23 research outputs found

    Disruption of FDPS/Rac1 Axis Radiosensitizes Pancreatic Ductal Adenocarcinoma by Attenuating DNA Damage Response and Immunosuppressive Signalling

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    BACKGROUND: Radiation therapy (RT) has a suboptimal effect in patients with pancreatic ductal adenocarcinoma (PDAC) due to intrinsic and acquired radioresistance (RR). Comprehensive bioinformatics and microarray analysis revealed that cholesterol biosynthesis (CBS) is involved in the RR of PDAC. We now tested the inhibition of the CBS pathway enzyme, farnesyl diphosphate synthase (FDPS), by zoledronic acid (Zol) to enhance radiation and activate immune cells. METHODS: We investigated the role of FDPS in PDAC RR using the following methods: in vitro cell-based assay, immunohistochemistry, immunofluorescence, immunoblot, cell-based cholesterol assay, RNA sequencing, tumouroids (KPC-murine and PDAC patient-derived), orthotopic models, and PDAC patient\u27s clinical study. FINDINGS: FDPS overexpression in PDAC tissues and cells (P \u3c 0.01 and P \u3c 0.05) is associated with poor RT response and survival (P = 0.024). CRISPR/Cas9 and pharmacological inhibition (Zol) of FDPS in human and mouse syngeneic PDAC cells in conjunction with RT conferred higher PDAC radiosensitivity in vitro (P \u3c 0.05, P \u3c 0.01, and P \u3c 0.001) and in vivo (P \u3c 0.05). Interestingly, murine (P = 0.01) and human (P = 0.0159) tumouroids treated with Zol+RT showed a significant growth reduction. Mechanistically, RNA-Seq analysis of the PDAC xenografts and patients-PBMCs revealed that Zol exerts radiosensitization by affecting Rac1 and Rho prenylation, thereby modulating DNA damage and radiation response signalling along with improved systemic immune cells activation. An ongoing phase I/II trial (NCT03073785) showed improved failure-free survival (FFS), enhanced immune cell activation, and decreased microenvironment-related genes upon Zol+RT treatment. INTERPRETATION: Our findings suggest that FDPS is a novel radiosensitization target for PDAC therapy. This study also provides a rationale to utilize Zol as a potential radiosensitizer and as an immunomodulator in PDAC and other cancers. FUNDING: National Institutes of Health (P50, P01, and R01)

    Critical Evaluation of Oncology Clinical Practice Guidelines

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    The Impact of Extent of Liver Resection Among Patients with Neuroendocrine Liver Metastasis: an International Multi-institutional Study

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    Background: Liver resection in patients with neuroendocrine liver metastasis (NELM) provides a survival benefit, yet the optimal extent of resection remains unknown. We sought to examine outcomes of patients undergoing non-anatomic (NAR) versus anatomic liver resection (AR) for NELM using a large international cohort of patients. Methods: Two hundred and fifty-eight patients who underwent curative intent liver resection from January 1990 to December 2016 were identified from eight institutions. Patients were excluded if they underwent concurrent ablation, had extrahepatic disease, underwent a debulking operation, or had mixed anatomic and non-anatomic resections. Overall (OS) and recurrence-free (RFS) survival were compared among patients based on the extent of liver resection (AR vs. NAR). Results: Most primary tumors were located in the pancreas (n = 117, 45.4%) or the small intestine (n = 65, 25.2%). Liver resection consisted of NAR (n = 126, 48.8%) or AR (n = 132, 51.2%) resection. The overwhelming majority of patients who underwent NAR had an estimated liver involvement of < 50% (NAR 109, 97.3% vs. AR n = 82, 65.6%; P < 0.001). Patients who underwent NAR also had higher rates of primary tumor lymph node metastasis (NAR n = 79, 71.2% vs. AR n = 37, 33.6%; P < 0.001) and microscopically positive margins (R1) (NAR n = 29, 25.7% vs. AR n = 16, 12.5%; P = 0.009). After a median follow-up of 47.7 months, 48 (18.6%) patients died and 37.0% (n = 95) had evidence of disease recurrence. Patients who underwent AR had both longer median OS (not reached) and RFS (not reached) versus patients who underwent NAR (median OS 138.3 months; median RFS 31.3 months) (both P < 0.01). After controlling for patient and disease-related factors, extent of liver resection was independently associated with an increased risk of recurrence (HR 2.39, 95% CI 1.04\u20135.48; P = 0.04) but not death (HR 1.92, 95% CI 0.40\u20139.28; P = 0.42). Conclusion: NAR was independently associated with a higher incidence of recurrence versus patients who undergo a formal anatomic hepatectomy among patients with NELM
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