Immune-checkpoint inhibitors in melanoma and kidney cancer: from sequencing to rational selection

Doxorubicin-Loaded Platelet Decoys for Enhanced Chemoimmunotherapy Against Triple-Negative Breast Cancer in Mice Model

Introduction

Triple-negative breast cancer (TNBC) is a highly aggressive subtype with a poor prognosis. Current single-agent checkpoint therapy has limited effectiveness in TNBC patients. In this study, we developed doxorubicin-loaded platelet decoys (PD@Dox) for chemotherapy and induction of tumor immunogenic cell death (ICD). By combining PD-1 antibody, PD@Dox has the potential to enhance tumor therapy through chemoimmunotherapy in vivo.

Methods

Platelet decoys were prepared using 0.1% Triton X-100 and co-incubated with doxorubicin to obtain PD@Dox. Characterization of PDs and PD@Dox was performed using electron microscopy and flow cytometry. We evaluated the properties of PD@Dox to retain platelets through sodium dodecyl sulfate-polyacrylamide gel electrophoresis, flow cytometry, and thromboelastometry. In vitro experiments assessed drug-loading capacity, release kinetics, and the enhanced antitumor activity of PD@Dox. The mechanism of PD@Dox was investigated through cell viability assays, apoptosis assays, Western blot analysis, and immunofluorescence staining. In vivo studies were performed using a TNBC tumor-bearing mouse model to assess the anticancer effects.

Results

Electron microscopic observations confirmed that platelet decoys and PD@Dox exhibited a round shape similar to normal platelets. Platelet decoys demonstrated superior drug uptake and loading capacity compared to platelets. Importantly, PD@Dox retained the ability to recognize and bind tumor cells. The released doxorubicin induced ICD, resulting in the release of tumor antigens and damage-related molecular patterns that recruit dendritic cells and activate antitumor immunity. Notably, the combination of PD@Dox and immune checkpoint blockade therapy using PD-1 antibody achieved significant therapeutic efficacy by blocking tumor immune escape and promoting ICD-induced T cell activation.

Conclusion

Our results suggest that PD@Dox, in combination with immune checkpoint blockade therapy, holds promise as a potential strategy for TNBC treatment.

Captopril, a Renin-Angiotensin System Inhibitor, Attenuates Tumour Progression in the Regenerating Liver Following Partial Hepatectomy

(1) Liver regeneration following partial hepatectomy for colorectal liver metastasis (CRLM) has been linked to tumour recurrence. Inhibition of the renin−angiotensin system (RASi) attenuates CRLM growth in the non-regenerating liver. This study investigates whether RASi exerts an antitumour effect within the regenerating liver following partial hepatectomy for CRLM and examines RASi-induced changes in the tumour immune microenvironment; (2) CRLM in mice was induced via intrasplenic injection of mouse colorectal tumour cells, followed by splenectomy on Day 0. Mice were treated with RASi captopril (250 mg/kg/day), or saline (control) from Day 4 to Day 16 (endpoint) and underwent 70% partial hepatectomy on Day 7. Liver and tumour samples were characterised by flow cytometry and immunofluorescence; (3) captopril treatment reduced tumour burden in mice following partial hepatectomy (p < 0.01). Captopril treatment reduced populations of myeloid-derived suppressor cells (MDSCs) (CD11b+Ly6CHi p < 0.05, CD11b+Ly6CLo p < 0.01) and increased PD-1 expression on infiltrating hepatic tissue-resident memory (TRM)-like CD8+ (p < 0.001) and double-negative (CD4-CD8-; p < 0.001) T cells; (4) RASi reduced CRLM growth in the regenerating liver and altered immune cell composition by reducing populations of immunosuppressive MDSCs and boosting populations of PD-1+ hepatic TRMs. Thus, RASi should be explored as an adjunct therapy for patients undergoing partial hepatectomy for CRLM.

CCR5 blockade inflames antitumor immunity in BAP1-mutant clear cell renal cell carcinoma

Background

Patients with BRCA1-associated protein 1 (BAP1)-mutant clear cell renal cell carcinoma (ccRCC) have worse prognosis. C-C chemokine receptor 5 (CCR5) plays an important role in ccRCC development and its expression is elevated in BAP1-mutant tumors.

Methods

533 patients with ccRCC from The Cancer Genome Atlas cohort and 797 patients with ccRCC from the Shanghai cohort were enrolled. In vitro and in vivo studies were conducted with human ccRCC tumors and murine tumor models. The association between BAP1 and CCR5 or its ligands was assessed by immunohistochemistry, flow cytometry, real-time PCR and ELISA. Survival was compared between different subpopulations of patients using Kaplan-Meier curve. Therapeutic effect of CCR5 blockade was validated using human ccRCC tumors and murine models.

Results

Expression of CCR5 and its ligands were elevated in BAP1-mutant patients with ccRCC. High CCR5 expression was indicative of poor prognosis in BAP1-low group of patients. CCR5 blockade prolonged the survival of tumor-bearing mice, resulting in enhanced cytotoxicity of T cells and antigen presentation of dendritic cells but repressed immune checkpoint expression. CCR5 ligands could recruit CCR5⁺ regulatory T cells to the tumor microenvironment. Additionally, BAP1-mutant ccRCC tumor cells secreted CCR5 ligands, which increased programmed cell death ligand 1 expression. However, both processes could be inhibited by CCR5 blockade. Study limitations include the unclear impact of CCR5 expressed by other cell populations.

Conclusions

CCR5 in BAP1-mutant ccRCC results in an immune-suppressive microenvironment. Targeting CCR5 could provide a potential therapeutic benefit for patients.

Trial registration number

NCT01358721, CA209-009.

The PI3K/mTOR Pathway Is Targeted by Rare Germline Variants in Patients with Both Melanoma and Renal Cell Carcinoma

Background: Malignant melanoma and RCC have different embryonic origins, no common lifestyle risk factors but intriguingly share biological properties such as immune regulation and radioresistance. An excess risk of malignant melanoma is observed in RCC patients and vice versa. This bidirectional association is poorly understood, and hypothetic genetic co-susceptibility remains largely unexplored. Results: We hereby provide a clinical and genetic description of a series of 125 cases affected by both malignant melanoma and RCC. Clinical germline mutation testing identified a pathogenic variant in a melanoma and/or RCC predisposing gene in 17/125 cases (13.6%). This included mutually exclusive variants in MITF (p.E318K locus, N = 9 cases), BAP1 (N = 3), CDKN2A (N = 2), FLCN (N = 2), and PTEN (N = 1). A subset of 46 early-onset cases, without underlying germline variation, was whole-exome sequenced. In this series, thirteen genes were significantly enriched in mostly exclusive rare variants predicted to be deleterious, compared to 19,751 controls of similar ancestry. The observed variation mainly consisted of novel or low-frequency variants (<0.01%) within genes displaying strong evolutionary mutational constraints along the PI3K/mTOR pathway, including PIK3CD, NFRKB, EP300, MTOR, and related epigenetic modifier SETD2. The screening of independently processed germline exomes from The Cancer Genome Atlas confirmed an association with melanoma and RCC but not with cancers of established differing etiology such as lung cancers. Conclusions: Our study highlights that an exome-wide case-control enrichment approach may better characterize the rare variant-based missing heritability of multiple primary cancers. In our series, the co-occurrence of malignant melanoma and RCC was associated with germline variation in the PI3K/mTOR signaling cascade, with potential relevance for early diagnostic and clinical management.

Tumor-associated Macrophage-derived Interleukin-23 Interlinks Kidney Cancer Glutamine Addiction with Immune Evasion

BACKGROUND

Glutamine addiction is a hallmark of clear cell renal cell carcinoma (ccRCC); yet whether glutamine metabolism impacts local immune surveillance is unclear. This knowledge may yield novel immunotherapeutic opportunities.

OBJECTIVE

To seek a potential therapeutic target in glutamine-addicted ccRCC.

DESIGN, SETTING, AND PARTICIPANTS

Tumors from ccRCC patients from a Shanghai cohort and ccRCC tumor data from The Cancer Genome Atlas (TCGA) cohort were analyzed. In vivo and in vitro studies were conducted with fresh human ccRCC tumors and murine tumor cells.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Immune cell numbers and functions were analyzed by flow cytometry. Glutamine and cytokine concentrations were determined. Survival was compared between different subpopulations of patients using Kaplan-Meier and Cox regression analyses.

RESULTS AND LIMITATIONS

We found that in ccRCC, high interleukin (IL)-23 expression was significantly associated with poor survival in both TCGA (overall survival [OS] hazard ratio [HR]=2.04, cancer-specific survival [CSS] HR=2.95; all p<0.001) and Shanghai (OS HR=2.07, CSS HR=3.92; all p<0.001) cohorts. IL-23 blockade prolongs the survival of tumor-bearing mice, promotes T-cell cytotoxicity in in vitro cultures of human ccRCC tumors, and augments the therapeutic benefits of anti-PD-1 antibodies. Mechanistically, glutamine consumption by ccRCC tumor cells results in the local deprivation of extracellular glutamine, which induces IL-23 secretion by tumor-infiltrating macrophages via the activation of hypoxia-inducible factor 1α (HIF1α). IL-23 activates regulatory T-cell proliferation and promotes IL-10 and transforming growth factor β expression, thereby suppressing tumor cell killing by cytotoxic lymphocytes. The positive correlations between glutamine metabolism, IL-23 levels, and Treg responses are confirmed in both TCGA cohort and tumors from Shanghai ccRCC patients. Study limitations include the unclear impacts of glutamine deprivation and IL-23 on other immune cells.

CONCLUSIONS

Macrophage-secreted IL-23 enhanced Treg functions in glutamine-addicted tumors; thus, IL-23 is a promising target for immunotherapy in ccRCC.

PATIENT SUMMARY

In this study, we analyzed the immune components in glutamine-addicted clear cell renal cell carcinoma (ccRCC) tumors from two patient cohorts and conducted both in vitro and in vivo studies. We found that ccRCC tumor cell-intrinsic glutamine metabolism orchestrates immune evasion via interleukin (IL)-23, and IL-23-high patients had significantly poorer survival than IL-23-low patients. IL-23 should thus be considered a therapeutic target in ccRCC, either alone or in combination with immune checkpoint inhibitors.