Fig. 4: PDAC cell-secreted CXCL2/5 activates the CXCR2-mTORC2-Cox2-PGE2 axis in fibroblasts for stress adaptation of PDAC cells.

a WB analyses of Cox2 and GAPDH (sample processing controls) in mPSCs (3D culture) incubated with recombinant CXCL2 (0.5βng/mL) or CXCL5 (0.1βΒ΅g/mL) for 24βh. Representative data of two independent repeats. b WB analysis of Cox2 and GAPDH (sample processing controls) in NIH3T3 cells treated with CM from Panc02.shCtrl, Panc02.shCXCL2, or Panc02.shCXCL5 cells cultured in 0% FBS for 72βh. Representative data of two independent repeats. c PGE2 concentration in CM from NIH3T3 cells treated with recombinant CXCL2 (0.5βng/mL) or CXCL5 (0.1βΒ΅g/mL) for 48βh (meanβΒ±βSD, t-test, nβ=β3 biological repeats). d Relative numbers of Panc02 cells treated with PGE2 in 0% FBS for 48βh (meanβΒ±βSD, t-test, nβ=β3 biological repeats). e Relative numbers of PANC-1 cells in upper chambers of Transwell units 3D-cocultured with hPSCs in lower chambers of Transwell units with or without Cel (4βnM) and Gem (20βnM) for 72βh (meanβΒ±βSD, t-test, nβ=β3 biological repeats). f Relative number of Panc02 cells treated with CM from WT mPSCs or Cox2β/β mPSCs activated by CM from Panc02 cells in 0% FBS for 48βh (meanβΒ±βSD, t-test, nβ=β3 biological repeats). g RPPA analysis of NIH3T3 cells treated with CM collected from Panc02.shCtrl and Panc02.shΞΆ cells cultured in 10% or 0% FBS medium. h WB analysis of pT346-NDRG1, NDRG1, and GAPDH (sample processing controls) in 3D-cultured hPSCs treated for 24βh with CM collected from 3D-cultured PANC-1.shCtrl and PANC-1.shΞΆ cells treated with vehicle/Gem (20βnM) for 24βh. Representative data of two independent repeats. i WB analysis of pT346-NDRG1, NDRG1, pS473-Akt, Akt, and GAPDH (sample processing controls) expression in 3D-cultured hPSCs treated with recombinant CXCL2 (15βng/mL) or CXCL5 (25βng/mL) for 24βh. Representative data of two independent repeats. j WB analysis of Rictor, pT346-NDRG1, NDRG1, Cox2, and GAPDH (sample processing controls) protein in NIH3T3.shCtrl and NIH3T3.shRictor cells treated for 24βh with recombinant CXCL2 (0.5βng/mL) or recombinant CXCL5 (0.1βΒ΅g/mL). Representative data of two independent repeats. k, l IHC staining of indicated proteins of PDAC tumor tissues from KPC and KPC-ΞΆfl/fl mice with indicated treatments (meanβΒ±βSD, t-test, nβ=β5 biological repeats, scale bar: 20βΒ΅m). m PDAC cells and fibroblasts together create the adaptive stress response circuit, which is essential for PDAC cell adaptation to stresses, including nutrient deprivation and chemotherapy-induced genotoxicity. Stressors promote the Yap1-CXCL2/5 signaling axis via NLK in 14-3-3ΞΆ-overexpressing PDAC cells, leading to the activation of the CXCR2-mTORC2-Cox2-PGE2 pathway in fibroblasts. Reciprocally, PGE2 from fibroblasts promotes PDAC cell survival and adaptive resistance to Gem.