve the accuracy of diagnosis for patients' treatment selection, prognostic counselling and development of risk-adjusted follow-up protocols. Extracellular vesicles (EVs) are lipid bilayer-delimited particles released by tumour cells which may provide a real-time snapshot of the entire tumour in a non-invasive way. EVs can regulate physiological processes and mediate systemic dissemination of various types of cancers. Emerging evidence suggests that EVs have crucial roles in PCa development and metastasis. Most importantly, EVs are directly derived from their parent cells with their information. EVs contain components including proteins, mRNAs, DNA fragments, non-coding RNAs and lipids, and play a critical role in intercellular communication. Therefore, EVs hold promise for the discovery of liquid biopsy-based biomarkers for PCa diagnosis. Here, we review the current approaches for EV isolation and analysis, summarise the recent advances in EV protein biomarkers in PCa and focus on liquid biopsy-based EV biomarkers in PCa diagnosis for personalised medicine.

CD44 variant 6 is associated with prostate cancer growth and chemo-/radiotherapy response in vivo.

We have previously demonstrated that CD44 variant 6 (CD44v6) is associated with prostate cancer (CaP) growth and therapeutic resistance in vitro, however, the role of CD44v6 in CaP in vivo is not fully understood. The purpose of this study is to investigate the effect of CD44v6 on CaP growth and chemo-/radiotherapy response in NOD/SCID mouse models in vivo and to validate its role as a therapeutic target for CaP therapy. CD44v6 was knocked down in PC-3M CaP cell line using short hairpin RNA. Subcutaneous (s.c.) and orthotopic CaP mouse xenografts were established. The effect of CD44v6 knockdown (KD) on tumour growth was evaluated in both s.c. and orthotopic models. Chemo-/radiotherapy response was evaluated in the s.c. model. Association of CD44v6 with PI3K/Akt pathway was validated using immunohistochemistry staining. We found that KD of CD44v6 significantly reduced tumour growth in both models, and enhanced the sensitivity of tumours to chemotherapy and radiotherapy in the s.c. model. In addition, we demonstrated that KD of CD44v6 is associated with downregulation of the PI3K/Akt/mTOR pathway. Our data confirm that CaP growth and chemo-/radiosensitivity in vivo is associated with CD44v6, which holds great promises as a therapeutic target in the treatment of CaP.

Exosomes in Cancer Radioresistance.

Radiation is a mainstay of cancer therapy. Radioresistance is a significant challenge in the treatment of locally advanced, recurrent and metastatic cancers. The mechanisms of radioresistance are complicated and still not completely understood. Exosomes are 40-150 nm vesicles released by cancer cells that contain pathogenic components, such as proteins, mRNAs, DNA fragments, non-coding RNAs, and lipids. Exosomes play a critical role in cancer progression, including cell-cell communication, tumor-stromal interactions, activation of signaling pathways, and immunomodulation. Emerging data indicate that radiation-derived exosomes increase tumor burden, decrease survival, cause radiation-induced bystander effects and promote radioresistance. In addition, radiation can change the contents of exosomes, which allows exosomes to be used as a prognostic and predictive biomarker to monitor radiation response. Therefore, understanding the roles and mechanisms of exosomes in radiation response may shed light on how exosomes play a role in radioresistance and open a new way in radiotherapy and translational medicine. In this review, we discuss recent advances in radiation-induced exosome changes in components, focus on the roles of exosome in radiation-induced bystander effect in cancer and emphasize the importance of exosomes in cancer progression and radioresistance for developing novel therapy.

Targeting MicroRNAs in Prostate Cancer Radiotherapy.

Radiotherapy is one of the most important treatment options for localized early-stage or advanced-stage prostate cancer (CaP). Radioresistance (relapse after radiotherapy) is a major challenge for the current radiotherapy. There is great interest in investigating mechanisms of radioresistance and developing novel treatment strategies to overcome radioresistance. MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression at the post-transcriptional level, participating in numerous physiological and pathological processes including cancer invasion, progression, metastasis and therapeutic resistance. Emerging evidence indicates that miRNAs play a critical role in the modulation of key cellular pathways that mediate response to radiation, influencing the radiosensitivity of the cancer cells through interplaying with other biological processes such as cell cycle checkpoints, apoptosis, autophagy, epithelial-mesenchymal transition and cancer stem cells. Here, we summarize several important miRNAs in CaP radiation response and then discuss the regulation of the major signalling pathways and biological processes by miRNAs in CaP radiotherapy. Finally, we emphasize on microRNAs as potential predictive biomarkers and/or therapeutic targets to improve CaP radiosensitivity.

Frequency of Angiomyolipomas Among Echogenic Nonshadowing Renal Masses (> 4 mm) Found at Ultrasound and the Utility of MRI for Diagnosis.

OBJECTIVE: The purpose of this study is to evaluate what percentage of echogenic nonshadowing renal lesions larger than 4 mm found at ultrasound are angiomyolipomas (AMLs) and to review how to diagnose AMLs, with particular emphasis on the increasing role played by MRI. MATERIALS AND METHODS: The study data were obtained at a single institution over a period of 45 months. Although some patients were being reviewed for specific symptoms, such as hematuria, pain, or recurrent urinary tract infections, most of the findings were incidental. Follow-up data on 158 lesions in 132 patients were available. Confirmation of diagnosis was made with follow-up imaging or with histopathologic examination. RESULTS: Ninety-eight (62.0%) of the lesions were AMLs, eight (5.1%) were renal cell carcinomas, three (1.9%) were oncocytomas, 17 (10.8%) were artifacts, seven (4.4%) were fat, five (3.2%) were calculi, another eight (5.1%) were scars, and 12 (7.6%) were complicated cysts. The mean age of patients with AML was significantly lower than that of patients without AML (61.71 [SD, 13.25] years vs 68.80 [SD, 17.85] years; p = 0.005). There was a female association with AMLs (p < 0.001). CONCLUSION: Echogenic nonshadowing renal lesions larger than 4 mm seen at ultrasound should not be assumed to represent an AML without follow-up because a percentage of renal cell carcinomas will be missed. Although certain ultrasound features can be useful in differentiating an AML from a renal cell carcinoma and CT is frequently diagnostic, an understanding of MRI is important because it can potentially detect lipid-poor AMLs.

Identification of protein biomarkers and signaling pathways associated with prostate cancer radioresistance using label-free LC-MS/MS proteomic approach.

Identifying biomarkers and signaling pathways are important for the management of prostate cancer (CaP) radioresistance. In this study, we identified differential proteins and signaling pathways from parental CaP cell lines and CaP radioresistant (RR) sublines using a label-free LC-MS/MS proteomics approach. A total of 309 signaling pathway proteins were identified to be significantly altered between CaP and CaP-RR cells (p ≤ 0.05, fold differences >1.5, ≥80% power). Among these proteins, nineteen are common among three paired CaP cell lines and associated with metastasis, progression and radioresistance. The PI3K/Akt, VEGF and glucose metabolism pathways were identified as the main pathways associated with CaP radioresistance. In addition, the identified potential protein markers were further validated in CaP-RR cell lines and subcutaneous (s.c) animal xenografts by western blotting and immunohistochemistry, respectively and protein aldolase A (ALDOA) was selected for a radiosensitivity study. We found the depletion of ALDOA combined with radiotherapy effectively reduced colony formation, induced more apoptosis and increased radiosensitivity in CaP-RR cells. Our findings indicate that CaP radioresistance is caused by multifactorial traits and downregulation of ALDOA increases radiosensitivity in CaP-RR cells, suggesting that controlling these identified proteins or signaling pathways in combination with radiotherapy may hold promise to overcome CaP radioresistance.

Proteomic identification of the lactate dehydrogenase A in a radioresistant prostate cancer xenograft mouse model for improving radiotherapy.

Radioresistance is a major challenge for prostate cancer (CaP) metastasis and recurrence after radiotherapy. This study aimed to identify potential protein markers and signaling pathways associated with radioresistance using a PC-3 radioresistant (RR) subcutaneous xenograft mouse model and verify the radiosensitization effect from a selected potential candidate. PC-3RR and PC-3 xenograft tumors were established and differential protein expression profiles from two groups of xenografts were analyzed using liquid chromatography tandem-mass spectrometry. One selected glycolysis marker, lactate dehydrogenase A (LDHA) was validated, and further investigated for its role in CaP radioresistance. We found that 378 proteins and 51 pathways were significantly differentially expressed between PC-3RR and PC-3 xenograft tumors, and that the glycolysis pathway is closely linked with CaP radioresistance. In addition, we also demonstrated that knock down of LDHA with siRNA or inhibition of LDHA activity with a LDHA specific inhibitor (FX-11), could sensitize PC-3RR cells to radiotherapy with reduced epithelial-mesenchymal transition, hypoxia, DNA repair ability and autophagy, as well as increased DNA double strand breaks and apoptosis. In summary, we identified a list of potential RR protein markers and important signaling pathways from a PC-3RR xenograft mouse model, and demonstrate that targeting LDHA combined with radiotherapy could increase radiosensitivity in RR CaP cells, suggesting that LDHA is an ideal therapeutic target to develop combination therapy for overcoming CaP radioresistance.