PDGFB as a vascular normalization agent in an ovarian cancer model treated with a gamma-secretase inhibitor

Experimental study of the vascular normalization window for tumors treated with apatinib and the efficacy of sequential chemotherapy with apatinib in lung cancer-bearing mice and patients

In the tumor vascular system, the vascular structure is disordered, the morphology is abnormal, and the structure of the blood vessel walls is incomplete, leading to leakage of the blood vessel wall, elevated interstitial fluid pressure, and elevated blood flow resistance. These alterations lead to local microenvironmental changes, which mainly manifest as a lack of oxygen and acidosis, further affecting the efficacy of chemotherapy drugs. Antiangiogenic drugs can normalize the abnormalities caused by tumor angiogenesis, thereby transferring oxygen and drugs to tumor cells more efficiently through normalized blood vessels and enhancing the efficacy of chemotherapy drugs. Apatinib is a specific VEGFR‐2 inhibitor that blocks the transmission of the VEGF/VEGFR‐2 signaling pathway. In this study, we constructed a nude mouse xenograft model of lung cancer and administered apatinib at different doses and times to detect the normalization of reactive blood vessels through VEGF, α‐SMA, college‐IV, HIF‐1α, and MMP. The ultrastructure of tumor blood vessels was observed by electron microscopy, and the dose and timing of apatinib‐induced normalization of lung cancer in nude mice were confirmed. Then, we observed the inhibitory effect of apatinib combined with pemetrexed on transplanted tumors of lung cancer cells in nude mice at different time points and observed whether combination pemetrexed chemotherapy showed more significant effects in the time window of vascular normalization induced by apatinib. The inhibition of the growth of transplanted tumors was examined. Then 20 patients with advanced non–small cell lung cancer were enrolled, and apatinib sequential chemotherapy drugs were applied as a third‐line chemotherapy regimen to observe its clinical efficacy.

Convergence of Wnt and Notch signaling controls ovarian cancer cell survival

In the last 40 years ovarian cancer mortality rates have slightly declined and, consequently, it continues to be the fifth cause of cancer death in women. In the present study, we showed that β-catenin signaling is involved in the functions of ovarian cancer cells and interacts with the Notch system. Wnt and Notch systems showed to be prosurvival for ovarian cancer cells and their inhibition impaired cell proliferation and migration. We also demonstrated that the inhibition of β-catenin by means of two molecules, XAV939 and ICG-001, decreased the proliferation of the IGROV1 and SKOV3 ovarian cancer cell lines and that ICG-001 increased the percentage of IGROV1 cells undergoing apoptosis. The simultaneous inhibition of β-catenin and Notch signaling, by using the DAPT inhibitor, decreased ovarian cancer cell proliferation to the same extent as targeting only the Wnt/β-catenin pathway. A similar effect was observed in IGROV1 cell migration with ICG-001 and DAPT. ICG-001 increased the Notch target genes Hes-1 and Hey-1 and increased Jagged1 expression. However, no changes were observed in Dll4 or Notch 1 and 4 expressions. Our results suggest that Notch and β-catenin signaling co-operate in ovarian cancer to ensure the proliferation and migration of cells and that this could be achieved, at least partly, by the upregulation of Notch Jagged1 ligand in the absence of Wnt signaling. We showed that the Wnt pathway crosstalks with Notch in ovarian cancer cell functions, which may have implications in ovarian cancer therapeutics.

Integrin CD11b activation drives anti-tumor innate immunity

Myeloid cells are recruited to damaged tissues where they can resolve infections and tumor growth or stimulate wound healing and tumor progression. Recruitment of these cells is regulated by integrins, a family of adhesion receptors that includes integrin CD11b. Here we report that, unexpectedly, integrin CD11b does not regulate myeloid cell recruitment to tumors but instead controls myeloid cell polarization and tumor growth. CD11b activation promotes pro-inflammatory macrophage polarization by stimulating expression of microRNA Let7a. In contrast, inhibition of CD11b prevents Let7a expression and induces cMyc expression, leading to immune suppressive macrophage polarization, vascular maturation, and accelerated tumor growth. Pharmacological activation of CD11b with a small molecule agonist, Leukadherin 1 (LA1), promotes pro-inflammatory macrophage polarization and suppresses tumor growth in animal models of murine and human cancer. These studies identify CD11b as negative regulator of immune suppression and a target for cancer immune therapy.