Linlin Gong

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.

Hepatocyte Growth Factor Induces Invasion and Migration of Ovarian Cancer Cells by Decreasing the Expression of E-cadherin, β-catenin, and Caveolin-1

Distant metastases are unusual occurrences at presentation and during the progression of epithelial ovarian cancer. There are no good clinical predictors of this phenomenon. In this study, we examined the role of hepatocyte growth factor (HGF) in cell metastasis in ovarian cancer HO8910 cells. We found that HGF has functions in biological processes essential to metastasis, including morphological remodeling, invasion and migration (P = 0.000, P = 0.001). Western blotting showed that in HGF treated group, the expression of E‐cadherin, β‐catenin, and caveolin‐1 was decreased as compared with the control group (P = 0.000, P = 0.002, P = 0.000). Immunofluorescence staining demonstrated that the population of E‐cadherin, β‐catenin, and caveolin‐1 at the cell membrane was downregulated. Reverse transcriptase polymerase chain reaction analysis revealed the decreased expression of E‐cadherin, β‐catenin, and caveolin‐1 at the mRNA level. Our data indicated that HGF leads to downregulation of E‐cadherin, β‐catenin, and caveolin‐1, disassembly of cell–cell contacts, and invasion and migration enhancement in human ovarian cancer cells. Anat Rec 293:1125–1133, 2010.

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.

Quantitative Proteomic Profiling the Molecular Signatures of Annexin A5 in Lung Squamous Carcinoma Cells.

Lung cancer remains the leading cancer killer around the world. It’s crucial to identify newer mechanism-based targets to effectively manage lung cancer. Annexin A5 (ANXA5) is a protein kinase C inhibitory protein and calcium dependent phospholipid-binding protein, which may act as an endogenous regulator of various pathophysiological processes. However, its molecular mechanism in lung cancer remains poorly understood. This study was designed to determine the mechanism of ANXA5 in lung cancer with a hope to obtain useful information to provide a new therapeutic target. We used a stable isotope dimethyl labeling based quantitative proteomic method to identify differentially expressed proteins in NSCLC cell lines after ANXA5 transfection. Out of 314 proteins, we identified 26 and 44 proteins that were down- and up-regulated upon ANXA5 modulation, respectively. The IPA analysis revealed that glycolysis and gluconeogenesis were the predominant pathways modulated by ANXA5. Multiple central nodes, namely HSPA5, FN1, PDIA6, ENO1, ALDOA, JUP and KRT6A appeared to occupy regulatory nodes in the protein-protein networks upon ANXA5 modulation. Taken together, ANXA5 appears to have pleotropic effects, as it modulates multiple key signaling pathways, supporting the potential usefulness of ANXA5 as a potential target in lung cancer. This study might provide a new insight into the mechanism of ANXA5 in lung cancer.

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.

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.