Therapeutic Use of Bacteriophage and Antibiotic Formulations for the Treatment of Antibiotic Resistant Acinetobacter Baumannii

Gemstone Team LYTICWidespread use of antibiotics has enriched global bacteria populations for strains possessing antibiotic resistance (AR) genes. Proliferation of AR genes and mechanisms have resulted in numerous multidrug resistant (MDR) infections for which there are no effective treatments. Acinetobacter baumannii is a major cause of hospital acquired (nosocomial) infections and is associated with outbreaks of MDR infections. Virulent bacteriophages (phages) present a way to remedy bacterial infections, while also having built-in mechanisms to circumvent resistance. This proposed study aims to develop a phage therapeutic targeting antibiotic resistant A. baumannii. The phages chosen for the final formulation exhibited high bactericidal activity and were able to infect several strains of A. baumannii from a provided library. Additionally, the phage-antibiotic synergy (PAS) effect was investigated in formulations with sub-lethal doses of ampicillin and chloramphenicol. The effectiveness of the phage therapeutic at different multiplicity of infections (MOI) and antibiotic concentrations were assessed relative to standard antibiotic doses. Well-plate studies suggest that higher MOI and antibiotic concentrations resulted in the greatest initial bactericidal effects, longest time to develop resistance, and lowest overall bacteria concentration. In future formulation studies, we would like to expand and optimize the current phage-antibiotic formulation and explore cocktail effects, whereby the formulation consists of a mixture of different phages that increases selective pressure

SOX2 and OCT4 mediate radiation and drug resistance in pancreatic tumor organoids

Abstract Pancreatic cancer has a five-year survival rate of only 10%, mostly due to late diagnosis and limited treatment options. In patients with unresectable disease, either FOLFIRINOX, a combination of 5-fluorouracil (5-FU), oxaliplatin and irinotecan, or gemcitabine plus nab-paclitaxel combined with radiation are frontline standard regimens. However, chemo-radiation therapy has shown limited success because patients develop resistance to chemotherapy and/or radiation. In this study, we evaluated the role of pancreatic cancer stem cells (CSC) using OCT4 and SOX2, CSC markers in mouse pancreatic tumor organoids. We treated pancreatic tumor organoids with 4 or 8 Gy of radiation, 10 μM of 5-FU (5-Fluorouracil), and 100 μM 3-Bromopyruvate (3BP), a promising anti-cancer drug, as a single treatment modalities, and in combination with RT. Our results showed significant upregulation of, OCT4, and SOX2 expression in pancreatic tumor organoids treated with 4 and 8 Gy of radiation, and downregulation following 5-FU treatment. The expression of CSC markers with increasing treatment dose exhibited elevated upregulation levels to radiation and downregulation to 5-FU chemotherapy drug. Conversely, when tumor organoids were treated with a combination of 5-FU and radiation, there was a significant inhibition in SOX2 and OCT4 expression, indicating CSC self-renewal inhibition. Noticeably, we also observed that human pancreatic tumor tissues exhibited heterogeneous and aberrant OCT4 and SOX2 expression as compared to normal pancreas, indicating their potential role in pancreatic cancer growth and therapy resistance. In addition, the combination of 5-FU and radiation treatment exhibited significant inhibition of the β-catenin pathway in pancreatic tumor organoids, resulting in sensitization to treatment and organoid death. In conclusion, our study emphasizes the crucial role of CSCs in therapeutic resistance in PC treatment. We recommend using tumor organoids as a model system to explore the impact of CSCs in PC and identify new therapeutic targets

Docetaxel radiosensitizes castration resistant prostate cancer by downregulating CAV-1

Purpose: Docetaxel (dox), a noted radiosensitizer, is one of the few chemotherapy drugs approved for castration-resistant prostate cancer (CRPC), though only a fraction of CRPCs respond to it. CAV-1, a critical regulator of radioresistance, has been known to modulate dox and radiation effects. Combining dox with radiotherapy may create a synergistic anticancer effect through CAV-1 and improve CRPC patients' response to therapy. Here, we investigate the effectiveness and molecular characteristics of dox and radiation combination therapy in vitro. Materials and Methods: We used live/dead assays to determine the IC50 of dox for PC3, DU-145, and TRAMP-C1 cells. Colony formation assay was used to determine the radioresponse of the same cells treated with radiation with/without IC50 dox (4, 8, 12 Gy). We performed gene expression analysis on public transcriptomic data collected from human-derived prostate cancer cell lines (C4-2, PC3, DU-145, LNCaP) treated with dox for 8, 16, and 72 hours. Cell cycle arrest and protein expression were assessed using flow cytometry and western blot, respectively. Results: Compared to radiation alone, combination therapy with dox significantly increased CRPC death in PC3 (1.48-fold, p  Conclusions: Our results suggest that dox sensitizes CRPC cells to radiation by downregulating CAV-1. Dox + radiation combination therapy may be effective at treating CRPC, especially subtypes associated with high CAV-1 expression, and should be studied further. </p