High expression of Notch2 drives tongue squamous cell carcinoma carcinogenesis

Regulation of the Notch signaling pathway by natural products for cancer therapy

The Notch signaling pathway is an evolutionarily conserved pathway that modulates normal biological processes involved in cellular differentiation, apoptosis, and stem cell self-renewal in a context-dependent fashion. Attributed to its pleiotropic physiological roles, both overexpression and silencing of the pathway are associated with the emergence, progression, and poorer prognosis in various types of cancer. To decrease disease incidence and promote survival, targeting Notch may have chemopreventive and anti-cancer effects. Natural products with profound historical origins have distinguished themselves from other therapies due to their easy access, high biological compatibility, low toxicity, and reliable effects at specific physiological sites in vivo. This review describes the Notch signaling pathway, particularly its normal activation process, and some main illnesses related to Notch signaling pathway dysregulation. Emphasis is placed on the effects and mechanisms of natural products targeting the Notch signaling pathway in diverse cancer types, including curcumin, ellagic acid (EA), resveratrol, genistein, epigallocatechin-3-gallate (EGCG), quercetin, and xanthohumol and so on. Existing evidence indicates that natural products are feasible solution to fight against cancer by targeting Notch signaling, either alone or in combination with current therapeutic agents.

Specific knockout of Notch2 in Treg cells significantly inhibits the growth and proliferation of head and neck squamous cell carcinoma in mice

OBJECTIVE

To investigate the effect of Notch2 gene knockout in Treg cells on head and neck squamous cell carcinoma (HNSCC) in mice.

METHODS

A mouse model of HNSCC was constructed. Flow cytometry and immunofluorescence were used to examine the numbers of related immune cells and programmed cell death in tumor cells in the spleen and tumor microenvironment of mice. Western blotting was used to measure the expression of related proteins in tumor tissues.

RESULTS

The tumor volume of regulatory T (Treg) cell-specific Notch2-knockout mice (experimental group) was significantly smaller than that of control mice (control group) (P < 0.05). Compared with those in the control group, the number of Treg cells and the expression of Ki67 in Treg cells in the spleen and tumor tissue were significantly decreased in the experimental group, while the numbers of CD45+ hematopoietic cells, CD4+ T cells, CD8+ T cells, T helper 1 (Th1) cells, CD11b+ cells (macrophages), and CD11b+CD11c+ cells (dendritic cells) and the expression of Ki67 in CD4+ T cells and CD8+ T cells were significantly increased (P < 0.05). There was no significant difference in the number of Th2 cells between the two groups (P > 0.05). Immunofluorescence analysis showed that the numbers of CD4+ T cells and CD8+ T cells in the tumor tissue in the experimental group were significantly higher than those in the control group (P < 0.05). Compared with that in the control group, programmed cell death in the experimental group was significantly increased (P < 0.05). Moreover, the expression levels of NLRP3, Caspase-1 and GSDMD in the tumor tissues of the experimental group were higher than those in the control group (P < 0.01), while the expression levels of BCL2, Bax, ATG5, LC3 and p62 were not significantly different (P > 0.05).

CONCLUSIONS

Specific knockout of the Notch2 gene in Treg cells significantly decreases the function of Treg cells, inhibits the growth of HNSCC and improves the immune microenvironment in mice, thus effectively treating HNSCC.

Ailanthone Inhibits Cell Proliferation in Tongue Squamous Cell Carcinoma via PI3K/AKT Pathway

Tongue squamous cell carcinoma (TSCC) is the most widespread and invasive subtype of oral cancer with high recurrence rates. Ailanthone (AIL) is an active ingredient in the plant extracts of Ailanthus altissima (Mill.) Swingle. Here, we showed that AIL inhibited the proliferation of human TSCC, the cell viability of Cal-27 and Tca8113 was significantly decreased after AIL treatment for 24 h. Hoechst 33258 staining demonstrated apoptotic characteristics (such as chromatin aggregation) after AIL treatment. The ratio of early- and late-apoptotic cells in AIL-treated Cal-27 and TCA8113 cells increased remarkably when compared with the control group. Bcl-2/Bax ratio and the levels of PARP1, caspase-9, and caspase-3 decreased after AIL treatment, accompanied by significant increase of cleaved PARP1, cleaved caspase-9, and caspase-3 in Cal-27 and TCA8113 cells. Meanwhile, AIL led to Cal-27 cell cycle arrest at G2/M phase. Western blot implied decreased levels of CDK1 and cyclin B1 after AIL treatment. The level of phospho-PI3K p55 subunit and p-Akt were significantly downregulated by AIL in both Cal-27 and TCA8113 cells. These findings implied the potential applications of AIL in the treatment of human TSCC.

Shooting at Moving and Hidden Targets-Tumour Cell Plasticity and the Notch Signalling Pathway in Head and Neck Squamous Cell Carcinomas

Head and Neck Squamous Cell Carcinoma (HNSCC) is often aggressive, with poor response to current therapies in approximately 40-50% of the patients. Current therapies are restricted to operation and irradiation, often combined with a small number of standard-of-care chemotherapeutic drugs, preferentially for advanced tumour patients. Only very recently, newer targeted therapies have entered the clinics, including Cetuximab, which targets the EGF receptor (EGFR), and several immune checkpoint inhibitors targeting the immune receptor PD-1 and its ligand PD-L1. HNSCC tumour tissues are characterized by a high degree of intra-tumour heterogeneity (ITH), and non-genetic alterations that may affect both non-transformed cells, such as cancer-associated fibroblasts (CAFs), and transformed carcinoma cells. This very high degree of heterogeneity likely contributes to acquired drug resistance, tumour dormancy, relapse, and distant or lymph node metastasis. ITH, in turn, is likely promoted by pronounced tumour cell plasticity, which manifests in highly dynamic and reversible phenomena such as of partial or hybrid forms of epithelial-to-mesenchymal transition (EMT), and enhanced tumour stemness. Stemness and tumour cell plasticity are strongly promoted by Notch signalling, which remains poorly understood especially in HNSCC. Here, we aim to elucidate how Notch signal may act both as a tumour suppressor and proto-oncogenic, probably during different stages of tumour cell initiation and progression. Notch signalling also interacts with numerous other signalling pathways, that may also have a decisive impact on tumour cell plasticity, acquired radio/chemoresistance, and metastatic progression of HNSCC. We outline the current stage of research related to Notch signalling, and how this pathway may be intricately interconnected with other, druggable targets and signalling mechanisms in HNSCC.

EGCG inhibits growth of tumoral lesions on lip and tongue of K-Ras transgenic mice through the Notch pathway

Epigallocatechin-3-gallate (EGCG), the main active ingredient of green tea, exhibits low toxic side effect and versatile bioactivities, and its anti-cancer effect has been extensively studied. Most of the studies used cancer cell lines and xenograft models. However, whether EGCG can prevent tumor onset after cancer-associated mutations occur is still controversial. In the present study, Krt14-cre/ERT-Kras transgenic mice were developed and the expression of K-RasG12D was induced by tamoxifen. Two weeks after induction, the K-Ras mutant mice developed exophytic tumoral lesions on the lips and tongues, with significant activation of Notch signaling pathway. Administration of EGCG effectively delayed the time of appearance, decreased the size and weight of tumoral lesions, relieved heterotypic hyperplasia of tumoral lesions, and prolonged the life of the mice. The Notch signaling pathway was significantly inhibited by EGCG in the tumoral lesions. Furthermore, EGCG significantly induced cell apoptosis and inhibited the proliferation of tongue cancer cells by blocking the activation of Notch signaling pathway. Taken together, these results indicate EGCG as an effective chemotherapeutic agent for tongue cancer by targeting Notch pathway.

RFC4 promotes the progression and growth of Oral Tongue squamous cell carcinoma in vivo and vitro

OBJECTIVE

Currently, many studies have found that RFC4 was up-regulated in various cancers, and related to the progression and development. While the effects of RFC4 in oral tongue squamous cell carcinoma remain unclear, the main purpose of this research is to explore the role of RFC4 in oral tongue squamous cell carcinoma.

METHODS

The expression of RFC4 in various cancers was analyzed in GEPIA database, and the results were further verified by IHC assay. The relationship between RFC4 and several clinical parameters was analyzed; the proliferation was further observed by knockdown RFC4 in vitro. Finally, we constructed related nude mouse models by planting cells subcutaneous of nude mice, and the discrepancy was observed.

RESULTS

Based on GEPIA database, RFC4 was up-regulated in various cancers, including colorectal cancer, breast cancer, prostate cancer, lung cancer, and liver cancer. RFC4 was up-regulated in oral tongue squamous cell carcinoma compared with the normal tissue from GEPIA online database; we further found that the expression of RFC4 was tightly associated with TNM stage (p = 0.005), but not with age, gender, and differentiation (p > 0.05). We further found that the proliferation of oral tongue squamous cell carcinoma was obviously restrained in vitro, and the carcinogenesis was also inhibited in vivo.

CONCLUSIONS

We found that RFC4 was up-regulated and related to the progression of oral tongue squamous cell carcinoma, and knockdown RFC4 could restrain the proliferation and progression. RFC4 might serve a potential biomarker and provide a new treatment strategy for lots of patients with oral tongue squamous cell carcinoma.