Effects of IGF-1 on Proliferation, Angiogenesis, Tumor Stem Cell Populations and Activation of AKT and Hedgehog Pathways in Oral Squamous Cell Carcinoma

Abstract

(1) Background: Activation of the PI3K-AKT pathway controls most hallmarks of cancer, and the hedgehog (HH) pathway has been associated with oral squamous cell carcinoma (OSCC) development and progression. We hypothesized that fibroblast-derived insulin-like growth factor-1 (IGF-1) acts in oral squamous cell carcinoma (OSCC) cells, leading to the non-canonical activation of the HH pathway, maintaining AKT activity and promoting tumor aggressiveness. (2) Methods: Primary fibroblasts (MF1) were genetically engineered for IGF-1 overexpression (MF1-IGF1) and CRISPR/Cas9-mediated IGF1R silencing was performed in SCC-4 cells. SCC-4 cells were co-cultured with fibroblasts or incubated with fibroblast conditioned medium (CM) or rIGF-1 for functional assays and the evaluation of AKT and HH pathways. (3) Results: Gene expression analysis confirmed IGF-1 overexpression in MF1-IGF1 and the absence of IGF-1 expression in SCC-4, while elevated IGF1R expression was detected. IGF1R silencing was associated with decreased survival of SCC-4 cells. Ihh was expressed in both MF1 and MF1-IGF1, and increased levels of GLI1 mRNA were observed in SCC-4 after stimulation with CM-MF1. Activation of both PI3K-AKT and the HH pathway (GLI1, Ihh and SMO) were identified in SCC-4 cells cultured in the presence of MF1-IGF1-CM. rIGF-1 promoted tumor cell proliferation, migration, invasion and tumorsphere formation, whereas CM-MF1 significantly stimulated angiogenesis. (4) Conclusions: IGF-1 exerts pro-tumorigenic effects by stimulating SCC-4 cell proliferation, migration, invasion and stemness. AKT and HH pathways were activated by IGF-1 in SCC-4, reinforcing its influence on the regulation of these signaling pathways.

Potential Use of Anti-Cancer Drugs for Treatment of Preeclampsia by Targeting the miRNA-IGF1R-PI3K-AKT Axis

“…It is therefore likely that such connections exist between hsa-let-7c and IGF1R/PI3K/Akt. The PI3K/Akt signaling pathways are common to PE and play key roles in many cellular processes [ 26 ], such as invasion of trophoblast [ 27 ], angiogenesis [ 28 ], and pro-inflammation [ 29 ]. Park JK demonstrated that inhibition of the PI3K-Akt pathway may decrease sFlt1 secretion in human placental hypoxia models, which provides a useful therapeutic approach for PE [ 30 ].…”

Cancer-Associated Fibroblasts in Oral Cancer: A Current Perspective on Function and Potential for Therapeutic Targeting

“…Fibroblasts have also shown to be a source of IGF-1 (insulin growth factor 1) in OSCC, which promotes tumour cell proliferation through activation of PI3K-AKT and Hedgehog signalling pathways [ 59 ]. The matrix-remodelling capabilities of CAF may also affect tumour proliferation [ 60 ]; CAF-secreted collagens, collagen8A1 and collagen11A1 [ 61 ], have been shown to modulate tumour cell growth through interaction with DDR1 (Discoidin domain receptor 1), which is overexpressed in HNSCC tissues.…”

Hedgehog/GLI1 Transcriptionally Regulates FANCD2 in Ovarian Tumor Cells: Its Inhibition Induces HR-Deficiency and Synergistic Lethality with PARP Inhibition.

“…Recent studies identified novel non-canonical regulation of GLI in various cancers. Especially, nuclear myocardin-related transcription factor in basal cell carcinoma [ 57 ], deregulated GSK3β in colon cancer cells [ 58 ], Ras–Raf–MEK ERK pathway in hepatocellular carcinoma [ 59 ], fibroblast-derived insulin-like growth factor-1 in oral squamous cell carcinoma [ 60 ], MAPK/ERK signaling in lung adenocarcinoma [ 61 ], transcriptionally-active androgen receptors in pancreatic cancer [ 62 ] and SOX2-BRD4 transcriptional complex in melanoma [ 63 ]. Additionally, studies in breast cancer models, EMT cells induce increased metastasis of weakly metastatic, non-EMT tumor cells in a paracrine manner, in part by non-cell autonomous activation of the GLI transcription factor.…”