CXCL5 induces tumor angiogenesis via enhancing the expression of FOXD1 mediated by the AKT/NF-κB pathway in colorectal cancer.

The mechanisms underlying the role of CXCL5 in tumor angiogenesis have not been fully defined. Here, we examined the effect of CXCL5 on tumor angiogenesis in colorectal cancer (CRC). Immunohistochemistry was used to monitor the expression of CXCL5 and CD31 in CRC patients' tissues. HUVEC cell lines stably transfected with shCXCR2 and shFOXD1 lentivirus plasmids were used in an in vitro study. Based on some molecular biological experiments in vitro and in vivo, we found that CXCL5 was upregulated in tumor tissues and that its level positively correlated with the expression of CD31. Next, we used recombinant human CXCL5 (rhCXCL5) to stimulate HUVECs and found that their tube formation ability, proliferation, and migration were enhanced by the activation of the AKT/NF-κB/FOXD1/VEGF-A pathway in a CXCR2-dependent manner. However, silencing of CXCR2 and FOXD1 or inhibition of the AKT and NF-κB pathways could attenuate the tube formation ability, proliferation, and migration of rhCXCL5-stimulated HUVECs in vitro. rhCXCL5 can promote angiogenesis in vivo in Matrigel plugs, and the overexpression of CXCL5 can also increase microvessel density in vivo in a subcutaneous xenotransplanted tumor model in nude mice. Taken together, our findings support CXCL5 as an angiogenic factor that can promote cell metastasis through tumor angiogenesis in CRC. Furthermore, we propose that FOXD1 is a novel regulator of VEGF-A. These observations open new avenues for therapeutic application of CXCL5 in tumor anti-angiogenesis.

Bone marrow-derived mesenchymal stromal cells promote colorectal cancer cell death under low-dose irradiation.

BACKGROUND: Radiotherapy remains one of the cornerstones to improve the outcome of colorectal cancer (CRC) patients. Radiotherapy of the CRC not only help to destroy cancer cells but also remodel the tumour microenvironment by enhancing tumour-specific tropism of bone marrow-derived mesenchymal stromal cell (BM-MSC) from the peripheral circulation. However, the role of local MSCs and recruited BM-MSC under radiation were not well defined. Indeed, the functions of BM-MSC without irradiation intervention remained controversial in tumour progression: BM-MSC was previously shown to modulate the immune function of major immune cells, resulting in an impaired immunological sensitivity and to induce an increased risk of tumour recurrence. In contrast, it could also secrete various cytokines and possess anticancer effect. METHODS: Three co-cultivation modules, 3D culture modules, and cancer organoids were established. The induction of cytokines secretion in hBM-MSCs after irradiation was analysed by ELISA array and flow cytometry. AutoMac separator was used to separate hBM-MSC and CRC automatically. Cells from the co-cultured group and the control group were then irradiated by UV-C lamp and X-ray. Proliferation assay and viability assay were performed. RESULTS: In this study, we show that BM-MSCs can induce the EMT progression of CRC cells in vitro. When irradiated with low doses of ultraviolet radiation and X-rays, BM-MSCs show an anti-tumour effect by secreting certain cytokine (TNF-α, IFN-γ) that lead to the inhibition of proliferation and induction of apoptosis of CRC cells. This was further verified in a 3D culture model of a CRC cell in vitro. Furthermore, irradiation on the co-culture system induced the cleavage of caspase3, and attenuated the phosphorylation of phosphatidylinositol 3-kinase (PI3K)/AKT and extracellular signal-regulated kinase in cancer cells. The signal pathways above might contribute to the cancer cell death. CONCLUSIONS: Taken together, we show that BM-MSC can potentially promote the effect of radiotherapy in CRC.

CCR6 promotes tumor angiogenesis via the AKT/NF-κB/VEGF pathway in colorectal cancer.

Chemokines and chemokine receptors play an important role in tumorigenesis. Angiogenesis is a vital part of the occurrence, development and metastasis of cancer. CCR6 is an important factor during tumor progression; however, its function in tumor angiogenesis is not fully understood. In our study, we found that CCR6 was significantly overexpressed in colorectal cancer (CRC) tissues and predicted a poor prognosis in CRC patients. We then verified the function of CCR6 on tumor angiogenesis in vivo and in vitro. We observed that silencing CCR6 could decrease angiogenesis by inhibiting the proliferation and migration of human umbilical vein endothelial cells (HUVECs), whereas overexpression of CCR6 can promote angiogenesis. Additionally, we investigated the molecular mechanisms and demonstrated that activation of the AKT/NF-κB pathway maybe involved in CCR6-mediated tumor angiogenesis, which was able to promote the secretion of vascular endothelial growth factor A (VEGF-A). In conclusion, CCR6 facilitates tumor angiogenesis via the AKT/NF-κB/VEGF pathway in colorectal cancer. CCR6 inhibition may be a novel option for anti-vascular treatment in CRC.

Homogeneous pancreatic cancer spheroids mimic growth pattern of circulating tumor cell clusters and macrometastases: displaying heterogeneity and crater-like structure on inner layer.

PURPOSE: Pancreatic cancer 3D in vitro models including multicellular tumor spheroid (MCTS), single cell-derived tumor spheroid (SCTS), tissue-derived tumor spheroid, and organotypic models provided powerful platforms to mimic in vivo tumor. Recent work supports that circulating tumor cell (CTC) clusters are more efficient in metastasis seeding than single CTCs. The purpose of this study is to establish 3D culture models which can mimic single CTC, monoclonal CTC clusters, and the expansion of macrometastases. METHODS: Seven pancreatic ductal adenocarcinoma cell lines were used to establish MCTS and SCTS using hanging drop and ultra-low attachment plates. Spheroid immunofluorescence staining, spheroid formation assay, immunoblotting, and literature review were performed to investigate molecular biomarkers and the morphological characteristics of pancreatic tumor spheroids. RESULTS: Single cells experienced different growth patterns to form SCTS, like signet ring-like cells, blastula-like structures, and solid core spheroids. However, golf ball-like hollow spheroids could also be detected, especially when DanG and Capan-1 cells were cultivated with fibroblast-conditioned medium (p < 0.05). The size of golf ball-like hollow spheroids hardly grew after getting matured. Only DanG and Capan-1 could establish SCTS- and MCTS-derived hollow spheroids using hanging drop plates and ultra-low attachment plates. Other PDA cell lines could also establish tumor spheroid with hanging drop plates by adding methylated cellulose. Tumor spheroids derived from pancreatic cancer cell line DanG possessed asymmetrically distributed proliferation center, immune-checkpoint properties. ß-catenin, Ki-67, and F-actin were active surrounding the crater-like structure distributing on the inner layer of viable rim cover of the spheroids, which was relevant to well-differentiated tumor cells. CONCLUSIONS: It is possible to establish 3D CTC cluster models from homogenous PDA cell lines using hanging drop and ultra-low attachment plates. PDA cell line displays its own intrinsic properties or heterogeneity. The mechanism of formation of the crater-like structure as well as golf ball-like structure needs further exploration.