Resistance mechanisms in melanoma to immuneoncologic therapy with checkpoint inhibitors

National Trends in Management of the Nodal Basin for Pediatric Patients With Occult Stage III Melanoma in the United States

BACKGROUND

Following the publication of recent trials (MSLT-I, MSLT-II, DeCOG), routine completion lymph node dissection (CLND) after positive sentinel lymph node biopsy (SLNB) is no longer recommended for adults with melanoma, while adjuvant immunotherapy (IO) was approved for selected patients with positive SLNB. Given the exclusion of pediatric patients from these studies, we aimed to characterize trends in nodal management for pediatric patients with Stage III melanoma.

PROCEDURE

The National Cancer Database (NCDB) was queried for pediatric patients (age ≤20 years) with melanoma (clinical Stage I/II; pathologic Stage III) who underwent resection from 2012 to 2019. The primary objective was to examine trends in the extent of nodal surgery, the number of lymph nodes examined, and adjuvant IO utilization. Secondary objectives included comparing overall survival (OS) by nodal management and receipt of adjuvant IO using Kaplan-Meier methods.

RESULTS

Overall, 98 patients met inclusion criteria. From 2012 to 2019, the percentage of patients receiving SLNB alone increased (from 13% to 89%); conversely, therapeutic lymph node dissection (TLND) decreased (from 60% to 0%), as did CLND (from 27% to 11%). Median lymph nodes examined decreased from 2012 to 2019 (from 22 to 2), while receipt of adjuvant IO increased (from 33% to 44%). OS did not differ by nodal management nor receipt of adjuvant IO.

CONCLUSIONS

The findings of this study support clinical observation after SLNB in pediatric patients with melanoma, as we noted de-escalation in the extent of nodal surgery without compromising OS. We also noted increasing utilization of adjuvant IO among patients with positive SLNB. Multidisciplinary discussion remains vital for managing melanoma in pediatric patients.

Advances in Understanding Drug Resistance Mechanisms and Innovative Clinical Treatments for Melanoma

OPINION STATEMENT

Melanoma, a highly invasive skin cancer resulting from melanocyte malignant transformation, is the third most common skin malignancy. Despite accounting for only 4% to 5% of all skin malignancies, it is responsible for 80% of skin cancer-related deaths. Targeted therapies and immune checkpoint inhibitors have improved survival rates, yet drug resistance remains a major challenge. In this review, I explore the latest research progress on melanoma drug resistance mechanisms and clinical treatment methods. This aims to provide insights for more effective treatment strategies and improve patient prognosis and quality of life. I also discuss potential strategies to overcome drug resistance based on the latest scientific findings, with a particular focus on the complex and multi-factorial drug resistance mechanisms of melanomas, including genetic mutations, epigenetic changes, and tumor microenvironment factors. Understanding these mechanisms is crucial for developing new drugs and combination therapies targeting drug-resistant tumors. Analyzing complex drug resistance pathways paves the way for personalized medical approaches, which is expected to provide enlightenment on breaking through drug resistance barriers and enhancing the effectiveness of melanoma treatment.

E2F1-induced autocrine IL-6 inflammatory loop mediates cancer-immune crosstalk that predicts T cell phenotype switching and therapeutic responsiveness

Melanoma is a metastatic, drug-refractory cancer with the ability to evade immunosurveillance. Cancer immune evasion involves interaction between tumor intrinsic properties and the microenvironment. The transcription factor E2F1 is a key driver of tumor evolution and metastasis. To explore E2F1's role in immune regulation in presence of aggressive melanoma cells, we established a coculture system and utilized transcriptome and cytokine arrays combined with bioinformatics and structural modeling. We identified an E2F1-dependent gene regulatory network with IL6 as a central hub. E2F1-induced IL-6 secretion unleashes an autocrine inflammatory feedback loop driving invasiveness and epithelial-to-mesenchymal transition. IL-6-activated STAT3 physically interacts with E2F1 and cooperatively enhances IL-6 expression by binding to an E2F1-STAT3-responsive promoter element. The E2F1-STAT3/IL-6 axis strongly modulates the immune niche and generates a crosstalk with CD4+ cells resulting in transcriptional changes of immunoregulatory genes in melanoma and immune cells that is indicative of an inflammatory and immunosuppressive environment. Clinical data from TCGA demonstrated that elevated E2F1, STAT3, and IL-6 correlate with infiltration of Th2, while simultaneously blocking Th1 in primary and metastatic melanomas. Strikingly, E2F1 depletion reduces the secretion of typical type-2 cytokines thereby launching a Th2-to-Th1 phenotype shift towards an antitumor immune response. The impact of activated E2F1-STAT3/IL-6 axis on melanoma-immune cell communication and its prognostic/therapeutic value was validated by mathematical modeling. This study addresses important molecular aspects of the tumor-associated microenvironment in modulating immune responses, and will contribute significantly to the improvement of future cancer therapies.

Targeting ULK1 Decreases IFNγ-Mediated Resistance to Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (ICI) have transformed the treatment of melanoma. However, the majority of patients have primary or acquired resistance to ICIs, limiting durable responses and patient survival. IFNγ signaling and the expression of IFNγ-stimulated genes correlate with either response or resistance to ICIs, in a context-dependent manner. While IFNγ-inducible immunostimulatory genes are required for response to ICIs, chronic IFNγ signaling induces the expression of immunosuppressive genes, promoting resistance to these therapies. Here, we show that high levels of Unc-51 like kinase 1 (ULK1) correlate with poor survival in patients with melanoma and overexpression of ULK1 in melanoma cells enhances IFNγ-induced expression of immunosuppressive genes, with minimal effects on the expression of immunostimulatory genes. In contrast, genetic or pharmacologic inhibition of ULK1 reduces expression of IFNγ-induced immunosuppressive genes. ULK1 binds IRF1 in the nuclear compartment of melanoma cells, controlling its binding to the programmed death-ligand 1 promoter region. In addition, pharmacologic inhibition of ULK1 in combination with anti-programmed cell death protein 1 therapy further reduces melanoma tumor growth in vivo. Our data suggest that targeting ULK1 represses IFNγ-dependent immunosuppression. These findings support the combination of ULK1 drug-targeted inhibition with ICIs for the treatment of patients with melanoma to improve response rates and patient outcomes.

IMPLICATIONS

This study identifies ULK1, activated downstream of IFNγ signaling, as a druggable target to overcome resistance mechanisms to ICI therapy in metastatic melanoma.

Photothermic therapy with cuttlefish ink-based nanoparticles in combination with anti-OX40 mAb achieve remission of triple-negative breast cancer

Immunostimulatory monoclonal antibodies (IS-mAb) have been proven to enhance the therapeutic effectiveness of various anticancer therapy. In the present investigation, we launched a separate combinational therapy for the treatment of triple-negative breast cancer (TNBC) using cuttlefish ink-based nanoparticles (CINPs) for photothermal therapy (PTT) and anti-OX40 antibody. Our goal was to increase the therapeutic response to the disease. CINPs were characterized by their physicochemical properties, which revealed that they had a hydrodynamic diameter ranging from 128 to 148 nm, a negative surface charge, and a high photothermal conversion efficiency under both in vitro and in vivo settings. In TNBC model, we evaluated the therapeutic effectiveness of the following groups: CINP-PTT + anti-OX40 Ab (G1), CINPs-PTT (G2), CINPs + anti-OX40 Ab (G3), anti-OX40 (G4) or PBS (G5). In each case, we assessed the efficacy of these groups against one another. The intratumor administration of all of the substances and therapies was performed. CINP-PTT + anti-OX40 Ab and CINP + anti-OX40 Ab (particularly CINP-PTT + anti-OX40 Ab) induced significant tumor regression in treated (breast) and non-treated (flank) tumor, and completely inhibited lung metastasis, thereby inducing a higher survival rate in mice in comparison to CINP-PTT, anti-OX40 Ab, or PBS. This was the case because in CINPs-treated tumors, particularly those treated with CINPs-PTT, intratumoral injection of CINPs increased the frequency of OX40, CD8 double-positive T cells. CINPs improved the conversion of the macrophage phenotype from M2 to M1 in vitro, which is significant from an immunological point of view. In addition, anti-OX40 Ab combined with CINPs or, more specifically, CINPs-PPT produced a larger frequency of preexisting and newly formed tumor-specific CD8 T cells, as well as an enhanced frequency of CD8 T cells infiltrating non-treated tumors, in comparison to respective monotherapies. When the data were taken into consideration as a whole, it seemed that CINPs-based PTT may effectively enhance the antitumor response effectiveness of anti-OX40 Ab.

Intersection of FcγRIIB, the microbiome, and checkpoint inhibitors in antitumor immunity

Fc receptors (FcRs) and the microbiome are both known to have an effect on the development and progression of cancers. Checkpoint inhibitors are a novel class of therapeutics which are used to combat cancer and are integrally linked to both FcRs and the microbiome. The use of checkpoint inhibitors has grown exponentially over the past decade, although many host factors affect both the efficacy and the safety of these therapeutics. Some of these host factors, including the microbiome and the expression of FcRs, are currently being investigated. Here we discuss the current understanding of FcRs (particularly the inhibitory FcγRIIB) and the microbiome in context of T cell immunity, inflammation, cancer, and checkpoint inhibition.