ECE-1 overexpression in head and neck cancer is associated with poor tumor differentiation and patient outcome

A non-canonical role of endothelin converting enzyme 1 (ECE1) in promoting lung cancer development via directly targeting protein kinase B (AKT)

BACKGROUND

Lung cancer is the second most common malignancy in the world, and lung adenocarcinoma (LUAD) in particular is the leading cause of cancer death worldwide. Endothelin converting enzyme 1 (ECE1) is a membrane-bound metalloprotease involved in endothelin-1 (ET-1) processing and regulates vasoconstriction. However, very few studies have reported the involvement of ECE1 in regulating tumor cell proliferation, and the mechanism remains poorly understood. Therefore, we aimed to determine the role of ECE1 in lung cancer development.

METHODS

The Cancer Genome Atlas database and Kaplan-Meier plotter were used to assess the association between ECE1 and lung cancer. The expression of ECE1 was detected using immunohistochemistry staining and western blotting. A variety of in vitro assays were performed to evaluate the effects of ECE1 on the colony formation, proliferation, migration and invasion using ECE1 knockdown lung cancer cells. The gene expression profiles regulated by ECE1 were investigated by RNA sequencing. An immunoprecipitation assay and immunofluorescence assay were used to evaluate the mechanism underlying the regulatory effect of ECE1 on protein kinase B (AKT). The effect of ECE1 on tumor development was assessed by xenografted lung cancer cells in either C57BL/6 mice or nude mice.

RESULTS

ECE1 was upregulated in LUAD and correlated with the poor prognosis of patients with LUAD. Functional studies showed that knockdown of ECE1 retarded the progression of tumors formed by lung cancer cells at least partly by inhibiting tumor cell proliferation. Moreover, ECE1 accelerated tumor cell proliferation through promoting AKT activation dispensable of its canonical target ET-1. Mechanically, ECE1 interacted with the pleckstrin homology (PH) domain of AKT and facilitated its translocation to the plasma membrane for activation. Furthermore, the inhibition of AKT activity counteracted the lung cancer cell growth inhibition observed both in vitro and in xenografts caused by ECE1 suppression.

CONCLUSIONS

The present study reveals a non-canonical function of ECE1 in regulating AKT activation and cell proliferation, which provides the basis for the development of a novel strategy for the intervention of cancer including LUAD by abrogating ECE1-AKT signaling.

Compartmental Surgery With Microvascular Free Flap Reconstruction in Patients With T1-T4 Squamous Cell Carcinoma of the Tongue: Analysis of Risk Factors, and Prognostic Value of the 8th Edition AJCC TNM Staging System

Compartmental surgery and primary reconstruction with microvascular free flaps represent the gold-standard in the treatment of oral tongue squamous cell carcinoma (OTSCC). However, there are still unclear clinical features that negatively affect the outcomes. This retrospective study included 80 consecutive patients with OTSCC who underwent compartmental surgery and primary reconstruction by free flap. The oncologic outcomes, the reliability of the 8th edition American Joint Committee on Cancer (AJCC) staging system and the prognostic factors were evaluated. Fifty-nine males and 21 females (mean age 57.8 years, range 27-81 years) were treated between November 2010 and March 2018 (one patient had two metachronous primaries). Seventy-one patients (88.75%, 52 males, 19 females, mean age of 57.9 years, range of 27-81 years) had no clinical history of previous head and neck radiotherapy and were considered as naive. Histology showed radical surgery on 80/81 lesions (98.8%), with excision margins >0.5 cm, while in 1 case (1.2%), a close posterior margin was found. According to the 8th AJCC classification, 37 patients (45.7%) were upstaged shifting from the clinical to the pathological stage, and 39 (48.1%) showed an upstaging while shifting from the 7th to the 8th AJCC staging system (no tumors were downstaged). Nodal involvement was confirmed in 33 patients (40.7%). Perineural and lymphovascular invasion were present in 9 (11.1%) and 11 (13.6%) cases, respectively. Twenty-two patients (27.1%) underwent adjuvant therapy. The 5-years disease-specific, overall, overall relapse-free, locoregional relapse-free and distant metastasis-free survival rates were 73.2, 66.8, 62.6, 67.4, and 86%, respectively. Patients with a lymph node ratio >0.09 experienced significantly worse outcomes. Univariate analysis showed that patients with previous radiotherapy, stage IV disease, nodal involvement, and lymphovascular invasion had significantly worse outcomes. Multivariate analysis focused naive patients and showed that lymphovascular invasion, advanced stage of disease, and node involvement resulted reliable prognostic factors, and patients with the same tumor stage and histological risk factors who did not undergo adjuvant therapy experienced significantly worse outcomes. In our series, surgery played a major role in the treatment of local extension; adjuvant therapy resulted strictly indicated in patients with advanced-stage disease associated with risk factors.