CAR-T cell therapy targeting surface expression of TYRP1 to treat cutaneous and rare melanoma subtypes

A major limitation to developing chimeric antigen receptor (CAR)-T cell therapies for solid tumors is identifying surface proteins highly expressed in tumors but not in normal tissues. Here, we identify Tyrosinase Related Protein 1 (TYRP1) as a CAR-T cell therapy target to treat patients with cutaneous and rare melanoma subtypes unresponsive to immune checkpoint blockade. TYRP1 is primarily located intracellularly in the melanosomes, with a small fraction being trafficked to the cell surface via vesicular transport. We develop a highly sensitive CAR-T cell therapy that detects surface TYRP1 in tumor cells with high TYRP1 overexpression and presents antitumor activity in vitro and in vivo in murine and patient-derived cutaneous, acral and uveal melanoma models. Furthermore, no systemic or off-tumor severe toxicities are observed in an immunocompetent murine model. The efficacy and safety profile of the TYRP1 CAR-T cell therapy supports the ongoing preparation of a phase I clinical trial.

Antiviral drug screen identifies DNA-damage response inhibitor as potent blocker of SARS-CoV-2 replication

SARS-CoV-2 has currently precipitated the COVID-19 global health crisis. We developed a medium-throughput drug-screening system and identified a small-molecule library of 34 of 430 protein kinase inhibitors that were capable of inhibiting the SARS-CoV-2 cytopathic effect in human epithelial cells. These drug inhibitors are in various stages of clinical trials. We detected key proteins involved in cellular signaling pathways mTOR-PI3K-AKT, ABL-BCR/MAPK, and DNA-damage response that are critical for SARS-CoV-2 infection. A drug-protein interaction-based secondary screen confirmed compounds, such as the ATR kinase inhibitor berzosertib and torin2 with anti-SARS-CoV-2 activity. Berzosertib exhibited potent antiviral activity against SARS-CoV-2 in multiple cell types and blocked replication at the post-entry step. Berzosertib inhibited replication of SARS-CoV-1 and the Middle East respiratory syndrome coronavirus (MERS-CoV) as well. Our study highlights key promising kinase inhibitors to constrain coronavirus replication as a host-directed therapy in the treatment of COVID-19 and beyond as well as provides an important mechanism of host-pathogen interactions.

Skin lesions serve as clues to relapse of pediatric blastic plasmacytoid dendritic cell neoplasm

A 10-year-old girl with a history of blastic plasmacytoid dendritic cell neoplasm, a rare malignancy in children, presented with recurrent skin eruptions beginning while on maintenance chemotherapy, including mildly pruritic skin-colored plaques, tender indurated nodules, and violaceous bound-down plaques. This case highlights an unusual presentation of relapsed blastic plasmacytoid dendritic cell neoplasm on chemotherapy, with skin lesions providing important clues to the progression of systemic disease.

Use of Becaplermin for nondiabetic ulcers: pyoderma gangrenosum and calciphylaxis

Large difficult to heal ulcers of various etiologies carry a high morbidity and mortality rate. Becaplermin is a recombinant platelet-derived growth factor approved for treatment of diabetic ulcers. In this two-case series, we report the use of becaplermin in the treatment of ulcers due to (i) calciphylaxis, an often fatal condition resulting from systemic calcification and thrombosis of vessels and (ii) pyoderma gangrenosum (PG), a neutrophilic dermatosis. We also report that topical collagenase worsened PG ulcers, consistent with pathergy. Becaplermin can be used to help treat ulcers resulting from calciphylaxis and PG. These encouraging results lend support for the utilization of becaplermin in the treatment of nondiabetic chronic ulcers of various etiologies.

Physiologic stress molecules activate an acute phase response and enhance macrophage antimicrobial activity to Mycobacterium leprae (INM3P.411)

Leprosy is a disease caused by the pathogen Mycobacterium leprae (mLEP). Patients can present with the progressive, lepromatous form of the disease or the self-limited, tuberculoid form of the disease. Physiologic stress is thought to inhibit host defense mediated by adrenergic catecholamines and neuroendocrine glucocorticoids. We hypothesize that acute treatment with adrenergic agents or glucocorticoids would inhibit in vitro macrophage mediated antimicrobial activity. Human monocyte-derived macrophages or mouse bone marrow-derived macrophages were treated with the adrenergic agonist metaproterenol hemisulfate (MPH, 1μM) or the glucocorticoid dexamethasone (Dex, 100nM) for two hours followed by LPS (100ng/ml) or mLEP (MOI 5). RNASeq was performed at various time points or an mLEP viability measurement was performed at 24 hours following infection. Unexpectedly, when compared to vehicle (DMSO), pretreatment with MPH resulted in greatly enhanced antimicrobial activity against mLEP, similar to interferon-γ pretreatment, whereas Dex resulted in a more modest induction of antimicrobial activity. Both Dex and MPH did not reduce the expression of the antimicrobial peptide cathelicidin, but did induce a dramatic increase in expression of genes involved in the acute phase response. Our findings suggest that molecules involved in the physiological stress response may be acutely beneficial during initial encounter with mLEP.

Global regulation of Toll-like receptor 4-induced inflammatory gene networks by physiologic stress signals in macrophages (INM7P.356)

Physiologic stress mediated through adrenergic (catecholamines) and neuroendocrine (glucocorticoids) signals negatively impacts cutaneous host defense to pathogens and worsens inflammatory skin conditions such as psoriasis. Toll-like receptors (TLRs) on macrophages and other innate immune cells sense danger signals and trigger innate and adaptive immunity, but whether these stress stimuli affect similar or exclusive TLR-dependent immune pathways is unclear. We hypothesize that quantitative analysis by RNAseq will provide critical information into the mechanism by which stress affects macrophage inflammatory signaling. Using RNASeq, we find distinct regulatory profiles for β-adrenergic agonist and GC on TLR4-mediated inflammatory responses. β-adrenergic stimuli are highly selective inhibitors of a small subset of TLR4-inducible genes, inhibiting less than 15 genes by 5-fold or more (80% inhibition), showing striking selectivity. Three of these genes, Il12b, Il27, and Il6, are induced with similar kinetics and high magnitude, suggesting similar regulation of these genes. In contrast, the glucocorticoid Dexamethasone (Dex) inhibited 22 of the 283 induced genes. Importantly, Dex targeted a different subset of inflammatory genes, including Il1b, Il1a, and Ptgs2. In conclusion, we found that adrenergic and neuroendocrine stress signaling targets distinct macrophage inflammatory responses, which may cooperate to inhibit different immune pathways during a physiologic stress response.

Stem cell quiescence acts as a tumour suppressor in squamous tumours

In some organs, adult stem cells are uniquely poised to serve as cancer cells of origin. It is unclear, however, whether tumorigenesis is influenced by the activation state of the adult stem cell. Hair follicle stem cells (HFSCs) act as cancer cells of origin for cutaneous squamous cell carcinoma (SCC) and undergo defined cycles of quiescence and activation. The data presented here show that HFSCs are unable to initiate tumors during the quiescent phase of the hair cycle, indicating that the mechanisms that keep HFSCs dormant are dominant to the gain of oncogenes (Ras) or the loss of tumor suppressors (p53). Furthermore, Pten activity is necessary for quiescence based tumor suppression, as its deletion alleviates tumor suppression without affecting proliferation. These data demonstrate that stem cell quiescence is a form of tumor suppression in HFSCs, and that Pten plays a role in maintaining quiescence in the presence of tumorigenic stimuli.

Major hepatectomy induces phenotypic changes in circulating dendritic cells and monocytes

INTRODUCTION

Patients undergoing major hepatectomy are at increased risk for post-operative morbidity and mortality, and changes in the phenotype of effector cells may predispose these patients to infectious sequelae.

METHODS

To better understand post-hepatectomy immune responses, peripheral blood from 15 hepatectomy patients was drawn immediately before and after liver resection and on post-operative days 1, 3, and 5. Circulating monocytes and dendritic cells were analyzed by flow cytometry for quantity, phenotype, activation status, human leukocyte antigen DR (HLA-DR) expression, and toll-like receptor-2 and -4 expression.

RESULTS

Major hepatectomy increased the numbers of activated CD16(bright) blood monocytes and the percentage of activated dendritic cells, although monocyte HLA-DR expression was reduced. These results may represent both dysfunctional antigen presentation and pending anergy, as well as cellular priming of immune effector cells. Better understanding of the alterations in innate immunity induced by hepatectomy may identify strategies to reduce infectious outcomes.