NK cells are a promising cellular immunotherapy for cancer. Cytokine-induced memory-like (ML) NK cells differentiate after activation with IL-12, IL-15, and IL-18, exhibit potent anti-tumor responses, and safely induce complete remissions in patients with leukemia. However, many cancers are not fully recognized via NK cell receptors. Chimeric antigen receptors (CAR) have been utilized to enhance tumor-specific recognition by effector lymphocytes. We hypothesized that memory-like differentiation and CAR-engineering would result in complementary improvements in NK cell responses against NK-resistant cancers. To test this idea, peripheral blood ML NK cells were modified to express an anti-CD19 CAR (19-CAR-ML), which displayed significantly increased IFN-γ production, degranulation, and specific killing against NK-resistant lymphoma lines and primary targets, compared to non-specific control CAR-ML NK cells or conventional CAR NK cells. The 19-CAR and ML responses were synergistic, CAR-specific, and required ITAM signaling. Furthermore, 19-CAR-ML NK generated from lymphoma patients exhibited improved responses against their autologous lymphoma. 19-CAR-ML NK cells controlled lymphoma burden in vivo and improved survival in human xenograft models. Thus, CAR engineering of ML NK cells enhanced responses against resistant cancers and warrant further investigation, with the potential to broaden ML NK cell recognition against a variety of NK cell-resistant tumors.

SUMMARY Greater than 85% of advanced breast cancer patients suffer from metastatic bone lesions yet the mechanisms that facilitate these metastases remain poorly understood. Recent studies suggest that tumor-derived factors initiate changes within the tumor microenvironment to facilitate metastasis. However, whether stromal-initiated changes are sufficient to drive increased metastasis in the bone remains an open question. Thus, we developed a model to induce reactive senescent osteoblasts and found that they increased breast cancer colonization of the bone. Analysis of senescent osteoblasts revealed that they failed to mineralize bone matrix, and increased local osteoclastogenesis; the latter process being driven by the senescence-associated secretory phenotype factor, IL-6. Neutralization of IL-6 was sufficient to limit senescence-induced osteoclastogenesis and tumor cell localization to bone, thereby reducing tumor burden. Together, these data suggest that a reactive stromal compartment can condition the niche, in the absence of tumor-derived signals, to facilitate metastatic tumor growth in the bone.

Summary The multi-domain scaffolding protein Scribble (Scrib) organizes key signaling complexes to specify basolateral cell polarity and suppress aberrant growth. In many human cancers, genetically normal Scrib mislocalizes from cell–cell junctions to the cytosol, correlating with enhanced growth signaling and malignancy. Here we confirm that expression of the epithelial-to-mesenchymal transcription factor (EMT-TF) Snail in benign epithelial cells leads to Scrib displacement from the plasma membrane, mimicking the mislocalization observed in aggressive cancers. Upon further examination, Snail promotes a transcriptional program that targets genes in the palmitoylation cycle, repressing many protein acyl transferases and elevating expression and activity of protein acyl thioesterase 2 (APT2). APT2 isoform-selective inhibition or knockdown rescued Scrib membrane localization and palmitoylation while attenuating MEK activation. Overall, inhibiting APT2 restores balance to the Scrib palmitoylation cycle, promoting membrane re-localization and growth attenuation. These findings emphasize the importance of S-palmitoylation as a post-translational gatekeeper of cell polarity-mediated tumor suppression.

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IMPORTANCE Better biomarkers are needed for human papillomavirus (HPV)-negative oropharyngeal cancer (OPC) to identify patients at risk of recurrence. Lymphopenia and an elevated ratio of neutrophils to lymphocytes (NLR) have been associated with poor disease outcomes in a number of solid tumors. OBJECTIVE To test the hypothesis that postradiotherapy lymphopenia and elevated NLR are associated with poor clinical outcomes. DESIGN, SETTING, AND PARTICIPANTS This single-institution retrospective analysis included patients with HPV-negative OPC treated from January 1, 1997, through January 4, 2017. Median follow-up was 37 months (range, 2-197 months). A total of 108 patients with HPV-negative OPC and at least 1 complete blood cell count 2 to 12 months after the start of radiotherapy were included. Data were analyzed from August 26 to September 7, 2017. INTERVENTIONS Surgery followed by radiotherapy vs definitive radiotherapy, with or without chemotherapy. MAIN OUTCOMES AND MEASURES Absolute lymphocyte (ALC) and absolute neutrophil (ANC) counts were tested as variables affecting locoregional control, recurrence-free survival, and overall survival. RESULTS Of a total of 108 patients included in the analysis (87.0% male; mean age, 56 years [range, 35-84 years]), 57 received surgery followed by postoperative radiotherapy and 51 received definitive radiotherapy. During treatment, 67 of 79 patients (84.8%) had grades 3 to 4 lymphopenia and 17 of 79 (21.5%) had grade 4 lymphopenia. The ANC recovered by 6 months after radiotherapy, but ALC remained depressed to 1 year after radiotherapy. Posttreatment lymphopenia and elevated NLR were associated with worse recurrence-free and overall survival. The estimated 3-year LRC in patients with and without grades 3 to 4 lymphopenia at 3 months after radiotherapy start was 73% vs 82% (hazard ratio [HR], 0.58; 95% CI, 0.19-1.8); estimated 3-year recurrence-free survival, 36% vs 63% (HR, 0.45; 95% CI, 0.23-0.87); and estimated 3-year overall survival, 34% vs 64% (HR, 0.45; 95% CI, 0.23-0.88). In multivariable analysis, an association with worse overall survival was found for definitive radiotherapy (HR, 3.3; 95% CI, 1.6-7.1) and grades 3 to 4 lymphopenia (HR, 2.6; 95% CI, 1.3-5.5) at 3 months after radiotherapy. CONCLUSIONS AND RELEVANCE Lymphopenia and NLR as early as 3 months after treatment start may serve as biomarkers of clinical outcomes in patients with HPV-negative OPC. These patients may benefit from adjuvant treatment intensification or closer surveillance.

Natural killer (NK) cells are innate lymphoid cells that eliminate cancer cells, produce cytokines, and are being investigated as a nascent cellular immunotherapy. Impaired NK cell function, expansion, and persistence remain key challenges for optimal clinical translation. One promising strategy to overcome these challenges is cytokine-induced memory-like (ML) differentiation, whereby NK cells acquire enhanced antitumor function after stimulation with interleukin-12 (IL-12), IL-15, and IL-18. Here, reduced-intensity conditioning (RIC) for HLA -haploidentical hematopoietic cell transplantation (HCT) was augmented with same-donor ML NK cells on day +7 and 3 weeks of N-803 (IL-15 superagonist) to treat patients with relapsed/refractory acute myeloid leukemia (AML) in a clinical trial (NCT02782546). In 15 patients, donor ML NK cells were well tolerated, and 87% of patients achieved a composite complete response at day +28, which corresponded with clearing high-risk mutations, including TP53 variants. NK cells were the major blood lymphocytes for 2 months after HCT with 1104-fold expansion (over 1 to 2 weeks). Phenotypic and transcriptional analyses identified donor ML NK cells as distinct from conventional NK cells and showed that ML NK cells persisted for over 2 months. ML NK cells expressed CD16, CD57, and high granzyme B and perforin, along with a unique transcription factor profile. ML NK cells differentiated in patients had enhanced ex vivo function compared to conventional NK cells from both patients and healthy donors. Overall, same-donor ML NK cell therapy with 3 weeks of N-803 support safely augmented RIC haplo-HCT for AML.

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IntroductionMetastatic involvement of groin nodes can alter radiation therapy planning for pelvic tumors. 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) can identify nodal metastases; however, interpretation of PET/CT-positive nodes can be complicated by non-malignant processes. We evaluated quantitative metrics as methods to identify groin metastases in patients with pelvic tumors by comparison with standard subjective interpretive criteria, with pathology as the reference standard.MethodsWe retrospectively identified patients with vulvar, vaginal, or anal cancers who underwent 18F-FDG PET/CT before pathologic evaluation of groin nodes between 2007 and 2017. Because patho-radiologic correlation was not possible for every node, one index node identified on imaging was selected for each groin. For each index node, standardized uptake value measurements, total lesion glycolysis, metabolic tumor volume, CT-based volume, and short and long axes were measured. Multivariate logistic regression was used to identify metrics predictive for pathologically positive groins and generate a probabilistic model. Area under the receiver-operating characteristic curves (AUCs) for the model were compared with clinical interpretation from the diagnostic report via a Wald’s χ2 test.ResultsOf 55 patients identified for analysis, 75 groins had pathologic evaluation resulting in 75 index groin nodes for analysis with 35 groins pathologically positive for malignancy. Logistic regression identified mean standardized-uptake-value (50% threshold) and short-axis length as the most predictive imaging metrics for metastatic nodal involvement. The probabilistic model performed better at predicting pathologic involvement compared with standard clinical interpretation on analysis (AUC 0.91, 95% CI 0.84 to 0.97 vs 0.80, 95% CI 0.71 to 0.89; p<0.01).DiscussionAccuracy of 18F-FDG PET/CT for detecting groin nodal metastases in patients with pelvic tumors may be improved with the use of quantitative metrics. Improving prediction of nodal metastases can aid with appropriate selection of patients for pathologic node evaluation and guide radiation volumes and doses.