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Chemerin [ [retinoic acid receptor responder 2], TIG2 [tazarotene induced gene 2 (TIG2)]] is a multifunctional cytokine initially described in skin cultures upon exposure to the synthetic retinoid tazarotene. Its secreted pro-form, prochemerin, is widely expressed, found systemically, and is readily converted into active chemerin by various proteases. Subsequent studies elucidated major roles of chemerin as both a leukocyte chemoattractant as well as an adipokine. Chemerin's main chemotactic receptor, the G-protein coupled receptor CMKLR1, is expressed on macrophages, dendritic, and NK cells. With respect to its role in immunology, chemerin mediates trafficking of these cells to sites of inflammation along its concentration gradient, and likely helps coordinate early responses, as it has been shown to have antimicrobial and angiogenic properties, as well. Recently, there has been mounting evidence that chemerin is an important factor in various cancers. As with its role in immune responses-where it can act as both a pro- and anti-inflammatory mediator-the potential functions or correlations chemerin has in or with cancer appears to be context dependent. Most studies, however, suggest a downregulation or loss of chemerin/ in malignancies compared to the normal tissue counterparts. Here, we perform a comprehensive review of the literature to date and summarize relevant findings in order to better define the roles of chemerin in the setting of the tumor microenvironment and tumor immune responses, with an ultimate focus on the potential for therapeutic intervention.

Imaging Mass Cytometry (IMC) is an emerging multiplexed imaging technology for analyzing complex microenvironments using more than 40 molecularly-specific channels. However, this modality has unique data processing requirements, particularly for patient tissue specimens where signal-to-noise ratios for markers can be low, despite optimization, and pixel intensity artifacts can deteriorate image quality and downstream analysis. Here we demonstrate an automated content-aware pipeline, IMC-Denoise, to restore IMC images deploying a differential intensity map-based restoration (DIMR) algorithm for removing hot pixels and a self-supervised deep learning algorithm for shot noise image filtering (DeepSNiF). IMC-Denoise outperforms existing methods for adaptive hot pixel and background noise removal, with significant image quality improvement in modeled data and datasets from multiple pathologies. This includes in technically challenging human bone marrow; we achieve noise level reduction of 87% for a 5.6-fold higher contrast-to-noise ratio, and more accurate background noise removal with approximately 2 × improved F1 score. Our approach enhances manual gating and automated phenotyping with cell-scale downstream analyses. Verified by manual annotations, spatial and density analysis for targeted cell groups reveal subtle but significant differences of cell populations in diseased bone marrow. We anticipate that IMC-Denoise will provide similar benefits across mass cytometric applications to more deeply characterize complex tissue microenvironments. Multiplexed imaging technologies can reveal the complex cellular and molecular profiles of tissue. Here, the authors develop and implement a denoising pipeline to significantly enhance imaging mass cytometry quality and improve single-cell analyses.

Although most prostate cancers are localized, and the majority are curable, recurrences occur in approximately 35% of men. Among patients with prostate-specific antigen (PSA) recurrence and PSA doubling time (PSADT) less than 15 months after radical prostatectomy, prostate cancer accounted for approximately 90% of the deaths by 15 years after recurrence. An immunosuppressive tumor microenvironment (TME) and impaired cellular immunity are likely largely responsible for the limited utility of checkpoint inhibitors (CPIs) in advanced prostate cancer compared with other tumor types. Thus, for immunologically “cold” malignancies such as prostate cancer, clinical trial development has pivoted towards novel approaches to enhance immune responses. Numerous clinical trials are currently evaluating combination immunomodulatory strategies incorporating vaccine-based therapies, checkpoint inhibitors, and chimeric antigen receptor (CAR) T cells. Other trials evaluate the efficacy and safety of these immunomodulatory agents’ combinations with standard approaches such as androgen deprivation therapy (ADT), taxane-based chemotherapy, radiotherapy, and targeted therapies such as tyrosine kinase inhibitors (TKI) and poly ADP ribose polymerase (PARP) inhibitors. Here, we will review promising immunotherapies in development and ongoing trials for metastatic castration-resistant prostate cancer (mCRPC). These novel trials will build on past experiences and promise to usher a new era to treat patients with mCRPC.

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. Immune checkpoint blockade is showing promise in cancer immune therapy, but many solid tumours are resistant. Authors here identify a pathway in T cells that leads to increased activity of C-terminal Src kinase, a negative regulator of T cell activity, thus disabling tumour infiltrating T cells and causing immune therapy resistance.

Opinion Statement The treatment landscape for metastatic castration-resistant prostate cancer (mCRPC) is rapidly evolving with the advent of PSMA-targeted radioligand therapies (RLTs) and bispecific T-cell engagers (BiTEs). These novel approaches provide new hope for patients who have progressed on standard therapies. However, their full clinical potential will be realized only by addressing key challenges, including tumor heterogeneity, resistance mechanisms, immune-related toxicities, and the immunosuppressive tumor microenvironment. Additionally, the optimal sequencing of these therapies at different stages of disease remains an open question. While most of these interventions are currently introduced in late-stage, heavily pretreated patients, ongoing clinical trials are exploring their role in earlier disease settings, where they may be more effective in altering the natural history of disease. PSMA-based RLTs, such as 177Lu-PSMA- 617, have demonstrated promising efficacy, particularly in patients with high PSMA expression. However, the presence of PSMA-negative or heterogeneous tumors necessitates the development of additional biomarkers and combination strategies. The ongoing PSMAddition trial may establish RLTs as an earlier-line treatment in hormone-sensitive metastatic prostate cancer, potentially shifting the standard of care. Moreover, mitigating toxicities through radioprotective agents may aid in expanding their clinical utility. BiTE therapies offer a different but complementary mechanism of action, leveraging T-cell engagement to drive tumor cell destruction. While cytokine release syndrome (CRS) and immunogenicity remain significant hurdles, modifications such as low-affinity CD3 binding and optimized dosing regimens are showing promise. The potential synergy of BiTEs with immune checkpoint inhibitors and tumor microenvironment-modulating agents should be further explored to enhance therapeutic efficacy. Given these advancements, the future of mCRPC treatment likely lies in a personalized, multimodal approach that integrates PSMA-based RLTs, BiTEs, and complementary therapies at earlier disease stages. Strategic biomarker-driven patient selection and combination regimens will be essential in optimizing outcomes while minimizing resistance and toxicity.

Infiltration of immune cells into the tumor microenvironment (TME) can regulate growth and survival of neoplastic cells, impacting tumorigenesis and tumor progression. Correlations between the number of effector immune cells present in a tumor and clinical outcomes in many human tumors, including breast, have been widely described. Current immunotherapies utilizing checkpoint inhibitors or co-stimulatory molecule agonists aim to activate effector immune cells. However, tumors often lack adequate effector cell numbers within the TME, resulting in suboptimal responses to these agents. Chemerin ( ) is a leukocyte chemoattractant widely expressed in many tissues and is known to recruit innate leukocytes. CMKLR1 is a chemotactic cellular receptor for chemerin and is expressed on subsets of dendritic cells, NK cells, and macrophages. We have previously shown that chemerin acts as a tumor suppressive cytokine in mouse melanoma models by recruiting innate immune defenses into the TME. Chemerin/ is down-regulated in many tumors, including breast, compared to normal tissue counterparts. Here, using a syngeneic orthotopic EMT6 breast carcinoma model, we show that forced overexpression of chemerin by tumor cells results in significant recruitment of NK cells and T cells within the TME. While chemerin secretion by EMT6 cells did not alter their phenotypic behavior , it did significantly suppress tumor growth . To define the cellular effectors required for this anti-tumor phenotype, we depleted NK cells or CD8+ T cells and found that either cell type is required for chemerin-dependent suppression of EMT6 tumor growth. Finally, we show significantly reduced levels of mRNA in human breast cancer samples compared to matched normal tissues. Thus, for the first time we have shown that increasing chemerin expression within the breast carcinoma TME can suppress growth by recruitment of NK and T cells, thereby supporting this approach as a promising immunotherapeutic strategy.

Cell-based immune therapies ranging from CAR-T cells to tumor infiltrating lymphocytes (TILs) and endogenous T-cell products, have produced unprecedented clinical responses in hematologic malignancies and are currently under active investigation for solid tumors. Nevertheless, several key challenges continue to limit the durability and breadth of clinical benefit. IL-7 is a pleiotropic cytokine that increases both the number and function of lymphocytes. Although not yet clinically approved, IL-7 has been used in over 620 adult and pediatric patients for a variety of reasons including, for example, to hasten bone marrow recovery after allogenic stem cell transplantation, to reverse lymphopenia due to HIV and idiopathic etiologies, to treat patients with various malignancies, and to boost vaccine responses. IL-7 is generally well-tolerated and effective in producing a durable increase in the number and function of CD4 and CD8 T cells. Recently, IL-7 has been used clinically in multiple myeloma patients receiving CAR-T cell therapy, in patients with urothelial cancer who are receiving checkpoint inhibitors, in patients undergoing endogenous lymphocyte cell therapy, and in critically-ill lymphopenic patients with COVID-19. The authors, all of whom have used IL-7 clinically, discuss how IL-7 effectively addresses all the major problems currently limiting adoptive cell therapies. Peering into the future, we believe that IL-7 will be a major advance as an adjuvant treatment in many cell therapies and hope that this commentary will expedite IL-7’s testing in multiple clinical settings.

Background Pancreatic ductal adenocarcinoma (PDAC) exhibits a profoundly immunosuppressive tumour microenvironment (TME) dominated by inflammatory monocytes (IMs) and tumour-associated macrophages (TAMs), which restrict adaptive immunity and drive resistance to immune checkpoint blockade (ICB). Recruitment of CCR2⁺ IMs by tumour-derived CCL2 is a central mechanism underlying TAM accumulation. Conventional gemcitabine (GEM) and small-molecule CCR2 inhibitors provide limited benefit due to poor intratumoural delivery, transient target engagement, and compensatory myeloid recruitment. Methods We engineered a CCR2-targeted nanotheranostic by conjugating a CCR2-binding peptide (ECL1i) and GEM onto ultrasmall copper nanoclusters (CuNCs-ECL1i-GEM; C-E-G). Therapeutic efficacy and immune remodelling were evaluated using orthotopic subcutaneous and the autochthonous PDAC mouse models model, using scRNAseq, flow cytometry, multiplex immunohistochemistry, and in vitro functional assays. Results C-E-G exhibited robust tumour accumulation and selectively eliminated CCR2⁺ TAMs without systemic myelotoxicity, while durably reprogramming residual macrophages. Mechanistically, C-E-G induced the emergence of an immunostimulatory CCRL2⁺ TAM subset through true macrophage repolarization rather than monocyte replacement. CCRL2⁺ TAMs accumulated intratumoural chemerin, upregulated antigen-presentation and co-stimulatory programs, and were essential for CD8⁺ T-cell recruitment and activation. Genetic and orthotopic studies confirmed their CCR2-independent origin and requirement for tumour control. C-E-G remodelled the TME toward a lymphocyte-permissive inflammatory state and synergized with ICB to induce complete tumour regression and prolong survival in KPPC mice. Conclusions CCR2-targeted cytotoxic nanotherapy eliminates immunosuppressive CCR2 + TAMs, reprograms the macrophage landscape including CCRL2⁺ TAMs, and unlocks durable anti-tumour immunity in PDAC, supporting translational development of this strategy.

BackgroundSipuleucel-T (sip-T) is a Food and Drug Administration (FDA)-approved autologous cellular immunotherapy for metastatic castration-resistant prostate cancer (mCRPC). We hypothesized that combining sip-T with interleukin (IL)-7, a homeostatic cytokine that enhances both B and T cell development and proliferation, would augment and prolong antigen-specific immune responses against both PA2024 (the immunogen for sip-T) and prostatic acid phosphatase (PAP).MethodsFifty-four patients with mCRPC treated with sip-T were subsequently enrolled and randomized 1:1 into observation (n=26) or IL-7 (n=28) arms of a phase II clinical trial (NCT01881867). Recombinant human (rh) IL-7 (CYT107) was given weekly×4. Immune responses were evaluated using flow cytometry, mass cytometry (CyTOF), interferon (IFN)-γ ELISpot, 3H-thymidine incorporation, and ELISA.ResultsTreatment with rhIL-7 was well tolerated. For the rhIL-7-treated, but not observation group, statistically significant lymphocyte subset expansion was found, with 2.3–2.6-fold increases in CD4+T, CD8+T, and CD56bright NK cells at week 6 compared with baseline. No significant differences in PA2024 or PAP-specific T cell responses measured by IFN-γ ELISpot assay were found between rhIL-7 and observation groups. However, antigen-specific T cell proliferative responses and humoral IgG and IgG/IgM responses significantly increased over time in the rhIL-7-treated group only. CyTOF analyses revealed pleiotropic effects of rhIL-7 on lymphocyte subsets, including increases in CD137 and intracellular IL-2 and IFN-γ expression. While not powered to detect clinical outcomes, we found that 31% of patients in the rhIL-7 group had prostate specific antigen (PSA) doubling times of >6 months, compared with 14% in the observation group.ConclusionsTreatment with rhIL-7 led to a significant expansion of CD4+ and CD8+ T cells, and CD56bright natural killer (NK) cells compared with observation after treatment with sip-T. The rhIL-7 treatment also led to improved antigen-specific humoral and T cell proliferative responses over time as well as to increased expression of activation markers and beneficial cytokines. This is the first study to evaluate the use of rhIL-7 after sip-T in patients with mCRPC and demonstrates encouraging results for combination approaches to augment beneficial immune responses.

BackgroundCheckMate 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.MethodsCheckMate 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.ResultsOutcomes (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.ConclusionsNivolumab 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 numberNCT03338790.