Immunohistochemical evaluation of insulin-like growth factor I receptor status in cervical cancer specimens

Anti-Condyloma acuminata mechanism of microRNAs-375 modulates HPV in cervical cancer cells via the UBE3A and IGF-1R pathway

The present study aimed to identify the probable anti-Condyloma acuminata (CA) mechanism of microRNA-375 (miRNA-375) in human papillomavirus (HPV). Firstly, the overexpression of miRNA-375 significantly suppressed cell proliferation, increased lactate dehydrogenase activity and induced apoptosis in HPV-18(+) cervical cancer cells. The overexpression of miRNA-375 significantly increased caspase-3 and caspase-9 activities, induced B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated X protein, tumor protein 53 and cyclin-dependent kinase inhibitor 1 protein expression and suppressed cyclin D1 and survivin protein expression in HPV-18(+) cervical cancer cells. The overexpression of miRNA-375 significantly suppressed the levels of protein expression of ubiquitin-protein ligase E3A (UBE3A) and Insulin-like growth factor-1 receptor (IGF-1R) in HPV-18(+) cervical cancer cells. To conclude, it was identified that the probable anti-CA mechanism of miRNA-375 modulates HPV through the UBE3A and IGF-1R pathway in cervical cancer cells.

HPV16 Down-Regulates the Insulin-Like Growth Factor Binding Protein 2 to Promote Epithelial Invasion in Organotypic Cultures

Cervical cancer is a multi-stage disease caused by human papillomaviruses (HPV) infection of cervical epithelial cells, but the mechanisms regulating disease progression are not clearly defined. Using 3-dimensional organotypic cultures, we demonstrate that HPV16 E6 and E7 proteins alter the secretome of primary human keratinocytes resulting in local epithelial invasion. Mechanistically, absence of the IGF-binding protein 2 (IGFBP2) caused increases in IGFI/II signalling and through crosstalk with KGF/FGFR2b/AKT, cell invasion. Repression of IGFBP2 is mediated by histone deacetylation at the IGFBP2 promoter and was reversed by treatment with histone deacetylase (HDAC) inhibitors. Our in vitro findings were confirmed in 50 invasive cancers and 79 cervical intra-epithelial neoplastic lesions caused by HPV16 infection, where IGFBP2 levels were reduced with increasing disease severity. In summary, the loss of IGFBP2 is associated with progression of premalignant disease, and sensitises cells to pro-invasive IGF signalling, and together with stromal derived factors promotes epithelial invasion.

IGF axis and other factors in HPV-related and HPV-unrelated carcinogenesis (review)

The insulin-like growth factor (IGF) axis promotes the growth of cells, tissues and organs. IGF-1 is mainly produced in the liver but is also secreted from local tissues. In the circulation, IGF-1 is bound to insulin-like binding proteins (IGFBPs), and when released it activates the insulin-like growth factor receptor (IGF-1R). The signal is further transmitted by intracellular signaling pathways leading to gene expression that regulates, among others, cell proliferation and survival. This review presents the IGF axis in the context of cell transformation and cancer development. Aspects involving IGF-1 deficiency and protection from cancer are also briefly described. Furthermore, human papillomaviruses (HPVs) interplaying with IGF axis components in cervical cancer development are described. These small dsDNA viruses are divided into low-risk and high-risk HPVs with regard to the potency of their oncogenic actions; they mainly infect epithelial or mucosal cells. Special attention is drawn to expression of two major HPV oncogenes (E6 and E7) initiating and maintaining cervical carcinogenesis, which is a multistep and multifactorial process; therefore, involvement of additional factors such as mitochondrial DNA changes, sex hormones, retinoic and folic acids are also discussed. Finally, IGF axis components and HPV oncogenes as targets in anticancer treatment are presented which include IGF-1R downregulation, RNA interference and anti-HPV therapeutic vaccines. The review concludes that despite an enormous advancement in research on IGF and HPV-related cancers, more molecular studies and clinical trials are needed before commercialized therapies are widely available for oncology patients.

Expression of hypoxic signaling markers in head and neck squamous cell carcinoma and its clinical significance

Hypoxia is a consistent finding in fast-growing tumors; it contributes to tumor progression and therapeutic responses. We explored the expression of hypoxia-associated biomarkers in head and neck squamous cell carcinoma (HNSCC) to assess their relationship with clinical factors in HNSCC. In total, 90 patients with HNSCC were enrolled. Expression of HIF-1α, HSP70, HSP90, VEGF, IGF-1R, and P16 was investigated by immunohistochemistry. Their correlations with clinical factors, including location of primary sites, T stage, N stage, M stage, HPV status, primary treatment success/failure, recurrences, disease-free survival (DFS), and overall survival, were analyzed. HIF-1α, HPS70, HPS90, VEGF, and IGF-1R were positive in 33 of 89 (37.1 %), 62 of 87 (71.3 %), 83 of 89 (93.3 %), 41 of 87 (47.1 %), and 50 of 56 (89.3 %) cases, respectively. Expression levels of some of these markers were correlated. High HIF-1α or HSP 70 correlated with poor DFS, and expression of HSP70 correlated with LN metastasis. HPV-related carcinomas showed high HSP 70 and IGF-1R expression. Hypoxia-associated proteins were highly expressed and associated with aggressive clinical features in HNSCC. Expression of HIF-1α or HSP70 can be considered poor prognostic indicator in HNSCC. Our results suggest that hypoxic signaling is activated in HNSCC, especially in HPV-related tumors.

Expression and role of nestin in human cervical intraepithelial neoplasia and cervical cancer

Nestin expression reportedly correlates with aggressive growth, metastasis, poor prognosis and presence of cancer stem cells (CSCs) in various tumors. In this study, we determined the expression and role of nestin in cervical intraepithelial neoplasia (CIN) and cervical cancer. We performed immunohistochemical and in situ hybridization analyses of nestin in 26 cases for each stage of CIN and 55 cervical cancer tissue samples. To examine the role of nestin in cervical cancer cells, we stably transfected expression vectors containing nestin cDNA into ME-180 cells. We studied the effects of increased nestin expression on cell proliferation, cell motility, invasion as well as sphere and soft agar formation. Nestin was not localized in the squamous epithelium in normal cervical tissues, but it was weakly expressed in the basal squamous epithelium of CIN 1. In CIN 2, nestin was localized to the basal to lower 2/3 of the squamous epithelium, whereas in CIN 3, it was localized to the majority of the squamous epithelium. Nestin was detected in all cases of invasive cervical cancer. Nestin mRNA was expressed in both ME-180 and CaSki cells. Growth rate, cell motility and invasion ability of stably nestin-transfected ME-180 cells were not different from empty vector-transfected ME-180 (mock cells). However, the nestin-transfected ME-180 cells formed more colonies and spheres compared to the mock cells. These findings suggest that nestin plays important roles in carcinogenesis and tumor formation of cervical cancer cells. Nestin may closely correlate with regulation of CSCs.

IGF1 mRNA isoform expression in the cervix of HPV-positive women with pre-cancerous and cancer lesions

Human papillomavirus (HPV) plays a crucial role in cervical cancer etiology. However, not all HPV-infected women develop cancer, indicating that additional cellular factors facilitate carcinogenesis. The aim of this study was to analyze the expression profile of insulin-like growth factor 1 (IGF1) isoforms in the context of FOX2, SP1 and IGF1 receptor (IGF1R) expression during HPV-dependent cervical carcinogenesis. One hundred and nine epithelial tissue samples from women with pre-cancerous and cancer lesions of the cervix were analyzed. HPV DNA was identified by PCR, and real-time PCR was used to quantify the expression levels of the analyzed genes. All IGF1 mRNA splicing isoforms were up-regulated in pre-cancerous cells, and a shift in the balance towards mitogenic IGF1Eb was observed in the cancer samples. IGF1 expression was controlled mainly by the P1 promoter, and an increase in P2 usage was observed in the cancer. Correlations between IGF1 mRNA splicing isoforms and the FOX2 splicing factor, as well as P1/P2 activity and SP1 transcription factor expression levels were detected. No correlation was observed between the expression of IGF1 and its receptor IGF1R. Our results suggest that IGF1, in particular its splicing profile, may be an additional prognostic factor in cervical carcinogenesis.