Knockdown of P4HA1 inhibits neovascularization via targeting glioma stem cell-endothelial cell transdifferentiation and disrupting vascular basement membrane

Abstract

Emerging evidence has demonstrated transdifferentiation process of glioma stem cells (GSCs) into endothelial cells (ECs) in glioma neovascularization. Herein, we focused on screening for genes that were differentially expressed in the transdifferentiation process using microarray analysis. Bioinformatics analysis revealed differential expression of the prolyl 4-hydroxylase subunit alpha-1 (P4HA1) gene. We determined that P4HA1 expression was correlated with histological grade, the level of Ki67 and microvessel density (MVD) in human glioma specimens. Knockdown of P4HA1 inhibited the proliferation, migration and tube formation of GSCs in vitro. In vivo studies revealed that the downregulation of P4HA1 inhibited intracranial tumor growth, prolonged the overall survival time of xenograft mice and suppressed the neovascularization in brain tumors. Moreover, P4HA1 regulates the expression of vascular endothelial growth factor A (VEGF-A), especially an anti-angiogenic isoform-VEGF165b. Additionally, knockdown of P4HA1 inhibited the synthesis of collagen IV, and hence disrupted the structures of vascular basement membranes (BMs) in gliomas. Our study indicates that P4HA1 plays a pivotal role in the process of GSC-EC transdifferentiation and the structural formation of vascular BMs.

Identification and Characterization of Metastasis-Associated Individualized Gene Expression Signature in Osteosarcoma

“…In prognosis-related GMPSs network, gene P4HA1 was a key node with highest degree. The previous study has reported that P4HA1 was the active catalytic component of prolyl 4-hydroxylase in cancers [28], glioma [29], prostate cancer [30] and pancreatic cancer [31], P4HA1 can promote chemoresistance, tumor growth and metastasis. The prognosis-related gene CD53 could form a MGPS with P4HA1 in OS patients.…”

Prolyl 4‐hydroxylase subunit alpha 1 (P4HA1) is a biomarker of poor prognosis in primary melanomas, and its depletion inhibits melanoma cell invasion and disrupts tumor blood vessel walls

“…In our analyses of primary melanoma tumors, both the tumor cells and the stromal fibroblasts produced P4HA1, although the tumor cells appeared to be the main producers. Also in other cancers, such as gliomas and prostate cancer, P4HA1 staining has mostly been reported in the tumor cells (Chakravarthi et al , ; Zhou et al , ). This is interesting, as fibroblasts are considered the main producers of collagens, which are the most important substrates for P4HA1.…”

“…Knockdown of P4HA1 has been reported to inhibit cancer cell proliferation in vitro and reduce tumor growth in xenograft models of breast and prostate cancer and gliomas (Chakravarthi et al , ; Gilkes et al , ; Zhou et al , ). In our melanoma model, the silencing of P4HA1 did not appear to interfere with tumor cell proliferation in vitro or in vivo , as assessed by staining with the cell proliferation marker Ki‐67 .…”

Inflammatory activation of microglia by Staphylococcus aureus caused phenotypic alterations and affected glioblastoma growth

“…To establish intracranial orthotopic tumour models, mice were anaesthetised with isoflurane and stabilized in a stereotactic apparatus (KOPF, USA). Then, a total of 2 × 10 4 GL261 cells were injected into the right striatum (1.8 mm medio‐lateral, 0.8 mm anterior‐posterior, and 3 mm dorso‐ventral) as previously described . The secondary injection of S. aureus or BV2 cells was given at the same location.…”

“…Then, a total of 2 × 10 4 GL261 cells were injected into the right striatum (1.8 mm medio-lateral, 0.8 mm anterior-posterior, and 3 mm dorso-ventral) as previously described. 16,17 The secondary injection of S. aureus or BV2 cells was given at the same location.…”