Guiyang Jiang

Abnormal expression of p120-catenin, E-cadherin, and small GTPases is significantly associated with malignant phenotype of human lung cancer

Studies on a variety of cell lines have shown that p120-catenin can directly regulate the stability of E-cadherin complexes and control the activity of small GTPases to influence cell adhesion. Despite this data, clinical studies of human solid tumors have not been reported to investigate these protein interactions. To explore the correlation between p120-catenin, E-cadherin, and small GTPases in human lung cancer, we examined the expression patterns of p120-catenin, E-cadherin, RhoA, Cdc42, and Rac1, and their prognostic significance in 138 patients with non-small cell lung cancer (NSCLC). While normal bronchial epithelium showed strong membrane expression of p120-catenin and E-cadherin, lung cancer tissues had reduced membrane expression and ectopic cytoplasmic expression of p120-catenin and E-cadherin. Expression of RhoA, Cdc42, and Rac1 was also found to be higher in tumor tissue than in normal lung tissue. A correlation between abnormal p120-catenin, E-cadherin expression, and overexpression of specific small GTPases was also associated with poor differentiation, high TNM stage, and lymph node metastasis in NSCLC patients. We also used an in vitro model to evaluate their expression, and to determine whether protein expression correlated with the invasive capacity of lung cancer cell lines. Consistent with our in vivo data, abnormal expression of p120-catenin and E-cadherin with overexpression of specific small GTPases were significantly associated with the high metastatic capacity of BE1 cells. Based on our results, we conclude that abnormal p120-catenin expression correlates with abnormal E-cadherin expression and specific small GTPase overexpression, which contribute to the malignancy-related to NSCLC.

Overexpression of SCC‐S2 correlates with lymph node metastasis and poor prognosis in patients with non‐small‐cell lung cancer

The objective of the current study was to investigate the expression pattern and clinicopathological significance of SCC‐S2 in patients with non‐small‐cell lung cancer (NSCLC). The expression profile of SCC‐S2 in NSCLC tissues and adjacent noncancerous lung tissues was detected by real‐time RT‐PCR, western blot analysis, and immunohistochemistry. In 25 lung cancer tissues examined, 18 (72%) of them exhibited stronger levels of SCC‐S2 mRNA compared with their corresponding normal tissues. SCC‐S2 protein level was up‐regulated in cancerous lung tissues compared to adjacent normal tissue. Moreover, the expression level of SCC‐S2 in 93 archived NSCLC tissues was measured by immunohistochemical staining. SCC‐S2 was found to be overexpressed in 71 of 93 (76.3%) human lung cancer samples and correlated with lymph node metastasis (P = 0.0181), p‐TNM stage (P = 0.0042), Ki‐67 expression (P = 0.0028), and poor survival (P = 0.012). In addition, depleting SCC‐S2 expression by small‐interfering RNA inhibited growth and invasion in lung cell lines. These results indicate that SCC‐S2 plays an important role in NSCLC and might be a useful therapeutic target of NSCLC. (Cancer Sci 2010)

δ‐Catenin promotes malignant phenotype of non‐small cell lung cancer by non‐competitive binding to E‐cadherin with p120ctn in cytoplasm

As a member of the catenin family, little is known about the clinical significance and possible mechanism of δ‐catenin expression in numerous tumours. We examined the expression of δ‐catenin by immunohistochemistry in 115 cases of non‐small cell lung cancer (NSCLC) (including 65 cases with follow‐up records and 50 cases with paired lymph node metastasis lesions). The mRNA and protein expression of δ‐catenin was also detected in 30 cases of paired lung cancer tissues and normal lung tissues by RT‐PCR and western blotting, respectively. Co‐immunoprecipitation was used to examine whether δ‐catenin competitively bound to E‐cadherin with p120ctn in lung cancer cells or not. The effects of δ‐catenin on the activity of small GTPases and the biological behaviour of lung cancer cells were explored by pull‐down assay, flow cytometry, MTT, and Matrigel invasive assay. The results showed that the mRNA and protein expression of δ‐catenin was increased in lung cancer tissues; the positive expression rate of δ‐catenin was significantly increased in adenocarcinoma, stage III–IV, paired lymph node metastasis lesions, and primary tumours with lymph node metastasis (all p < 0.05); and the postoperative survival period of patients with δ‐catenin‐positive expression was shorter than that of patients with δ‐catenin‐negative expression (p < 0.05). No competition between δ‐catenin and p120ctn for binding to E‐cadherin in cytoplasm was found in two lung cancer cell lines. By regulating the activity of small GTPases and changing the cell cycle, δ‐catenin could promote the proliferation and invasion of lung cancer cells. We conclude that δ‐catenin is an oncoprotein overexpressed in NSCLC and that increased δ‐catenin expression is critical for maintenance of the malignant phenotype of lung cancer. Copyright

Cytoplasmic Kaiso is associated with poor prognosis in non-small cell lung cancer

BackgroundKaiso has been identified as a new member of the POZ-zinc finger family of transcription factors that are implicated in development and cancer. Although controversy still exists, Kaiso is supposed to be involved in human cancer. However, there is limited information regarding the clinical significance of cytoplasmic/nuclear Kaiso in human lung cancer.MethodsIn this study, immunohistochemical studies were performed on 20 cases of normal lung tissues and 294 cases of non-small cell lung cancer (NSCLC), including 50 cases of paired lymph node metastases and 88 cases with complete follow-up records. Three lung cancer cell lines showing primarily nuclear localization of Kaiso were selected to examine whether roles of Kaiso in cytoplasm and in nucleus are identical. Nuclear Kaiso was down-regulated by shRNA technology or addition a specific Kaiso antibody in these cell lines. The proliferative and invasive abilities were evaluated by MTT and Matrigel invasive assay, transcription of Kaisos target gene matrilysin was detected by RT-PCR.ResultsKaiso was primarily expressed in the cytoplasm of lung cancer tissues. Overall positive cytoplasmic expression rate was 63.61% (187/294). The positive cytoplasmic expression of Kaiso was higher in advanced TNM stages (III+IV) of NSCLC, compared to lower stages (I+II) (p = 0.019). A correlation between cytoplasmic Kaiso expression and lymph node metastasis was found (p = 0.003). In 50 paired cases, cytoplasmic expression of Kaiso was 78.0% (41/50) in primary sites and 90.0% (45/50) in lymph node metastases (p = 0.001). The lung cancer-related 5-year survival rate was significantly lower in patients who were cytoplasmic Kaiso-positive (22.22%), compared to those with cytoplasmic Kaiso-negative tumors (64.00%) (p = 0.005). Nuclear Kaiso staining was seen in occasional cases with only a 5.10% (15/294) positive rate and was not associated with any clinicopathological features of NSCLC. Furthermore, after the down-regulation of the nuclear expresses Kaiso in vitro, both proliferative and invasive abilities of three cancer cell lines were significantly enhanced, along with the up-regulation of Kaiso target gene, matrilysin.ConclusionOur data suggest cytoplasmic Kaiso expression is associated with poor prognosis of NSCLC and various subcellular localizations of Kaiso may play differential biological roles in NSCLC.

Kaiso is expressed in lung cancer: Its expression and localization is affected by p120ctn

BACKGROUND Kaiso is a recently identified transcription factor that binds to p120-catenin (p120ctn), an Armadillo catenin and cell adhesion cofactor. However, clinical studies of human solid tumors have not been reported to investigate relationship between these proteins. METHODS Expression and localization of Kaiso and p120ctn were examined in 196 lung cancer specimens (including 55 cases of paired lymph node metastases and 80 cases with complete follow-up records) by immunohistochemistry. Three lung cancer cell lines, BE1, SPC, and A549 were used to establish p120ctn stably ablated or overexpressed cell lines. Co-immunoprecipitation was used to confirm p120ctn bind Kaiso in lung cancer tissue and cell lines. Localization and expression levels of Kaiso were detected via immunofluorescence, cytoplasmic vs. nuclear fractionation Western blot analysis and reverse transcription-polymerase chain reaction. RESULTS Cytoplasmic Kaiso expression was evident in 115 (58.7%), and abnormal p120ctn expression was noted in 168 (85.7%). Cytoplasmic Kaiso and abnormal p120ctn expressions were associated with higher degree of malignancy (high-stage and lymph node metastases, all P<0.05). Abnormal p120ctn and cytoplasmic Kaiso expressions were higher in matched autologous nodal metastases than in primary growths. The lung cancer-related 5-year survival rate was significantly lower in patients who were cytoplasmic Kaiso-positive (22.9%; P=0.029) or abnormal p120ctn expression (20.6%; P=0.001). Multivariate analysis showed abnormal p120ctn expression was an independent factor defining the clinicopathological characters of patients. Cytoplasmic Kaiso expression was correlated with cytoplasmic p120ctn, they formed Kaiso-p120ctn complex in lung cancer tissues and cell lines. In addition, p120ctn ablation and overexpression altered Kaiso subcellular localization and protein level. Although both isoforms can regulate subcellular localization and protein levels of Kaiso, we found that only p120ctn isoform 3, but not isoform 1, directly interacts with Kaiso. CONCLUSION p120ctn and Kaiso might co-participate in the progression and lymph node metastasis of lung cancer. p120ctn regulates expression and localization of Kaiso in lung cancer cells.

Downregulation of HDPR1 is associated with poor prognosis and affects expression levels of p120-catenin and β-catenin in nonsmall cell lung cancer

HDPR1 (human homologue of Dapper) is considered as a Dishevelled (DVL) antagonist in WNT signaling. We recently reported that DVL was associated with cytoplasmic accumulation of β‐catenin in nonsmall cell lung cancer (NSCLC). Whether cytoplasmic accumulation of β‐catenin is correlated with HDPR1 is unclear. Xenopus Dapper (XDpr) was found to stabilize p120‐catenin (p120ctn) in Xenopus embryogenesis. However, whether HDPR1 can regulate p120ctn expression level is not reported. Furthermore, how HDPR1 influences invasiveness in lung carcinogenesis is also not well understood. In this study, our aims were to explore the effects of HDPR1 on the lung carcinogenesis and to examine the relationship among HDPR1, β‐catenin, and p120ctn. Immunohistochemical analysis in 120 NSCLC tissues showed that HDPR1 was significantly lower in 82 specimens (68.3%). Reverse transcription (RT)‐polymerase chain reaction (PCR) and Western blotting analysis showed that the mRNA and protein expression of HDPR1 were lower in tumor tissues as compared to corresponding nontumorous tissues. Moreover, reduced HDPR1 expression was related to the clinicopathological factors and was an independent risk factor for prognosis of the patients with NSCLC. In addition, HDPR1 expression was also associated with the expression of p120ctn and β‐catenin in lung cancer tissues. Knockdown of HDPR1 gene enhanced the invasive ability of lung cancer cells, which was dependent on p120ctn and independent of β‐catenin. In conclusion, the function of HDPR1 on regulating p120ctn may play an important role in human lung carcinogenesis. Restoration of HDPR1 gene may be a new therapeutic target of lung cancer.

p120-catenin isoform 3 regulates subcellular localization of Kaiso and promotes invasion in lung cancer cells via a phosphorylation-dependent mechanism

p120-catenin regulates E-cadherin stability at the plasma membrane as well as Rho GTPase activity in the cytoplasm, and also interacts with the transcriptional repressor, Kaiso, in the nucleus. However, the role of different isoforms and the phosphorylated state of p120-catenin in the nucleus is poorly understood. In the present study, we show that p120-catenin isoform 3 interacts with Kaiso in lung cancer cells by immunoprecipitation. Nuclear-cytoplasmic extraction and immunofluorescence confirmed that Kaiso shuttled out of the nucleus via p120-catenin isoform 3. The cytoplasmic enrichment of Kaiso by p120-catenin isoform 3 was abolished due to the inhibition of chromosomal region maintenance-dependent nuclear export via leptomycin. The lung tumor tissue and cell lines expressed higher levels of the serine 288 phosphorylated form. Also, serine 288 phosphorylation in p120-catenin isoform 3 enhanced the binding with Kaiso. Moreover, immunofluorescence and transwell invasion assay showed that the phosphorylation of serine and threonine sites in p120-catenin induced F-actin remodelling and promoted the invasion of lung cancer cells. Collectively, our data establish that p120-catenin isoform 3 regulates the nuclear export of Kaiso and promotes invasion in lung cancer cells via a phosphorylation-dependent mechanism. Serine 288 phosphorylation can contribute to lung cancer progression.

Ascertaining an Appropriate Diagnostic Algorithm Using EGFR Mutation-Specific Antibodies to Detect EGFR Status in Non-Small-Cell Lung Cancer

Background Epidermal growth factor receptor (EGFR) mutation status is the most valuable indicator in the screening of non-small-cell lung cancer (NSCLC) patients for tyrosine kinase inhibitor (TKI) therapy. Accurate, rapid and economical methods of detecting EGFR mutations have become important. The use of two mutation-specific antibodies targeting the delE746-A750 mutation in exon 19 and L858R mutation in exon 21 makes this task possible, but the lack of consensually acceptable criteria for positive results limits the application of this antibody based mutation detection. Methods We collected 399 specimens from NSCLC patients (145 resection specimens, 220 biopsy specimens, and 34 cytology specimens) whose EGFR mutation status had been detected by TaqMan PCR assay. Immunohistochemical (IHC) analyses using EGFR mutation-specific antibodies were employed for all samples. After staining and scoring, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated in accordance with different levels of positive grades in comparison with the results of PCR-based assay. Results In IHC-based analyses, 144 cases were scored 0, 104 cases were scored 1+, 103 cases were scored 2+, and 48 cases were scored 3+. With the molecular-based results were set as the “gold standard”, the prevalence of mutation was 6.94% (10/144), 23.08% (24/104), 67.96% (70/103) and 100% (48/48), respectively, for samples with scores 0, 1+, 2+ and 3+. When score 3+ was considered positive, the specificity and PPV were 100%; if only score 0 was considered negative, 93.06% NPV was obtained. Conclusion Patients with score 3+ have a perfect PPV (100%), and may accept TKI treatment directly without any molecular-based assays. Patients with score 0 had high NPV (93.06%), which could reach 97.22% when the detection of total EGFR was applied. However, samples with score 1+ or 2+ are unreliable and need further verification of EGFR mutation status by molecular-based assays.

Impact of p120-catenin Isoforms 1A and 3A on Epithelial Mesenchymal Transition of Lung Cancer Cells Expressing E-cadherin in Different Subcellular Locations

The epithelial mesenchymal transition (EMT) is an important process in tumor development. Despite previous investigations, it remains unclear how p120-catenin (p120ctn) isoforms 1A and 3A affect the EMT of tumor cells. Here we investigated expression of p120ctn, E-cadherin and vimentin in 78 human non-small cell lung cancer (NSCLC) samples by immunohistochemistry and found that p120ctn membrane expression positively correlated with E-cadherin expression (P<0.001) and negatively correlated with vimentin expression and lymph node metastasis (P<0.05). Meanwhile, p120ctn cytoplasmic expression negatively correlated with E-cadherin expression (P<0.001) and positively correlated with vimentin expression and lymph node metastasis (P<0.05). Cells expressing high (H460 and SPC) and low (H1299 and LK2) levels of p120ctn were screen to investigate its impact on EMT. E-cadherin was restricted to the cell membrane in H460 and H1299 cells, whereas it was expressed in the cytoplasm of SPC and LK2 cells. Ablation of endogenous p120ctn isoform 1A in cells expressing high levels of the protein resulted in decreased E-cadherin expression, increased N-cadherin, vimentin and snail expression and enhanced invasiveness in H460 cells. Meanwhile, completely opposite results were observed in SPC cells. Furthermore, transfection of in H1299 cells expressing low p120ctn levels with the p120ctn isoform 1A plasmid resulted in increased E-cadherin expression, decreased N-cadherin, vimentin and snail expression and weakened invasiveness, while LK2 cells showed completely opposite results. Both cell lines expressing low p120ctn levels and transfected with the p120ctn isoform 3A plasmid appeared to have increased E-cadherin expression, decreased N-cadherin, vimentin and snail expression and weakened invasiveness. In conclusion, in cells with membrane E-cadherin, both p120ctn isoforms 1A and 3A inhibited EMT and decreased cell invasiveness. In cells with cytoplasmic E-cadherin, p120ctn isoform 1A promoted EMT and increased cell invasiveness, while p120ctn isoform 3A inhibited the EMT and decreased cell invasiveness.

WWC3 regulates the Wnt and Hippo pathways via Dishevelled proteins and large tumour suppressor 1, to suppress lung cancer invasion and metastasis: WWC3 inhibits invasion and metastasis

The scaffolding protein WWC (WW and C2‐domain containing) family is known to regulate cell proliferation and organ size via the Hippo signalling pathway. However, the expression level of WWC3 in human tumours and the mechanisms underlying its role in cellular signal transduction have not yet been reported. Herein, we explored the potential roles of WWC3 in lung cancer cells and the corresponding molecular mechanisms. We found low WWC3 expression in both lung cancer cell lines and lung cancer specimens, which was associated with low differentiation, advanced pTNM stage, positive lymph node metastasis, and poor prognosis in patients with lung cancer. Moreover, the overexpression of WWC3 inhibited the proliferation and invasiveness of lung cancer cells. These effects were mediated by the inhibition and stimulation of the Wnt and Hippo pathways, respectively, in vitro and in vivo. Specifically, WWC3 interacts with Dishevelled (Dvl) proteins, prevents casein kinase 1ϵ from phosphorylating Dvls, and inhibits β‐catenin nuclear translocation to inhibit the Wnt pathway. Deleting the WW and C‐terminal PDZ‐binding domains of WWC3 abrogated these effects. Moreover, the interaction of WWC3 with Dvls reduced the interaction between WWC3 and large tumour suppressor 1 (LATS1), as well as decreasing LATS1 phosphorylation to increase the nuclear importation of yes‐associated protein (YAP) and attenuate the Hippo pathway. Deleting the WW domain of WWC3 abrogated this effect. These findings demonstrate the molecular interplay between WWC3, Dvls, and LATS1, and reveal a link between the Wnt and Hippo pathways, which provides a potential target for clinical intervention in lung cancer. Copyright