We generated an antibody specific for phosphorylated PD-1-Y248 and examined PD-1pY248<sup>+</sup> (pPD-1) expression in human T cells. pPD-1 was upregulated by TCR/CD3 + CD28 stimulation and simultaneous PD-1 ligation. pPD-1<sup>+</sup>CD8<sup>+</sup> T cells were identified in human peripheral blood and had impaired effector function. pPD-1<sup>+</sup> T cells were also detected in tumor-draining lymph nodes of tumor bearing mice and in biopsies of patients with glioblastoma multiform.
Hepatic expression of IGFBPrP1, α-smooth muscle actin (α-SMA), transforming growth factor β 1 (TGFβ1), collagen I, MMPs/TIMPs, Sonic Hedgehog (Shh), and glioblastoma family transcription factors (Gli1) were investigated by immunohistochemical staining and Western blotting analysis.
After polydatin treatment, the main components of the Shh pathway, including Shh, Patched (Ptc), Smoothened (Smo), and glioblastoma-1 (Gli1), were upregulated at the mRNA and protein levels.
Taken together, our results indicate that overall glioblastoma tumor growth suppression by penfluridol was associated with Akt-mediated inhibition of GLI1.
Further investigation found that the expression of the glioblastoma transcription factor (Gli) significantly increased in TGF-β1-stimulated neuroblastoma cells undergoing EMT, accordingly, interfering with Gli1/2 expression inhibited TGF-β1-induced EMT in neuroblastoma cells.
Cyclopamine treatment effectively increased apoptosis and inhibited cell proliferation, migration, and epithelial-to-mesenchymal transition (EMT) by downregulating the Hh final arbiter glioblastoma 1 (Gli1), which regulates the transcription of target genes in the nucleus.
A mutation in Patched, Smoothened or Gli1, which regulate the Hh signaling pathway, might lead to the onset of glioblastoma, basal cell carcinoma, medulloblastoma and rhabdomyosarcoma.
These results provide further insight into the oncogenic mechanisms of the HH pathway in glioblastoma and demonstrate a cooperative signaling axis between the HH/GLI1 and IGF pathways to propagate malignant GSC phenotypes.
The molecular cloning of the gli gene from a glioblastoma illustrates the powerful analytic nature of these laboratory techniques and the investigative potential of a cloned gene.