Effects Of Matrix Stiffness On Primary Pancreatic Cancer...

3. Results (620-current730) 3.1 Softer substrate regulates proliferation of primary pancreatic cancer cells To study the effects of matrix stiffness on primary pancreatic cell proliferation, we first developed a 2D hydrogel system with stiffness (SSM) that mimic those of healthy pancreatic tissue and cancerous pancreas previously characterized. Briefly, the cancerous pancreatic tissue had a larger range of SSM (2kPa – 30kPa) and a higher average SSM than normal tissue (0.8 – 4 kPa). Consequently, to account for the variability of stiffness on cancerous tissue, our model included two groups of PA hydrogels with Acrylamide:Bisacrylamide (Ac:Bis) ratios of: (1) 6%:0.075% and (2) 10%:0.075% 25kPa yielding an average SSM of 8kPa and 25kPa†¦show more content†¦We examined the viability of the cells in response to the chemotherapeutic as a function of the matrix stiffness (Figure 2C). We observed that as the cells underwent apoptosis they detached from the substrates. Consequently, we collected the media before (Day 7) and after (Day 10) the chemotherapy to quantify the nu mber of cells in suspension. As depicted on Figure 2C, the PC cells cultured on softer substrates experience larger increase in dead cells resulting from the chemotherapy compared to the PC cells growing on stiffer substrates. As Figure 2A shows, both Gemcitabine concentrations lead to a change in cell morphology and a higher decrease in cell area on the softer PC tumors (3kPa and 8kPa) compared to the stiffer PC tumors (25kPa and control group). To further explore the effect of matrix stiffness on the response of PC cells to chemotherapy, we used enzymatic activity as a metric of cell proliferation. We perform alamarBlue ® assay before adding the Gemcitabine treatment and after 72hrs of treatment. As depicted in Figure 2B, there is a dramatic (x-x for 2um and xx for 5uM) decrease of the enzymatic activity of the PC cells growing on softer substrates in response to the chemotherapy. On the other hand, the PC cells growing on stiffer matrices shows no decrease of enzymatic activity when treated with 2  µM of Gemcitabine and a xx when treated with 5 µM of