Project description:Pancreatic ductal adenocarcinoma (PDAC) has a characteristically dense stroma comprised predominantly of cancer associated fibroblasts (CAFs). CAFs promote tumor growth, metastasis and treatment resistance. We aimed to investigate the molecular changes and functional consequences associated with chemotherapy treatment of PDAC CAFs. Chemoresistant immortalized CAFs (R-CAFs) were generated by continuous incubation in 100nM gemcitabine. Gene expression differences between treatment naïve CAFs (N-CAFs) and R-CAFs were compared by array analysis. Immortalized human pancreatic CAFs were grown for 30 days in either control media or media containing 100nM gemcitabine. RNA was then isolated and hybidized on U133 Plus 2.0 Affymetrix arrays.
Project description:Pancreatic ductal adenocarcinoma (PDAC) has a characteristically dense stroma comprised predominantly of cancer associated fibroblasts (CAFs). CAFs promote tumor growth, metastasis and treatment resistance. We aimed to investigate the molecular changes and functional consequences associated with chemotherapy treatment of PDAC CAFs. Chemoresistant immortalized CAFs (R-CAFs) were generated by continuous incubation in 100nM gemcitabine. Gene expression differences between treatment naïve CAFs (N-CAFs) and R-CAFs were compared by array analysis.
Project description:We developed a multi-paratopic VEGF decoy receptor (Ate-Grab) by fusing the scFv of atezolizumab to VEGF-Grab to target PD-L1 expressing cells in tumor microenvironment. We compared the single-cell transcriptomes of gemcitabine-treated and Ate-Grab with Gemcitabine-treated Pan02 tumors. We confirmed the subtype of cancer-associated fibroblasts(CAFs) that modulates the collagen inside the tumor microenvrionment. In the Ate-Grab+Gemcitabine group, it was confirmed that new CAFs were regulated.
Project description:Cancer associated fibroblasts (CAFs) comprise the majority of the tumor bulk of pancreatic adenocarcinomas (PDACs). Current efforts to eradicate these tumors focus predominantly on targeting the proliferation of rapidly growing cancer epithelial cells. We know that this is largely ineffective with resistance arising in most tumors following exposure to chemotherapy. Despite the long-standing recognition of the prominence of CAFs in PDAC, the effect of chemotherapy on CAFs and how they may contribute to drug resistance in neighboring cancer cells is not well characterized. Here we show that CAFs exposed to chemotherapy play an active role in regulating the survival and proliferation of cancer cells. We found that CAFs are intrinsically resistant to gemcitabine, the chemotherapeutic standard of care for PDAC. Further, CAFs exposed to gemcitabine significantly increase the release of extracellular vesicles called exosomes. These exosomes increased chemoresistance-inducing factor, Snail, in recipient epithelial cells and promote proliferation and drug resistance. Finally, treatment of gemcitabine-exposed CAFs with an inhibitor of exosome release, GW4869, significantly reduces survival in co-cultured epithelial cells, signifying an important role of CAF exosomes in chemotherapeutic drug resistance. Collectively, these findings show the potential for exosome inhibitors as treatment options alongside chemotherapy for overcoming PDAC chemoresistance.
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:Zhu2015 - Combined gemcitabine and birinapant
in pancreatic cancer cells - basic PD model
Mathematical model to illustrate the
effectiveness of combination chemotherapy involving gemcitabine and
birinapant against pancreatic cancer.
This model is described in the article:
Mechanism-based mathematical
modeling of combined gemcitabine and birinapant in pancreatic
cancer cells.
Zhu X, Straubinger RM, Jusko
WJ.
J Pharmacokinet Pharmacodyn 2015 Oct;
42(5): 477-496
Abstract:
Combination chemotherapy is standard treatment for
pancreatic cancer. However, current drugs lack efficacy for
most patients, and selection and evaluation of new combination
regimens is empirical and time-consuming. The efficacy of
gemcitabine, a standard-of-care agent, combined with
birinapant, a pro-apoptotic antagonist of Inhibitor of
Apoptosis Proteins (IAPs), was investigated in pancreatic
cancer cells. PANC-1 cells were treated with vehicle,
gemcitabine (6, 10, 20 nM), birinapant (50, 200, 500 nM), and
combinations of the two drugs. Temporal changes in cell
numbers, cell cycle distribution, and apoptosis were measured.
A basic pharmacodynamic (PD) model based on cell numbers, and a
mechanism-based PD model integrating all measurements, were
developed. The basic PD model indicated that synergistic
effects occurred in both cell proliferation and death
processes. The mechanism-based model captured key features of
drug action: temporary cell cycle arrest in S phase induced by
gemcitabine alone, apoptosis induced by birinapant alone, and
prolonged cell cycle arrest and enhanced apoptosis induced by
the combination. A drug interaction term Ψ was employed in
the models to signify interactions of the combination when data
were limited. When more experimental information was utilized,
Ψ values approaching 1 indicated that specific mechanisms
of interactions were captured better. PD modeling identified
the potential benefit of combining gemcitabine and birinapant,
and characterized the key interaction pathways. An optimal
treatment schedule of pretreatment with gemcitabine for 24-48 h
was suggested based on model predictions and was verified
experimentally. This approach provides a generalizable modeling
platform for exploring combinations of cytostatic and cytotoxic
agents in cancer cell culture studies.
This model is hosted on
BioModels Database
and identified by:
BIOMD0000000668.
To cite BioModels Database, please use:
Chelliah V et al. BioModels: ten-year
anniversary. Nucl. Acids Res. 2015, 43(Database
issue):D542-8.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.