Notch1 Overexpression Associates With Poor Prognosis in Human Laryngeal Squamous Cell Carcinoma

Effect of Notch1 signaling on cellular proliferation and apoptosis in human laryngeal carcinoma

Background

The occurrence and development of malignancies include excessive proliferation and apoptosis resistance in tumor cells. This study aimed to identify the effects of Notch1 signaling on proliferation and apoptosis of laryngeal cancer cells in a hypoxic microenvironment.

Methods

Notch1 and Ki-67 expression in laryngeal squamous cell carcinoma (LSCC) tissues was detected by immunohistochemistry. The apoptotic index (AI) of LSCC was evaluated by the TUNEL method. Small interfering RNA (siRNA) was used to inhibit Notch1 expression in laryngeal cancer cells. Real-time PCR was used to measure Notch1, Hes1, and Hey1 mRNA expression, and Western blotting was used to measure Notch1 and Notch1 intracellular domain (N1ICD) protein expression. Annexin V-FITC/propidium iodide staining and Cell Counting Kit-8 assays were used to measure cell apoptosis and proliferation, respectively.

Results

Notch1 expression was significantly related to the proliferation index (PI) and AI in LSCC tissues. Hypoxia could induce proliferation and inhibit apoptosis in cancer cells. Notch1 expression and Notch1 signaling activity could be upregulated by hypoxia. Suppressing Notch1 signaling activity in hypoxic cells could decrease proliferation and increase apoptosis.

Conclusions

Our study has demonstrated that hypoxia may promote proliferation and inhibit apoptosis of laryngeal cancer cells. Notch1 signaling may play a pivotal role in regulating the proliferation and apoptosis resistance of laryngeal cancer cells under hypoxic conditions.

Overview on Molecular Biomarkers for Laryngeal Cancer: Looking for New Answers to an Old Problem

Laryngeal squamous cell cancer (LSCC) accounts for almost 25-30% of all head and neck squamous cell cancers and is clustered according to the affected districts, as this determines distinct tendency to recur and metastasize. A major role for numerous genetic alterations in driving the onset and progression of this neoplasm is emerging. However, major efforts are still required for the identification of molecular markers useful for both early diagnosis and prognostic definition of LSCC that is still characterized by significant morbidity and mortality. Non-coding RNAs appear the most promising as they circulate in all the biological fluids allowing liquid biopsy determination, as well as due to their quick and characteristic modulation useful for non-invasive detection and monitoring of cancer. Other critical aspects are related to recent progress in circulating tumor cells and DNA detection, in metastatic status and chemo-refractoriness prediction, and in the functional interaction of LSCC with chronic inflammation and innate immunity. We review all these aspects taking into account the progress of the technologies in the field of next generation sequencing.

The prognostic value of inositol polyphosphate 5-phosphatase in cutaneous squamous cell carcinoma

BACKGROUND

Inositol polyphosphate 5-phosphatase (INPP5A) has been shown to play a role in development and progression of cutaneous squamous cell carcinoma (cSCC). The goal of the current study was to explore the prognostic value of INPP5A expression in cSCC.

METHODS

A total of 189 cases of actinic keratosis and SCC in 174 patients were identified; clinical and outcome data were abstracted, histopathology was rereviewed, and immunohistochemical staining and interpretation was performed for INPP5A.

RESULTS

The majority of tumors (89.4%) had an INPP5A score of 2 or 3. No patients had complete loss of INPP5A. Tumors with an INPP5A score of 1 were more likely to be intermediate- to high-risk tumors (Brigham and Women's Hospital stage ≥T2a 85.0% vs 23.7% [P < .0001]) characterized by a larger diameter (2.4 cm vs 1.3 cm [P = .0004]), moderate-to-poor differentiation (86.7% vs 17.6% [P < .0001]), and perineural invasion (37.5% vs 5.3%, [P < .0001]). An INPP5A score of 1 was associated with a worse 3-year survival (a rate of 42.3% [hazard ratio, 2.81, P = .0006]) and a local metastasis rate of 48.0% (hazard ratio, 4.71; P < .0001).

CONCLUSIONS

Low INPP5A scores are predictive of aggressive tumors and may be a useful adjunct to guide clinical management of cSCC.

Notch1 ablation radiosensitizes glioblastoma cells

Broad specific Notch1 inhibitors suppress glioblastoma multiforme (GBM) growth but have significant gastrointestinal toxicities. Here, we examined Notch1 expression in GBM tissue specimens and its correlation with the overall survival (OS) of GBM patients. Furthermore, using the CRISPR/Cas9 system, we investigated the effects of Notch1 downregulation on clonogenic growth and angiogenesis of GBM cells and xenografts. Immunohistochemistry showed positive Notch1 expression in 71% (49/69) of GBM tissues. Our multivariate Cox regression analysis further revealed that Notch1 expression was an independent adverse prognostic factor for OS. Notch1 downregulation suppressed the growth of GBM cells U87MG and U251. The mean duration to reach 6 x the starting volume was 18.3 days for xenografts with Notch1 downregulation and 13.4 days for the control xenografts. Immunofluorescent staining further disclosed that Notch1 downregulation markedly increased the number of γH2AX foci and radiosensitized GBM cells. Notch1 downregulation also impaired angiogenesis and attenuated VEGF and hypoxic response to irradiation in xenografts. In conclusion, Notch1 ablation inhibited GBM cell proliferation and neovascularization and radiosensitized GBM cells and xenografts, suggesting a pivotal role of Notch1 in tumor growth, angiogenesis, and radioresistance in GBM.

Notch1 Overexpression Correlates to Improved Survival in Cancer of the Oropharynx

Objectives The Notch1 signaling pathway has recently been shown to be highly dysregulated in head and neck squamous cell carcinoma, but the value of Notch1 as a predictive biomarker is yet to be elucidated in oropharyngeal squamous cell carcinoma (OPSCC). The objective of this study is to evaluate Notch1 expression in surgical OPSCC specimens and determine clinicopathologic correlates. Study Design Case series with planned data collection. Setting Tertiary academic medical center. Subjects and Methods Surgical specimens from 181 patients with OPSCC were collected to create a tissue microarray (TMA). Human papillomavirus (HPV) status and Notch1 expression were determined and correlated with clinicopathologic characteristics. Results In univariate analysis, Notch1 expression correlated with improved survival as a categorical variable (hazard ratio [HR], 0.346; P < .0001) and correlated with HPV/p16 positivity as a continuous variable ( P < .0001). In multivariate analysis, Notch1 expression retained significance in HPV-positive (HR, 0.303; P = .033) and HPV-negative (HR, 0.416; P = .0055) subgroups. Similarly, Notch1 expression positively correlated with survival in p16-positive (HR, 0.469; P = .031) and p16-negative subgroups (HR, 0.310; P = .014). Conclusions In the largest OPSCC cohort to date, we found that Notch1 receptor expression positively correlates with overall survival, regardless of HPV or p16 status. Furthermore, we found higher Notch1 receptor expression in HPV/p16-positive tumors than their HPV/p16-negative counterparts.

Cancer Stem Cell Signaling during Repopulation in Head and Neck Cancer

The aim of the study was to investigate cancer stem signaling during the repopulation response of a head and neck squamous cell cancer (HNSCC) xenograft after radiation treatment. Xenografts were generated from low passage HNSCC cells and were treated with either sham radiation or 15 Gy in one fraction. At different time points, days 0, 3, and 10 for controls and days 4, 7, 12, and 21, after irradiation, 3 tumors per group were harvested for global gene expression, pathway analysis, and immunohistochemical evaluation. 316 genes were identified that were associated with a series of stem cell-related genes and were differentially expressed (p ≤ 0.01 and 1.5-fold) at a minimum of one time point in UT-SCC-14 xenografts after radiation. The largest network of genes that showed significant changes after irradiation was associated with CD44, NOTCH1, and MET. c-MET and ALDH1A3 staining correlated with the changes in gene expression. A clear pattern emerged that was consistent with the growth inhibition data in that genes associated with stem cell pathways were most active at day 7 and day 12 after irradiation. The MET/CD44 axis seemed to be an important component of the repopulation response.

Overexpression of Notch1 is associated with the progression of cervical cancer

Cervical cancer is the third most common malignancy worldwide, accounting for 250,000 mortalities annually. Notch1, an important regulator of cell-fate decisions and differentiation, has been found to be overexpressed in certain types of cancer. However, the role of Notch1 in cervical carcinogenesis remains unclear. In the present study, immunohistochemical staining and western blot analysis revealed that Notch1 expression was significantly higher in cervical cancer tissues than that in normal cervical tissues. Furthermore, statistical analysis revealed that Notch1 expression was significantly associated with tumor differentiation and tumor stage. These findings indicated that Notch1 expression was associated with the progression of cervical cancer. The western blot assay also identified a positive correlation between Notch1 and Ki67 expression in cervical cancer tissues, which suggested that Notch1 expression may be associated with the proliferation of cervical cancer. In order to further evaluate the specific role of Notch1 in cervical cancer progression, its expression in SiHa and C33A cells was knocked down using small interfering RNA. It was revealed that the knockdown of Notch1 in SiHa and C33A cells resulted in significant inhibition of cell proliferation and colony formation in vitro. These results indicated that Notch1 was able to promote cell proliferation in cervical cancer. In conclusion, the results of the present study indicated that Notch1 may function as a promoter in cervical carcinogenesis.

Cleaved NOTCH1 Expression Pattern in Head and Neck Squamous Cell Carcinoma Is Associated with NOTCH1 Mutation, HPV Status, and High-Risk Features

The Notch pathway is frequently altered in head and neck squamous cell carcinomas (HNSCC); however, the clinical significance of NOTCH1 dysregulation is poorly understood. This study was designed to characterize expression of the transcriptionally active NOTCH1 intracellular domain (NICD1) in HNSCCs and evaluate its association with NOTCH1 mutation status and clinical parameters. IHC for NICD1 was performed on 79 previously sequenced archival HNSCCs with known NOTCH1 mutation status. Three distinct immunohistochemical staining patterns were identified: positive/peripheral (47%), positive/nonperipheral (34%), and negative (19%). NICD1 expression was associated with NOTCH1 mutation status (P < 0.001). Most NOTCH1-wild-type tumors were peripheral (55%), whereas mutated NOTCH1 tumors were most commonly negative (47%). Nonperipheral tumors were more likely than peripheral tumors to have extracapsular spread [adjusted odds ratio (aOR), 16.01; 95% confidence interval (CI), 1.92-133.46; P = 0.010] and poor differentiation (aOR, 5.27; 95% CI, 0.90-30.86; P = 0.066). Negative staining tumors tended to be poorly differentiated (aOR, 24.71; 95% CI, 1.53-399.33; P = 0.024) and were less likely to be human papillomavirus (HPV) positive (aOR, 0.043; 95% CI, 0.001-1.59; P = 0.087). NOTCH1 mutagenesis was significantly associated with HPV status, with NOTCH1-wild-type tumors more likely to be HPV positive than NOTCH1-mutated tumors (aOR, 19.06; 95% CI, 1.31-276.15; P = 0.031). TP53 disruptive mutations were not associated with NICD1 expression or NOTCH1 mutation. In conclusion, NICD1 is expressed in three distinct patterns in HNSCC that are significantly associated with high-risk features. These findings further support a dual role for NOTCH1 as both tumor suppressor and oncogene in HNSCC. Further research is necessary to clarify the role of NOTCH1 in HNSCC and understand the clinical and therapeutic implications therein.