Wenqiang Chen

Background: The primary aim of this Phase 1 clinical trial was to study the safety and dose of a cholecystokinin receptor antagonist, proglumide, in combination with gemcitabine/nab-paclitaxel (GEM-NAB-P) in patients with metastatic pancreatic cancer. The secondary aim was to study the effects of proglumide with GEM-NAB-P on the tumor microenvironment (TME) with tumor biopsies and a blood biomarker assay. An exploratory aim studied the effects of proglumide treatment on cancer-related pain. Methods: Gemcitabine-naïve patients were treated with GEM-NAB-P plus proglumide 1200 mg/day. Tumor biopsies and a liquid biopsy serum sample for analysis of a microRNA biomarker panel were collected pre- and on-treatment to study the TME. McGill pain surveys were done at baseline, week 8 and at the end of treatment. The study was approved and registered (NCT05827055). Results: The mean age of the patients was 68.2 years (range 54–74 years). The starting dose was well-tolerated with no unexpected treatment-related adverse events observed. Multiplex immunohistochemical analysis of tumor biopsies at baseline and week 8 revealed a significant reduction in Ki67+ cells, collagen1α1, and M2-polarized tumor-associated macrophages (TAMs). Week 8 tumor biopsies demonstrated a significant increase in CD8+ T-cells and natural killer cells compared to baseline. The blood biomarker panel showed a significant inverse change in microRNAs associated with decreasing fibrosis and metastasis. The McGill pain scores showed less pain at week 24 or end-of-treatment compared to baseline. Conclusions: Proglumide demonstrates a favorable safety profile when combined with standard chemotherapy for metastatic pancreatic cancer. Its unique ability to remodel TME and alleviate cancer-related pain highlights its potential, warranting further research.

Pancreatic cancer is characterized by an extensive fibrotic stroma largely driven by activated pancreatic stellate cells (PSCs)/fibroblasts, which also function to support tumor growth and metastasis. Cholecystokinin-B receptors (CCK-BRs) are expressed on pancreatic stellate cells (PSCs) and have emerged as a key regulator of PSC activation and tumor-stromal interactions. We hypothesized that disrupting CCK-BR function shifts PSCs to a more quiescent phenotype and reduces their pro-fibrotic and tumor-supportive activity to decrease growth of pancreatic cancer. Murine PSCs were genetically engineered with CRISPR-Cas9 to knockout the CCK-BR. In a series of experiments, the role of the CCK-BR expression was evaluated on cell migration, proliferation, differentially expressed genes, molecular signaling pathways, and in co-culture with murine pancreatic cancer epithelial cells. Next, primary human pancreatic stellate cells were treated with proglumide, a CCK-BR antagonist, to study the effects of pharmacologic blockade of the CCK-BR on cellular signaling and proliferative pathways by RNA sequencing. Knockout of the CCK-BR led to significant decreases in PSC activation and the ability to stimulate growth of pancreatic cancer cells in co-culture. Both genetic knockdown and pharmacologic blockade of the CCK-BR downregulated genes implicated in fibrosis, proliferation, fibroblast activation, and tumorigenesis, while genes implicated in apoptosis and tumor suppression were upregulated. Flow cytometry showed increased apoptosis markers in CCK-BR-knockout cells compared to controls. These experiments combine transcriptomic profiling with functional validation to provide a comprehensive analysis of how targeting CCK-BR interrupts the cross-communication between cancer cells and fibroblasts. Blockade or downregulation of the CCK-BR on pancreatic fibroblasts may provide a strategy to disrupt oncogenic signaling pathways and reprogram the tumor microenvironment.

Background: New strategies are needed to improve the response to immune checkpoint inhibitors for the treatment of hepatocellular carcinoma. Methods: Mice bearing HCC tumors were treated with PBS (control), a PD-1 antibody (PD-1Ab), proglumide, or the combination of proglumide and the PD-1Ab. The tumor microenvironment (TME) was evaluated histologically for fibrosis and by immunohistochemistry for immune cells. To investigate the mechanisms involved in T-cell efficiency, mouse spleen cells were isolated and examined for T-cell exhaustion markers and cytokine release. The mouse microbiome was analyzed using whole-genome sequencing before therapy and at the end of the study. Results: The combination of proglumide with a PD-1Ab decreased tumoral fibrosis better than monotherapy, and altered the immune cell signature in the TME by decreasing M2-polarized macrophages and increasing the influx of CD8+ T-cells. Proglumide monotherapy or in combination with the PD-1Ab decreased T-cell exhaustion markers and improved cytokine release. The combination therapy resulted in changes to the microbiome, including increased beneficial bacteria and genera known to enhance the efficacy of ICIs. Conclusions: Co-administration of proglumide with ICIs resulted in remodeling of the TME, changing a “cold” tumor to a “hot” immune-responsive tumor, activating T-cells, and altering the host microbiome to a population of bacteria that are beneficial.

Concentration of Gapmer measured in tumors and tissues

Viable cell numbers of AsPC-1 cells transfected with Gapmer-90

Serum chemistries (mean ± SEM) obtained at necropsy

Precision medicine and genomic profiling with target-specific therapy directed to cancer cell receptors have improved the outcome of many recalcitrant cancers. Strategies to deliver gene therapy to downregulate cancer driver genes have been challenging in vivo. Pancreatic cancer has the poorest survival of all solid tumors due to the lack of target-specific therapies and its characteristic tumor microenvironment with dense fibrosis and abundant immunosuppressive M2-polarized macrophages. In this study, we designed a panel of locked nucleic acid gapmer antisense oligonucleotides directed to human gastrin mRNA. We tested their efficacy by downregulation of mRNA and growth inhibition in vitro. The most effective gapmer, gapmer-90, was modified for in vivo therapeutics by thiol–maleimide click chemistry to render it target-specific to the cholecystokinin-B receptor. This G-protein–coupled receptor is overexpressed in pancreatic cancers. Mice bearing orthotopic human pancreatic tumors were treated with PBS (control), an untargeted gapmer, or receptor-targeted gapmers at low (60 nmol/L) and high (120 nmol/L) concentrations. Uptake of the gapmer was measured in tissues using a complementary probe. We found that the receptor-targeted gapmer significantly enhanced uptake in vivo and decreased growth and metastases of human pancreatic tumors in a dose-related fashion without off-target toxicity. The target-specific gapmer also altered the tumor microenvironment by decreasing fibrosis and reducing M2-polarized macrophages. Collectively, our results provide evidence that locked nucleic acid gapmers are a unique tool to deliver antisense oligonucleotides for therapy to recalcitrant cancers. Rendering the gapmers target-specific allows for selective uptake by receptor internalization, improving efficacy and decreasing off-target toxicity.

Chemical structure of the targeted LNA Gapmer-90.

Cytotoxicity assay was performed by flow cytometry