Neoantigen responses, immune correlates, and favorable outcomes after ipilimumab treatment of patients with prostate cancer

Advances in and prospects of immunotherapy for prostate cancer

Immunotherapy has shown promising therapeutic effects in hematological malignancies and certain solid tumors and has emerged as a critical and highly potential treatment modality for cancer. However, prostate cancer falls under the category of immune-resistant cold tumors, for which immunotherapy exhibits limited efficacy in patients with solid tumors. Thus, it is important to gain a deeper understanding of the tumor microenvironment in prostate cancer to facilitate immune system activation and overcome immune suppression to advance immunotherapy for prostate cancer. In this review, we discuss the immunosuppressive microenvironment of prostate cancer, which is characterized by the presence of few tumor-infiltrating lymphocytes, abundant immunosuppressive cells, low immunogenicity, and a noninflammatory phenotype, which significantly influences the efficacy of immunotherapy for prostate cancer. Immunotherapy is mainly achieved by activating the host immune system and overcoming immunosuppression. In this regard, we summarize the therapeutic advances in immune checkpoint blockade, immunogenic cell death, reversal of the immunosuppressive tumor microenvironment, tumor vaccines, immune adjuvants, chimeric antigen receptor T-cell therapy, and overcoming penetration barriers in prostate cancer, with the aim of providing novel research insights and approaches to enhance the effectiveness of immunotherapy for prostate cancer.

Neoantigen-specific T cell help outperforms non-specific help in multi-antigen DNA vaccination against cancer

CD4+ T helper antigens are essential components of cancer vaccines, but the relevance of the source of these MHC class II-restricted antigens remains underexplored. To compare the effectiveness of tumor-specific versus tumor-unrelated helper antigens, we designed three DNA vaccines for the murine MC-38 colon carcinoma, encoding CD8+ T cell neoantigens alone (noHELP) or in combination with either "universal" helper antigens (uniHELP) or helper neoantigens (neoHELP). Both types of helped vaccines increased the frequency of vaccine-induced CD8+ T cells, and particularly uniHELP increased the fraction of KLRG1+ and PD-1low effector cells. However, when mice were subsequently injected with MC-38 cells, only neoHELP vaccination resulted in significantly better tumor control than noHELP. In contrast to uniHELP, neoHELP-induced tumor control was dependent on the presence of CD4+ T cells, while both vaccines relied on CD8+ T cells. In line with this, neoHELP variants containing wild-type counterparts of the CD4+ or CD8+ T cell neoantigens displayed reduced tumor control. These data indicate that optimal personalized cancer vaccines should include MHC class II-restricted neoantigens to elicit tumor-specific CD4+ T cell help.

mtPCDI: a machine learning-based prognostic model for prostate cancer recurrence

Background

This research seeks to formulate a prognostic model for forecasting prostate cancer recurrence by examining the interaction between mitochondrial function and programmed cell death (PCD).

Methods

The research involved analyzing four gene expression datasets from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) using univariate Cox regression. These analyses identified genes linked with mitochondrial function and PCD that correlate with recurrence prognosis. Various machine learning algorithms were then employed to construct an optimal predictive model.

Results

A key outcome was the creation of a mitochondrial-related programmed cell death index (mtPCDI), which effectively predicts the prognosis of prostate cancer patients. It was observed that individuals with lower mtPCDI exhibited higher immune activity, correlating with better recurrence outcomes.

Conclusion

The study demonstrates that mtPCDI can be used for personalized risk assessment and therapeutic decision-making, highlighting its clinical significance and providing insights into the biological processes affecting prostate cancer recurrence.

Telomerase related molecular subtype and risk model reveal immune activity and evaluate prognosis and immunotherapy response in prostate cancer

BACKGROUND

Prostate cancer ranks among the six most lethal malignancies worldwide. Telomerase, a reverse transcriptase enzyme, plays a pivotal role in extending cellular telomeres and is intimately associated with cell proliferation and division. However, the interconnection between prostate cancer and telomerase-related genes (TEASEs) remains unclear.

METHODS

Somatic mutations and copy number alterations of TEASEs were comprehensively analyzed. Subsequently, the transcripts of prostate cancer patients in TCGA and GEO databases were integrated to delineate new molecular subtypes. Followed by constructing a risk model containing nine characteristic genes through Lasso regression and Cox prognostic analysis among different subtypes. Various aspects including prognosis, tumor microenvironment (TME), landscape of immunity, tumor mutational burden (TMB), stem cell correlation, and median inhibitory concentration amongst different risk groups were compared. Finally, the expression, prognosis, and malignant biological behavior of ZW10 interactor (ZWINT) in vitro was explored.

RESULTS

TEASEs exhibited a notably high mutation frequency. Three distinct molecular subtypes and two gene subclusters based on TEASEs were delineated, displaying significant associations with prognosis, immune function regulation, and clinical characteristics. Low-risk patients demonstrated superior prognosis and better response to immunotherapy. Conversely, high-risk patients exhibited higher TMB and stronger stem cell correlations. It was also found that the patients' sensitivity to chemotherapy agents was impacted by the risk score. Finally, ZWINT's potential as a novel diagnostic and prognostic biomarker for prostate cancer was validated.

CONCLUSIONS

TEASEs play a pivotal role in modulating immune regulation and immunotherapeutic responses, thereby significantly impacting the diagnosis, prognosis, and treatment strategies for affected patients.

CDK4/6 Alters TBK1 Phosphorylation to Inhibit the STING Signaling Pathway in Prostate Cancer

The efficacy of immunotherapy in patients with prostate cancer is limited due to the "cold" tumor microenvironment and the paucity of neoantigens. The STING-TBK1-IRF3 signaling axis is involved in innate immunity and has been increasingly recognized as a candidate target for cancer immunotherapy. Here, we found that treatment with CDK4/6 inhibitors stimulates the STING pathway and enhances the antitumor effect of STING agonists in prostate cancer. Mechanistically, CDK4/6 phosphorylated TBK1 at S527 to inactivate the STING signaling pathway independent of RB1 in prostate cancer cells. CDK4/6-mediated phosphorylation of RB1 at S249/T252 also induced the interaction of RB1 with TBK1 to diminish the phosphorylation of TBK1 at S172, which suppressed STING pathway activation. Overall, this study showed that CDK4/6 suppresses the STING pathway through RB1-dependent and RB1-independent pathways, indicating that CDK4/6 inhibition could be a potential strategy to overcome immunosuppression in prostate cancer. Significance: Inhibiting CDK4/6 activates STING-TBK1-IRF3 signaling in prostate cancer by regulating TBK1 phosphorylation, suggesting that the combination of CDK4/6 inhibitors and STING agonists could be an effective approach to stimulate innate immunity.

Computational Methods for Predicting Key Interactions in T Cell-Mediated Adaptive Immunity

The adaptive immune system recognizes pathogen- and cancer-specific features and is endowed with memory, enabling it to respond quickly and efficiently to repeated encounters with the same antigens. T cells play a central role in the adaptive immune system by directly targeting intracellular pathogens and helping to activate B cells to secrete antibodies. Several fundamental protein interactions-including those between major histocompatibility complex (MHC) proteins and antigen-derived peptides as well as between T cell receptors and peptide-MHC complexes-underlie the ability of T cells to recognize antigens with great precision. Computational approaches to predict these interactions are increasingly being used for medically relevant applications, including vaccine design and prediction of patient response to cancer immunotherapies. We provide computational researchers with an accessible introduction to the adaptive immune system, review computational approaches to predict the key protein interactions underlying T cell-mediated adaptive immunity, and highlight remaining challenges.

Mesenchymal stem cell-derived exosomes for management of prostate cancer: An updated view

Prostate cancer represents the second most prevalent form of cancer found in males, and stands as the fifth primary contributor to cancer-induced mortality on a global scale. Research has shown that transplanted mesenchymal stem cells (MSCs) can migrate by homing to tumor sites in the body. In prostate cancer, researchers have explored the fact that MSC-based therapies (including genetically modified delivery vehicles or vectors) and MSC-derived exosomes are emerging as attractive options to improve the efficacy and safety of traditional cancer therapies. In addition, researchers have reported new insights into the application of extracellular vesicle (EV)-MSC therapy as a novel treatment option that could provide a more effective and targeted approach to prostate cancer treatment. Moreover, the new generation of exosomes, which contain biologically functional molecules as signal transducers between cells, can simultaneously deliver different therapeutic agents and induce an anti-tumor phenotype in immune cells and their recruitment to the tumor site. The results of the current research on the use of MSCs in the treatment of prostate cancer may be helpful to researchers and clinicians working in this field. Nevertheless, it is crucial to emphasize that although dual-role MSCs show promise as a therapeutic modality for managing prostate cancer, further investigation is imperative to comprehensively grasp their safety and effectiveness. Ongoing clinical trials are being conducted to assess the viability of MSCs in the management of prostate cancer. The results of these trials will help determine the viability of this approach. Based on the current literature, engineered MSCs-EV offer great potential for application in targeted tumor therapy.

Advancing nanotechnology for neoantigen-based cancer theranostics

Neoantigens play a pivotal role in the field of tumour therapy, encompassing the stimulation of anti-tumour immune response and the enhancement of tumour targeting capability. Nonetheless, numerous factors directly influence the effectiveness of neoantigens in bolstering anti-tumour immune responses, including neoantigen quantity and specificity, uptake rates by antigen-presenting cells (APCs), residence duration within the tumour microenvironment (TME), and their ability to facilitate the maturation of APCs for immune response activation. Nanotechnology assumes a significant role in several aspects, including facilitating neoantigen release, promoting neoantigen delivery to antigen-presenting cells, augmenting neoantigen uptake by dendritic cells, shielding neoantigens from protease degradation, and optimizing interactions between neoantigens and the immune system. Consequently, the development of nanotechnology synergistically enhances the efficacy of neoantigens in cancer theranostics. In this review, we provide an overview of neoantigen sources, the mechanisms of neoantigen-induced immune responses, and the evolution of precision neoantigen-based nanomedicine. This encompasses various therapeutic modalities, such as neoantigen-based immunotherapy, phototherapy, radiotherapy, chemotherapy, chemodynamic therapy, and other strategies tailored to augment precision in cancer therapeutics. We also discuss the current challenges and prospects in the application of neoantigen-based precision nanomedicine, aiming to expedite its clinical translation.

Synergizing Thermal Ablation Modalities with Immunotherapy: Enough to Induce Systemic Antitumoral Immunity?

Thermal ablation modalities (cryoablation, radiofrequency ablation, and microwave ablation) have long been noted to occasionally induce a systemic antitumoral response. With the widespread use of checkpoint inhibitors, there is a significant interest in whether thermal ablation can promote immune system tumor recognition and increase checkpoint inhibitor response rates. In this review, we examine the current state of preclinical and clinical evidence examining the combination of checkpoint inhibitor therapies and thermal ablation modalities as well as discuss remaining the unanswered questions and directions for future research.

Recent advances in personalized cancer immunotherapy with immune checkpoint inhibitors, T cells and vaccines

The results of genomic and molecular profiling of cancer patients can be effectively applied to immunotherapy agents, including immune checkpoint inhibitors, to select the most appropriate treatment. In addition, accurate prediction of neoantigens facilitates the development of individualized cancer vaccines and T-cell therapy. This review summarizes the biomarker(s) predicting responses to immune checkpoint inhibitors and focuses on current strategies to identify and isolate neoantigen-reactive T cells as well as the clinical development of neoantigen-based therapeutics. The results suggest that maximal T-cell stimulation and expansion can be achieved with combination therapies that enhance antigen-presenting cells' function and optimal T-cell priming in lymph nodes.

Utilization of cancer immunotherapy in sub-Saharan Africa

Introduction

The Lancet Oncology Commission for sub-Saharan Africa (SSA) predicts that cancer deaths will double from 520,158 per year to more than 1 million per year by the year 2040. These striking figures indicate a need to urgently evaluate cancer treatment infrastructure and resources in the region. Studies have found immunotherapy to be effective for the treatment of advanced-stage cancer, which almost 70% of patients in SSA present with. Despite immunotherapy's significant therapeutic potential, its utilization in SSA is not well documented. The purpose of this study was to evaluate the landscape of immunotherapy in SSA.

Methods

A Qualtrics survey assessing the existing infrastructure and training for safe immunotherapy administration was developed and distributed online via email and WhatsApp to 3,231 healthcare providers across SSA, with a target audience of healthcare providers serving patients with cancer. The survey contained 22 questions evaluating the accessibility, use, knowledge, and training on immunotherapy in SSA. Responses were collected between January and February 2023. Microsoft Excel was used to summarize and visually present the distribution of responses as counts and proportions.

Results

292 responses were included from 28 countries in SSA. 29% of all respondents indicated their clinic has easy access to cancer immunotherapy and 46% indicated their clinic currently practices it. Of clinics that practiced immunotherapy (n = 133), 12% used genomic sequencing to assess the tumor mutational burden biomarker, and 44% assessed expression of the PD-L1 biomarker prior to immunotherapy administration. 46% of all respondents were familiar with immunotherapy. 11% indicated being adequately trained to administer it. Of these (n=33), 52% indicated also being trained to manage immune-related adverse events related to immunotherapy administration.

Conclusion

Immunotherapy utilization and training is low in SSA and insufficient for the rising cancer burden. Increased accessibility and usage of biomarker testing to predict immunotherapy response, incorporation of immunotherapy training into continuous medical education, and increased access to immunotherapy drugs may be prerequisites for expanded utilization of immunotherapy in SSA.

Efficacy and safety of immune checkpoint inhibitors for patients with prostate cancer: a systematic review and meta-analysis

Immunotherapy has revolutionized the treatment paradigm of many cancers, however, its effectiveness in prostate cancer patients is still under question. In the present systematic review and meta-analysis, we sought for assessing the efficacy and safety of Immune checkpoint inhibitors (ICIs) in patients with prostate cancer. PubMed, Scopus, Web of Science, and EMBASE databases were searched on Aguste 19, 2022. Thirty five studies met the eligibility criteria. The median overall survival (mOS) of all treatments was 14.1 months, with the longest and shortest mOS was seen among patients who received anti-CTLA-4 monotherapy and anti-PD-1/PD-L1+anti-CTLA-4 regimen at 24.9 and 9.2 months, respectively. Noteworthy, all types of adverse events had the lowest incidence in the anti-PD-1/PD-L1 monotherapy group. Considering the ICI monotherapy regimens, we found that fatigue, diarrhea, and infusion reaction had the highest incidence rates. Future studies evaluating the efficacy and safety of novel combination therapies with ICIs are warranted.

Prostate cancer immunotherapy: Improving clinical outcomes with a multi-pronged approach

Cancer immunotherapy has gained traction in recent years owing to remarkable tumor clearance in some patients. Despite the notable success of immune checkpoint blockade (ICB) in multiple malignancies, engagement of the immune system for targeted prostate cancer (PCa) therapy is still in its infancy. Multiple factors contribute to limited response, including the heterogeneity of PCa, the cold tumor microenvironment, and a low number of neoantigens. Significant effort is being invested in improving immune-based PCa therapies. This review is a summary of the status of immunotherapy in treating PCa, with a discussion of multiple immune modalities, including vaccines, adoptively transferred T cells, and bispecific T cell engagers, some of which are undergoing clinical trials. In addition, this review also focuses on emerging mechanism-based small-molecule tyrosine kinase inhibitors with immune modulatory properties that, either as single agents or in combination with other immunotherapies, have the potential to improve clinical outcomes.

Chemerin triggers migration of a CD8 T cell subset with natural killer cell functions

The recruitment of cells with effector functions into the tumor microenvironment holds potential for delaying cancer progression. We show that subsets of human CD28-effector CD8 T cells, CCR7- CD45RO+ effector memory, and CCR7- CD45RO- effector memory RA phenotypes, express the chemerin receptor CMKLR1 and bind chemerin via the receptor. CMKLR1-expressing human CD8 effector memory T cells present gene, protein, and cytotoxic features of NK cells. Active chemerin promotes chemotaxis of CMKLR1-expressing CD8 effector memory cells and triggers activation of the α4β1 integrin. In an experimental prostate tumor mouse model, chemerin expression is downregulated in the tumor microenvironment, which is associated with few tumor-infiltrating CD8+ T cells, while forced overexpression of chemerin by mouse prostate cancer cells leads to an accumulation of intra-tumor CD8+ T cells. Furthermore, α4 integrin blockade abrogated the chemerin-dependent recruitment of CD8+ T effector memory cells into implanted prostate tumors in vivo. The results identify a role for chemerin:CMKLR1 in defining a specialized NK-like CD8 T cell, and suggest the use of chemerin-dependent modalities to target effector CMKLR1-expressing T cells to the tumor microenvironment for immunotherapeutic purposes.

Immunogenomic profiles associated with response to life-prolonging agents in prostate cancer

Prostate cancer is the most commonly diagnosed cancer but the management of advanced prostate cancer remains a therapeutic challenge, despite the survival benefits imparted by several therapeutic discoveries targeting different molecular pathways. The mechanisms of resistance to androgen deprivation and tumour progression to lethal metastatic variants are often regulated by androgen receptor (AR) bypass mechanisms and/or neuroendocrine differentiation. Moreover, recent data also suggested the involvement of adaptive and innate infiltrated immune cells in prostate tumour progression. Improvements in cancer genome analyses contributed to a better understanding of antitumour immunity and provided solutions for targeting highly cancer-specific neoantigens generated from somatic mutations in individual patients. In this review, we investigated the current knowledge on the interplay between cancer development and the complex mechanisms of immune regulation. Particularly, we focused on the role of tumour immune microenvironment, generally characterised by strong barriers for immunotherapy, and we discuss the rationale for the potential application of single agent and combination immune-targeting strategies that could lead to improved outcomes. Careful selection based on clinical and genomic factors may allow identification of patients who could benefit from this treatment approach in multiple settings (from localised to advanced prostate tumour) and in different histological subtypes (from adenocarcinoma to neuroendocrine prostate cancer).

Emerging Immunotherapy Approaches for Treating Prostate Cancer

Immunotherapy has emerged as an important approach for cancer treatment, but its clinical efficacy has been limited in prostate cancer compared to other malignancies. This review summarizes key immunotherapy strategies under evaluation for prostate cancer, including immune checkpoint inhibitors, bispecific T cell-engaging antibodies, chimeric antigen receptor (CAR) T cells, therapeutic vaccines, and cytokines. For each modality, the rationale stemming from preclinical studies is discussed along with outcomes from completed clinical trials and strategies to improve clinical efficacy that are being tested in ongoing clinical trials. Imperative endeavors include biomarker discovery for patient selection, deciphering resistance mechanisms, refining cellular therapies such as CAR T cells, and early-stage intervention were reviewed. These ongoing efforts instill optimism that immunotherapy may eventually deliver significant clinical benefits and expand treatment options for patients with advanced prostate cancer.

The screening, identification, design and clinical application of tumor-specific neoantigens for TCR-T cells

Recent advances in neoantigen research have accelerated the development of tumor immunotherapies, including adoptive cell therapies (ACTs), cancer vaccines and antibody-based therapies, particularly for solid tumors. With the development of next-generation sequencing and bioinformatics technology, the rapid identification and prediction of tumor-specific antigens (TSAs) has become possible. Compared with tumor-associated antigens (TAAs), highly immunogenic TSAs provide new targets for personalized tumor immunotherapy and can be used as prospective indicators for predicting tumor patient survival, prognosis, and immune checkpoint blockade response. Here, the identification and characterization of neoantigens and the clinical application of neoantigen-based TCR-T immunotherapy strategies are summarized, and the current status, inherent challenges, and clinical translational potential of these strategies are discussed.

Multiplex protein analysis and ensemble machine learning methods of fine needle aspirates from prostate cancer patients reveal potential diagnostic signatures associated with tumour grade

BACKGROUND

Improved molecular diagnosis is needed in prostate cancer (PC). Fine needle aspiration (FNA) is a minimally invasive biopsy technique, less traumatic compared to core needle biopsy, and could be useful for diagnosis of PC. Molecular biomarkers (BMs) in FNA-samples can be assessed for prediction, eg of immunotherapy efficacy before treatment as well as at treatment decision time points during disease progression.

METHODS

In the present pilot study, the expression levels of 151 BM proteins were analysed by proximity extension assay in FNA-samples from 16 patients, including benign prostate lesions (n = 3) and cancers (n = 13). An ensemble data analysis strategy was applied using several machine learning models.

RESULTS

Twelve potentially predictive BM proteins correlating with International Society of Urological Pathology grade groups were identified, among them vimentin, tissue factor pathway inhibitor 2, and integrin beta-5. The validity of the results was supported by network analysis that showed functional associations between most of the identified putative BMs. We also showed that multiple immune checkpoint targets can be assessed (eg PD-L1, CD137, and Galectin-9), which may support the selection of immunotherapy in advanced PC. Results are promising but need further validation in a larger cohort.

CONCLUSIONS

Our pilot study represents a "proof of concept" and shows that multiplex profiling of potential diagnostic and predictive BM proteins is feasible on tumour material obtained by FNA sampling of prostate cancer. Moreover, our results demonstrate that an ensemble data analysis strategy may facilitate the identification of BM signatures in pilot studies when the patient cohort is limited.

Histone H2A Lys130 acetylation epigenetically regulates androgen production in prostate cancer

The testicular androgen biosynthesis is well understood, however, how cancer cells gauge dwindling androgen to dexterously initiate its de novo synthesis remained elusive. We uncover dual-phosphorylated form of sterol regulatory element-binding protein 1 (SREBF1), pY673/951-SREBF1 that acts as an androgen sensor, and dissociates from androgen receptor (AR) in androgen deficient environment, followed by nuclear translocation. SREBF1 recruits KAT2A/GCN5 to deposit epigenetic marks, histone H2A Lys130-acetylation (H2A-K130ac) in SREBF1, reigniting de novo lipogenesis & steroidogenesis. Androgen prevents SREBF1 nuclear translocation, promoting T cell exhaustion. Nuclear SREBF1 and H2A-K130ac levels are significantly increased and directly correlated with late-stage prostate cancer, reversal of which sensitizes castration-resistant prostate cancer (CRPC) to androgen synthesis inhibitor, Abiraterone. Further, we identify a distinct CRPC lipid signature resembling lipid profile of prostate cancer in African American (AA) men. Overall, pY-SREBF1/H2A-K130ac signaling explains cancer sex bias and reveal synchronous inhibition of KAT2A and Tyr-kinases as an effective therapeutic strategy.

Adaptive Immunity in Genitourinary Cancers

CONTEXT

While urothelial and renal cell cancers have exhibited modest responses to novel immune checkpoint inhibitors targeting the programmed death ligand 1 and its receptor, response rates in patients with prostate cancer have remained poor. The factors underlying suboptimal outcomes observed in patients treated with novel immunotherapies are still to be resolved.

OBJECTIVE

To review the literature and describe the key adaptive immune physiological events associated with cancer progression and therapeutic response in genitourinary (GU) cancers.

EVIDENCE ACQUISITION

We performed a nonsystematic, collaborative narrative review to highlight recent advancements leading to the current state of knowledge on the critical mediators of antitumor adaptive immunity to GU cancers. Further, we discuss the findings on the pre- and post-treatment immunological events that either are unique to each of the three cancer types or exhibit overlapping clinical associations.

EVIDENCE SYNTHESIS

Aging-associated immune function decline is a major factor underlying poor outcomes observed in patients treated with both conventional and novel immunotherapies. Other cancer immunobiological aspects associated with suboptimal responses in GU cancers include the overall tumor mutational burden, mutations in specific tumor suppressor/DNA damage repair genes (KDM6A, PTEN, STAG2, TP53, ATM, and BRCA2), and abundance of multiple functional states of adaptive immune cells and their spatiotemporal localization within the tumor immune microenvironment. Understanding these mechanisms may potentially lead to the development of prognostic and predictive biomarkers such as immune cell infiltration profiles and tertiary lymphoid structures (TLSs) that associate with variable clinical outcomes depending on the nature of the novel immunotherapeutic approach. Implementation of newer immune-monitoring technologies and improved preclinical modeling systems will augment our understanding of the host and tumor intrinsic factors contributing to the variability of responses to immunotherapies.

CONCLUSIONS

Despite the tremendous progress made in the understanding of dynamic and static adaptive immune elements within the tumor immune landscape, several knowledge gaps remain. A comprehensive knowledge thus gained will lead to precision immunotherapy, improved drug sequencing, and a therapeutic response.

PATIENT SUMMARY

We performed a collaborative review by a diverse group of experts in the field to examine our understanding of the events and crosstalk between cancer cells and the patient's immune system that are associated with responses to novel immunotherapies. An evolving understanding of tumor-intrinsic and host-related immune alterations, both before and after therapy, will aid in the discovery of promising markers of responses to immunotherapy as well as the development of unique therapeutic approaches for the management of genitourinary cancers.

A novel integrated approach to predicting cancer immunotherapy efficacy

Immunotherapies have revolutionized cancer treatment modalities; however, predicting clinical response accurately and reliably remains challenging. Neoantigen load is considered as a fundamental genetic determinant of therapeutic response. However, only a few predicted neoantigens are highly immunogenic, with little focus on intratumor heterogeneity (ITH) in the neoantigen landscape and its link with different features in the tumor microenvironment. To address this issue, we comprehensively characterized neoantigens arising from nonsynonymous mutations and gene fusions in lung cancer and melanoma. We developed a composite NEO2IS to characterize interplays between cancer and CD8+ T-cell populations. NEO2IS improved prediction accuracy of patient responses to immune-checkpoint blockades (ICBs). We found that TCR repertoire diversity was consistent with the neoantigen heterogeneity under evolutionary selections. Our defined neoantigen ITH score (NEOITHS) reflected infiltration degree of CD8+ T lymphocytes with different differentiation states and manifested the impact of negative selection pressure on CD8+ T-cell lineage heterogeneity or tumor ecosystem plasticity. We classified tumors into distinct immune subtypes and examined how neoantigen-T cells interactions affected disease progression and treatment response. Overall, our integrated framework helps profile neoantigen patterns that elicit T-cell immunoreactivity, enhance the understanding of evolving tumor-immune interplays and improve prediction of ICBs efficacy.

Immune checkpoint therapy-current perspectives and future directions

Immune checkpoint therapy (ICT) has dramatically altered clinical outcomes for cancer patients and conferred durable clinical benefits, including cure in a subset of patients. Varying response rates across tumor types and the need for predictive biomarkers to optimize patient selection to maximize efficacy and minimize toxicities prompted efforts to unravel immune and non-immune factors regulating the responses to ICT. This review highlights the biology of anti-tumor immunity underlying response and resistance to ICT, discusses efforts to address the current challenges with ICT, and outlines strategies to guide the development of subsequent clinical trials and combinatorial efforts with ICT.

Epigenetic mechanism of therapeutic resistance and potential of epigenetic therapeutics in chemorefractory prostate cancer

Prostate cancer is the second leading cause of cancer death among men in the United States. Depending upon the histopathological subtypes of prostate cancers, various therapeutic options, such as androgen deprivation therapy (ADT), androgen receptor signaling inhibitors (ARSI), immunotherapy, and chemotherapy, are available to treat prostate cancer. While these therapeutics are effective in the initial stages during treatments, the tumors subsequently develop resistance to these therapies. Despite all the progress made so far, therapeutic resistance remains a major challenge in the treatment of prostate cancer. Although various mechanisms have been reported for the resistance development in prostate cancer, altered expression of genes either directly or indirectly involved in drug response pathways is a common event. In addition to the genetic basis of gene regulation such as mutations and gene amplifications, epigenetic alterations involved in the aberrant expression of genes have frequently been shown to be associated not only with cancer initiation and progression but also with therapeutic resistance development. There are several review articles compiling reports on genetic mechanisms involved in therapeutic resistance in prostate cancer. However, epigenetic mechanisms for the therapeutic resistance development in prostate cancer have not yet been summarized in a review article. Therefore, the objective of this article is to compile various reports and provide a comprehensive review of the epigenetic aberrations, and aberrant expression of genes by epigenetic mechanisms involved in CRPCs and therapeutic resistance development in prostate cancer. Additionally, the potential of epigenetic-based therapeutics in the treatment of chemorefractory prostate cancer as evidenced by clinical trials has also been discussed.

Targeting the chromatin effector Pygo2 promotes cytotoxic T cell responses and overcomes immunotherapy resistance in prostate cancer

The noninflamed microenvironment in prostate cancer represents a barrier to immunotherapy. Genetic alterations underlying cancer cell-intrinsic oncogenic signaling are increasingly appreciated for their role in shaping the immune landscape. Recently, we identified Pygopus 2 (PYGO2) as the driver oncogene for the amplicon at 1q21.3 in prostate cancer. Here, using transgenic mouse models of metastatic prostate adenocarcinoma, we found that Pygo2 deletion decelerated tumor progression, diminished metastases, and extended survival. Pygo2 loss augmented the activation and infiltration of cytotoxic T lymphocytes (CTLs) and sensitized tumor cells to T cell killing. Mechanistically, Pygo2 orchestrated a p53/Sp1/Kit/Ido1 signaling network to foster a microenvironment hostile to CTLs. Genetic or pharmacological inhibition of Pygo2 enhanced the antitumor efficacy of immunotherapies using immune checkpoint blockade (ICB), adoptive cell transfer, or agents inhibiting myeloid-derived suppressor cells. In human prostate cancer samples, Pygo2 expression was inversely correlated with the infiltration of CD8+ T cells. Analysis of the ICB clinical data showed association between high PYGO2 level and worse outcome. Together, our results highlight a potential path to improve immunotherapy using Pygo2-targeted therapy for advanced prostate cancer.

Tumor immune contexture predicts recurrence after prostatectomy and efficacy of androgen deprivation and immunotherapy in prostate cancer

BACKGROUND

Prostate cancer is one of the most common cancers in men with notable interpatient heterogeneity. Implications of the immune microenvironment in predicting the biochemical recurrence-free survival (BCRFS) after radical prostatectomy and the efficacy of systemic therapies in prostate cancer remain ambiguous.

METHODS

The tumor immune contexture score (TICS) involving eight immune contexture-related signatures was developed using seven cohorts of 1120 patients treated with radical prostatectomy (training: GSE46602, GSE54460, GSE70769, and GSE94767; validation: GSE70768, DKFZ2018, and TCGA). The association between the TICS and treatment efficacy was investigated in GSE111177 (androgen deprivation therapy [ADT]) and EGAS00001004050 (ipilimumab).

RESULTS

A high TICS was associated with prolonged BCRFS after radical prostatectomy in the training (HR = 0.32, 95% CI 0.24-0.45, P < 0.001) and the validation cohorts (HR = 0.45, 95% CI 0.32-0.62, P < 0.001). The TICS showed stable prognostic power independent of tumor stage, surgical margin, pre-treatment prostatic specific antigen (PSA), and Gleason score (multivariable HR = 0.50, 95% CI 0.39-0.63, P < 0.001). Adding the TICS into the prognostic model constructed using clinicopathological features significantly improved its 1/2/3/4/5-year area under curve (P < 0.05). A low TICS was associated with high homologous recombination deficiency scores, abnormally activated pathways concerning DNA replication, cell cycle, steroid hormone biosynthesis, and drug metabolism, and fewer tumor-infiltrating immune cells (P < 0.05). The patients with a high TICS had favorable BCRFS with ADT (HR = 0.25, 95% CI 0.06-0.99, P = 0.034) or ipilimumab monotherapy (HR = 0.23, 95% CI 0.06-0.81, P = 0.012).

CONCLUSIONS

Our study delineates the associations of tumor immune contexture with molecular features, recurrence after radical prostatectomy, and the efficacy of ADT and immunotherapy. The TICS may improve the existing risk stratification systems and serve as a patient-selection tool for ADT and immunotherapy in prostate cancer.

High intratumoral plasma cells content in primary prostate cancer defines a subset of tumors with potential susceptibility to immune-based treatments

BACKGROUND

Data on advanced prostate cancer (PCa) suggest more prior systemic therapies might reduce tumor immune responsiveness. In treatment-naïve primary PCa, recent work correlated intratumoral plasma cell content with enhanced tumor immune-responsiveness. We sought to identify features of localized PCa at a high risk of recurrence following local treatment with high plasma cell content to help focus future immune-based neoadjuvant trials.

METHODS

We performed retrospective analyses of molecular profiles from three independent cohorts of over 1300 prostate tumors. We used Wilcoxon Rank Sum to compare molecular pathways between tumors with high and low intratumoral plasma cell content and multivariable Cox proportional hazards regression analyses to assess metastasis-free survival.

RESULTS

We validated an expression-based signature for intratumoral plasma cell content in 113 primary prostate tumors with both RNA-expression data and digital image quantification of CD138+ cells (plasma cell marker) based on immunohistochemisty. The signature showed castration-resistant tumors (n = 101) with more prior systemic therapies contained lower plasma cell content. In high-grade primary PCa, tumors with high plasma cell content were associated with increased predicted response to immunotherapy and decreased response to androgen-deprivation therapy. Master regulator analyses identified upregulated transcription factors implicated in immune (e.g. SKAP1, IL-16, and HCLS1), and B-cell activity (e.g. VAV1, SP140, and FLI-1) in plasma cell-high tumors. Master regulators overactivated in tumors with low plasma cell content were associated with shorter metastasis-free survival following radical prostatectomy.

CONCLUSIONS

Markers of plasma cell activity might be leveraged to augment clinical trial targeting and selection and better understand the potential for immune-based treatments in patients with PCa at a high risk of recurrence following local treatment.

Identification and validation of RB1 as an immune-related prognostic signature based on tumor mutation burdens in bladder cancer

Bladder cancer (BCa) is one of the most common malignant tumors in the urinary system. Developing effective prognostic gene and exploring the immune cells that affect the prognosis of tumor are required. Full transcriptome data ( n = 433), clinical information ( n = 581) and mutation sequencing ( n = 412) were obtained from The Cancer Genome Atlas and independent mutation sequencing data of 101 samples were acquired from International Cancer Genome Consortium. Statistical processing was conducted using R packages. Gene biologically functional research was performed with gene set enrichment analysis based on Kyoto Encyclopedia of Genes and Genomes database. Twenty-two types of immune cell infiltration were assessed and calculated in 398 samples of BCa. Furthermore, the expression of immune-related prognostic signature was verified. The relationship between prognostic gene and immune cells was explored preliminarily. Tumor mutation burdens of mutant-type groups were higher than wild-type groups of 19 genes, except for FGFR3 and CREBBP. Kaplan-Meier analysis showed that high frequency of retinoblastomal 1 (RB1) mutation led to poor prognosis of BCa patients and was an independent prognostic factor ( P = 0.004; HR = 1.776). Proportions and correlation of 22 types of immune cells in 433 samples were determined. We found that RB1 expression decreased in BCa validated through quantitative PCR and immunohistochemistry. In addition, regulatory T cells (Tregs) were detected as a negatively correlated type of immune cell to mutation of RB1, whereas fluorescence costaining showed that Foxp3 expression of Tregs infiltration was negatively related to the expression of RB1. Mutation of RB1 can be identified as an independent prognostic predictor of BCa, and it may suppress the infiltration of Tregs in BCa tissues, increasing the incidence of tumor immune escape.

Progression in immunotherapy for advanced prostate cancer

Prostate cancer is one of the most common malignant cancers of the male genitourinary system and has high morbidity and mortality. Currently, treatment modalities for localized prostate cancer focus mainly on radical prostatectomy or radical radiation therapy. Some patients still experience disease recurrence or progression after these treatments, while others are already at an advanced stage or have metastases at the time of diagnosis. With the continuous development and progress of medicine in recent years, immunotherapy has become a revolutionary cancer treatment, and has achieved remarkable accomplishments in the treatment of hematologic malignancies. A variety of immunotherapies have also appeared in the field of advanced prostate cancer treatment, including therapeutic vaccines and immune checkpoint therapies. Despite the discrepancy between the results of some immunotherapy studies, immunotherapy for prostate cancer has shown some initial success, especially in combination immunotherapies. Currently, immunotherapy is mainly used in advanced prostate cancer, especially in patients with metastatic castration-resistant prostate cancer. However, with the development of more clinical trials of immunotherapy, more evidence will be provided supporting the rational application of immunotherapy in the future.

ncRNA-mediated overexpression of ubiquitin-specific proteinase 13 contributes to the progression of prostate cancer via modulating AR signaling, DNA damage repair and immune infiltration

Metastatic castration-resistant prostate cancer (mCRPC) is a lethal form of prostate cancer, and the molecular mechanism driving mCRPC progression has not yet been fully elucidated. Immunotherapies such as chimeric antigen receptor, T-cell therapy and immune checkpoint blockade have exerted promising antitumor effects in hematological and solid tumor malignancies; however, no encouraging responses have been observed against mCRPC. The deubiquitinase USP13 functions as a tumor suppressor in many human cancers, as it sustains the protein stability of PTEN and TP53; however, its role in prostate cancer (PCa) and involvement in DNA damage and AR signaling remain unclear. In the current study, we explored the prognostic value of USP13 in PCa based on the TCGA database, and we analyzed the expression of USP13 in PCa tissues and adjacent normal tissues based on TCGA and our cohort. The results suggested that USP13 is overexpressed in PCa tumors and has the potential to be an independent biomarker for the overall survival of PCa patients. Additionally, enrichment analysis indicated that USP13 may participate in the AR pathway and PI3k/Wnt signaling, which are closely related to PCa progression. We also observed a significant correlation between the expression of USP13 and AR-related genes, DDR genes and mismatch repair genes based on the TCGA_PRAD dataset, which further supported the critical role of USP13 in AR activation and the DNA damage response of PCa. USP13 was also found to be enriched in protein neddylation, and expression of USP13 was significantly associated with infiltration of immune cells and expression of immunomodulators. Taken together, our study revealed a key role of USP13 in contributing to PCa progression by participating in multiple oncogenic signaling pathways, the DNA damage response and the immunosuppressive tumor microenvironment. Targeting USP13 may inhibit tumor growth and provide additional benefits in cooperation with DDR inhibitors and immunotherapy.

Tumor Mutational Burden by Whole-Genome Sequencing in Resected NSCLC of Never Smokers

BACKGROUND

Data are scarce about tumor mutational burden (TMB) as a biomarker in never smokers with non-small cell lung cancer (NSCLC).

METHODS

TMB was assessed by whole-genome sequencing (WGS) and compared with in silico reduced whole-exome sequencing (WES) and targeted commercial next-generation sequencing (NGS) gene panels in 92 paired tumor-normal samples from never smokers who underwent NSCLC resection with curative intent. Analyses were performed to test for association with survival after surgery and to identify the optimal prognostic TMB cutoff.

RESULTS

Tumors of never smokers with NSCLC had low TMB scores (median 1.57 mutations/Mb; range, 0.13-17.94). A TMB cutoff of 1.70 mutations/Mb was associated with a 5-year overall survival of 58% in the high-TMB (42% of cases) compared with 86% in low-TMB patients (Wald P = 0.0029). TMB scores from WGS and WES were highly correlated (Spearman ρ = 0.93, P < 2.2e-16). TMB scores from NGS panels demonstrated high intraindividual fluctuations and identified high-TMB patients with 65% concordance in average compared with WGS.

CONCLUSIONS

In resected NSCLC of never smokers, high TMB was associated with worse prognosis. WES provided a good estimate of TMB while targeted NGS panels seem to lack adequate depth and resolution in the setting of low mutation burden.

IMPACT

TMB is a prognostic indicator of survival in resected NSCLC from individuals who never smoked. In this setting of low mutation counts, TMB can be accurately measured by WGS or WES, but not NGS panels.

Inhibiting ACK1-mediated phosphorylation of C-terminal Src kinase counteracts prostate cancer immune checkpoint blockade resistance

Solid tumours are highly refractory to immune checkpoint blockade (ICB) therapies due to the functional impairment of effector T cells and their inefficient trafficking to tumours. T-cell activation is negatively regulated by C-terminal Src kinase (CSK); however, the exact mechanism remains unknown. Here we show that the conserved oncogenic tyrosine kinase Activated CDC42 kinase 1 (ACK1) is able to phosphorylate CSK at Tyrosine 18 (pY18), which enhances CSK function, constraining T-cell activation. Mice deficient in the Tnk2 gene encoding Ack1, are characterized by diminished CSK Y18-phosphorylation and spontaneous activation of CD8+ and CD4+ T cells, resulting in inhibited growth of transplanted ICB-resistant tumours. Furthermore, ICB treatment of castration-resistant prostate cancer (CRPC) patients results in re-activation of ACK1/pY18-CSK signalling, confirming the involvement of this pathway in ICB insensitivity. An ACK1 small-molecule inhibitor, (R)-9b, recapitulates inhibition of ICB-resistant tumours, which provides evidence for ACK1 enzymatic activity playing a pivotal role in generating ICB resistance. Overall, our study identifies an important mechanism of ICB resistance and holds potential for expanding the scope of ICB therapy to tumours that are currently unresponsive.

Hsp90β inhibition upregulates interferon response and enhances immune checkpoint blockade therapy in murine tumors

Response resistance to the immune checkpoint blockade (ICB) immunotherapy remains a major clinical challenge that may be overcome through the rational combination of ICB and specific targeted therapeutics. One emerging combination strategy is based on sensitizing ICB-refractory tumors with antagonists of 90kD heat shock protein (Hsp90) that target all four isoforms. However, pan-Hsp90 inhibitors are limited by the modest efficacy, on-target and off-tumor toxicities, and induction of the heat shock response (HSR) that overrides the effect of Hsp90 inhibition. Recently, we developed Hsp90β-selective inhibitors that were cytotoxic to cancer cells but did not induce HSR in vitro. Here, we report that the Hsp90β inhibitor NDNB1182 downregulated CDK4 (an Hsp90β-dependent client protein) and induced the expression of endogenous retroviral elements and interferon-stimulated genes. In syngeneic mouse models of prostate cancer and breast cancer, NDNB1182 significantly augmented the efficacy of ICB therapy. Furthermore, NDNB1182 showed superior tolerability to the pan-Hsp90 inhibitor Ganetespib in mice. Our findings provide evidence that Hsp90β inhibition is a potentially effective and safe regimen to combine with ICB to treat immunotherapy-refractory solid tumors.

The established chemokine-related prognostic gene signature in prostate cancer: Implications for anti-androgen and immunotherapies

Background

Prostate cancer (PCa) was one of the most common malignancies among men, while the prognosis for PCa patients was poor, especially for patients with recurrent and advanced diseases.

Materials and methods

Five PCa cohorts were downloaded from The Cancer Genome Atlas and Gene Expression Omnibus databases, and the biochemical recurrence (BCR)-related chemokine genes were identified by LASSO-Cox regression. The chemokine-related prognostic gene signature (CRPGS) was established, and its association with PCa patients’ clinical, pathological and immune characteristics was analyzed. The association between CRPGS and PCa patients’ responses to androgen deprivation therapy (ADT) and immunotherapy was analyzed. The CRPGS was compared with other previously published molecular signatures, and the CRPGS was externally validated in our real-world AHMU-PC cohort.

Results

Four recurrence-free survival (RFS)-related chemokine genes (CXCL14, CCL20, CCL24, and CCL26) were identified, and the CRPGS was established based on the four identified chemokine genes, and TCGA-PRAD patients with high riskscores exhibited poorer RFS, which was validated in the GSE70768 cohort. The CRPGS was associated with the clinical, pathological, and immune characteristics of PCa patients. Low-risk PCa patients were predicted to respond better to ADT and immunotherapy. By comparing with other molecular signatures, the CRPGS could classify PCa patients into two risk groups well, and the CRPGS was associated with the m6A level, as well as TP53 and SPOP mutation status of PCa patients. In the AHMU-PC cohort, the CRPGS was associated with the advanced pathology stage and Gleason score.

Conclusions

The identified chemokine genes and CRPGS were associated with the prognosis of PCa, which could predict PCa patients’ responses to anti-androgen and immunotherapies.

The role of DNA damage repair (DDR) system in response to immune checkpoint inhibitor (ICI) therapy

As our understanding of the mechanisms of cancer treatment has increased, a growing number of studies demonstrate pathways through which DNA damage repair (DDR) affects the immune system. At the same time, the varied response of patients to immune checkpoint blockade (ICB) therapy has prompted the discovery of various predictive biomarkers and the study of combination therapy. Here, our investigation explores the interactions involved in combination therapy, accompanied by a review that summarizes currently identified and promising predictors of response to immune checkpoint inhibitors (ICIs) that are useful for classifying oncology patients. In addition, this work, which discusses immunogenicity and several components of the tumor immune microenvironment, serves to illustrate the mechanism by which higher response rates and improved efficacy of DDR inhibitors (DDRi) in combination with ICIs are achieved.

Harnessing gene fusion-derived neoantigens for 'cold' breast and prostate tumor immunotherapy

Breast and prostate cancers are generally considered immunologically 'cold' tumors due to multiple mechanisms rendering them unresponsive to immune checkpoint blockade therapies. With little success in garnering positive outcomes in modern immunotherapeutic clinical trials, it is prudent to re-examine the role of immunogenic neoantigens in these cold tumors. Gene fusions are driver mutations in hormone-driven cancers that can result in alternative mutation-specific neoantigens to promote immunotherapy sensitivity. This review focuses on 1) gene fusion formation mechanisms in neoantigen generation; 2) gene fusion neoantigens in cancer immunotherapeutic strategies and associated clinical trials; and 3) challenges and opportunities in computational and liquid biopsy technologies. This review is anticipated to initiate further research into gene fusion neoantigens of cold tumors for further experimental validation.

The efficacy and safety of immune checkpoint inhibitors in metastatic castration-resistant prostate cancer: A systematic review and meta-analysis

BACKGROUND

We aim to assess the efficacy and safety profiles of immune checkpoint inhibitors in patients with metastatic castration-resistant prostate cancer using a meta-analysis.

METHODS

We extracted and examined data from phase I, II and III clinical trials from PubMed, Embase, Web of Science, and Cochrane Library, which included patients with metastatic castration-resistant prostate cancer who were treated with immune checkpoint inhibitors. We performed a meta-analysis to investigate several indexes of efficacy and safety, including the objective response rate, 1-year overall survival (OS) rate, prostate-specific antigen response rate, and adverse event rate of immune checkpoint inhibitors. The material data were calculated and pooled using The R Project for Statistical Computing and STATA 12.0 software.

RESULTS

We identified 12 clinical trials in our study. We assessed the pooled frequencies of all-grade AEs and grade ≥ 3 AEs first and showed 0.82 (95% CI: 0.74-0.91, I2 = 94%, P < .01) and 0.42 (95% CI: 0.33-0.54, I2 = 96%, P < .01), respectively. The objective response rate was 0.10 (95% CI: 0.04-0.19, I2 = 70%, P < .01), and the 1-year OS and prostate-specific antigen response rate were 0.55 (95% CI: 0.45-0.67, I2 = 93%, P < .01) and 0.18 (95% CI: 0.16-0.20, I2 = 43%, P = .03), respectively.

CONCLUSION

The immune checkpoint inhibitors therapy was well tolerated and showed potential to improve tumor responses in patients with metastatic castration-resistant prostate cancer.

Nivolumab plus rucaparib for metastatic castration-resistant prostate cancer: results from the phase 2 CheckMate 9KD trial

BACKGROUND

CheckMate 9KD (NCT03338790) is a non-randomized, multicohort, phase 2 trial of nivolumab plus other anticancer treatments for metastatic castration-resistant prostate cancer (mCRPC). We report results from cohorts A1 and A2 of CheckMate 9KD, specifically evaluating nivolumab plus rucaparib.

METHODS

CheckMate 9KD enrolled adult patients with histologically confirmed mCRPC, ongoing androgen deprivation therapy, and an Eastern Cooperative Oncology Group performance status of 0-1. Cohort A1 included patients with postchemotherapy mCRPC (1-2 prior taxane-based regimens) and ≤2 prior novel hormonal therapies (eg, abiraterone, enzalutamide, apalutamide); cohort A2 included patients with chemotherapy-naïve mCRPC and prior novel hormonal therapy. Patients received nivolumab 480 mg every 4 weeks plus rucaparib 600 mg two times per day (nivolumab dosing ≤2 years). Coprimary endpoints were objective response rate (ORR) per Prostate Cancer Clinical Trials Working Group 3 and prostate-specific antigen response rate (PSA50-RR; ≥50% PSA reduction) in all-treated patients and patients with homologous recombination deficiency (HRD)-positive tumors, determined before enrollment. Secondary endpoints included radiographic progression-free survival (rPFS), overall survival (OS), and safety.

RESULTS

Outcomes (95% CI) among all-treated, HRD-positive, and BRCA1/2-positive populations for cohort A1 were confirmed ORR: 10.3% (3.9-21.2) (n=58), 17.2% (5.8-35.8) (n=29), and 33.3% (7.5-70.1) (n=9); confirmed PSA50-RR: 11.9% (5.9-20.8) (n=84), 18.2% (8.2-32.7) (n=44), and 41.7% (15.2-72.3) (n=12); median rPFS: 4.9 (3.7-5.7) (n=88), 5.8 (3.7-8.4) (n=45), and 5.6 (2.8-15.7) (n=12) months; and median OS: 13.9 (10.4-15.8) (n=88), 15.4 (11.4-18.2) (n=45), and 15.2 (3.0-not estimable) (n=12) months. For cohort A2 they were confirmed ORR: 15.4% (5.9-30.5) (n=39), 25.0% (8.7-49.1) (n=20), and 33.3% (7.5-70.1) (n=9); confirmed PSA50-RR: 27.3% (17.0-39.6) (n=66), 41.9 (24.5-60.9) (n=31), and 84.6% (54.6-98.1) (n=13); median rPFS: 8.1 (5.6-10.9) (n=71), 10.9 (6.7-12.0) (n=34), and 10.9 (5.6-12.0) (n=15) months; and median OS: 20.2 (14.1-22.8) (n=71), 22.7 (14.1-not estimable) (n=34), and 20.2 (11.1-not estimable) (n=15) months. In cohorts A1 and A2, respectively, the most common any-grade and grade 3-4 treatment-related adverse events (TRAEs) were nausea (40.9% and 40.8%) and anemia (20.5% and 14.1%). Discontinuation rates due to TRAEs were 27.3% and 23.9%, respectively.

CONCLUSIONS

Nivolumab plus rucaparib is active in patients with HRD-positive postchemotherapy or chemotherapy-naïve mCRPC, particularly those harboring BRCA1/2 mutations. Safety was as expected, with no new signals identified. Whether the addition of nivolumab incrementally improves outcomes versus rucaparib alone cannot be determined from this trial.

TRIAL REGISTRATION NUMBER

NCT03338790.

The Role of Long Non-Coding RNAs in Epithelial-Mesenchymal Transition-Related Signaling Pathways in Prostate Cancer

Prostate cancer (PCa) is one of the most common male malignancies with frequent remote invasion and metastasis, leading to high mortality. Epithelial-mesenchymal transition (EMT) is a fundamental process in embryonic development and plays a key role in tumor proliferation, invasion and metastasis. Numerous long non-coding RNAs (lncRNAs) could regulate the occurrence and development of EMT through various complex molecular mechanisms involving multiple signaling pathways in PCa. Given the importance of EMT and lncRNAs in the progression of tumor metastasis, we recapitulate the research progress of EMT-related signaling pathways regulated by lncRNAs in PCa, including AR signaling, STAT3 signaling, Wnt/β-catenin signaling, PTEN/PI3K/AKT signaling, TGF-β/Smad and NF-κB signaling pathways. Furthermore, we summarize four modes of how lncRNAs participate in the EMT process of PCa via regulating relevant signaling pathways.

Chimeric adenoviral (Ad5.F35) and listeria vector prime-boost immunization is safe and effective for cancer immunotherapy

Strategies to augment immunity to self/neoantigens expressed by cancers are urgently needed to expand the proportion of patients benefiting from immunotherapy, particularly for GI cancers where only a fraction of patients respond to immunotherapies. However, current vaccine strategies are limited by poor immunogenicity, pre-existing vector-specific immunity, and vaccine-induced vector-specific immunity. Here, we examined a prime-boost strategy using a chimeric adenoviral vector (Ad5.F35) that resists pre-existing immunity followed by recombinant Listeria monocytogenes (Lm) to amplify immunity to the GI cancer antigen GUCY2C. This previously unexplored combination enhanced the quantity, avidity, polyfunctionality, and antitumor efficacy of GUCY2C-specific effector CD8+ T cells, without toxicity in any tissue, including GUCY2C-expressing intestines and brain. Importantly, this combination was partially resistant to pre-existing immunity to Ad5 which is endemic in human populations and vector-specific immunity did not limit the ability of multiple Lm administrations to repeatedly enhance GUCY2C-specific responses. Broadly, these findings suggest that cancer patient immunizations targeting self/neoantigens, as well as immunizations for difficult infectious diseases (HIV, malaria, etc), may be most successful using a combination of Ad5.F35-based priming, followed by Lm-based boosting. More specifically, Lm-GUCY2C may be utilized to amplify GUCY2C-specific immunity in patients receiving adenovirus-based GUCY2C vaccines currently in clinical trials to prevent or treat recurrent GI cancer.

Neoadjuvant immunotherapy across cancers: meeting report from the Immunotherapy Bridge-December 1st-2nd, 2021

After the success of immunotherapy in the treatment of advanced metastatic cancer, further evaluation in earlier settings, including high-risk, surgically-resectable disease is underway. Potential benefits of a neoadjuvant immunotherapeutic approach include presurgical tumor shrinkage, reduced surgical morbidity, early eradication of micrometastases and prevention of distant disease, and greater antigen-specific T cell response. For some cancers, pathologic response has been established as a surrogate measure for long-term outcomes, therefore offering the ability for early and objective assessment of treatment efficacy and the potential to inform and personalize adjuvant treatment clinical decision-making. Leveraging the neoadjuvant treatment setting offers the ability to deeply interrogate longitudinal tissue in order to gain translatable, pan-malignancy insights into response and mechanisms of resistance to immunotherapy. Neoadjuvant immunotherapy across cancers was a focus of discussion at the virtual Immunotherapy Bridge meeting (December 1-2, 2021). Clinical, biomarker, and pathologic insights from prostate, breast, colon, and non-small-cell lung cancers, melanoma and non-melanoma skin cancers were discussed and are summarized in this report.

The androgen receptor is a therapeutic target in desmoplastic small round cell sarcoma

Desmoplastic small round cell tumor (DSRCT) is an aggressive, usually incurable sarcoma subtype that predominantly occurs in post-pubertal young males. Recent evidence suggests that the androgen receptor (AR) can promote tumor progression in DSRCTs. However, the mechanism of AR-induced oncogenic stimulation remains undetermined. Herein, we demonstrate that enzalutamide and AR-directed antisense oligonucleotides (AR-ASO) block 5α-dihydrotestosterone (DHT)-induced DSRCT cell proliferation and reduce xenograft tumor burden. Gene expression analysis and chromatin immunoprecipitation sequencing (ChIP-seq) were performed to elucidate how AR signaling regulates cellular epigenetic programs. Remarkably, ChIP-seq revealed novel DSRCT-specific AR DNA binding sites adjacent to key oncogenic regulators, including WT1 (the C-terminal partner of the pathognomonic fusion protein) and FOXF1. Additionally, AR occupied enhancer sites that regulate the Wnt pathway, neural differentiation, and embryonic organ development, implicating AR in dysfunctional cell lineage commitment. Our findings have direct clinical implications given the widespread availability of FDA-approved androgen-targeted agents used for prostate cancer.

Androgen receptor can promote tumour progression in desmoplastic small round cell tumour (DSRCT), an aggressive paediatric malignancy that predominantly affects young males. Here, the authors show that DSRCT is an AR-driven malignancy and sensitive to androgen deprivation therapy

Overcoming Immune Resistance With Radiation Therapy in Prostate Cancer

Prostate cancer is the second most common cancer in men and represents a significant healthcare burden worldwide. Therapeutic options in the metastatic castration-resistant setting remain limited, despite advances in androgen deprivation therapy, precision medicine and targeted therapies. In this review, we summarize the role of immunotherapy in prostate cancer and offer perspectives on opportunities for future development, based on current knowledge of the immunosuppressive tumor microenvironment. Furthermore, we discuss the potential for synergistic therapeutic strategies with modern radiotherapy, through modulation of the tumor microenvironment. Emerging clinical and pre-clinical data suggest that radiation can convert immune desert tumors into an inflamed immunological hub, potentially sensitive to immunotherapy.

Sensitive identification of neoantigens and cognate TCRs in human solid tumors

The identification of patient-specific tumor antigens is complicated by the low frequency of T cells specific for each tumor antigen. Here we describe NeoScreen, a method that enables the sensitive identification of rare tumor (neo)antigens and of cognate T cell receptors (TCRs) expressed by tumor-infiltrating lymphocytes. T cells transduced with tumor antigen-specific TCRs identified by NeoScreen mediate regression of established tumors in patient-derived xenograft mice.

Anti-PD-L1 plus enzalutamide does not improve overall survival in prostate cancer

The addition of atezolizumab (anti-PD-L1) to enzalutamide (androgen receptor antagonist) did not prolong survival in metastatic prostate cancer.¹ Efficacy with immunotherapies in prostate cancer will require additional studies to elucidate and target mechanisms of resistance within the prostate tumor microenvironment.

Identification of neoantigens for individualized therapeutic cancer vaccines

Somatic mutations in cancer cells can generate tumour-specific neoepitopes, which are recognized by autologous T cells in the host. As neoepitopes are not subject to central immune tolerance and are not expressed in healthy tissues, they are attractive targets for therapeutic cancer vaccines. Because the vast majority of cancer mutations are unique to the individual patient, harnessing the full potential of this rich source of targets requires individualized treatment approaches. Many computational algorithms and machine-learning tools have been developed to identify mutations in sequence data, to prioritize those that are more likely to be recognized by T cells and to design tailored vaccines for every patient. In this Review, we fill the gaps between the understanding of basic mechanisms of T cell recognition of neoantigens and the computational approaches for discovery of somatic mutations and neoantigen prediction for cancer immunotherapy. We present a new classification of neoantigens, distinguishing between guarding, restrained and ignored neoantigens, based on how they confer proficient antitumour immunity in a given clinical context. Such context-based differentiation will contribute to a framework that connects neoantigen biology to the clinical setting and medical peculiarities of cancer, and will enable future neoantigen-based therapies to provide greater clinical benefit.

Understanding of Immune Escape Mechanisms and Advances in Cancer Immunotherapy

Tumor immune escape has emerged as the most significant barrier to cancer therapy. A thorough understanding of tumor immune escape therapy mechanisms is critical for further improving clinical treatment strategies. Currently, research indicates that combining several immunotherapies can boost antitumor efficacy and encourage T cells to play a more active part in the immune assault. To generate a more substantial therapeutic impact, it can establish an ideal tumor microenvironment (TME), encourage T cells to play a role, prevent T cell immune function reversal, and minimize tumor immune tolerance. In this review, we will examine the mechanisms of tumor immune escape and the limits of tumor immune escape therapy, focusing on the current development of immunotherapy based on tumor immune escape mechanisms. Individualized tumor treatment is becoming increasingly apparent as future treatment strategies. In addition, we forecast the future research direction of cancer and the clinical approach for cancer immunotherapy. It will serve as a better reference for researchers working in cancer therapy research.

A m6Avalue predictive of prostate cancer stemness, tumor immune landscape and immunotherapy response

The molecular mechanisms underpinning prostate cancer (PCa) progression are incompletely understood, and precise stratification of aggressive primary PCa (pri-PCa) from indolent ones poses a major clinical challenge. Here, we comprehensively dissect, genomically and transcriptomically, the m⁶A (N ⁶-methyladenosine) pathway as a whole in PCa. Expression, but not the genomic alteration, repertoire of the full set of 24 m⁶A regulators at the population level successfully stratifies pri-PCa into three m⁶A clusters with distinct molecular and clinical features. These three m⁶A modification patterns closely correlate with androgen receptor signaling, stemness, proliferation and tumor immunogenicity of cancer cells, and stroma activity and immune landscape of tumor microenvironment (TME). We observe a discrepancy between a potentially higher neoantigen production and a deficiency in antigen presentation processes in aggressive PCa, offering insights into the failure of immunotherapy. Identification of PCa-specific m⁶A phenotype-associated genes provides a basis for construction of m⁶Avalue to measure m⁶A methylation patterns in individual patients. Tumors with lower m⁶Avalue are relatively indolent with abundant immune cell infiltration and stroma activity. Interestingly, m⁶Avalue separates PCa TME into fibrotic and nonfibrotic phenotypes (instead of previously reported immune-proficient or -desert phenotypes in other cancer types). Significantly, m⁶Avalue can be used to predict drug response and clinical immunotherapy efficacy in both castration-resistant PCa and other cancer types. Therefore, our study establishes m⁶A methylation modification pattern as a determinant in PCa progression via impacting cancer cell aggressiveness and TME remodeling.