Membrane bound IL-21 based NK cell feeder cells drive robust expansion and metabolic activation of NK cells.

NK cell adoptive therapy is a promising cancer therapeutic approach, but there are significant challenges that limiting its feasibility and clinical efficacy. One difficulty is the paucity of clinical grade manufacturing platforms to support the large scale expansion of highly active NK cells. We created an NK cell feeder cell line termed 'NKF' through overexpressing membrane bound IL-21 that is capable of inducing robust and sustained proliferation (>10,000-fold expansion at 5 weeks) of highly cytotoxic NK cells. The expanded NK cells exhibit increased cytotoxic function against a panel of blood cancer and solid tumor cells as compared to IL-2-activated non-expanded NK cells. The NKF-expanded NK cells also demonstrate efficacy in mouse models of human sarcoma and T cell leukemia. Mechanistic studies revealed that membrane-bound IL-21 leads to an activation of a STAT3/c-Myc pathway and increased NK cell metabolism with a shift towards aerobic glycolysis. The NKF feeder cell line is a promising new platform that enables the large scale proliferation of highly active NK cells in support of large scale third party NK cell clinical studies that have been recently intiatied. These results also provide mechanistic insights into how membrane-bound IL-21 regulates NK cell expansion.

Scalp Dermatitis in Patients Sensitized to Components of Hair Products.

BACKGROUND: Allergic contact dermatitis is an inflammatory condition that less commonly presents with scalp involvement. Recently, T regulatory cells have been documented to be residents of hair follicles, illuminating why contact allergens are less likely to elicit dermatitis in the scalp. OBJECTIVE: The aims of the study were to determine the prevalence of scalp symptoms, with and without other affected areas, in patients presenting for evaluation of allergic contact dermatitis and to determine the allergens most likely to be associated with scalp dermatitis. METHODS: We examined allergens commonly found in hair products and stratified positive patch test results by the following affected areas: face, eyelid, neck, or hands, where exposure by runoff is common, versus scalp. CONCLUSIONS: Para-phenylenediamine (PPD) is the most common allergen in patients with scalp dermatitis. The rate of PPD sensitization is higher in nonwhite compared with white patients. In the small number of patients with isolated scalp involvement, positive patch tests to PPD were documented in a minority. Other allergens found in hair products may present without scalp symptoms. Patients with dermatitis affecting areas other than the scalp should provide their hair product ingredients to guide patch test selection.

Mismatch repair-signature mutations activate gene enhancers across human colorectal cancer epigenomes.

Commonly-mutated genes have been found for many cancers, but less is known about mutations in cis-regulatory elements. We leverage gains in tumor-specific enhancer activity, coupled with allele-biased mutation detection from H3K27ac ChIP-seq data, to pinpoint potential enhancer-activating mutations in colorectal cancer (CRC). Analysis of a genetically-diverse cohort of CRC specimens revealed that microsatellite instable (MSI) samples have a high indel rate within active enhancers. Enhancers with indels show evidence of positive selection, increased target gene expression, and a subset is highly recurrent. The indels affect short homopolymer tracts of A/T and increase affinity for FOX transcription factors. We further demonstrate that signature mismatch-repair (MMR) mutations activate enhancers using a xenograft tumor metastasis model, where mutations are induced naturally via CRISPR/Cas9 inactivation of MLH1 prior to tumor cell injection. Our results suggest that MMR signature mutations activate enhancers in CRC tumor epigenomes to provide a selective advantage.

Correction: Inhibiting TGF-beta signaling preserves the function of highly activated, in vitro expanded natural killer cells in AML and colon cancer models.

[This corrects the article DOI: 10.1371/journal.pone.0191358.].

Inhibiting TGF-beta signaling preserves the function of highly activated, in vitro expanded natural killer cells in AML and colon cancer models.

Natural killer cells harnessed from healthy individuals can be expanded ex vivo using various platforms to produce large doses for adoptive transfer into cancer patients. During such expansion, NK cells are increasingly activated and more efficient at killing cancer cells. Adoptive transfer however introduces these activated cells into a highly immunosuppressive tumor microenvironment mediated in part by excessive transforming growth factor beta (TGF-beta) from both cancer cells and their surrounding stroma. This microenvironment ultimately limits the clinical efficacy of NK cell therapy. In this study, we examined the use of a TGF-beta receptor kinase inhibitor, LY2157299, in preserving the cytotoxic function of ex vivo expanded, highly activated NK cells following sustained exposure to pathologic levels of TGF-beta in vitro and in a liver metastases model of colon cancer. Using myeloid leukemia and colon cancer cell lines, we show that the TGF-beta driven impairment of NK cell cytotoxicity is mitigated by LY2157299. We demonstrate this effect using quantitative cytotoxicity assays as well as by showing a preserved activated phenotype with high NKG2D/CD16 expression and enhanced cytokine production. In a mouse liver metastases model of colon cancer, we observed significantly improved eradication of liver metastases in mice treated with adoptive NK cells combined with LY2157299 compared with mice receiving NK cells or TGF beta inhibition alone. We propose that the therapeutic efficacy of adoptive NK cell therapy clinically will be markedly enhanced by complementary approaches targeting TGF-beta signaling in vivo.