Tumor Derived IGFBP2 Promotes Metastasis Of Pancreatic Cancer Through M2 Macrophages

BackgroundPancreatic ductal adenocarcinoma,usually referred to as pancreatic cancer,is one of the lethal tumors in humans and is known as the "king of cancer".The early onset of pancreatic cancer is insidious,and the early symptoms are not obvious.There are often symptoms such as weight loss,loss of appetite,and back pain.Therefore,many patients have already developed distant metastases when they see a doctor,and it is difficult to perform surgical treatment;and there are many patients who can receive surgical treatment.Distant metastases will occur after surgery.Therefore,analyzing the mechanism of pancreatic cancer metastasis is of great significance for the diagnosis and treatment of pancreatic cancer.Most previous studies have focused on the substance of pancreatic cancer,and the final transformation effect is not ideal.Our study found that IGFBP2 in the parenchyma of pancreatic cancer can promote the metastasis of pancreatic cancer through M2 macrophages in the interstitium.After taking corresponding intervention measures for IGFBP2-M2 macrophages,it can reduce the metastasis of pancreatic cancer.This not only confirms the mutual influence between the tumor parenchyma and the interstitium of pancreatic cancer,but also suggests that we should take effective intervention measures for the interstitial components of the tumor in addition to measures for the parenchymal tumor cells when studying the diagnosis and treatment of pancreatic cancer.This is expected to bring a new direction to the diagnosis and treatment of pancreatic cancer.Purpose1.The mechanism of IGFBP2 promoting the increase of M2 macrophage infiltration in pancreatic cancer2.The mechanism of IGFBP2 promoting M2-type polarization of macrophages3.Explore the feasibility of blocking IGFBP2-M2 macrophages to reduce pancreatic cancer metastasisMethods1.We collected postoperative specimens and pathological data of 137 patients with pancreatic cancer,and analyzed the correlation between the expression level of IGFBP2,the number of M2 macrophage infiltration and the metastasis of pancreatic cancer;2.Treat macrophages with the medium supernatants of pancreatic cancer cell lines overexpressing IGFBP2 and control cell lines to confirm that IGFBP2 promotes the phenomenon of M2 type polarization of macrophages.The macrophages were treated with IGFBP2 recombinant protein,exosomes derived from overexpressing IGFBP2 cell stable lines and control cells,respectively,to confirm its promotion of M2 type polarization of macrophages;3.Use Western Blot,real-time fluorescent quantitative PCR,immunofluorescence and other technologies to confirm the specific mechanism of pancreatic cancer to promote the M2 polarization of macrophages through its secreted IGFBP2;.4.Through the stable line of IGFBP2 point mutation and the stable line of IGFBP2 with the signal peptide removed,it is confirmed that IGFBP2 can also promote the M2-type polarization of macrophages through exosomes.Use micro RNA sequencing technology to confirm the specific molecules in exosomes that promote the M2-type polarization of macrophages and their specific mechanisms;5.Intervene in the above-mentioned mechanism to explore the feasibility and effectiveness of blocking IGFBP2-M2 macrophages to reduce pancreatic cancer metastasis.Results1.The expression level of IGFBP2 in pancreatic cancer and the number of M2 macrophages infiltrated are positively correlated with pancreatic cancer metastasis;2.Pancreatic cancer can act on ILK in macrophages through secreted IGFBP2 to reduce the expression of PTEN,thereby promoting the M2 polarization of macrophages.3.In pancreatic cancer,IGFBP2 can up-regulate the expression level of miR-221 through transcriptional regulation,and then transfer miR-221 to macrophages through exosomes,resulting in a decrease in PTEN expression,thereby reducing the M1 type polarization of macrophages.Increase the M2-type polarization of macrophages;4.It has been verified by experiments in mice that both the removal of mononuclear-macrophages in mice and the removal of exosomes in mice can significantly reduce the occurrence of pancreatic cancer metastasis.Conclusion1.Pancreatic cancer can directly promote the M2 polarization of macrophages through the secreted IGFBP2;2.IGFBP2 in pancreatic cancer cells can up-regulate the expression of miR-221 through transcriptional regulation,and after being transported to macrophages via exosomes,it promotes M2-type polarization by inhibiting the expression of PTEN;3.The increased infiltration of M2 type macrophages can promote the metastasis of pancreatic cancer;4.Clearing macrophages and clearing exosomes to reduce the infiltration of M2 macrophages can effectively reduce the occurrence of pancreatic cancer metastasis.