Antitumor effect of insulin-like growth factor-1 receptor inhibition in head and neck squamous cell carcinoma

Oral submucous fibrosis stimulates invasion and epithelial-mesenchymal transition in oral squamous cell carcinoma by activating MMP-2 and IGF-IR

Oral submucous fibrosis (OSF) involves a high risk of malignant transformation and has been implicated in oral cancer. Limited studies have been conducted on the role of OSF in relation to the invasive capabilities and epithelial-mesenchymal transition (EMT) in oral cancer. Herein, we investigated the effects of OSF on the microenvironment of human oral cancer cells. The results showed that the conditioned medium (CM) of fibrotic buccal mucosal fibroblasts (fBMFs) strongly induced the invasion of oral cancer cells and increased the activities of matrix metalloproteinase-2. OSF significantly induced the EMT in oral cancer cells and downregulated epithelial markers, such as E-cadherin, but significantly elevated vimentin, fibronectin, N-cadherin, RhoA, Rac-1 and FAK. Insulin-like growth factor-1 (IGF-1) was elevated in OSF. The protein levels of the IGF-1R were upregulated specifically in fBMF CM treatment for oral cancer cells, and the IGFR gene was confirmed by The Cancer Genome Atlas patient transcriptome data. The Kaplan-Meier curve analysis revealed that patients with oral squamous cell carcinoma and high IGFR expression levels had poorer 5-year survival than those with low IGFR expression (p = 0.004). The fBMF-stimulated EMT cell model may recapture some of the molecular changes during EMT progression in clinical patients with oral cancer.

Unraveling the Resistance of IGF-Pathway Inhibition in Ewing Sarcoma

Simple Summary

The insulin-like growth factor-1 receptor (IGF1R) is a receptor commonly overexpressed and overactivated in a variety of cancers, including Ewing sarcoma, and promotes cell growth and survival. After promising results with targeting and inhibiting the receptor in vitro, multiple different IGF1R targeting compounds have been clinically tried but showed limited efficacy. Here we discuss several possible resistance mechanisms which could explain why IGF1R targeting fails in the clinic and discuss possible ways to overcome these resistances.

Abstract

Insulin-like growth factor-1 receptor (IGF1R) inhibitors are effective in preclinical studies, but so far, no convincing benefit in clinical studies has been observed, except in some rare cases of sustained response in Ewing sarcoma patients. The mechanism of resistance is unknown, but several hypotheses are proposed. In this review, multiple possible mechanisms of resistance to IGF-targeted therapies are discussed, including activated insulin signaling, pituitary-driven feedback loops through growth hormone (GH) secretion and autocrine loops. Additionally, the outcomes of clinical trials of IGF1-targeted therapies are discussed, as well as strategies to overcome the possible resistance mechanisms. In conclusion, lowering the plasma insulin levels or blocking its activity could provide an additional target in cancer therapy in combination with IGF1 inhibition. Furthermore, because Ewing sarcoma cells predominantly express the insulin receptor A (IRA) and healthy tissue insulin receptor B (IRB), it may be possible to synthesize a specific IRA inhibitor.

Circulating Insulin-Like Growth Factor-1 and Risk of Total and 19 Site-Specific Cancers: Cohort Study Analyses from the UK Biobank

BACKGROUND

Insulin-like growth factor-1 (IGF-1) has been implicated in several malignancies, but few studies have examined multiple cancers simultaneously. We sought to conduct systematic assessments of the association between IGF-1 and cancer risk.

METHODS

We conducted a prospective analysis between IGF-1 and incident total and 19 site-specific cancers among 412,645 individuals enrolled in the UK Biobank with follow-up to 2016. IGF-1 was measured using blood samples provided at the baseline examination. HR and 95% confidence interval (CI) were calculated with multivariable-adjusted Cox models with IGF-1 modeled both in sex-specific quintiles and continuously.

RESULTS

Participants were followed for a median of 7.2 years. We observed positive associations between circulating IGF-1 and overall cancer risk for both men (HR = 1.03 per 5-nmol/L increment in IGF-1; 95% CI, 1.01-1.06) and women (HR = 1.03; 95% CI, 1.01-1.06). For specific sites, we observed positive associations for breast (HR = 1.10; 95% CI, 1.07-1.14), prostate (1.09; 95% CI, 1.05-1.12), colorectum (1.07; 95% CI, 1.02-1.11), melanoma (1.08; 95% CI, 1.01-1.15), kidney (1.10; 95% CI, 1.00-1.20), and thyroid (1.22; 95% CI, 1.05-1.42) and inverse associations for lung (0.91; 95% CI, 0.86-0.96), ovaries (0.86; 95% CI, 0.77-0.95), head and neck (0.90; 95% CI, 0.82-0.99), and liver (0.32; 95% CI, 0.26-0.38). The inverse association between IGF-1 and lung cancer was observed only in ever-smokers (HR_ever-smoker = 0.88 vs. HR_never-smoker = 1.14; P_interaction = 0.0005). Analyses comparing extreme quintiles were consistent.

CONCLUSIONS

IGF-1 is modestly associated with increased risk of total cancer in both men and women but demonstrated divergent associations for site-specific cancers.

IMPACT

Our study suggests that IGF-1 could serve as a target for cancer prevention or treatment.