Anti-programmed cell death receptor-1 (PD-1) antibodies represent an effective treatment opinion for advanced melanoma and non-small-cell lung cancer, as well as other cancerous entities. Immune checkpoint inhibitors such as anti-PD-1 antibody result in a unique side-effect profile, commonly described as immune-related adverse events (irAE). These irAE affect the skin, gastrointestinal tract, liver, endocrine system and other organ systems. We report two cases of oral lichenoid reaction showing multiple ulcers associated with nivolumab treatment. Both patients presented with multiple ulcers covered with fibrinous plaque over the entire oral mucosa, lips and tongue. Histopathological examination of ulceration showed epithelial necrosis and subepidermal clefts with dense band-like layers of lymphohistiocytic infiltrate within the upper dermis. Nivolumab was interrupted in both cases. Case 1 responded well to topical corticosteroids. Case 2 required oral corticosteroids, however, nivolumab could be restarted without recurrence of oral ulcers. We provide a comprehensive review of reported cases of lichenoid reaction showing multiple oral ulcers associated with anti-PD-1 therapy to date. Early recognition and management may improve treatment, avoid discontinuation of life-saving therapy and maintain quality of life in these patients.

Methionine addiction, a fundamental and general hallmark of cancer, known as the Hoffman Effect, is due to altered use of methionine for increased and aberrant transmethylation reactions. However, the linkage of methionine addiction and malignancy of cancer cells is incompletely understood. An isogenic pair of methionine-addicted parental osteosarcoma cells and their rare methionine-independent revertant cells enabled us to compare them for malignancy, their epithelial-mesenchymal phenotype, and pattern of histone-H3 lysine-methylation. Methionine-independent revertant 143B osteosarcoma cells (143B-R) were selected from methionine-addicted parental cells (143B-P) by their chronic growth in low-methionine culture medium for 4 passages, which was depleted of methionine by recombinant methioninase (rMETase). Cell-migration capacity was compared with a wound-healing assay and invasion capability was compared with a transwell assay in 143B-P and 143B-R cells in vitro. Tumor growth and metastatic potential were compared after orthotopic cell-injection into the tibia bone of nude mice in vivo. Epithelial-mesenchymal phenotypic expression and the status of H3 lysine-methylation were determined with western immunoblotting. 143B-P cells had an IC50 of 0.20 U/ml and 143B-R cells had an IC50 of 0.68 U/ml for treatment with rMETase, demonstrating that 143B-R cells had regained the ability to grow in low methionine conditions. 143B-R cells had reduced cell migration and invasion capability in vitro, formed much smaller tumors than 143B-P cells and lost metastatic potential in vivo, indicating loss of malignancy in 143B-R cells. 143B-R cells showed gain of the epithelial marker, ZO-1 and loss of mesenchymal markers, vimentin, Snail, and Slug and, an increase of histone H3K9me3 and H3K27me3 methylation and a decrease of H3K4me3, H3K36me3, and H3K79me3 methylation, along with their loss of malignancy. These results suggest that shifting the balance in histone methylases might be a way to decrease the malignant potential of cells. The present results demonstrate the rationale to target methionine addiction for improved sarcoma therapy.

The bulge area of the hair follicle contains hair-follicle-associated pluripotent (HAP) stem cells. Here, we present effective cryopreservation procedures of the human hair follicle that preserve the differentiation potential of HAP stem cells. Whole hair follicles isolated from human scalp were cryopreserved by a slow-rate cooling medium and stored in liquid nitrogen. A careful thawing method was used to collect the upper parts of the human hair follicles which were cultured for four weeks in a Dulbecco’s Modified Eagle’s Medium with fetal bovine serum (FBS). Proliferating hair follicle cells were then shifted to DMEM/Ham’s Nutrient Mixture F-12 medium without FBS and allowed to grow for one week. These proliferating cells were able to produce HAP stem cell colonies with multilineage differentiation capacity. They produced keratinocytes, smooth muscle cells, cardiac muscle cells, neurons and glial cells. Interestingly, these cryopreserved hair follicles produced pluripotent HAP stem cell colonies similar to fresh follicles. These findings suggest that the cryopreserved whole human hair follicle preserves the ability to produce HAP stem cells, which will enable any individual to preserve a bank of these stem cells for personalized regenerative medicine.

We have previously demonstrated that nestin-expressing hair follicle-associated-pluripotent (HAP) stem cells are located in the bulge area. HAP stem cells have been previously shown to differentiate to neurons, glial cells, keratinocytes, smooth-muscle cells, melanocytes and cardiac-muscle cells in vitro. Subsequently, we demonstrated that HAP stem cells could effect nerve and spinal cord regeneration in mouse models, differentiating to Schwann cells and neurons. In previous studies, we established an efficient protocol for the differentiation of cardiac-muscle cells from mouse HAP stem cells. In the present study, we isolated the upper part of human hair follicles containing human HAP (hHAP) stem cells. The upper parts of human hair follicles were suspended in DMEM containing 10% FBS where they differentiated to cardiac-muscle cells as well as neurons, glial cells, keratinocytes and smooth-muscle cells. This method is appropriate for future use with human hair follicles to produce hHAP stem cells in sufficient quantities for future heart, nerve and spinal cord regeneration in the clinic.