Silencing LMNB1 Contributes to the Suppression of Lung Adenocarcinoma Development

Abstract

Purpose: Lung cancer has been recognized as the most fatal malignant tumor with the highest morbidity and mortality in recent years.

Materials and methods: In this study, we found that LMNB1, which is an important component protein of the nuclear skeleton, was significantly upregulated in lung adenocarcinoma (LUAD) and correlated with the pathological stage as well as lymphatic metastasis.

Results: In vitro loss-of-function study utilizing LMNB1 knockdown LUAD cell lines demonstrated that depletion of LMNB1 inhibited development of LUAD through regulating cell proliferation, cell apoptosis, cell cycle and cell motility. Decreased tumorigenesis of LMNB1 knockdown LUAD cells was proved in mice xenograft models. Moreover, the mechanism by which LMNB1 promotes LUAD was explored through the expression evaluation of apoptosis-related proteins and cancer-related signaling pathways.

Conclusion: In conclusion, our study identified LMNB1 as a tumor promotor and a potential therapeutic target in LUAD.

Keywords: LMNB1; cell apoptosis; cell proliferation; lung adenocarcinoma; lung cancer.

Figure 1

Identification of LMNB1 as potential tumor promotor in LUAD. (A) RNA-seq was performed to identify differentially expressed genes (DEGs) in LUAD tumor tissues and normal tissues. (B) Endogenous expression of several selected DEGs was detected by qPCR in NCI-H1299 cells. (C) Celigo cell counting assay was utilized to evaluate the inhibition of cell proliferation by knockdown of the selected DEGs. (D, E) The expression of LMNB1 in LUAD tumor tissues and normal tissues was detected by qPCR (D) and immunohistochemistry analysis (E). (F) Kaplan–Meier survival analysis was performed to show the correlation between LMNB1 expression and prognosis of LUAD patients. *P<0.001.

Figure 2

Depletion of LMNB1 inhibits cell proliferation and migration, induces cell apoptosis and cell cycle arrest. (A) qPCR and Western blotting were performed to assess the knockdown efficiency of LMNB1 in LUAD cells. (B) Effects of LMNB1 knockdown on cell proliferation was determined by Celigo cell counting assay. (C, D) Influence of LMNB1 depletion on cell apoptosis and cell cycle distribution was detected by flow cytometry. (E, F) Impacts of LMNB1 knockdown on LUAD cell migration was examined by wound-healing (E) and transwell (F) assays. *P<0.05, **P<0.01, ***P<0.001.

Figure 3

Exploration of mechanism by which LMNB1 regulates LUAD. (A, B) Human apoptosis antibody array was performed to identify differentially expressed apoptosis-related proteins in NCI-H1299 cells with or without LMNB1 knockdown. (C) Western blotting was performed to detect the changes in expression of proteins in cancer-related signaling pathways. *P<0.05, **P<0.01.

Figure 4

LMNB1 knockdown reduces tumorigenesis of LUAD cells in vivo. (A) Tumor volume was calculated based on tumor size measured at indicated time intervals. Inset: photo of the removed xenografts. (B) In vivo imaging was performed to evaluate tumor growth. (C) The total intensity of bioluminescence was scanned to represent the tumor burden. (D) Tumor weight was measured after sacrificing mice. (E) The expression of Ki67 in tumor sections was detected by immunohistochemistry analysis. *P<0.01, **P<0.001.