Improving Pore Characteristics, Mechanical Properties and Thermal Performances of Near-Net Shape Manufacturing Phenolic Resin Aerogels.

Thermally stable high-performance phenolic resin aerogels (PRAs) are of great interest for thermal insulation because of their light weight, fire retardancy and low thermal conductivity. However, the drawbacks of PRA synthesis, such as long processing time, inherent brittleness and significant shrinkage during drying, greatly restrict their wide applications. In this work, PRAs were synthesized at ambient pressure through a near-net shape manufacturing technique, where boron-containing thermosetting phenolic resin (BPR) was introduced into the conventional linear phenolic resin (LPR) to improve the pore characteristics, mechanical properties and thermal performances. Compared with the traditional LPR-synthesized aerogel, the processing time and the linear shrinkage rate during the drying of the PRAs could be significantly reduced, which was attributed to the enhanced rigidity and the unique bimodal pore size distribution. Furthermore, no catastrophic failure and almost no mechanical degradation were observed on the PRAs, even with a compressive strain of up to 60% at temperatures ranging from 25 to 200 °C, indicating low brittleness and excellent thermo-mechanical stability. The PRAs also showed outstanding fire retardancy. On the other hand, the PRAs with a density of 0.194 g/cm3 possessed a high Young's modulus of 12.85 MPa and a low thermal conductivity of 0.038 W/(m·K).

Reactive Oxygen Species Induced Upregulation of TRPV1 in Dorsal Root Ganglia Results in Low Back Pain in Rats.

Background: Dorsal root ganglia (DRGs) contain sensory neurons that innervate intervertebral discs (IVDs) and may play a critical role in mediating low-back pain (LBP), but the potential pathophysiological mechanism needs to be clarified. Methods: A discogenic LBP model in rats was established by penetration of a lumbar IVD. The severity of LBP was evaluated through behavioral analysis, and the gene and protein expression levels of pro-algesic peptide substance P (SP) and calcitonin gene-related peptide (CGRP) in DRGs were quantified. The level of reactive oxygen species (ROS) in bilateral lumbar DRGs was also quantified using dihydroethidium staining. Subsequently, hydrogen peroxide solution or N-acetyl-L-cysteine was injected into DRGs to evaluate the change in LBP, and gene and protein expression levels of transient receptor potential vanilloid-1 (TRPV1) in DRGs were analyzed. Finally, an inhibitor or activator of TRPV1 was injected into DRGs to observe the change in LBP. Results: The rats had remarkable LBP after disc puncture, manifesting as mechanical and cold allodynia and increased expression of the pro-algesic peptides SP and CGRP in DRGs. Furthermore, there was significant overexpression of ROS in bilateral lumbar DRGs, while manipulation of the level of ROS in DRGs attenuated or aggravated LBP in rats. In addition, excessive ROS in DRGs stimulated upregulation of TRPV1 in DRGs. Finally, activation or inhibition of TRPV1 in DRGs resulted in a significant increase or decrease of discogenic LBP, respectively, suggesting that ROS-induced TRPV1 has a strong correlation with discogenic LBP. Conclusion: Increased ROS in DRGs play a primary pathological role in puncture-induced discogenic LBP, and excessive ROS-induced upregulation of TRPV1 in DRGs may be the underlying pathophysiological mechanism to cause nerve sensitization and discogenic LBP. Therapeutic targeting of ROS or TRPV1 in DRGs may provide a promising method for the treatment of discogenic LBP.

Strengthening Mechanism and Damping Properties of SiCf/Al-Mg Composites Prepared by Combining Colloidal Dispersion with a Squeeze Melt Infiltration Process.

SiC-fiber-reinforced Al-Mg matrix composites with different mass fractions of Mg were fabricated by combining colloidal dispersion with a squeeze melt infiltration process. The microstructure, mechanical and damping properties, and the corresponding mechanisms were investigated. Microstructure analyses found that SiCf/Al-Mg composites presented a homogeneous distribution of SiC fibers, and the relative density was higher than 97% when the mass fraction of Mg was less than 20%; the fiber-matrix interface bonded well, and no obvious reaction occurred at the interface. The SiCf/Al-10Mg composite exhibited the best flexural strength (372 MPa) and elastic modulus (161.7 GPa). The fracture strain of the composites decreased with an increase in the mass fraction of Mg. This could be attributed to the strengthened interfacial bonding due to the introduction of Mg. The damping capacity at RT increased dramatically with an increase in the strain when the strain amplitude was higher than 0.001%, which was better than the alloys with similar composition, demonstrating a positive effect of the SiC fiber on improving the damping capacity of composite; the damping capacity at a temperature beyond 200 °C indicated a monotonic increase tendency with the testing temperature. This could be attributed to the second phase, which formed more strong pinning points and increased the dislocation energy needed to break away from the strong pinning points.

A Prospective Randomized Trial of Neoadjuvant Chemohormonal Therapy vs Hormonal Therapy in Locally Advanced Prostate Cancer Treated by Radical Prostatectomy.

PURPOSE: Benefits of docetaxel-based neoadjuvant chemohormonal therapy (NCHT) before radical prostatectomy (RP) remain largely unknown. We explored whether docetaxel-based NCHT would bring pathological benefits and improve biochemical progression-free survival (bPFS) over neoadjuvant hormonal therapy (NHT) in locally advanced prostate cancer. MATERIALS AND METHODS: A randomized trial was designed recruiting 141 locally advanced, high-risk prostate cancer patients who were randomly assigned at the ratio of 2:1 to the NCHT group (75 mg/m2 body surface area every 3 weeks plus androgen deprivation therapy for 6 cycles) and the NHT group (androgen deprivation therapy for 24 weeks). The primary end point was 3-year bPFS. Secondary end points were pathological response including pathological downstaging and minimal residual disease rates. RESULTS: The NCHT group showed significant benefits in 3-year bPFS compared to the NHT group (29% vs 9.5%, P = .002). At a median follow-up of 53 months, the NCHT group achieved a significantly longer median bPFS time than the NHT group (17 months vs 14 months). No significant differences were found between the 2 groups in pathological downstaging and minimal residual disease rates. CONCLUSIONS: NCHT plus RP achieved significant bPFS benefits when compared with NHT plus RP in high-risk, locally advanced prostate cancer. A larger cohort with longer follow-up duration is essential in further investigation.

PDIA2 has a dual function in promoting androgen deprivation therapy induced venous thrombosis events and castrate resistant prostate cancer progression.

Androgen deprivation therapy (ADT) is the first line of treatment for metastatic prostate cancer (PCa) that effectively delays the tumor progression. However, it also increases the risk of venous thrombosis event (VTE) in patients, a leading cause of mortality. How a pro-thrombotic cascade is induced by ADT remains poorly understood. Here, we report that protein disulfide isomerase A2 (PDIA2) is upregulated in PCa cells to promote VTE formation and enhance PCa cells resistant to ADT. Using various in vitro and in vivo models, we demonstrated a dual function of PDIA2 that enhances tumor-mediated pro-coagulation activity via tumor-derived extracellular vehicles (EVs). It also stimulates PCa cell proliferation, colony formation, and xenograft growth androgen-independently. Mechanistically, PDIA2 activates the tissue factor (TF) on EVs through its isomerase activity, which subsequently triggers a pro-thrombotic cascade in the blood. Additionally, TF-containing EVs can activate the Src kinase inside PCa cells to enhance the AR signaling ligand independently. Androgen deprivation does not alter PDIA2 expression in PCa cells but enhances PDIA2 translocation to the cell membrane and EVs via suppressing the clathrin-dependent endocytic process. Co-recruitment of AR and FOXA1 to the PDIA2 promoter is required for PDIA2 transcription under androgen-deprived conditions. Importantly, blocking PDIA2 isomerase activity suppresses the pro-coagulation activity of patient plasma, PCa cell, and xenograft samples as well as castrate-resistant PCa xenograft growth. These results demonstrate that PDIA2 promotes VTE and tumor progression via activating TF from tumor-derived EVs. They rationalize pharmacological inhibition of PDIA2 to suppress ADT-induced VTE and castrate-resistant tumor progression.

Triggering pyroptosis enhances the antitumor efficacy of PARP inhibitors in prostate cancer.

PURPOSE: PARP inhibitors have revolutionized the treatment landscape for advanced prostate cancer (PCa) patients who harboring mutations in homologous recombination repair (HRR) genes. However, the molecular mechanisms underlying PARP inhibitors function beyond DNA damage repair pathways remain elusive, and identifying novel predictive targets that favorably respond to PARP inhibitors in PCa is an active area of research. METHODS: The expression of GSDME in PCa cell lines and human PCa samples was determined by western blotting. Targeted bisulfite sequencing, gene enrichment analysis (GSEA), clone formation, construction of the stably transfected cell lines, lactate dehydrogenase (LDH) assay, western blotting as well as a mouse model of subcutaneous xenografts were used to investigate the role of GSDME in PCa. The combinational therapeutic effect of olaparib and decitabine was determined using both in vitro and in vivo experiments. RESULTS: We have found low expression of GSDME in PCa. Interestingly, we demonstrated that GSDME activity is robustly induced in olaparib-treated cells undergoing pyroptosis, and that high methylation of the GSDME promoter dampens its activity in PCa cells. Intriguingly, genetically overexpressing GSDME does not inhibit tumor cell proliferation but instead confers sensitivity to olaparib. Furthermore, pharmacological treatment with the combination of olaparib and decitabine synergistically induces GSDME expression and cleavage through caspase-3 activation, thus promoting pyroptosis and enhancing anti-tumor response, ultimately resulting in tumor remission. CONCLUSION: Our findings highlight a novel therapeutic strategy for enhancing the long-term response to olaparib beyond HRR-deficient tumors in PCa, underscoring the critical role of GSDME in regulating tumorigenesis.

Klotho-beta attenuates Rab8a-mediated exosome regulation and promotes prostate cancer progression.

Tumor-secreted exosomes have a wide range of effects on the growth, metastasis, and drug resistance of cancer cells. However, whether and how the molecular mechanisms that regulate the secretion of exosomes could affect tumor progression remains poorly understood. Klotho beta (KLB) has been reported dysregulated in prostate cancer, but its function remains unknown. Herein, we first determined that KLB was upregulated in prostate cancer and its expression level was positively correlated with prostate cancer malignant phenotype both in vitro and in vivo. Intriguingly, KLB overexpression could impair the release of exosomes and cause the intracellular accumulation of multivesicular bodies (MVBs) in prostate cancer cells. Mechanistically, KLB attenuated exosomes secretion through a Rab8a-dependent pathway. Rab8a was downregulated in KLB overexpressing cells whereas overexpression of Rab8a could rescue the impaired release of exosomes and attenuate the KLB-induced malignant phenotype of prostate cancer both in vitro and in vivo. Taken together, this study has unveiled the tumor-promoting role of KLB mediated by its regulation on exosomes secretion through a Rab8a-dependent mechanism. These findings could be exploited to develop novel theranostic targets for prostate cancer.

Engineering the MoS2 /MXene Heterostructure for Precise and Noninvasive Diagnosis of Prostate Cancer with Clinical Specimens.

High-throughput metabolic fingerprinting has been deemed one of the most promising strategies for addressing the high false positive rate of prostate cancer (PCa) diagnosis in the prostate-specific antigen (PSA) gray zone. However, the current metabolic fingerprinting remains challenging in achieving high-precision metabolite detection in complex biological samples (e.g., serum and urine). Herein, a novel self-assembly MoS2 /MXene heterostructure nanocomposite with a tailored doping ratio of 10% is presented as a matrix for laser desorption ionization mass spectrometry analysis in clinical biosamples. Notably, owing to the two-dimensional architecture and doping effect, MoS2 /MXene demonstrates favorable laser desorption ionization performance with low adsorption energy, which is evidenced by efficient urinary metabolic fingerprinting with an enhanced area under curve (AUC) diagnosis capability of 0.959 relative to that of serum metabolic fingerprinting (AUC = 0.902) for the diagnosis of PCa in the PSA gray zone. Thus, this MoS2 /MXene heterostructure is anticipated to offer a novel strategy to precisely and noninvasively diagnose PCa in the PSA gray zone.

Ultrafast deposition of polydopamine for high-performance fiber-reinforced high-temperature ceramic composites.

The low deposition time efficiency and small thickness limit the expansion of polydopamine (PDA) application to fiber-reinforced high-temperature ceramic composites. In this work, the electric field-assisted polymerization (EFAP) route was developed to improve the deposition time efficiency of PDA coating and overcome the thickness limitation. Carbonized polydopamine (C-PDA) coating was used as the interphase of carbon fiber-reinforced ZrB2-based composites (Cf/ZrB2-based composite) to bond rigid fibers and brittle ceramics, where C-PDA coating was prepared by the carbonization of PDA coating. Firstly, uniform and dense PDA coatings were deposited on carbon fibers (Cf) by EFAP. The thickness of PDA coating reached the micron level (over 1800 nm) for the first time. Benefiting from the EFAP route promoting the oxidation process of dopamine (DA) and accelerating the aggregation and in-situ polymerization of DA and its derivatives on the surface of Cf, the deposition rate of PDA coating reached 5589 nm/h, which was 3 orders of magnitude higher than that of the traditional self-polymerization process. By adjusting the EFAP parameters (e.g. DA-concentration, current, and deposition time), the thickness of PDA coating could be conveniently designed from nano-scale to micro-scale. Then, PDA coating was pyrolyzed to obtain C-PDA coating. C-PDA coating was well bonded on Cf without visible cross-sticking among neighboring fibers. C-PDA coating presented a layered structure and the thickness of C-PDA coating could be designed by controlling the thickness of PDA. C-PDA coating was used as the interfacial phase of the Cf/ZrB2-based composite, which ensured that the composite possessed good load-bearing capacity and thermal stability. Moreover, extraordinary damage resistance of the composite was achieved, with work of fracture up to 9936 ± 548 J/m2 at room temperature and 19,082 ± 3458 J/m2 at 1800 °C. The current work provides a high time efficiency processing route for depositing PDA coating on carbon fibers and demonstrates the attractive potential of PDA coating in fiber-reinforced high-temperature ceramic composites.

Efficacy of neoadjuvant docetaxel + cisplatin chemo-hormonal therapy versus docetaxel chemo-hormonal therapy in patients with locally advanced prostate cancer with germline DNA damage repair gene alterations.

Purpose: To assess the efficacy and safety of neoadjuvant docetaxel + cisplatin chemotherapy with androgen deprivation therapy for the treatment of locally advanced prostate cancer (PCa) in patients harboring germline DNA damage repair genes (gDDR) defects. Methods: We conducted a prospective observational study in patients with locally advanced PCa confirmed with gDDR defects through next-generation sequencing. All patients received either docetaxel + cisplatin (platinum-group) or docetaxel chemo-hormonal therapy (docetaxel group) followed by radical prostatectomy with extended lymphadenectomy. The primary end point was biochemical progression-free survival (bPFS) and secondary end points include postoperative pathological response and safety assessment during the study period. Results: A total of 36 patients were included in the study, among whom 14 and 22 patients received docetaxel + cisplatin and docetaxel treatment, respectively. Down-staging of Tumor (T), Nodes (N), and Metastasis (M) stages was observed in 11 (78.57%) and 9 (40.9%) patients (p = 0.041), respectively, in the docetaxel + cisplatin group and docetaxel group. The median bPFS was 7.76 months (95% CI 0.770-14.748) and not reached in the docetaxel group and docetaxel + cisplatin group, respectively. bPFS was significantly longer in the docetaxel + cisplatin group (p = 0.039) with a hazard ratio of 0.386 (95% CI 0.151-0.987, p < 0.05). Furthermore, one patient discontinued docetaxel + cisplatin after second cycle due to severe liver insufficiency which was confirmed as viral hepatitis A and no significant perioperative complications was observed in either group. Conclusion: This study suggests that cisplatin may increase docetaxel anticancer activity with tolerable safety profile in patients with locally advanced PCa carrying gDDR defects in the neoadjuvant setting, a hypothesis which will require prospective, randomized confirmation.

Prostate cancer treatment - China's perspective.

Prostate cancer (PCa) incidence and mortality have rapidly increased in China. Notably, unique epidemiological characteristics of PCa are found in the Chinese PCa population, including a low but rising incidence and an inferior but improving disease prognosis. Consequently, the current treatment landscape of PCa in China demonstrates distinct features. Establishing a more thorough understanding of the characteristics of Chinese patients may help provide novel insights into potential treatment strategies for PCa patients. Herein, we review the epidemiological status and differences in treatment modalities of Chinese PCa patients. In addition, we discuss the underlying socioeconomic and biological factors that contribute to such diversity and further propose directions for future efforts in optimizing the PCa treatment in China.

Identification and validation of a poor clinical outcome subtype of primary prostate cancer with Midkine abundance.

Recent studies identified Midkine (MDK) as playing a key role in immune regulation. In this study, we aimed to discover the clinical significance and translational relevance in prostate cancer (PCa). We retrospectively analyzed 759 PCa patients who underwent radical prostatectomy from Huashan Hospital, Fudan University (training cohort, n = 369) and Chinese Prostate Cancer Consortium (validation cohort, n = 390). A total of 325 PCa patients from The Cancer Genome Atlas (TCGA) database (external cohort) were analyzed for exploration. Immune landscape and antitumor immunity were assessed through immunohistochemistry and flow cytometry. Patient-derived explant culture system was applied for evaluating the targeting potential of MDK. We found that intratumoral MDK expression correlated with PCa progression, which indicated an unfavorable biochemical recurrence (BCR)-free survival for postoperative PCa patients. Addition of MDK expression to the postoperative risk assessment tool CAPRA-S could improve its prognostic value. Tumors with MDK abundance characterized the tumor-infiltrating CD8+ T cells with less cytotoxicity production and increased immune checkpoint expression, which were accompanied by enriched immunosuppressive contexture. Moreover, MDK inhibition could reactivate CD8+ T cell antitumor immunity. MDK mRNA expression negatively correlated with androgen receptor activity signature and positively associated with radiotherapy-related signature. In conclusion, intratumoral MDK expression could serve as an independent prognosticator for BCR in postoperative PCa patients. MDK expression impaired the antitumor function of CD8+ T cells through orchestrating an immunoevasive microenvironment, which could be reversed by MDK inhibition. Moreover, tumors with MDK enrichment possessed potential sensitivity to postoperative radiotherapy while resistance to adjuvant hormonal therapy of PCa. MDK could be considered as a potential therapeutic target for PCa.

m6A-induced repression of SIAH1 facilitates alternative splicing of androgen receptor variant 7 by regulating CPSF1.

Androgen receptor splice variant 7 (AR-v7), a constitutively active transcription factor, plays a crucial role in the progression of castration-resistant prostate cancer (CRPC). Here, we found that the cleavage and polyadenylation specificity factor 1 (CPSF1) (the largest subunit of the multi-protein cleavage and polyadenylation specificity complex), regulated by the E3 ubiquitin ligases SIAH1, promoted AR-v7 expression. The data from microarray-based analysis and clinical specimen-based analysis showed that SIAH1 expression was decreased in PCa and was negatively correlated with aggressive phenotypes of PCa. SIAH1 repressed PCa cell growth and invasion under castrate conditions. SIAH1 directly interacted with CPSF1 and promoted ubiquitination and degradation of CPSF1. CPSF1 expression was negatively correlated with SIAH1 expression, but positively with PCa progression. CPSF1 overexpression switched the AR splicing pattern and facilitated the generation of the oncogenic isoform (AR-v7) by binding to the AAUAAA polyadenylation signal contained in AR-cryptic exon CE3. Functionally, SIAH1 acted as a tumor suppressor in PCa pathogenesis by repressing CPSF1-mediated AR-v7 generation. Finally, we demonstrated that m6A methylation was concerned with the repression of SIAH1 in PCa. Our results define SIAH1/CPSF1/AR-v7 axis as a regulatory factor of PCa progression, providing a promising target for treating PCa.

Erratum: Downregulation of circ-TRPS1 suppressed prostatic cancer prognoses by regulating miR-124-3p/EZH2 axis-mediated stemness.

[This corrects the article on p. 4372 in vol. 10, PMID: 33415005.].

MXene-assisted organic electrochemical transistor biosensor with multiple spiral interdigitated electrodes for sensitive quantification of fPSA/tPSA.

BACKGROUND: The ratio of fPSA/tPSA in the "grey zone" of tPSA with the concentration range between 4 ng/ml and 10 ng/ml is significant for diagnosis of prostate cancer, and highly efficiency quantification of the ratio of fPSA/tPSA remain elusive mainly because of their extremely low concentration in patients' peripheral blood with high biosample complexity. METHODS: We presented an interdigitated spiral-based MXene-assisted organic electrochemical transistors (isMOECTs) biosensor for highly sensitive determination of fPSA/tPSA. The combination of MXene and the interdigitated multiple spiral architecture synergistically assisted the amplification of amperometric signal of biosensor with dual functionalizations of anti-tPSA and anti-fPSA. RESULTS: The ultrasensitivity of the biosensor was enhanced by tunable multiple spiral architecture and MXene nanomaterials; and the sensor exhibited improved detection limit of tPSA and fPSA down to 0.01 pg/ml and acceptable performance of selectivity, repeatability and stability. Moreover, the isMOECTs displayed area under the curve (AUC) value of 0.8138, confirming the potential applications of isMOECTs in clinics. CONCLUSIONS: The merits of isMOECTs biosensor demonstrated the reliability of MXene-assisted organic electrochemical transistor biosensor with multiple interdigitated spiral for ultrasensitive quantification of fPSA/tPSA, suggesting potential current and future point-of-care testing applications.

Use of Circulating Tumor DNA for the Clinical Management of Metastatic Castration-Resistant Prostate Cancer: A Multicenter, Real-World Study.

BACKGROUND: This study aimed to describe the aberrations of DNA damage repair genes and other important driving genes in Chinese patients with metastatic castration-resistant prostate cancer (mCRPC) using circulating tumor (ctDNA) sequencing and to evaluate the associations between the clinical outcomes of multiple therapies and key genomic alterations in mCRPC, especially DNA damage repair genes. PATIENTS AND METHODS: A total of 292 Chinese patients with mCRPC enrolled from 8 centers. Multigene targeted sequencing was performed on 306 ctDNA samples and 23 matched tumor biopsies. The frequency of genomic alterations were compared with the Stand Up to Cancer-Prostate Cancer Foundation (SU2C-PCF) cohort. The Kaplan-Meier method was used to evaluate progression-free survival (PFS) following standard systemic treatments for mCRPC. Cox regression analyses were performed to determine prognostic factors associated with PFS resulting from treatments for mCRPC. RESULTS: In total, 33 of 36 (91.7%) mutations were found consistently between ctDNA and paired biopsy samples. The most common recurrent genomic alterations were found in AR (34.6%), TP53 (19.5%), CDK12 (15.4%), BRCA2 (13%), and RB1 (5.8%). The frequency of CDK12 alterations (15.4%) in our cohort was significantly higher than that in Western populations (5%-7%). AR amplification and TP53 and/or RB1 alterations were associated with resistance to abiraterone or docetaxel. Patients with a CDK12 defect showed rapid disease progression after abiraterone treatment. However, the clinical outcome after docetaxel treatment was similar between patients with and without CDK12 defects. In multivariate Cox regression analysis, a CDK12 defect was significantly associated with inferior PFS after abiraterone treatment. Patients with a BRCA2 defect showed marked response to both PARP inhibitors and platinum-based chemotherapy. CONCLUSIONS: Our study explored the genomic landscape of Chinese patients with mCRPC at different treatment stages using minimally invasive methods and evaluated the clinical implications of the driver genomic alterations on patients' response to the most widely used therapies for mCRPC. We observed a significantly higher alteration frequency of CDK12 in our cohort compared with the SU2C-PCF cohort.

Targeted inhibition of SIRT6 via engineered exosomes impairs tumorigenesis and metastasis in prostate cancer.

The treatment for metastatic castration-resistant prostate cancer patients remains a great challenge in the clinic and continuously demands discoveries of new targets and therapies. Here, we assess the function and therapeutic value of SIRT6 in metastatic castration-resistant prostate cancer. Methods: The expression of SIRT6 was examined in prostate cancer tissue microarray by immunohistochemistry staining. The functions of SIRT6 and underlying mechanisms were elucidated by in vitro and in vivo experiments. We also developed an efficient method to silence SIRT6 by aptamer-modified exosomes carrying small interfering RNA and tested the therapeutic effect in the xenograft mice models. Results: SIRT6 expression is positively correlated with prostate cancer progression. Loss of SIRT6 significantly suppressed proliferation and metastasis of prostate cancer cell lines both in vitro and in vivo. SIRT6-driven prostate cancer displays activation of multiple cancer-related signaling pathways, especially the Notch pathway. Silencing SIRT6 by siRNA delivered through engineered exosomes inhibited tumor growth and metastasis. Conclusions: SIRT6 is identified as a driver and therapeutic target for metastatic prostate cancer in our findings, and inhibition of SIRT6 by engineered exosomes can serve as a promising therapeutic tool for clinical application.

Distinct Response to Platinum-Based Chemotherapy among Patients with Metastatic Castration-Resistant Prostate Cancer Harboring Alterations in Genes Involved in Homologous Recombination.

PURPOSE: We aimed to explore the association between genomic status and clinical outcome of platinum-based chemotherapy among patients with metastatic castration-resistant prostate cancer (mCRPC). MATERIALS AND METHODS: We conducted a retrospective study of 55 patients with mCRPC who received platinum-based chemotherapy after the progression to docetaxel chemotherapy and underwent genomic profiling of 14 homologous recombination (HR) pathway genes. Progression-free survival (PFS) was analyzed using the Kaplan-Meier method. RESULTS: Of 55 patients, 23 harbored genomic defects in HR pathway genes. Median prostate specific antigen (PSA)-PFS for the HR defect group was 6.7 months compared with 2.6 months for the no HR defect group (p=0.001). The patients harboring somatic HR defect displayed shorter PSA-PFS than those harboring germline HR defect (4.5 months vs not available; p=0.066). The PSA50 (patients who survived for 12 weeks and had a PSA decline over 50% from baseline) response rate displayed higher in patients harboring BRCA2 or ATM defect (6/8, 75.0%) than in those harboring CDK12 defect (2/9, 22.2%; p=0.06). Patients harboring BRCA2 or ATM defect displayed prolonged PSA-PFS, compared with those harboring CDK12 defect and those harboring other HR defect (p=0.038). In multivariate Cox regression analysis, HR defect and BRCA2 or ATM defect were independent significant factors associated with superior PAS-PFS to platinum-based chemotherapy. CONCLUSIONS: The patients with mCRPC harboring alterations in different HR genes displayed distinct response to platinum-based chemotherapy. Patients with mCRPC harboring genomic defects in crucial HR genes either in the germline or somatic, especially BRCA2 and ATM, might experience superior outcomes to platinum-based chemotherapy, compared with those harboring CDK12 defect.

HOXD13 suppresses prostate cancer metastasis and BMP4-induced epithelial-mesenchymal transition by inhibiting SMAD1.

The HOX genes are a group of highly conserved Homeobox-containing genes that control the body plan organization during development. However, their contributions to tumorigenesis and tumor progression remain uncertain and controversial. Here we provided evidence of tumor-suppressive activity of HOXD13 in prostate cancer. HOXD13 depletion contributes to more aggressiveness of prostate cancer cells in vitro and in vivo. These effects were corroborated in a metastatic mice model, where we observed more bone metastatic lesions formed by prostate cancer cells with HOXD13 ablation. Mechanistically, HOXD13 prevents BMP4-induced epithelial-mesenchymal transition (EMT) by inhibiting mothers against decapentaplegic homolog 1 (SMAD1) transcription. Both bioinformation and our tissue microarray cohort data show that HOXD13 expression inversely correlated in advanced prostate cancer patient specimens. Our findings establish HOXD13 as a negative regulator of prostate cancer progression and metastasis by preventing BMP4/SMAD1 signaling, and potentially suggest new strategies for targeting metastatic prostate cancer.