Refining Immuno-Oncology Approaches in Metastatic Prostate Cancer: Transcending Current Limitations

Glucocorticoids in lung cancer: Navigating the balance between immunosuppression and therapeutic efficacy

Glucocorticoids (GCs), a class of hormones secreted by the adrenal glands, are released into the bloodstream to maintain homeostasis and modulate responses to various stressors. These hormones function by binding to the widely expressed GC receptor (GR), thereby regulating a wide range of pathophysiological processes, especially in metabolism and immunity. The role of GCs in the tumor immune microenvironment (TIME) of lung cancer (LC) has been a focal point of research. As immunosuppressive agents, GCs exert a crucial impact on the occurrence, progression, and treatment of LC. In the TIME of LC, GCs act as a constantly swinging pendulum, simultaneously offering tumor-suppressive properties while diminishing the efficacy of immune-based therapies. The present study reviews the role and mechanisms of GCs in the TIME of LC.

Re-sensitization to pembrolizumab following PSMA-CD3 T-cell redirection therapy with JNJ-081 in a patient with mismatch repair-deficient metastatic castration-resistant prostate cancer: a case report

While checkpoint inhibitor therapy has revolutionized the treatment landscape of some solid tumors, it has shown limited efficacy in metastatic castration-resistant prostate cancers (mCRPC). A small (~3-5%) but clinically distinct subset of mCRPC tumors have a DNA mismatch repair deficiency (dMMR) and develop a hypermutation phenotype with elevated tumor mutational burden and high microsatellite instability (MSI-H). Retrospective analyses have shown dMMR/MSI-H status to be a predictive biomarker for response to pembrolizumab in prostate tumors. Here, in this report, we present a case of a patient with mCRPC harboring a somatic dMMR who had progressed on pembrolizumab after an initial response. He enrolled on a clinical trial with JNJ-081, a prostate-specific membrane antigen-CD3 bispecific T-cell engager antibody and experienced a partial response with course complicated by cytokine release syndrome. On progression, he was reinitiated on pembrolizumab and experienced an exceptional second response, with his prostate-specific antigen falling from a high of 20.01 to undetectable after 6 weeks and remaining undetectable for >11 months. To our knowledge, this represents the first reported case of bispecific T-cell engager-mediated re-sensitization to checkpoint inhibitor therapy in any cancer.

Integrated analysis of single-cell and bulk RNA sequencing identifies a signature based on macrophage marker genes involved in prostate cancer prognosis and treatment responsiveness

In the tumor microenvironment, tumor-associated macrophages (TAMs) interact with cancer cells and contribute to the progression of solid tumors. Nonetheless, the clinical significance of TAM-related biomarkers in prostate cancer (PCa) is largely unexplored. The present study aimed to construct a macrophage-related signature (MRS) for predicting PCa patient prognosis based on macrophage marker genes. Six cohorts comprising 1056 PCa patients with RNA-Seq and follow-up data were enrolled. Based on macrophage marker genes identified by single-cell RNA-sequencing (scRNA-seq) analysis, univariate analysis, least absolute shrinkage and selection operator (Lasso)-Cox regression, and machine learning procedures were performed to derive a consensus MRS. Receiver operating characteristic curve (ROC), concordance index, and decision curve analyses were used to confirm the predictive capacity of the MRS. The predictive performance of the MRS for recurrence-free survival (RFS) was stable and robust, and the MRS outperformed traditional clinical variables. Furthermore, high-MRS-score patients presented abundant macrophage infiltration and high-expression levels of immune checkpoints (CTLA4, HAVCR2, and CD86). The frequency of mutations was relatively high in the high-MRS-score subgroup. However, the low-MRS-score patients had a better response to immune checkpoint blockade (ICB) and leuprolide-based adjuvant chemotherapy. Notably, abnormal ATF3 expression may be associated with docetaxel and cabazitaxel resistance in PCa cells, T stage, and the Gleason score. In this study, a novel MRS was first developed and validated to accurately predict patient survival outcomes, evaluate immune characteristics, infer therapeutic benefits, and provide an auxiliary tool for personalized therapy.

Phase II Trial of Sipuleucel-T and Stereotactic Ablative Body Radiation for Patients with Metastatic Castrate-Resistant Prostate Cancer

(1) We hypothesized that adding concurrent stereotactic ablative radiotherapy (SAbR) would increase the time to progression in patients with metastatic castrate-resistant prostate cancer (mCRPCA) treated with sipuleucel-T. (2) Patients with a history of prostate cancer (PC), radiographic evidence of metastatic disease, and rising prostate-specific antigen (PSA) > 0.2 ng/dL on castrate testosterone levels were enrolled in this single-arm phase II clinical trial and treated with sipuleucel-T and SAbR. The primary endpoint was time to progression (TTP). Cellular and humoral responses were measured using ELISpot and Luminex multiplex assays, respectively. (3) Twenty patients with mCRPC were enrolled and treated with SAbR to 1−3 sites. Treatment was well tolerated with 51, 8, and 4 treatment-related grade 1, 2, and 3 toxicities, respectively, and no grade 4 or 5 adverse events. At a median follow-up of 15.5 months, the median TTP was 11.2 weeks (95% CI; 6.8−14.0 weeks). Median OS was 76.8 weeks (95% CI; 41.6−130.8 weeks). This regimen induced both humoral and cellular immune responses. Baseline M-MDSC levels were elevated in mCRPC patients compared to healthy donors (p = 0.004) and a decline in M-MDSC was associated with biochemical response (p = 0.044). Responders had lower baseline uric acid levels (p = 0.05). No clear correlation with radiographic response was observed. (4) While the regimen was safe, the PC-antigen-specific immune response induced by SAbR did not yield a synergistic clinical benefit for patients treated with sipuleucel-T compared to the historically reported outcomes.

The modern therapeutic & imaging landscape of metastatic prostate cancer: a primer for radiologists

Prostate cancer represents one of the leading causes of cancer-related mortality in the United States and the most common cancer among men. Treatment paradigms for the management of advanced stages of prostate cancer have continued to evolve in recent years. These advancements in the therapeutic landscape of metastatic prostate cancer and diagnostic imaging modalities have fundamentally changed the treatment of patients with prostate cancer. In this review article we provide a primer for radiologists highlighting the most recent developments in treatment options and imaging techniques utilized in the modern oncologic management of metastatic prostate cancer. We will examine current therapy options and associated toxicities with an emphasis on relevant imaging findings commonly encountered by radiologists. We also summarize the role of modalities including CT, MRI, PET, bone scintigraphy, and PET in the diagnosis and follow-up of patients with metastatic prostate cancer.

A Novel Ferroptosis-Based Molecular Signature Associated with Biochemical Recurrence-Free Survival and Tumor Immune Microenvironment of Prostate Cancer

Objective: To identify ferroptosis-related molecular clusters, and to develop and validate a ferroptosis-based molecular signature for predicting biochemical recurrence-free survival (BCRFS) and tumor immune microenvironment of prostate cancer (PCa). Materials and Methods: The clinical data and transcriptome data of PCa were downloaded from TCGA and GEO database. Ferroptosis-related genes (FRGs) were obtained from FerrDb database. We performed consensus clustering analysis to identify ferroptosis-related molecular subtypes for PCa. Univariate and multivariate Cox regression analysis were used to establish a ferroptosis-based signature for predicting BCRFS. Internal verification, external verification and subgroup survival analysis were then successfully performed. Results: There was a total of 40 differentially expressed FRGs in PCa. We then identified three ferroptosis-related molecular clusters of PCa, which have significantly different immune infiltrating cells, tumor immune microenvironment and PD-L1 expression level. More importantly, a novel ferroptosis-based signature for predicting BCRFS of PCa based on four FRGs (including ASNS, GPT2, NFE2L2, RRM2) was developed. Internal and external verifications were then successfully performed. Patients with high-risk score were associated with significant poor BCRFS compared with those with low-risk score in training cohort, testing cohort and validating cohort, respectively. The area under time-dependent Receiver Operating Characteristic (ROC) curve were 0.755, 0.705 and 0.726 in training cohort, testing cohort and validating cohort, respectively, indicating the great performance of this signature. Independent prognostic analysis indicated that this signature was an independent predictor for BCRFS of PCa. Subgroup analysis revealed that this signature was particularly suitable for younger or stage T III-IV or stage N0 or cluster 1-2 PCa patients. Patients with high-risk score have significantly different tumor immune microenvironment in comparison with those with low-risk score. The results of qRT-PCR successfully verified the mRNA expression levels of ASNS, GPT2, RRM2 and NFE2L2 in DU-145 and RWPE-1 cells while the results of IHC staining exactly verified the relative protein expression levels of ASNS, GPT2, RRM2 and NFE2L2 between PCa and BPH tissues. Conclusions: This study successfully identified three ferroptosis-related molecular clusters. Besides, we developed and validated a novel ferroptosis-based molecular signature, which performed well in predicting BCRFS and tumor immune microenvironment of PCa.

An Insight on Novel Molecular Pathways in Metastatic Prostate Cancer: A Focus on DDR, MSI and AKT

Prostate cancer is still one of the main causes of cancer-related death in the male population, regardless of the advancements in the treatment scenario. The genetic knowledge on prostate cancer is widely increasing, allowing researchers to identify novel promising molecular targets and treatment approaches. Genomic profiling has evidenced that DNA damage repair genes’ alterations are quite frequent in metastatic, castration resistant prostate cancer and specific therapies can interfere with this pathway, showing promising activity in this setting. Microsatellite instability is gaining attention as it seems to represent a predictive factor of the response to immunotherapy. Furthermore, the PTEN-PI3K-AKT pathway is another possible treatment target being investigated. In this review, we explore the current knowledge on these frequent genomic alterations of metastatic prostate cancer, their possible therapeutic repercussions and the promising future treatments under evaluation.

Molecular Characterization of Prostate Cancers in the Precision Medicine Era

Prostate cancer (PCa) therapy has been recently revolutionized by the approval of new therapeutic agents in the metastatic setting. However, the optimal therapeutic strategy in such patients should be individualized in the light of prognostic and predictive molecular factors, which have been recently studied: androgen receptor (AR) alterations, PTEN-PI3K-AKT pathway deregulation, homologous recombination deficiency (HRD), mismatch repair deficiency (MMRd), and tumor microenvironment (TME) modifications. In this review, we highlighted the clinical impact of prognostic and predictive molecular factors in PCa patients' outcomes, identifying biologically distinct subtypes. We further analyzed the relevant methods to detect these factors, both on tissue, i.e., immunohistochemistry (IHC) and molecular tests, and blood, i.e., analysis of circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA). Moreover, we discussed the main pros and cons of such techniques, depicting their present and future roles in PCa management, throughout the precision medicine era.

Overcoming Immune Resistance in Prostate Cancer: Challenges and Advances

Simple Summary

Immunotherapy has changed the landscape of treatment modalities available for many different types of malignancies. However, the factors that influence the success of immunotherapeutics have not been as clearly seen in advanced prostate cancer, likely due to immunosuppressive factors that exist within the prostate cancer tumor microenvironment. While there have been many immunotherapeutics used for prostate cancer, the majority have targeted a single immunosuppressive mechanism resulting in limited clinical efficacy. More recent research centered on elucidating the key mechanisms of immune resistance in the prostate tumor microenvironment has led to the discovery of a range of new treatment targets. With that in mind, many clinical trials have now set out to evaluate combination immunotherapeutic strategies in patients with advanced prostate cancer, in the hopes of circumventing the immunosuppressive mechanisms.

Abstract

The use of immunotherapy has become a critical treatment modality in many advanced cancers. However, immunotherapy in prostate cancer has not been met with similar success. Multiple interrelated mechanisms, such as low tumor mutational burden, immunosuppressive cells, and impaired cellular immunity, appear to subvert the immune system, creating an immunosuppressive tumor microenvironment and leading to lower treatment efficacy in advanced prostate cancer. The lethality of metastatic castrate-resistant prostate cancer is driven by the lack of therapeutic regimens capable of generating durable responses. Multiple strategies are currently being tested to overcome immune resistance including combining various classes of treatment modalities. Several completed and ongoing trials have shown that combining vaccines or checkpoint inhibitors with hormonal therapy, radiotherapy, antibody–drug conjugates, chimeric antigen receptor T cell therapy, or chemotherapy may enhance immune responses and induce long-lasting clinical responses without significant toxicity. Here, we review the current state of immunotherapy for prostate cancer, as well as tumor-specific mechanisms underlying therapeutic resistance, with a comprehensive look at the current preclinical and clinical immunotherapeutic strategies aimed at overcoming the immunosuppressive tumor microenvironment and impaired cellular immunity that have largely limited the utility of immunotherapy in advanced prostate cancer.

CACNA1C is a prognostic predictor for patients with ovarian cancer

BACKGROUND

CACNA1C, as a type of voltage-dependent calcium ion transmembrane channel, played regulatory roles in the development and progress of multiple tumors. This study was aimed to analyze the roles of CACNA1C in ovarian cancer (OC) of overall survival (OS) and to explore its relationships with immunity.

METHODS

Single gene mRNA sequencing data and corresponding clinical information were obtained from The Cancer Genome Atlas Database (TCGA) and the International Cancer Genome Consortium (ICGC) datasets. Gene set enrichment analysis (GSEA) was used to identify CACNA1C-related signal pathways. Univariate and multivariate Cox regression analyses were applied to evaluate independent prognostic factors. Besides, associations between CACNA1C and immunity were also explored.

RESULTS

CACNA1C had a lower expression in OC tumor tissues than in normal tissues (P < 0.001), with significant OS (P = 0.013) and a low diagnostic efficiency. We further validated the expression levels of CACNA1C in OC by means of the ICGC dataset (P = 0.01), qRT-PCR results (P < 0.001) and the HPA database. Univariate and multivariate Cox hazard regression analyses indicated that CACNA1C could be an independent risk factor of OS for OC patients (both P < 0.001). Five significant CACNA1C-related signaling pathways were identified by means of GSEA. As for genetic alteration analysis, altered CACNA1C groups were significantly associated with OS (P = 0.0169), progression-free survival (P = 0.0404), disease-free survival (P = 0.0417) and disease-specific survival (P = 9.280e-3), compared with unaltered groups in OC. Besides, CACNA1C was dramatically associated with microsatellite instability (MSI) and immunity.

CONCLUSIONS

Our results shed light on that CACNA1C could be a prognostic predictor of OS in OC and it was closely related to immunity.

Glyoxalase-1-Dependent Methylglyoxal Depletion Sustains PD-L1 Expression in Metastatic Prostate Cancer Cells: A Novel Mechanism in Cancer Immunosurveillance Escape and a Potential Novel Target to Overcome PD-L1 Blockade Resistance

Simple Summary

Metastatic prostate cancer (mPCa) is a well-known lethal condition. One of the mechanisms through which PCa cells become so aggressive is the avoidance of immune surveillance that further fosters cell growth, invasion, and migration. PD-L1/PD-1 axis plays a crucial role in inhibiting cytotoxic T cells and maintaining an immunosuppressive cancer microenvironment. Hence, targeting PD-L1/PD-1 axis represents a potential way to control mPCa. Unfortunately, mPCa patients do not respond to PD-L1/PD-1 axis blockade, focusing the research to understand the possible underpinning mechanisms. Our results provide a novel pathway taking part in cancer immunosurveillance escape and in the above-mentioned immunotherapy resistance, which provides the basis for additional studies aimed at developing novel therapeutic opportunities, possibly also in combination with antibodies blocking PD-L1/PD-1 axis.

Abstract

Metastatic prostate cancer (mPCa) is a disease for which to date there is not curative therapy. Even the recent and attractive immunotherapeutic approaches targeting PD-L1, an immune checkpoint protein which helps cancer cells to escape from immunosurveillance, have proved ineffective. A better understanding of the molecular mechanisms contributing to keep an immunosuppressive microenvironment associated with tumor progression and refractoriness to PD-L1 inhibitors is urgently needed. In the present study, by using gene silencing and specific activators or scavengers, we demonstrated, in mPCa cell models, that methylglyoxal (MG), a potent precursor of advanced glycation end products (AGEs), especially 5-hydro-5-methylimidazolone (MG-H1), and its metabolizing enzyme, glyoxalase 1 (Glo1), contribute to maintain an immunosuppressive microenvironment through MG-H1-mediated PD-L1 up-regulation and to promote cancer progression. Moreover, our findings suggest that this novel mechanism might be responsible, at least in part, of mPCa resistance to PD-L1 inhibitors, such as atezolizumab, and that targeting it may sensitize cells to this PD-L1 inhibitor. These findings provide novel insights into the mechanisms of mPCa immunosurveillance escape and help in providing the basis to foster in vivo research toward novel therapeutic strategies for immunotherapy of mPCa.

Downregulation of hsa_circ_0001836 Induces Pyroptosis Cell Death in Glioma Cells via Epigenetically Upregulating NLRP1

Background

It has been shown that circular RNAs (circRNAs) play a vital role in the progression of glioma. Recently, hsa_circ_0001836 was found to be upregulated in glioma tissues, but the role of hsa_circ_0001836 in glioma remains unclear.

Methods

EdU staining and flow cytometry assays were used to measure the viability and death of glioma cells. In addition, scanning electron microscopy (SEM) was used to observe the morphology of cells undergoing cell death.

Results

Hsa_circ_0001836 expression was upregulated in U251MG and SHG-44 cells. In addition, hsa_circ_0001836 knockdown significantly reduced the viability and proliferation of U251MG and SHG-44 cells. Moreover, hsa_circ_0001836 knockdown markedly induced the pyroptosis of U251MG and SHG-44 cells, evidenced by the increased expressions of NLRP1, cleaved caspase 1 and GSDMD-N. Meanwhile, methylation specific PCR (MSP) results indicated that hsa_circ_0001836 knockdown epigenetically increased NLRP1 expression via mediating DNA demethylation of NLRP1 promoter region. Furthermore, downregulation of hsa_circ_0001836 notably induced pyroptosis and inhibited tumor growth in a mouse xenograft model of glioma.

Conclusion

Collectively, hsa_circ_0001836 knockdown could induce pyroptosis cell death in glioma cells in vitro and in vivo via epigenetically upregulating NLRP1 expression. These findings suggested that hsa_circ_0001836 may serve as a potential therapeutic target for the treatment of glioma.