Blocking the PCNA/NKp44 Checkpoint to Stimulate NK Cell Responses to Multiple Myeloma.

Multiple Myeloma (MM) is a devastating malignancy that evades immune destruction using multiple mechanisms. The NKp44 receptor interacts with PCNA (Proliferating Cell Nuclear Antigen) and may inhibit NK cells' functions. Here we studied in vitro the expression and function of PCNA on MM cells. First, we show that PCNA is present on the cell membrane of five out of six MM cell lines, using novel anti-PCNA mAb developed to recognize membrane-associated PCNA. Next, we stained primary bone marrow (BM) mononuclear cells from MM patients and showed significant staining of membrane-associated PCNA in the fraction of CD38+CD138+ BM cells that contain the MM cells. Importantly, blocking of the membrane PCNA on MM cells enhanced the activity of NK cells, including IFN-γ-secretion and degranulation. Our results highlight the possible blocking of the NKp44-PCNA immune checkpoint by the mAb 14-25-9 antibody to enhance NK cell responses against MM, providing a novel treatment option.

Vertebrae but not femur marrow fat transiently decreases in response to body weight loss in an 18-month randomized control trial.

BACKGROUND: Increased levels of bone marrow adipose tissue (BMAT) are negatively associated with skeletal health and hematopoiesis. BMAT is known to increase with age; however, the effect of long-term weight loss on BMAT is still unknown. OBJECTIVE: In this study, we examined BMAT response to lifestyle-induced weight loss in 138 participants (mean age 48 y; mean body mass index 31 kg/m2), who participated in the CENTRAL-MRI trial. METHODS: Participants were randomized for dietary intervention of low-fat or low-carb, with or without physical activity. Magnetic resonance imaging (MRI) was used to quantify BMAT and other fat depots at baseline, six and eighteen months of intervention. Blood biomarkers were also measured at the same time points. RESULTS: At baseline, the L3 vertebrae BMAT is positively associated with age, HDL cholesterol, HbA1c and adiponectin; but not with other fat depots or other metabolic markers tested. Following six months of dietary intervention, the L3 BMAT declined by an average of 3.1 %, followed by a return to baseline after eighteen months (p < 0.001 and p = 0.189 compared to baseline, respectively). The decrease of BMAT during the first six months was associated with a decrease in waist circumference, cholesterol, proximal-femur BMAT, and superficial subcutaneous adipose tissue (SAT), as well as with younger age. Nevertheless, BMAT changes did not correlate with changes in other fat depots. CONCLUSIONS: We conclude that physiological weight loss can transiently reduce BMAT in adults, and this effect is more prominent in younger adults. Our findings suggest that BMAT storage and dynamics are largely independent of other fat depots or cardio-metabolic risk markers, highlighting its unique functions.

High throughput screen for the improvement of inducible promoters for tumor microenvironment cues.

Cancer immunotherapies are highly potent and are gaining wide clinical usage. However, severe side effects require focusing effector immune cell activities on the tumor microenvironment (TME). We recently developed a chimeric antigen receptor tumor-induced vector (CARTIV), a synthetic promoter activated by TME factors. To improve CARTIV functions including background, activation levels, and synergism, we screened a library of promoters with variations in key positions. Here, we present a screening method involving turning ON/OFF stimulating TNFα and IFNγ cytokines, followed by sequential cell sorting. Sequencing of enriched promoters identified seventeen candidates, which were cloned and whose activities were then validated, leading to the identification of two CARTIVs with lower background and higher induction. We further combined a third hypoxia element with the two-factor CARTIV, demonstrating additional modular improvement. Our study presents a method of fine-tuning synthetic promoters for desired immunotherapy needs.