Faculty Bibliography

The bone marrow (BM) is altered in obesity to promote myeloid cell generation, but the mechanisms driving these changes remain unclear. Here, we show that obesogenic stimuli promote adipose tissue macrophages to recruit neutrophils from the BM in mice. Recruitment of BM neutrophils activates hematopoietic stem cells, which produce myeloid cells that accumulate in the circulation and drive inflammation. This recruitment is not resolved by weight loss, leading to sustained myelopoiesis in previously obese mice. Inhibiting neutrophil recruitment out of the BM in obese mice or during weight loss reduces BM myelopoiesis and adipose tissue inflammation, and improves glucose tolerance. In humans with obesity, plasma neutrophil chemokines are increased, correlate with increased insulin resistance, but do not decrease with weight loss. Our results demonstrate that neutrophil recruitment is a key mediator of myelopoiesis during obesity, and targeting this pathway is a potential strategy to improve inflammation during obesity and weight loss.

Pathologically activated immunosuppressive neutrophils impair cancer immunotherapy efficacy. The chemokine receptor CXCR4, a central regulator of hematopoiesis and neutrophil biology, represents an attractive target. Here, we fuse a secreted CXCR4 partial agonist, trefoil factor 2 (TFF2), to mouse serum albumin (MSA) and demonstrate that TFF2-MSA peptide synergizes with anti-PD-1 to inhibit primary tumor growth and distant metastases and prolongs survival in gastric cancer (GC) mouse models. Using histidine decarboxylase (Hdc)-GFP transgenic mice to track polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC) in vivo, we find that TFF2-MSA selectively reduces the Hdc-GFP⁺CXCR4^high immunosuppressive neutrophils, thereby boosting CD8⁺ T cell-mediated tumor killing with anti-PD-1. Importantly, TFF2-MSA reduces bone marrow granulopoiesis, contrasting with CXCR4 antagonism, which fails to confer therapeutic benefits. In GC patients, elevated CXCR4⁺LOX-1⁺ low-density neutrophils correlate with lower circulating TFF2 levels. Collectively, our studies introduce a strategy that utilizes CXCR4 partial agonism to restore anti-PD-1 sensitivity by targeting immunosuppressive neutrophils and granulopoiesis.

BACKGROUND:The parasympathetic branch of the autonomic nervous system has shown tumor-suppressive effects in preclinical models of pancreatic adenocarcinoma (PDAC) by inhibiting cancer stem cells and suppressing inflammatory cytokine production. Based on these findings, we hypothesized that bethanechol, an FDA-approved parasympathomimetic agent targeting muscarinic receptors, could enhance treatment efficacy in PDAC. METHODS:We conducted a Phase 0/window of opportunity study evaluating short term parasympathetic activation with fixed dose bethanechol (100 mg twice daily) in subjects with resectable or borderline resectable PDAC prior to surgery. The primary endpoint was change in cell proliferation by Ki-67 expression compared to stage matched controls. Secondary endpoints included tissue expression of stem cell markers (CD44), infiltrating immune cells (CD8a, Granzyme B, and CD68), and changes in circulating inflammatory cytokine concentrations. RESULTS:Seventeen patients were enrolled with 13 eligible for analysis of endpoints. Median age was 74 (59-86), 6 female (46%), all ECOG 0-1 and median duration of treatment was 8 days (7-13). R0 resections were achieved in 9 patients (69%). There was no difference in Ki67 and CD44 tissue biomarkers between bethanechol-treated and control samples. Decreased numbers of Granzyme B-expressing cells were seen in bethanechol-treated tissues. Bethanechol treatment was associated with suppression of circulating IL-18. The most common treatment related adverse events (TRAE) were hot flashes (30.7%), urinary frequency (15.4%), increased salivation (15.4%), hyperhidrosis (7.7%), and nausea (7.7%). There were no Grade 3 or higher adverse effects. No surgical complications were attributed to bethanechol treatment. CONCLUSION/CONCLUSIONS:Bethanechol 100 mg twice daily is well tolerated in patients with PDAC in this small phase 0/window of opportunity study (NCT03572283). Bethanechol treatment was associated with decreased Granzyme B positive cells and decreased circulating IL-18 consistent with an anti-inflammatory role for parasympathetic muscarinic signaling in PDAC.

Cancer-associated fibroblasts (CAFs) and nerves, components of the tumor microenvironment, have each been shown to directly promote gastrointestinal cancers. However, it remains unknown whether these cells interact with each other to regulate cancer progression. We found that in colorectal cancer (CRC) norepinephrine induces ADRB2-dependent nerve growth factor (NGF) secretion from CAFs, which in turn increases intra-tumor sympathetic innervation and norepinephrine accumulation. Adrenergic stimulation accelerates CRC growth through ADRA2A/Gi-mediated activation of Yes-Associated Protein (YAP). NGF from CAFs directly enhances CRC cell growth via the PI3K/AKT pathway. Treatment with a tropomyosin receptor kinase (Trk) inhibitor decreased YAP and AKT activation and CRC progression in mice. In human CRC, high NGF expression is associated with the mesenchymal-like tumor subtype and poor patient survival. These findings suggest a central role for reciprocal CAF-nerve crosstalk in promoting CRC progression. Blocking this feedforward loop with a Trk inhibitor may represent a potential therapeutic approach for CRC.

Here, we present a protocol for rapidly isolating single cells from the mouse pancreas, minimizing damage caused by digestive enzymes in exocrine cells. We guide you through steps to optimize the dissection sequence, enzyme composition, and operational procedures, resulting in high yields of viable pancreatic single cells. This protocol can be applied across a wide range of research areas, including single-cell sequencing, gene expression profiling, primary cell culture, and even the development of spheroids or organoids. For complete details on the use and execution of this protocol, please refer to Jiang et al. (2023).¹.

BACKGROUND:Perineural invasion (PNI) and nerve density within the tumor microenvironment (TME) have long been associated with worse outcomes in head and neck squamous cell carcinoma (HNSCC). This prompted an investigation into how nerves within the tumor microenvironment affect the adaptive immune system and tumor growth. METHODS:We used RNA sequencing analysis of human tumor tissue from a recent HNSCC clinical trial, proteomics of human nerves from HNSCC patients, and syngeneic orthotopic murine models of HPV-unrelated HNSCC to investigate how sensory nerves modulate the adaptive immune system. FINDINGS/RESULTS:Calcitonin gene-related peptide (CGRP) directly inhibited CD8 T cell activity in vitro, and blocking sensory nerve function surgically, pharmacologically, or genetically increased CD8 and CD4 T cell activity in vivo. CONCLUSIONS:Our data support sensory nerves playing a role in accelerating tumor growth by directly acting on the adaptive immune system to decrease Th1 CD4 T cells and activated CD8 T cells in the TME. These data support further investigation into the role of sensory nerves in the TME of HNSCC and points toward the possible treatment efficacy of blocking sensory nerve function or specifically inhibiting CGRP release or activity within the TME to improve outcomes. FUNDING/BACKGROUND:1R01DE028282-01, 1R01DE028529-01, 1P50CA261605-01 (to S.D.K.), 1R01CA284651-01 (to S.D.K.), and F31 DE029997 (to L.B.D.).

While adult pancreatic stem cells are thought not to exist, it is now appreciated that the acinar compartment harbors progenitors, including tissue-repairing facultative progenitors (FPs). Here, we study a pancreatic acinar population marked by trefoil factor 2 (Tff2) expression. Long-term lineage tracing and single-cell RNA sequencing (scRNA-seq) analysis of Tff2-DTR-CreER^T2-targeted cells defines a transit-amplifying progenitor (TAP) population that contributes to normal homeostasis. Following acute and chronic injury, Tff2⁺ cells, distinct from FPs, undergo depopulation but are eventually replenished. At baseline, oncogenic Kras^G12D-targeted Tff2⁺ cells are resistant to PDAC initiation. However, Kras^G12D activation in Tff2⁺ cells leads to survival and clonal expansion following pancreatitis and a cancer stem/progenitor cell-like state. Selective ablation of Tff2⁺ cells prior to Kras^G12D activation in Mist1⁺ acinar or Dclk1⁺ FP cells results in enhanced tumorigenesis, which can be partially rescued by adenoviral Tff2 treatment. Together, Tff2 defines a pancreatic TAP population that protects against Kras-driven carcinogenesis.

BACKGROUND:Methods for screening agents earlier in development and strategies for conducting smaller randomized controlled trials (RCTs) are needed. METHODS:We retrospectively applied a tumor growth model to estimate the rates of growth of pancreatic cancer using radiographic tumor measurements or serum CA 19-9 values from 3033 patients with stages III-IV PDAC who were enrolled in 8 clinical trials or were included in 2 large real-world data sets. RESULTS:g correlated inversely with OS and was consistently lower in the experimental arms than in the control arms of RCTs. At the individual patient level, g was significantly faster for lesions metastatic to the liver relative to those localized to the pancreas. Regardless of regimen, g increased toward the end of therapy, often by over 3-fold. CONCLUSIONS:Growth rates of PDAC can be determined using radiographic tumor measurement and CA 19-9 values. g is inversely associated with OS and can differentiate therapies within the same trial and across trials. g can also be used to characterize changes in the behavior of an individual's PDAC, such as differences in the growth rate of lesions based on metastatic site, and the emergence of chemoresistance. We provide examples of how g can be used to benchmark phase II and III clinical data to a virtual reference arm to inform go/no go decisions and consider novel trial designs to optimize and accelerate drug development.

Recent advances in cancer neuroscience necessitate the systematic analysis of neural influences in cancer as potential therapeutic targets in oncology. Here, we outline recommendations for future preclinical and translational research in this field.