Elucidating the mechanism of miRNA-214 in the regulation of gingival carcinoma

The potential role of miRNAs in the pathogenesis of salivary gland cancer - A Focus on signaling pathways interplay

Salivary gland cancer (SGC) is immensely heterogeneous, both in terms of its physical manifestation and its aggressiveness. Developing a novel diagnostic and prognostic detection method based on the noninvasive profiling of microribonucleic acids (miRs) could be a goal for the clinical management of these specific malignancies, sparing the patients' valuable time. miRs are promising candidates as prognostic biomarkers and therapeutic targets or factors that can advance the therapy of SGC due to their ability to posttranscriptionally regulate the expression of various genes involved in cell proliferation, differentiation, cell cycle, apoptosis, invasion, and angiogenesis. Depending on their biological function, many miRs may contribute to the development of SGC. Therefore, this article serves as an accelerated study guide for SGC and the biogenesis of miRs. Here, we shall list the miRs whose function in SGC pathogenesis has recently been determined with an emphasis on their potential applications as therapeutic targets. We will also offer a synopsis of the current state of knowledge about oncogenic and tumor suppressor miRs in relation to SGC.

Adenoid Cystic Carcinoma of the Gingiva: A Case Report and Literature Review

OBJECTIVES

Adenoid cystic carcinoma (ACC) is a commonly encountered salivary gland malignancy. However, it rarely occurs in the gingiva, an area generally thought to be devoid of minor salivary glands. We present a case occurring in this unusual site and review other reported cases.

METHODS

A 56 year-old male presented with a right-sided mandibular toothache for 1 year and underwent dental extraction. Due to persistent pain, follow up examination revealed a large gingival lesion. A biopsy was positive for adenoid cystic carcinoma.

RESULTS

The patient underwent a complete right segmental mandibulectomy and was reconstructed with a fibular osteocutaneous free flap. Three months postoperatively, during the planning for adjuvant radiation therapy, the patient developed pain in the left mandible. Imaging revealed extensive involvement of the left native mandible. Deep bone biopsies in several areas of the left mandible revealed ACC. He then underwent a complete left hemi-mandibulectomy and reconstruction with a fibular osteocutaneous free flap. Tensor fascia lata suspension slings were placed due to concern for an open mouth deformity attributable to disruption of bilateral masticator slings. He will undergo adjuvant radiation therapy. Our review of the literature revealed 50 cases of gingival ACC published since 1972. Disease recurrence and distant metastases were noted in several patients, occurring at the latest after 30 years follow-up.

CONCLUSIONS

Given its indolent behavior, high proclivity for late recurrence and metastasis, and overall infrequency, ACC represents a pathology that requires early diagnosis and comprehensive long-term surveillance. While ACC is well described in oral cavity sites with high densities of minor salivary glands, it is not commonly seen in the gingiva. As such, gingival ACC may display a unique biological and/or clinical character. We offer the first literature review of this rare entity.

The natural product lapiferin inhibits cell proliferation and promotes cell apoptosis in gingival squamous cell carcinoma via P21 regulation

Gingival squamous cell carcinoma (GSCC) is responsible fora large proportion of oral cavity malignancies. GSCC is characterized by rapid cell growth, and progressive invasion and migration. P21 is a widely recognized tumor suppressor, which is induced by P53 activation; however, drugs that aim to promote P21‑mediated tumor suppression remain to be identified. A natural compound library was used to perform broad‑spectrum screening of drugs that could promote P21 expression. Subsequently, the effects of the screened drug on GSCC cell proliferation and apoptosis were evaluated. The results of the present study suggested that lapiferin was the most effective natural compound that promoted the expression of P21 at both mRNA and protein levels. Lapiferin inhibited proliferation and enhanced apoptosis of YD‑38 GSCC cells in a dose‑dependent manner. Furthermore, following treatment with lapiferin, the critical cell cycle regulators cell division cycle 25C and cyclin B1 and tumor cell proliferation markers proliferating cell nuclear antigen and Ki67 were markedly decreased. In addition, pro‑apoptotic proteins were promoted following treatment of YD‑38 cells with lapiferin. Following the depletion ofP21 expression, lapiferin‑mediated inhibition of cell proliferation and enhancement of cell apoptosis were significantly reduced. These results indicated that lapiferin may exert potent antitumor effects on GSCC via regulation of P21; therefore, lapiferin may be considered a potential, natural therapeutic agent for the treatment of GSCC.

Efficient miRNA Inhibitor Delivery with Graphene Oxide-Polyethylenimine to Inhibit Oral Squamous Cell Carcinoma

Background

MicroRNAs (miRNAs) are widely believed to be promising targets for oral squamous cell carcinoma (OSCC) gene therapy. miR-214 has been identified as a promoter of OSCC aggression and metastasis.

Methods

Graphene oxide-polyethylenimine (GO-PEI) complexes were prepared and loaded with a miRNA inhibitor at different N/P ratios. The transfection efficiency of GO-PEI-inhibitor was tested in Cal27 and SCC9 cells. Moreover, the tumor inhibition ability of GO-PEI-inhibitor was measured in an OSCC xenograft mouse model by intratumoral injection.

Results

Here, we show that a GO-PEI complex efficiently delivers a miR-214 inhibitor into OSCC cells and controls the intracellular release of the miR-214 inhibitor. These results indicate that the GO-PEI-miR-214 inhibitor complex efficiently inhibited cellular miR-214, resulting in a decrease in OSCC cell invasion and migration and an increase in cell apoptosis by targeting PTEN and p53. In the xenograft mouse model, the GO-PEI-miR-214 inhibitor complex significantly prevented tumor volume growth.

Conclusion

This study indicates that functionalized GO-PEI with low toxicity has promising potential for miRNA delivery for the treatment of OSCC.