Phospholipase D activation mediates growth and migration of colon cancer cells interacting with cancer-associated fibroblasts.

Cancer-associated fibroblasts of the stroma play a major role in tumor promoting processes. In this study we evaluated the significance of Phospholipase D (PLD) enzyme activity in promoting human colon cancer malignant potency when interacting with proximal colonic fibroblasts. Human colon cancer cell lines SW480 and HCT116, and colonic fibroblasts CCD-18Co were used as an in vitro model. PLD's activity was measured in resting cancer cells and after culturing with fibroblasts and cancer-associated fibroblasts (CAFs) conditioned medium. The viability and migration level of the cancer cells alone and after co-culturing with fibroblast or CAFs conditioned medium were evaluated, with and without adding a PLD inhibitor. Exposure of colon cancer cells to CAFs conditioned medium significantly increased the level of PLD activity in the cancer cells (p<0.0001). Exposure of colon cancer to resting and activated fibroblast conditioned medium significantly enhanced the number of viable cancer cells as well as its migration level measured following 24 and 48 hours. Adding a PLD inhibitor significantly reduced the elevation of cell viability and migration of the colon cancer cells exposed to fibroblasts conditioned medium (p<0.005). In this in vitro model, inhibition of PLD significantly decreased proliferation and migration levels of colon cancer cells generated by stromal fibroblasts. This provides evidence that the PLD signaling pathway is directly involved in stroma-cancer interactions in the colon, thereby promoting cancer progression. Further research is needed in order to evaluate PLD as a target in colon cancer prevention or therapy.

Inhibition of TNFα in peritoneal fluids of patients following colorectal resection attenuates the postoperative stress-related increase in colon cancer cell migration: A prospective, in vitro study.

BACKGROUND AND OBJECTIVES: Surgical trauma in patients undergoing colorectal cancer resection generates local and systemic inflammatory responses that can affect oncological outcomes. Post-operative peritoneal fluids of patients undergoing colorectal surgery increase the pro-malignant effect of cancer cells in vitro with correlation to elevated TNFα in these fluids. This study evaluated whether inhibiting TNFα in patients' postoperative fluid biopsies would attenuate this effect. METHODS: Peritoneal fluids from 53 patients undergoing colorectal surgery were sampled before and daily after surgery via intra-abdominal drains. Fluid biopsies were evaluated for their impact on the migration capacity of colon cancer cells and for cytokine levels. TNFα was inhibited using infliximab and cell migration was reevaluated. RESULTS: Colon cancer migration capacity was increased in postoperative fluid biopsies from all patients (P < 0.005) and was elevated compared to pre-resection levels. Infliximab attenuated this effect in >90%, decreasing migration capacity by 30% (p < 0.001). CONCLUSIONS: Inhibition of TNFα in postoperative peritoneal fluids attenuates the increase in cancer cell migration capacity generated following colorectal resection. These findings correlate with other studies suggesting that attenuation of the post-operative inflammatory response may have oncological benefit. Clinical studies are needed to evaluate the effect of peri-operative TNFα inhibition in clinical settings.

Postcolectomy Peritoneal Environment Increases Colon Cancer Cell Migration Capacity.

Background. Clinical data and animal models support an association between postoperative inflammatory response and the risk of colorectal cancer recurrence. Our aim was to evaluate postoperative peritoneal inflammation and its impact on cultured colon cancer cells' migration capacity. Methods. 23 patients undergoing elective colorectal resection with uneventful recovery were prospectively enrolled. Patients were operated on for both malignant and benign etiologies. Peritoneal fluids collected at surgery initiation and after surgery were evaluated for their effect on migration potential of human colon cancer cells using an in vitro scratch assay and on TNF-α, IL-1ß, IL-6, and IL-10 levels using bead-based fluorokine-linked multianalyte profiling. Results. Postoperative peritoneal fluid from all patients increased the migration capacity of colon cancer cells compared to preoperative levels. This effect was significant during the first two postoperative days and decreased thereafter. The increase in colon cancer cell migration capacity correlated with increased levels of peritoneal TNF-α and IL-10. Conclusion. In this pilot study, we have demonstrated that the intraperitoneal environment following colorectal resection significantly enhances colon cancer cells migration capacity. This effect is associated with postoperative intra-abdominal cytokines level. A larger scale study in colorectal cancer patients is needed in order to correlate these findings with perioperative parameters and clinical outcome.