Tumor-stromal cross-talk modulating the therapeutic response in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant solid tumor with a dismal prognosis. The stroma component makes up to 90% of the tumor mass and is thought to be one of the main reasons for the tumor's high chemoresistance. Cancer associated fibroblasts (CAFs) have previously been identified to be the key stromal players. This is the first time we provide detailed in vitro experiments investigating tumor-stromal interactions when exposed to three well-known chemotherapeutic agents. Monocultures, indirect and direct co-cultures of two PDAC cell lines (AsPC and Panc-1) and six primary patients derived CAFs were treated with gemcitabine, nab-paclitaxel and the γ-secretase-inhibitor (GSI) DAPT. The cell viability of each component was measured with XTT. Finally, IL-6 concentrations of the supernatants were analyzed. On the contrary to PDAC cell lines, CAF monocultures hardly responded to any treatment which suggested that stroma (CAFs) itself is more resistant to standard chemo-treatments than the epithelial cancer cells. Moreover, only a weak chemotherapeutic response was observed in direct co-cultures of cancer cells with CAFs. A change in the morphology of direct co-cultures was accompanied with the chemoresistance. CAFs were observed to build cage-like structures around agglomerates of tumor cells. High levels of IL-6 were also associated with a reduced response to therapy. Indirect co-cultures make the tumor-stromal interaction more complex. CAFs are highly chemoresistant. Direct cell-cell contact and high levels of IL-6 correlate with a high chemoresistance.

Neumann CCM ，von Hörschelmann E ，Reutzel-Selke A ，Seidel E ，Sauer IM ，Pratschke J ，Bahra M ，Schmuck RB ... -  《Hepatobiliary & Pancreatic Diseases International》

Patient-specific modeling of stroma-mediated chemoresistance of pancreatic cancer using a three-dimensional organoid-fibroblast co-culture system.

Cancer-associated fibroblasts (CAFs) are considered to play a fundamental role in pancreatic ductal adenocarcinoma (PDAC) progression and chemoresistance. Patient-derived organoids have demonstrated great potential as tumor avatars for drug response prediction in PDAC, yet they disregard the influence of stromal components on chemosensitivity. We established direct three-dimensional (3D) co-cultures of primary PDAC organoids and patient-matched CAFs to investigate the effect of the fibroblastic compartment on sensitivity to gemcitabine, 5-fluorouracil and paclitaxel treatments using an image-based drug assay. Single-cell RNA sequencing was performed for three organoid/CAF pairs in mono- and co-culture to uncover transcriptional changes induced by tumor-stroma interaction. Upon co-culture with CAFs, we observed increased proliferation and reduced chemotherapy-induced cell death of PDAC organoids. Single-cell RNA sequencing data evidenced induction of a pro-inflammatory phenotype in CAFs in co-cultures. Organoids showed increased expression of genes associated with epithelial-to-mesenchymal transition (EMT) in co-cultures and several potential receptor-ligand interactions related to EMT were identified, supporting a key role of CAF-driven induction of EMT in PDAC chemoresistance. Our results demonstrate the potential of personalized PDAC co-cultures models not only for drug response profiling but also for unraveling the molecular mechanisms involved in the chemoresistance-supporting role of the tumor stroma.

Schuth S ，Le Blanc S ，Krieger TG ，Jabs J ，Schenk M ，Giese NA ，Büchler MW ，Eils R ，Conrad C ，Strobel O ... -  《JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH》

Micro-RNA-21 Regulates Cancer-Associated Fibroblast-Mediated Drug Resistance in Pancreatic Cancer.

Zhang L ，Yao J ，Li W ，Zhang C ... -  《-》

Chemotherapy-Induced Inflammatory Gene Signature and Protumorigenic Phenotype in Pancreatic CAFs via Stress-Associated MAPK.

Pancreatic ductal adenocarcinoma (PDAC) has a characteristically dense stroma comprised predominantly of cancer-associated fibroblasts (CAF). CAFs promote tumor growth, metastasis, and treatment resistance. This study aimed to investigate the molecular changes and functional consequences associated with chemotherapy treatment of PDAC CAFs. Chemoresistant immortalized CAFs (R-CAF) were generated by continuous incubation in gemcitabine. Gene expression differences between treatment-naïve CAFs (N-CAF) and R-CAFs were compared by array analysis. Functionally, tumor cells (TC) were exposed to N-CAF- or R-CAF-conditioned media and assayed for migration, invasion, and viability in vitro Furthermore, a coinjection (TC and CAF) model was used to compare tumor growth in vivo R-CAFs increased TC viability, migration, and invasion compared with N-CAFs. In vivo, TCs coinjected with R-CAFs grew larger than those accompanied by N-CAFs. Genomic analysis demonstrated that R-CAFs had increased expression of various inflammatory mediators, similar to the previously described senescence-associated secretory phenotype (SASP). In addition, SASP mediators were found to be upregulated in response to short duration treatment with gemcitabine in both immortalized and primary CAFs. Inhibition of stress-associated MAPK signaling (P38 MAPK or JNK) attenuated SASP induction as well as the tumor-supportive functions of chemotherapy-treated CAFs in vitro and in vivo These results identify a negative consequence of chemotherapy on the PDAC microenvironment that could be targeted to improve the efficacy of current therapeutic regimens. Chemotherapy treatment of pancreatic cancer-associated fibroblasts results in a proinflammatory response driven by stress-associated MAPK signaling that enhances tumor cell growth and invasiveness. Mol Cancer Res; 14(5); 437-47. ©2016 AACR.

Toste PA ，Nguyen AH ，Kadera BE ，Duong M ，Wu N ，Gawlas I ，Tran LM ，Bikhchandani M ，Li L ，Patel SG ，Dawson DW ，Donahue TR ... -  《-》

Inhibiting tumor necrosis factor-alpha diminishes desmoplasia and inflammation to overcome chemoresistance in pancreatic ductal adenocarcinoma.

Zhao X ，Fan W ，Xu Z ，Chen H ，He Y ，Yang G ，Yang G ，Hu H ，Tang S ，Wang P ，Zhang Z ，Xu P ，Yu M ... -  《Oncotarget》