Finally, immunohistochemical analysis was carried out to test whether the coexpression of integrin β1 and Notch1 in the samples from HNSCC patients correlated with their survival.
We also assessed the sensitivity of two HNSCC cell lines to the Notch1 inhibitor of N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT).
These results suggested that concomitant inhibition of the Notch1 and EGFR pathways represented a rational strategy for promoting apoptosis in HNSCC and overcoming treatment resistance.
Immunohistochemistry (IHC) of human HNSCC tissues demonstrated that elevation of the Notch1 downstream target HES1 was correlated with MDSC, TAM and Treg markers and with immune checkpoint molecules.
HNSCC early death was significantly associated with 3+ mutations (odds ratio [OR] = 2.78, 95% confidence interval [CI] = 1.16, 6.69), NOTCH1 mutations in non-Hispanic whites (OR = 5.51; 95% CI = 1.22-24.83) and TP53 mutations in Hispanic whites (OR = 3.84; 95% CI = 1.08-13.68) in multivariable analysis adjusted for age, sex, tumor site, and tumor stage.
The findings indicate that betel quid chewing is highly associated with NOTCH1 SMs (especially with changes in EGF-like domains), and that rs139994842 may potentially serve as an early predictive and prognostic biomarker for the occurrence and development of HNSCC.
The investigated chromosomal regions, in particular those with CN-LOH, harbored some interesting genes, such as HIC1, DOCK8, KANK1, and NOTCH1 whose role, mutations and epigenetic modifications in HNSCC deserve to be investigated, in order to understand the significance of CN-LOH events in HNSCC pathogenesis.
Emphasis is placed on the therapeutic implications of genes frequently altered in HNSCCs (i.e., TP53, PIK3CA, and NOTCH1) and their corresponding pathways, with a particular focus on recent findings of Notch signaling pathway activation in HNSCC.
In-depth characterization analysis revealed polyploidy in DNA content; a doubling time of some 24h; high tumorigenicity in immunodeficient mice; higher invasive potential and more sensitive to radiation and cisplatin compared with HeLa cell line; upregulated Ki67, Notch1, EGFR, and CK5 protein levels; negative infection of human papillomavirus (HPV) and mycoplasma; expression of head and neck squamous cell carcinoma (HNSCC) biomarkers; mutations of TP53 in exons 5 and 8; a near-triploid karyotype with complex structural aberrations; and dozens of dysregulated genes and miRNAs.
Recent studies showed that head and neck squamous cell carcinoma (HNSCC) including oral squamous cell carcinoma (OSCC) of Caucasian, Chinese and Indian patients frequently have NOTCH1 mutations.