Metastasis Prediction: Mechanobiology-based Determination of Metastatic Risk in Pancreatic Tumors

Background: The main cause of cancer-related deaths is metastasis. A critical step in metastases formation is invasion of cancer cells through tissue. Invading metastatic cells are dynamic, rapidly changing morphology and applying forces to their surroundings. Evaluating forceful interactions of cells on an impenetrable, synthetic gel, we have previously shown that subsets of invasive breast-cancer cells indent gels while benign cells do not. The reliable separation between cells with high and low metastatic potential (MP) was achieved. Here, we show that the mechanical invasiveness of fresh, human, primary-site pancreatic tumors agrees with the clinical histopathology and matches results in established cell-lines.

Methods: We have seeded cells from pancreatic cell-lines or from fresh, human pancreatic tissue samples on physiological-stiffness polyacrylamide gels. Within 1-hr of seeding, we determine percentage of indenting cells and the attained depths, using fluorescence microscopy. In cell-lines, we relate to amount of cells trespassing 8µm-pores of transwell migration assay within 72h. For tumor samples, clinical histopathology and patient outcomes are used as gold-standard.

Results: We quantitatively distinguished between pancreatic cell-lines with high and low MP in a statistically-significant manner; we found high correlation of our invasiveness results with transwell migration assay. Results obtained in cell-lines match tumor samples. The indentation depths and amounts of indenting cells from metastatic adenocarcinoma tumors were significantly higher compared to non-invasive fibrotic tumors.

Conclusion: We provide rapid (2hr) prediction for metastatic likelihood in agreement with the clinical histopathology and patient’s outcome. Early prediction can critically affect choice of patient-specific treatment and increase life-expectancy.