Thymic hyperplasia following double immune checkpoint inhibitor therapy in two patients with stage IV melanoma

Characterization of immune checkpoint inhibitor-induced cardiotoxicity reveals interleukin-17A as a driver of cardiac dysfunction after anti-PD-1 treatment

BACKGROUND AND PURPOSE

Immune checkpoint inhibitors (ICI), such as anti-PD-1 monoclonal antibodies, have revolutionized cancer therapy by enhancing the cytotoxic effects of T-cells against tumours. However, enhanced T-cell activity also may cause myocarditis and cardiotoxicity. Our understanding of the mechanisms of ICI-induced cardiotoxicity is limited. Here, we aimed to investigate the effect of PD-1 inhibition on cardiac function and explore the molecular mechanisms of ICI-induced cardiotoxicity.

EXPERIMENTAL APPROACH

C57BL6/J and BALB/c mice were treated with isotype control or anti-PD-1 antibody. Echocardiography was used to assess cardiac function. Cardiac transcriptomic changes were investigated by bulk RNA sequencing. Inflammatory changes were assessed by qRT-PCR and immunohistochemistry in heart, thymus, and spleen of the animals. In follow-up experiments, anti-CD4 and anti-IL-17A antibodies were used along with PD-1 blockade in C57BL/6J mice.

KEY RESULTS

Anti-PD-1 treatment led to cardiac dysfunction and left ventricular dilation in C57BL/6J mice, with increased nitrosative stress. Only mild inflammation was observed in the heart. However, PD-1 inhibition resulted in enhanced thymic inflammatory signalling, where Il17a increased most prominently. In BALB/c mice, cardiac dysfunction was not evident, and thymic inflammatory activation was more balanced. Inhibition of IL-17A prevented anti-PD-1-induced cardiac dysfunction in C57BL6/J mice. Comparing myocardial transcriptomic changes in C57BL/6J and BALB/c mice, differentially regulated genes (Dmd, Ass1, Chrm2, Nfkbia, Stat3, Gsk3b, Cxcl9, Fxyd2, and Ldb3) were revealed, related to cardiac structure, signalling, and inflammation.

CONCLUSIONS

PD-1 blockade induces cardiac dysfunction in mice with increased IL-17 signalling in the thymus. Pharmacological inhibition of IL-17A treatment prevents ICI-induced cardiac dysfunction.

FDG PET/CT for Assessment of Immune Therapy: Opportunities and Understanding Pitfalls

Immune checkpoint blockade has demonstrated the ability to modulate the immune system to produce durable responses in a wide range of cancers and has significantly impacted the standard of care. However, many cancer patients still do not respond to immune checkpoint blockade or have a limited duration of antitumor responses. Moreover, immune-related adverse events caused by immune checkpoint blockade can be severe and debilitating for some patients, limiting continuation of therapy and resulting in severe autoimmune conditions. Standard-of-care conventional anatomic imaging modalities and tumor response criteria have limitations to adequately assess tumor responses, especially early in the course of therapy, for risk-adapted clinical management to inform care of patients treated with immunotherapy. Molecular imaging with position emission tomography (PET) provides a noninvasive functional biomarker of tumor response, and of immune activation, for patients on immune-based therapies to help address these needs. 18F-FDG (FDG) PET/CT is readily available clinically and a number of studies have evaluated the use of this agent for assessment of prognosis, treatment response and immune activation for patients treated with immune checkpoint blockade. In this review paper, we discuss the current oncologic applications and imaging needs of cancer immunotherapy, recent studies applying FDG PET/CT for tumor response assessment, and evaluation of immune-related adverse events for improving clinical management. We largely focus on metastatic melanoma; however, we generalize where applicable to immunotherapy in other tumor types. We also briefly discuss PET imaging and quantitation as well as emerging non-FDG PET imaging radiotracers for cancer immunotherapy imaging.

Anlotinib Exerts Anti-Cancer Effects on KRAS-Mutated Lung Cancer Cell Through Suppressing the MEK/ERK Pathway

Background

With a high frequency of 30%, KRAS mutations in patients with non-small cell lung cancer (NSCLC) often lead to their poor response to most anti-cancer therapies. As a multi-target tyrosine kinase inhibitor, Anlotinib shows clinical efficacy against several types of cancer. However, its effects on KRAS mutant NSCLC and the underlying molecular mechanisms remain unclear.

Materials and Methods

Cell counting Kit-8 assay, colony formation assay, flow cytometry analysis, wound healing scratch assay, Transwell assay and xenograft mouse model were used to evaluate the anti-cancer effects of Anlotinib. The potential molecular mechanisms were determined by immunohistochemistry (IHC) and Western blotting.

Results

Anlotinib inhibited proliferation of KRAS mutant lung cancer cells and induced apoptosis in vitro. In addition, the migration and invasion abilities of these cells were also decreased after treatment with Anlotinib. It significantly suppressed tumor growth in vivo and prolonged the survival of the xenograft-bearing mice, which correlated to lower expression levels of Ki67 in the tumor tissues. Mechanistically, Anlotinib downregulated MEK and ERK as well as their phosphorylated forms in the KRAS mutant lung cancer cells.

Conclusion

Anlotinib inhibits the growth of KRAS mutant lung cancer cells partly via the suppression of the MEK/ERK pathway. Our findings provide novel insights into treating recalcitrant KRAS mutated NSCLC.

Hypophysitis induced by immune checkpoint inhibitors: a 10-year assessment

Introduction: Hypophysitis caused by immune checkpoint inhibitors (ICIs) has risen to the medical attention during the past decade. ICIs are monoclonal antibodies that block the interaction between molecules that normally inhibit the function of effector T cells, ultimately increasing their ability to destroy cancer cells but also causing immune-related adverse events, such as hypophysitis. Ipilimumab, a CTLA-4 blocker, was the first ICI approved from the Food and Drug Administration for advanced melanoma patients in 2011. Several additional ICIs targeting CTLA-4, PD-1, or PD-L1 are now used in many clinical trials, making it important for physicians to recognize and treat hypophysitis adequately.Areas covered: This review will provide insights into the mechanisms of pituitary toxicity, highlight the complexity of clinical phenotypes of ICI hypophysitis, and offer practical recommendations.Expert opinion: ICI hypophysitis differs in many respects from primary hypophysitis, and also according to the type of ICI that caused it. Its pathogenesis remains unknown, although the expression of CTLA-4 and PD-1 on pituitary cells could play a role. The diagnosis is mainly clinical since there are no specific serological markers and MRI findings are subtle. The treatment is based on long-term hormone replacement and does not typically require discontinuation of immunotherapy.