Lihong Hao

Fructose-Bisphosphate Aldolase A Is a Potential Metastasis-Associated Marker of Lung Squamous Cell Carcinoma and Promotes Lung Cell Tumorigenesis and Migration

Fructose-bisphosphate aldolase A (ALDOA) is a key enzyme in glycolysis and is responsible for catalyzing the reversible conversion of fructose-1,6-bisphosphate to glyceraldehydes-3-phosphate and dihydroxyacetone phosphate. ALDOA contributes to various cellular functions such as muscle maintenance, regulation of cell shape and mobility, striated muscle contraction, actin filament organization and ATP biosynthetic process. Here, we reported that ALDOA is a highly expressed in lung squamous cell carcinoma (LSCC) and its expression level is correlated with LSCC metastasis, grades, differentiation status and poor prognosis. Depletion of ALDOA expression in the lung squamous carcinoma NCI-H520 cells reduces the capabilities of cell motility and tumorigenesis. These data suggest that ALDOA could be a potential marker for LSCC metastasis and a therapeutic target for drug development.

Caveolin‐1 is an Important Factor for the Metastasis and Proliferation of Human Small Cell Lung Cancer NCI‐H446 Cell

Caveolin‐1 (CAV‐1) has been reported to play an important role in the development of a variety of human cancers. CAV‐1 expression is revealed to be reduced or absent in the malignant tumor cells of small cell lung cancers (SCLC). This study was performed to investigate the influences of the stable expression of CAV‐1 on the metastasis and proliferation of SCLC in vitro. The wild‐type CAV‐1 gene was successfully transfected into the NCI‐H446 cells and was stably expressed in the NCI‐H446 cells. The effects of CAV‐1 on the morphology, proliferation, and metastasis potential for NCI‐H446 cell were evaluated by crystal violet staining, MTT analysis, transwell assay, and scratch wound assay, respectively. Western blot and gelatin zymography were used to examine the expression changes of the metastasis‐related MMP‐3 and E‐cadherin. Stable expression of CVA‐1 was observed in the H446‐CAV‐1 cells, which enlarged the cell shape with filopodia. The proliferation of H446‐CAV‐1 was inhibited, while its migration and invasion abilities were promoted in vitro. The re‐expression of CAV‐1 reduced the expression of E‐cadherin, while it increased the protein expression and enzyme activity of MMP‐3. Taken together, the cellular proliferation of the NCI‐H446 could be inhibited by the re‐expression of CAV‐1. CAV‐1 might increase the cell metastasis potential through the interaction with E‐cadherin and MMP‐3 genes. These in vitro findings confirm the involvement of CAV‐1 in the proliferation and metastasis of SCLC. Anat Rec, 2009.

Caveolin-1 knockdown is associated with the metastasis and proliferation of human lung cancer cell line NCI-H460

Caveolin-1 (CAV-1), one component of caveolae, involves in multiple cellular processes and signal transductions. We previously showed that the expression of CAV-1 gene in NCI-H446 cells inhibited cell proliferation and promoted cell metastasis. Here we explore the function of CAV-1 on tumor growth and metastasis by using NCI-H460 in vitro. First, we established NCI-H460 cell line, which CAV-1 was stably knockdown. Then we investigated the effects of CAV-1 on the morphology, proliferation, cell cycle and metastasis potential for NCI-H460 cell by crystal violet stains, CCK-8, colony formation, flow cytometry, scratch-wound assay and transwell assay. Western blot was used to examine the expression changes of cyclin D1, PCNA, E-cadherin and β-catenin. Our results showed stable knockdown of CAV-1 inhibited the proliferation of NCI-H460 cells. Cell cycle of the transfected cells was arrested in G1/S phase and the expressions of cyclin D1 and PCNA protein were downregulated. Downregulation of CAV-1 promoted the migration and invasion abilities of NCI-H460 cells in vitro. The expression of β-catenin increased and the level of E-cadherin decreased. In summary, our findings provide experimental evidence that CAV-1 may function as a proproliferative and antimetastatic gene in NCI-H460 cell line.

Elevated GAPDH expression is associated with the proliferation and invasion of lung and esophageal squamous cell carcinomas.

Glyceraldehyde‐3‐phosphate dehydrogenase, is one of the most investigated housekeeping genes and widely used as an internal control in analysis of gene expression levels. The present study was designed to assess whether GAPDH is associated with cancer cell growth and progression and, therefore may not be a good internal control in cancer research. Our results from clinical tissue studies showed that the levels of GAPDH protein were significantly up‐regulated in lung squamous cell carcinoma tissues, compared with the adjacent normal lung tissues, and this was confirmed by western blotting and immunohistochemistry. GAPDH knockdown by siRNA resulted in significant reductions in proliferation, migration, and invasion of lung squamous carcinoma cells in vitro. In a nude mouse cancer xenograft model, GAPDH knockdown significantly inhibited the cell proliferation and migration/invasion in vivo. In summary, GAPDH may not be an appropriate internal control for gene expression studies, especially in cancer research. The role of GAPDH in cancer development and progression should be further examined in pre‐clinical and clinical studies.

Elevated eukaryotic elongation factor 2 expression is involved in proliferation and invasion of lung squamous cell carcinoma

Eukaryotic elongation factor 2 (EF2), is a critical enzyme solely responsible for catalyzing the translocation of the elongated peptidyl-tRNA from the A to P sites of the ribosome during the process of protein synthesis. EF2 is found to be highly expressed in a variety of malignant tumors and is correlated with cancer cell progression and recurrence. The present study was designed to uncover the function of EF2 on lung squamous cell carcinoma (LSCC) cancer cell growth and progression. Our results from clinical tissue studies showed that EF2 protein was significantly overexpressed in LSCC tissues, compared with the adjacent normal lung tissues, which was confirmed by western blotting and tissue microarray. Forced expression of EF2 resulted in the enhancement of lung squamous carcinoma NCI-H520 cells growth through promotion of G2/M progression in cell cycle, activating Akt and Cdc2/Cyclin B1. In nude mice cancer xenograft model, overexpression of EF2 significantly facilitated cell proliferation in vivo. Furthermore, forced expression of EF2 in the cells increased the capabilities of migration and invasion by changing the expressions of EMT-related proteins and genes. These results provided novel insights into the role of EF2 in tumorigenesis and progression in LSCC. EF2-targeted therapy could become a good strategy for the clinical treatment of LSCC.

Proteomics-based identification of tumor relevant proteins in lung adenocarcinoma

BACKGROUND Lung cancer has the highest mortality rate among malignant tumors. Proteomics is a powerful tool to identify protein biomarkers. The identification of protein biomarkers associated with lung adenocarcinoma would have significance for making prognoses and designing targeted therapies. METHODS In our study, we applied a two-dimensional difference gel electrophoresis approach coupled to a matrix-assisted laser desorption/ionization time-of-flight mass spectrometric analysis for the identification of proteins differentially expressed between lung adenocarcinoma and the paired normal bronchial epithelial tissues derived from seven patients (four of them developed distant metastasis after operation). In addition, we chose two candidate proteins and examine their expression levels in lung adenocarcinoma and adjacent normal tissues using immunohistochemistry methods, and their expression levels in serum of patients and healthy donors by ELISA. RESULT In this study, 173 proteins were found to be differentially expressed (ratio>1.5 or<-1.5, P≤0.05), and 22 of them were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Thirteen proteins were at lower levels in the lung adenocarcinoma group, while nine proteins were at higher abundance. Immunohistochemistry analysis confirmed the expression levels of the two candidate proteins. The differential expression of the candidate secreted protein in serum from lung adenocarcinoma samples and healthy controls was showed by ELISA. CONCLUSION Our results demonstrated a differential protein expression pattern for lung adenocarcinoma compared with the paired normal bronchial epithelial tissues. Further functional validation of candidate proteins is ongoing and might provide new insights in lung adenocarcinoma.

Screening and Identification of Distant Metastasis-Related Differentially Expressed Genes in Human Squamous Cell Lung Carcinoma

Distant metastasis is one of the leading causes of lung cancer death. Detecting the early‐stage molecular alternations in primary tumors, such as gene expression differences, provides a “prognostic” value to the precaution of tumor metastasis. The aim of this article is to screen and identify the metastasis‐related genes in human squamous cell lung carcinoma. Primary tumor tissues of nine patients with subsequent metastasis and eight patients without metastasis were selected to perform the gene microarray experiment. GO and pathway analyses were used to determine the differentially expressed genes. Two identified genes were further validated by real‐time quantitative reverse transcription polymerase chain reaction (PCR) (real‐time qRT‐PCR). Two hundred and thirty‐eight differentially expressed genes were detected in gene chip experiment, including 51 up‐regulated genes and 187 down‐regulated genes. These genes were involved in several cellular processes, including cell adhesion, cell cycle regulation, and apoptosis. GO analysis showed that the differentially expressed genes participated in a wide ranging of metastasis‐related processes, including extracellular region and regulation of liquid surface tension. In addition, pathway analysis demonstrated that the differentially expressed genes were enriched in pathways related to cell cycle and Wnt signaling. Real‐time qRT‐PCR validation experiment of LCN2 and PDZK1IP1 showed a consistent up‐regulation in the metastasis group. The metastasis of human squamous cell lung carcinoma is a complex process that is regulated by multiple gene alternations on the expression levels. The 238 differentially expressed genes identified in this study presumably contain a core set of genes involved in tumor metastasis. The real‐time qRT‐PCR results of PDZK1IP1 and LCN2 validated the reliability of this gene microarray experiment. Anat Rec, 2012.

PRP19 upregulation inhibits cell proliferation in lung adenocarcinomas by p21-mediated induction of cell cycle arrest

Precursor messenger RNA processing factor 19 (PRP19) is known to be a critical component of the eukaryotic spliceosomal machinery and DNA damage repair system, the deregulation of which leads to many disease conditions. In many human cancers, PRP19 expression is upregulated, but its functional significance and corresponding underlying mechanisms remain to be addressed. Focusing on lung carcinomas, PRP19 upregulation was achieved by plasmid transfection into A549 adenocarcinoma cells. The transfected cells were then subjected to several in vitro and in vivo assays following in situ assessment of the protein in paired clinical lung tissues. We report that PRP19 expression is elevated in lung carcinoma tissues compared to non-tumor tissues. Following its upregulation, PRP19 repressed cell proliferation and tumor growth by upregulating the expression of the cell cycle arrest protein p21.

Overexpression of JAKMIP1 associates with Wnt/beta-catenin pathway activation and promotes cancer cell proliferation in vitro

JAKMIP1 is a member of the recently characterized JAKMIP1 family of proteins. It has been suggested that JAKMIP1 may play a role in various cell programs, such as cytoskeleton rearrangement, cell polarization, intracellular transport or even cell signaling activities. We examined its protein expression in tumor and followed it with a model that captures its impact on activities of some tumor-linked signaling pathways as well as how its upregulation affects cell proliferation. Here, we demonstrate that JAKMIP1 is highly expressed in tumor samples than in normal tissues. Additionally, higher expression of this protein may activate Wnt signaling activity, potentiate beta-catenin accumulation and enhance proliferation of cancer cells.