Gene Summary

Gene:CD82; CD82 molecule
Aliases: R2, 4F9, C33, IA4, ST6, GR15, KAI1, SAR2, TSPAN27
Summary:This metastasis suppressor gene product is a membrane glycoprotein that is a member of the transmembrane 4 superfamily. Expression of this gene has been shown to be downregulated in tumor progression of human cancers and can be activated by p53 through a consensus binding sequence in the promoter. Its expression and that of p53 are strongly correlated, and the loss of expression of these two proteins is associated with poor survival for prostate cancer patients. Two alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. [provided by RefSeq, Jul 2008]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:CD82 antigen
Source:NCBIAccessed: 09 March, 2017


What does this gene/protein do?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 09 March 2017 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 09 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (8)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: CD82 (cancer-related)

Singh R, Bhatt ML, Singh SP, et al.
Expression Levels of Tetraspanin KAI1/CD82 in Breast Cancers in North Indian Females.
Asian Pac J Cancer Prev. 2016; 17(7):3431-6 [PubMed] Related Publications
BACKGROUND: Carcinogenesis is a multifaceted intricate cellular mechanism of transformation of the normal functions of a cell into neoplastic alterations. Metastasis may result in failure of conventional treatment and death Hence, research on metastatic suppressors in cancer is a high priority. The metastatic suppressor gene CD82, also known as KAI1, is a member of the transmembrane 4 superfamily which was first identified in carcinoma of prostate. Little work has been done on this gene in breast cancer. Herein, we aimed to determine the gene and protein level expression of CD82/KAI1 in breast cancer and its role as a prognosticator.
MATERIALS AND METHODS: In this study, 83 histologically proven cases of breast cancer and a similar number of controls were included. Patient age ranged from 1870 years. Quantitative Real Time Polymerase Chain Reaction (qRT PCR) and immunohistochemistry (IHC) were used to investigate KAI1 expression at gene and protein levels, respectively. Statistical analysis was done to correlate expression of KAI1 and clinicopathological parameters.
RESULTS: It was revealed that: (i) KAI1 was remarkably diminished in metastatic vs non metastatic breast cancer both at the gene and the protein levels (P<.05); (ii) KAI1 expression levels were strongly correlated with TNM staging, histological grade and advanced stage (p<0.001) and no association was found with any other studied parameter; (iii) Lastly, a significant correlation was observed between expression of KAI1 and overall median survival of BC patients (P = 0.04).
CONCLUSIONS: Our results suggest that lack of expression of the KAI1 might indicate a more aggressive form of breast cancer. Loss of KAI1 may be considered a significant prognostic marker in predicting metastatic manifestation. When evaluated along with the clinical and pathological factors, KAI1 expression may be beneficial to tailor aggressive therapeutic strategies for such patients.

Chai J, Ju J, Zhang SW, et al.
p12CDK2-AP1 interacts with CD82 to regulate the proliferation and survival of human oral squamous cell carcinoma cells.
Oncol Rep. 2016; 36(2):737-44 [PubMed] Related Publications
p12 cyclin-dependent kinase 2 (CDK2)-associating protein 1 (p12CDK2-AP1) has been demonstrated to negatively regulate the activity of CDK2. However, the underlying molecular mechanism remains largely unknown. We aimed to determine the potential binding proteins of p12CDK2-AP1 and to elucidate the role of p12CDK2-AP1 in the regulation of the proliferation, invasion, apoptosis, and in vivo growth of human oral squamous cell carcinoma cells. The protein-protein interaction was predicted using computational decision templates. The predicted p12CDK2‑AP1 interacting proteins were overexpressed in human oral squamous cell carcinoma OSCC-15 cells, and the protein binding was examined using co-precipitation (Co-IP). Cell proliferation and invasion were determined via MTT assay and Transwell system, respectively. Cell apoptosis was evaluated using Annexin V-FITC/PI double staining followed by flow cytometric analysis. The in vivo growth of OSCC-15 cells was examined in nude mouse tumor xenografts. We found that overexpression of either p12CDK2-AP1 or CD82 significantly suppressed the proliferation and invasion but promoted the apoptosis of OSCC-15 cells (P<0.05). Importantly, combined overexpression of p12CDK2-AP1 and CD82 showed synergistic antitumor activity compared with the overexpression of a single protein alone (P<0.05). Additionally, the simultaneous overexpression of p12CDK2-AP1 and CD82 significantly suppressed the in vivo tumor growth of OSCC-15 cells in nude mice compared with the negative control (P<0.05). Our findings indicate that p12CDK2-AP1 interacts with CD82 to play a functional role in suppressing the in vitro and in vivo growth of OSCC-15 cells.

Tsui KH, Lin YH, Chung LC, et al.
Prostate-derived ets factor represses tumorigenesis and modulates epithelial-to-mesenchymal transition in bladder carcinoma cells.
Cancer Lett. 2016; 375(1):142-51 [PubMed] Related Publications
Prostate-derived Ets (E-twenty six) factor (PDEF), an epithelium-specific member of the Ets family of transcription factors, has been shown to play a role in suppressing the development of many epithelium-derived cancers such as prostate and breast cancer. It is not clear, however, whether PDEF is involved in the development or progression of bladder cancer. In a comparison between normal urothelium and bladder tumor tissue, we identified significant decreases of PDEF in the tumor tissue. Further, the immunohistochemistry assays indicated a significantly higher immunostaining of PDEF in low-grade bladder tumors. Additionally, the highly differentiated transitional-cell bladder carcinoma RT-4 cells expressed significantly more PDEF levels than the bladder carcinoma HT1376 and the T24 cells. Ectopic overexpression of PDEF attenuated proliferation, invasion, and tumorigenesis of bladder carcinoma cells in vitro and in vivo. PDEF enhanced the expression levels of mammary serine protease inhibitor (MASPIN), N-myc downstream regulated gene 1 (NDRG1), KAI1, and B-cell translocation gene 2 (BTG2). PDEF modulated epithelial-mesenchymal-transition (EMT) by upregulating E-cadherin expression and downregulating the expression of N-cadherin, SNAIL, SLUG, and vimentin, leading to lower migration and invasion abilities of bladder carcinoma cells. Filamentous actin (F-actin) polarization and remodeling were observed in PDEF-knockdown RT-4 cells. Our results suggest that PDEF gene expression is associated with the extent of bladder neoplasia and PDEF modulated the expressions of EMT-related genes. The induction of BTG2, NDRG1, MASPIN, and KAI1 gene expressions by PDEF may explain the inhibitory functions of PDEF on the proliferation, invasion, and tumorigenesis in bladder carcinoma cells.

Karashima T, Kuroda N, Taguchi T, et al.
Chromophobe renal cell carcinoma, eosinophilic variant with papillary growth: a case report.
Int J Clin Exp Pathol. 2015; 8(10):13590-5 [PubMed] Free Access to Full Article Related Publications
We report the case of an 80-year-old man who presented with pathologically diagnosed chromophobe renal cell carcinoma composed of eosinophilic cells with partial papillary growth. The patient had a 2.5 cm diameter renal mass incidentally detected by abdominal ultrasound examination. Laparoscopic left partial nephrectomy was performed under a diagnosis of left renal tumor. Histopathology demonstrated uniform eosinophilic cuboidal cells growing with a partially papillary pattern: differential diagnosis of oncocytoma, papillary renal cell carcinoma, or oncocytic papillary renal cell carcinoma was necessary. Immunohistochemical staining with anti-monoclonal antibody 31 and -CD82 antibody, and choroid iron staining, were positive. Cytogenetic analysis by comparative genomic hybridization showed gains of chromosomes 1p, 9q, 19q, 20, and 21q, and losses of chromosomes 1p and q, 2q, 6q and 7q, leading to diagnosis of chromophobe RCC. We describe differential diagnosis for chromophobe renal cell carcinoma, eosinophilic variant, growing in a papillary fashion in the kidney.

Gong X, Tao Y, Zhou L, et al.
[Expressions of Snail, Slug and KAI1 proteins in cervical carcinoma and their clinicopathological significance].
Nan Fang Yi Ke Da Xue Xue Bao. 2015; 35(12):1733-8 [PubMed] Related Publications
OBJECTIVE: To explore the expression of Snail and Slug in primary cervical squamous cell carcinoma (CSCC) and their relationship with KAI1 expression.
METHODS: The expressions of Snail, Slug, and KAI1 proteins were examined by immunohistochemistry in 154 specimens of CSCC tissues, 50 specimens of cervical intraepithelial neoplasm (CIN), and 40 specimens of normal cervical tissues.
RESULTS: The positivity rates of Snail, Slug, and KAI1 expression were 0%, 2.5%, and 95.0% in normal cervical tissues, 32.0%, 34.0% and 64.0% in CIN tissues, and 66.2%, 66.9%, and 43.5% in CSCC tissues, respectively, showing significant differences in the rates among the 3 groups (P<0.05). The expressions of Snail, Slug, and KAI1 were significantly correlated with the histological grades of the tumor, depth of invasion, lymph node metastasis, International Federation of Gynecology and Obstetrics (FIGO) stages, and postoperative survival time (P<0.05). The expressions of Snail and Slug were positively correlated (r=0.752, P<0.001), and both of them were negatively correlated with the expression of KAI1 (P<0.001). Kaplan-Meier analysis showed that patients positive for Snail and Slug had significantly lower survival rates than the negative patients (P<0.001), while a positive expression of KAI1 was associated with a higher survival rate of the patients. Cox regression analysis identified Snail, KAI1, and FIGO stage as independent factors that affected the outcomes of CSCC (P<0.05).
CONCLUSION: The expressions of Snail, Slug, and KAI1 are related to the tumor grade, FIGO stage, invasive depth, lymph node metastasis, and prognosis of CSCC, and their combined detection can help estimate the outcomes of the patients.

Zhu C, He L, Zhou X, et al.
Sulfatase 2 promotes breast cancer progression through regulating some tumor-related factors.
Oncol Rep. 2016; 35(3):1318-28 [PubMed] Free Access to Full Article Related Publications
In previous studies Sulf2 has been evidenced to play an important role in tumor progression through editing sulfate moieties on heparan sulfate proteoglycans (HSPGs) and modulating heparin binding growth factors. However, the role of Sulf2 in breast cancer progression is still poorly understood. In the present study, we hypothesized that Sulf2 promoted breast cancer progression. Two different breast cancer cell lines, MCF-7 and MDA-MB-231, were chosen for this study because of high and low Sulf2 expression levels. We also altered their Sulf2 expression by establishing Sulf2 knockdown and overexpressing breast cancer cell lines MCF-7 shSulf2 and MDA-MB-231 Sulf2. To evaluate the functions of Sulf2, cell proliferation, apoptosis, cell cycle, invasion, mobility and adhesion of these cell lines were measured in vitro, and xenograft formation, invasion and metastasis ability were examined in vivo. Furthermore, expression of related genes were screened and were certified in these cell lines. We found that Sulf2 increased breast cancer proliferation, invasion, mobility and adhesion both in vitro and in vivo. Sulf2 also decreased cisplatin inducing breast cancer apoptosis without affecting the cell cycle. Sulf2 upregulated c-fos induced growth factor (FIGF) and nuclear receptor subfamily 4 group A member 3 (NR4A3) expression and downregulated the cluster of differentiation 82 (CD82) and platelet-derived growth factor C (PDGFC) expression in breast cancer. Our data confirmed that Sulf2 promoted breast cancer progression and regulated the expression of tumor-related genes in breast cancer.

Zhou XL, Wang M
Expression levels of survivin, Bcl-2, and KAI1 proteins in cervical cancer and their correlation with metastasis.
Genet Mol Res. 2015; 14(4):17059-67 [PubMed] Related Publications
Cervical cancer is associated with abnormal expression of multiple genes. Survivin and Bcl-2 proteins are apoptosis inhibitors. The tumor suppressor gene CD82, which encodes the protein KAI1, is downregulated in cervical cancer, and is associated with differentiation degree. We investigated the expression levels of three proteins and their correlation with metastasis in cervical cancer by comparing them in different cervical lesions. Immunohistochemistry was used to detect their three protein expression levels in the normal cervix, chronic cervicitis, cervical intraepithelial neoplasia (CIN) lesions, and cervical cancer. The relationships between the protein expression levels and tumor type, clinical stage, tissue differentiation, invasion, and metastasis were analyzed. Survivin and Bcl-2 expression levels in cervical cancer were significantly higher than in the normal cervix, chronic cervicitis, or CIN (P < 0.05). KAI1 expression was markedly lower in cervical cancer than in the normal cervix, chronic cervicitis, or CIN (P < 0.05). There was no statistical difference between the expression levels of the three proteins in CIN and chronic cervicitis, but there were differences in expression between CIN and normal cervical tissues (P < 0.05). Bcl-2 and survivin levels were positively correlated while KAI1 expression was negatively correlated with clinical stage. Survivin and KAI1 expression levels were associated with lymph node metastasis (P < 0.05), and KAI1 expression was positively related with differentiation degree (P < 0.05). Survivin, Bcl-2, and KAI1 are metastasis-related factors in cervical cancer. Overexpression of survivin and Bcl-2, and low expression of KAI1 promotes cervical cancer progress and metastasis.

Bae JA, Kho DH, Sun EG, et al.
Elevated Coexpression of KITENIN and the ErbB4 CYT-2 Isoform Promotes the Transition from Colon Adenoma to Carcinoma Following APC loss.
Clin Cancer Res. 2016; 22(5):1284-94 [PubMed] Related Publications
PURPOSE AND EXPERIMENTAL DESIGN: The molecular events in the malignant progression of colon adenoma after loss of adenomatous polyposis coli (APC) are not fully understood. KITENIN (KAI1 C-terminal interacting tetraspanin) increases the invasiveness of colorectal cancer cells, and we identified a novel EGFR-independent oncogenic signal of EGF that works under coexpressed KITENIN and ErbB4. Here we tested whether elevated KITENIN and ErbB4 contribute to further progression of intestinal adenoma following APC loss.
RESULTS: The intestinal tissues of villin-KITENIN transgenic mice in which villin-driven KITENIN expression induces increased c-Jun expression exhibit mild epithelial cell proliferation but no epithelial lineage changes compared with those of nontransgenic mice. Among the four ErbB4 isoforms, JM-a/CYT-2 and JM-b/CYT-2 exhibited the highest AP-1 activity when cells coexpressing KITENIN and each isoform were stimulated by EGF. Interestingly, predominant overexpression of the ErB4-CYT-2 mRNA as well as increased EGFR expression were observed in intestinal adenoma of APC(min/+) mice, which makes the microenvironment of activated EGF signaling. When we crossed villin-KITENIN mice with APC(min/+) mice, intestinal tumor tissues in the crossed mice showed the characteristics of early-stage invading adenocarcinoma. In patients with colorectal cancer, ErbB4-CYT-2 mRNA expression was significantly greater in tumor tissues than in normal adjacent tissues, but no significant differences in tumor tissue expression were found between different colorectal cancer stages. Furthermore, the mRNA expression of KITENIN and that of ErbB4-CYT-2 were positively correlated in human colorectal cancer tissue.
CONCLUSIONS: Elevated coexpression of KITENIN and ErbB4-CYT-2 promotes the transition of colon adenoma to adenocarcinoma within an APC loss-associated tumor microenvironment.

Oh HH, Park KJ, Kim N, et al.
Impact of KITENIN on tumor angiogenesis and lymphangiogenesis in colorectal cancer.
Oncol Rep. 2016; 35(1):253-60 [PubMed] Related Publications
Angiogenesis and lymphangiogenesis are involved in the dissemination of tumor cells from solid tumors to regional lymph nodes and various distant sites. KAI1 COOH-terminal interacting tetraspanin (KITENIN) contributes to tumor progression and poor clinical outcomes in various cancers including colorectal cancer. The aim of the present study was to evaluate whether KITENIN affects tumor angiogenesis and lymphangiogenesis in colorectal cancer. A KITENIN small interfering RNA vector was used to silence KITENIN expression in colorectal cancer cell lines including DLD1 and SW480 cells. To evaluate the ability of KITENIN to induce angiogenesis and lymphangiogenesis in human umbilical vein endothelial cells (HUVECs) and lymphatic endothelial cells (HLECs), we performed Matrigel invasion and tube formation assays. Immunohistochemistry was used to determine the expression of KITENIN in colorectal cancer tissues. Angiogenesis and lymphangiogenesis were evaluated by immunostaining with CD34 and D2-40 antibodies. KITENIN silencing inhibited both HUVEC invasion and tube formation in the DLD1 and SW480 cells. KITENIN silencing led to decreased expression of the angiogenic inducers vascular endothelial growth factor (VEGF)-A and hypoxia-inducible factor-1α and increased expression of the angiogenic inhibitor angiostatin. KITENIN silencing did not inhibit either HLEC invasion or tube formation in all tested cells, but it resulted in decreased expression of the lymphangiogenic inducer VEGF-C. KITENIN expression was significantly associated with tumor stage, depth of invasion, lymph node and distant metastases and poor survival. The mean microvessel density was significantly higher in the KITENIN-positive tumors than that in the KITENIN-negative tumors. However, the mean lymphatic vessel density of KITENIN-positive tumors was not significantly higher than that of the KITENIN-negative tumors. These results suggest that KITENIN promotes tumor progression by enhancing angiogenesis in colorectal cancer.

Wu Q, Yang Y, Wu S, et al.
Evaluation of the correlation of KAI1/CD82, CD44, MMP7 and β-catenin in the prediction of prognosis and metastasis in colorectal carcinoma.
Diagn Pathol. 2015; 10:176 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: To investigate the relationship of KAI1/CD82, CD44, matrix metalloproteinase 7 (MMP7) and β-catenin, and examine its association with clinicopathological features, metastasis and prognosis in colorectal carcinoma (CRC).
METHODS: Immunohistochemical (IHC) analysis was used to detect the expression of KAI1/CD82, CD44, MMP7 and β-catenin in 174 archival surgical specimens of human CRC. Furthermore, clinicopathological features such as age, sex and so on were also collected retrospectively.
RESULTS: CD44, MMP7 and β-catenin expression was positively associated with distant metastasis, lymph node metastasis and tumor-node-metastasis (TNM) stage. However, decreased KAI1/CD82 expression correlated significantly with distant metastasis, lymph node metastasis and TNM stage. KAI1/CD82 expression showed a negative correlation with CD44, MMP7 and β-catenin. Furthermore, β-catenin expression showed a positive correlation with CD44 and MMP7. Multivariate logistic regression analysis showed that KAI1/CD82 and β-catenin expression were significantly associated with lymph node metastasis and KAI1/CD82 was significantly associated with distant metastasis. Kaplan-Meier analysis revealed that CD44, MMP7 and β-catenin expression was negatively correlated with overall survival (OS), while KAI1/CD82 expression was positively correlated with OS. Low KAI1/CD82 expression and high expression of CD44, MMP7 and β-catenin was associated with a poor prognosis in CRC. Multivariate Cox regression analysis indicated that the expression of KAI1/CD82, MMP7 and β-catenin were independent predictors of OS in CRC.
CONCLUSION: The expression of KAI1/CD82, CD44, MMP7 and β-catenin is related to tumor metastasis and prognosis in CRC. Combined detection of these factors may be of significant value in predicting the prognosis and metastasis in CRC patients.

Yang Y, Park SY, Nguyen TT, et al.
Lichen Secondary Metabolite, Physciosporin, Inhibits Lung Cancer Cell Motility.
PLoS One. 2015; 10(9):e0137889 [PubMed] Free Access to Full Article Related Publications
Lichens produce various unique chemicals that can be used for pharmaceutical purposes. To screen for novel lichen secondary metabolites showing inhibitory activity against lung cancer cell motility, we tested acetone extracts of 13 lichen samples collected in Chile. Physciosporin, isolated from Pseudocyphellaria coriacea (Hook f. & Taylor) D.J. Galloway & P. James, was identified as an effective compound and showed significant inhibitory activity in migration and invasion assays against human lung cancer cells. Physciosporin treatment reduced both protein and mRNA levels of N-cadherin with concomitant decreases in the levels of epithelial-mesenchymal transition markers such as snail and twist. Physciosporin also suppressed KITENIN (KAI1 C-terminal interacting tetraspanin)-mediated AP-1 activity in both the absence and presence of epidermal growth factor stimulation. Quantitative real-time PCR analysis showed that the expression of the metastasis suppressor gene, KAI1, was increased while that of the metastasis enhancer gene, KITENIN, was dramatically decreased by physciosporin. Particularly, the activity of 3'-untranslated region of KITENIN was decreased by physciosporin. Moreover, Cdc42 and Rac1 activities were decreased by physciosporin. These results demonstrated that the lichen secondary metabolite, physciosporin, inhibits lung cancer cell motility through novel mechanisms of action.

Feng J, Huang C, Wren JD, et al.
Tetraspanin CD82: a suppressor of solid tumors and a modulator of membrane heterogeneity.
Cancer Metastasis Rev. 2015; 34(4):619-33 [PubMed] Related Publications
Tetraspanin CD82 suppresses the progression and metastasis of a wide range of solid malignant tumors. However, its roles in tumorigenesis and hematopoietic malignancy remain unclear. Ubiquitously expressed CD82 restrains cell migration and cell invasion by modulating both cell-matrix and cell-cell adhesiveness and confining outside-in pro-motility signaling. This restraint at least contributes to, if not determines, the metastasis-suppressive activity and, also likely, the physiological functions of CD82. As a modulator of cell membrane heterogeneity, CD82 alters microdomains, trafficking, and topography of the membrane by changing the membrane molecular landscape. The functional activities of membrane molecules and the cytoskeletal interaction of the cell membrane are subsequently altered, followed by changes in cellular functions. Given its pathological and physiological importance, CD82 is a promising candidate for clinically predicting and blocking tumor progression and metastasis and also an emerging model protein for mechanistically understanding cell membrane organization and heterogeneity.

Nishioka C, Ikezoe T, Takeuchi A, et al.
The novel function of CD82 and its impact on BCL2L12 via AKT/STAT5 signal pathway in acute myelogenous leukemia cells.
Leukemia. 2015; 29(12):2296-306 [PubMed] Related Publications
The aim of this study was to explore the biological functions of a tetraspanin family protein CD82 expressed aberrantly in chemotherapy-resistant CD34(+)/CD38(-) acute myelogenous leukemia (AML) cells. Microarray analysis of patient-isolated CD34(+)/CD38(-) AML cells revealed that the levels of anti-apoptotic protein BCL2L12 were downregulated after CD82 depletion by specific short hairpin RNA (shRNA). Western blot analysis indicated that BCL2L12 was aberrantly expressed in patient-isolated AML cells and AML cell lines. Furthermore, CD82 blockade by a specific antibody downregulated BCL2L12 in parallel with dephosphorylation of signal transducer and activator of transcription 5 (STAT5) and AKT, whereas pharmacological inhibition of STAT5 and AKT activation decreased BCL2L12 expression in leukemia cells. In addition, shRNA-mediated downregulation of BCL2L12 increased the levels of cleaved caspase-3 and suppressed proliferation of leukemia cells, impairing their engraftment in immunodeficient mice. Taken together, our results indicate that CD82 regulated BCL2L12 expression via STAT5A and AKT signaling and stimulated proliferation and engrafting of leukemia cells, suggesting that CD82 and BCL2L12 may be promising therapeutic targets in AML.

Zhang G, Cheng Y, Chen G, et al.
Loss of tumor suppressors KAI1 and p27 identifies a unique subgroup of primary melanoma patients with poor prognosis.
Oncotarget. 2015; 6(26):23026-35 [PubMed] Free Access to Full Article Related Publications
Primary melanoma, a highly aggressive malignancy, exhibits heterogeneity in biologic behaviors, clinical characteristics, metastasis potential and mortality. The present study sought to identify the molecular signatures that define a subgroup of primary melanomas with high risks of metastasis and mortality. First, we identified the markers that best differentiated metastatic melanomas from primary melanomas by examining the expression of seven previously reported biomarkers (BRAF, Dicer, Fbw7, KAI1, MMP2, p27 and Tip60) in a training cohort consisting of 145 primary melanomas and 105 metastatic melanomas. KAI1 and p27, both tumor suppressors, emerged as best candidates. Loss of both tumor suppressors occurred in the majority (74.29%) of metastatic melanomas. Further, a subset (metastatic like, or "ML", 33.10%) of primary melanomas also lost these two tumor suppressors. Kaplan-Meier analysis indicated that ML subgroup of primary melanoma patients had much worse 5 year survival compared with other primary melanoma patients (P = 0.002). The result was confirmed in an independent validation cohort with 92 primary melanomas (P = 0.030) and in the combined cohort with 237 melanoma patients (P = 3.00E-4). Additionally, compared to KAI1 and p27 as an individual prognostic marker, the combined signature is more closely associated with melanoma patient survival (P = 0.025, 0.264 and 0.009, respectively). In conclusion, loss of both KAI1 and p27 defines a subgroup of primary melanoma patients with poor prognosis. This molecular signature may help in metastatic melanoma diagnosis and may provide information useful in identifying high-risk primary melanoma patients for more intensive clinical surveillance in the future.

Zhou L, Yu L, Wu S, et al.
Clinicopathological significance of KAI1 expression and epithelial-mesenchymal transition in non-small cell lung cancer.
World J Surg Oncol. 2015; 13:234 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: KAI1 and epithelial-mesenchymal transition (EMT) is related to both angiogenesis and lymphangiogenesis and is an important target in new cancer treatment strategies. We aimed to investigate the KAI1 and marker of EMT expression and correlation with lymph node metastasis (LNM) and explore their prognostic impact in non-small cell lung cancer (NSCLC).
METHODS: Tumor tissue specimens from 312 resected patients with stage I-IIIA NSCLC were obtained. Immunohistochemistry was used to assess the expression of the molecular markers KAI1, E-cadherin (E-cad), vimentin, CD34, and D2-40.
RESULTS: There were 153 N0 and 159 N+ patients. Tumor cell expression of KAI1and the marker of EMT, lymphatic vessel density (LVD), and microvessel density (MVD) were related to LNM. In multivariate analyses, the ages of patients, high tumor cell KAI1 expression, EMT, and the scores of MVD were independent factor of prognosis.
CONCLUSIONS: Tumor cell KAI1 expression, EMT, LVD, and MVD correlate with LNM. Thus, the detection of KAI1, expression of markers of EMT, and the scores of MVD may be used as a potential indicator of NSCLC prognosis.

Tang Y, Bhandaru M, Cheng Y, et al.
The role of the metastasis suppressor gene KAI1 in melanoma angiogenesis.
Pigment Cell Melanoma Res. 2015; 28(6):696-706 [PubMed] Related Publications
The tetraspan protein KAI1 (CD82) has been previously shown to have important roles in cell migration, invasion, and melanoma prognosis. In this study, we investigated the role of KAI1 regarding melanoma angiogenesis. KAI1 overexpression strongly suppressed the growth of the human umbilical vein endothelial cells and their tubular structure formation in vitro. Also, KAI1 was able to inhibit both interleukin-6 (IL-6) and VEGF at mRNA and protein levels. Using nude mice in the in vivo study, we showed that KAI1, through the regulation of ING4, inhibited blood vessel formation in matrigel plugs along with the downregulation of IL-6 and VEGF, and the recruitment of CD31-positive cells. Finally, we found that KAI1 was able to suppress the activity of a serine/threonine kinase Akt by suppressing Akt phosphorylation (Ser473). Taken together, our results suggested that KAI1 was able to suppress melanoma angiogenesis by downregulating IL-6 and VEGF expression, and the restoration of KAI1 functionality offered a new approach in human melanoma treatment.

Nishioka C, Ikezoe T, Yokoyama A
Blockade of CD82 by a monoclonal antibody potentiates anti-leukemia effects of AraC in vivo.
Cancer Med. 2015; 4(9):1426-31 [PubMed] Free Access to Full Article Related Publications
We recently found that CD82 inhibits matrix metalloproteinase 9 and augments adhesion of CD34(+) /CD38(-) acute myelogenous leukemia (AML) cells to the bone marrow (BM) microenvironment. The present study found that the use of an anti-CD82 monoclonal antibody (CD82 mAb) mobilized CD34(+) leukemia cells from BM into the peripheral blood in a humanized AML murine model. The use of CD82 mAb in combination with cytarabine (AraC) significantly prolonged survival of immunodeficient mice-bearing human AML cells than did treatment with either AraC or CD82 mAb alone. Taken together, the combination of an anti-leukemic agent and the mobilizing agent CD82 mAb may be a promising treatment strategy to treat patients with AML.

Nishioka C, Ikezoe T, Yang J, Yokoyama A
Tetraspanin Family Member, CD82, Regulates Expression of EZH2 via Inactivation of p38 MAPK Signaling in Leukemia Cells.
PLoS One. 2015; 10(5):e0125017 [PubMed] Free Access to Full Article Related Publications
PURPOSE: We recently found that the tetraspanin family member, CD82, which is aberrantly expressed in chemotherapy-resistant CD34(+)/CD38- acute myelogenous leukemia (AML) cells, negatively regulates matrix metalloproteinase 9, and plays an important role in enabling CD34(+)/CD38(-) AML cells to adhere to the bone marrow microenvironment. This study explored novel functions of CD82 that contribute to AML progression.
MATERIALS AND METHODS: We employed microarray analysis comparing the gene expression profiles between CD34(+)/CD38(-) AML cells transduced with CD82 shRNA and CD34(+)/CD38(-) AML cells transduced with control shRNA. Real-time RT-PCR and western blot analysis were performed to examine the effect of CD82 knockdown on the expression of the polycomb group member, enhancer of zeste homolog 2 (EZH2), in leukemia cells. A chromatin immunoprecipitation assay was performed to examine the effect of CD82 expression on the amount of EZH2 bound to the promoter regions of tumor suppressor genes in leukemia cells. We also utilized methylation-specific PCR to examine whether CD82 expression influences the methylation status of the tumor suppressor gene promoter regions in leukemia cells.
RESULTS: Microarray analysis revealed that levels of EZH2 decreased after shRNA-mediated depletion of CD82 in CD34(+)/CD38(-) AML cells. Moreover, the antibody-mediated blockade of CD82 in leukemia cells lowered EZH2 expression via activation of p38 MAPK signaling, decreased the amount of EZH2 bound to the promoter regions of the tumor suppressor genes, and inhibited histone H3 lysine 27 trimethylation in these promoter regions, resulting in upregulation of the tumor suppressors at both the mRNA and protein levels.

Yoshihama N, Yamaguchi K, Chigita S, et al.
A Novel Function of CD82/KAI1 in Sialyl Lewis Antigen-Mediated Adhesion of Cancer Cells: Evidence for an Anti-Metastasis Effect by Down-Regulation of Sialyl Lewis Antigens.
PLoS One. 2015; 10(4):e0124743 [PubMed] Free Access to Full Article Related Publications
We have recently elucidated a novel function for CD82 in E-cadherin-mediated homocellular adhesion; due to this function, it can inhibit cancer cell dissociation from the primary cancer nest and limit metastasis. However, the effect of CD82 on selectin ligand-mediated heterocellular adhesion has not yet been elucidated. In this study, we focused on the effects of the metastasis suppressor CD82/KAI1 on heterocellular adhesion of cancer cells to the endothelium of blood vessels in order to further elucidate the function of tetraspanins. The over-expression of CD82 in cancer cells led to the inhibition of experimentally induced lung metastases in mice and significantly inhibited the adhesion of these cells to human umbilical vein epithelial cells (HUVECs) in vitro. Pre-treatment of the cells with function-perturbing antibodies against sLea/x significantly inhibited the adhesion of CD82-negative cells to HUVECs. In addition, cells over-expressing CD82 exhibited reduced expression of sLea/x compared to CD82-negative wild-type cells. Significant down-regulation of ST3 β-galactoside α-2, 3-sialyltransferase 4 (ST3GAL4) was detected by cDNA microarray, real-time PCR, and western blotting analyses. Knockdown of ST3GAL4 on CD82-negative wild-type cells inhibited expression of sLex and reduced cell adhesion to HUVECs. We concluded that CD82 decreases sLea/x expression via the down-regulation of ST3GAL4 expression and thereby reduces the adhesion of cancer cells to blood vessels, which results in inhibition of metastasis.

Yang CH, Chou HC, Fu YN, et al.
EGFR over-expression in non-small cell lung cancers harboring EGFR mutations is associated with marked down-regulation of CD82.
Biochim Biophys Acta. 2015; 1852(7):1540-9 [PubMed] Related Publications
Epidermal growth factor receptor (EGFR) gene mutations are strongly associated with lung adenocarcinoma and favorable response to EGFR tyrosine kinase inhibitor. The mutated EGFR proteins (EGFRs) are hyper-phosphorylated and refractory to receptor down-regulation. To address the discrepancy between hyper-phosphorylation and lack of down-regulation of mutant EGFRs, we have examined the expression of EGFR negative regulators in non-small cell lung cancer (NSCLC) cell lines. We found that NSCLC cell lines expressing mutant EGFRs often had low expression of various negative regulators for EGFR. Among them, tumor suppressor CD82 was up-regulated by wild type (WT) EGFR but down-regulated by mutant EGFRs. Reconstitution of CD82 exerted stronger suppressive effects on mutant EGFRs than on WT EGFR. Active exportation of CD82 through the exosome was one of the mechanisms involved in achieving the overall CD82 down-regulation in mutant EGFR-expressing lung cancer cell lines. Over-expression of mutant EGFR protein frequently occurred in the lung cancer tissues of mutant EGFR-transgenic mice and also associated with CD82 down-regulation. Immunoblot analyses on the tumor tissues from 23 lung adenocarcinoma patients (12 with WT EGFR, and 11 with mutant EGFRs) also identified significantly stronger down-regulation of CD82 in tumors with mutant EGFRs than WT. Our data indicate that CD82 down-regulation could be a critical step involved in the EGFR over-expression and the stronger tumorigenic activity triggered by EGFR mutations. Up-regulation of the CD82 level may become a promising new treatment strategy for lung adenocarcinoma.

Han Z, Chen Z, Zheng R, et al.
Clinicopathological significance of CD133 and CD44 expression in infiltrating ductal carcinoma and their relationship to angiogenesis.
World J Surg Oncol. 2015; 13:56 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Breast cancer is the leading cause of cancer death in females worldwide, and the majority type is infiltrating ductal carcinoma (IDC). Most of IDC patients died of metastasis and recurrence. Cancer stem cells (CSCs) are defined with the ability to be self-renewal and potentially promote proliferation and formation of tumors. CSCs are related to angiogenesis and are important targets in new cancer treatment strategies. In this study, we purposed to investigate on expression and clinical significances of CSCs marked by CD133 and CD44 in IDC and their relationship to angiogenesis.
METHODS: The specimens of IDC from 325 Chinese patients with follow-up were analyzed for CD133, CD44, CD82, and CD34 protein expression by immunohistochemical staining. The Pearson chi-square test and t test were used to assess the associations among the positive staining of these markers and clinicopathological characteristics. Postoperative overall survival time in these patients with IDC was analyzed by univariate and multivariate analyses.
RESULTS: In IDC tissues, positive rates of 48.6%, 53.8%, and 42.2% were obtained for CD133, CD44, and CD82 protein, respectively; the mean score of microvessel density (MVD) was 20.5 ± 7.0 in IDC group. And there was a significant difference between the two groups. There was a positive relationship between the expression of CD133, CD44, and the score of MVD and the grades of tumor, lymph node metastasis, tumor-node-metastasis (TNM) stages (all P < 0.05); and the expression of CD82 was negatively related to grades of tumor, lymph node metastasis, and TNM stages (all P < 0.05). The overall mean survival time of the patients with CD133, CD44, and the score of MVD (≥21) positive expression was lower than that of patients with negative expression. The overall mean survival time of patients of CD82-positive expression was longer than that of patients of the negative expression group. The positive expression of CD133 and CD82, and TNM stages were independent prognostic factors of IDC (P < 0.05).
CONCLUSIONS: CSCs, angiogenesis, and aberrant expression of CD82 may be involved in the initiation, development, metastasis, and recurrence. It is suggested that CSCs, angiogenesis, and CD82 be possible as a therapeutic marker for anti-tumor therapy.

Zheng S, Li S, Wang H, et al.
[Isolation and identification of CD133 positive and negative cells from human lung cancer and screening of the differential genes between the positive and negative cells].
Zhongguo Fei Ai Za Zhi. 2015; 18(3):123-30 [PubMed] Related Publications
BACKGROUND AND OBJECTIVE: It has been proven that cancer stem cell existed in variety of cancer, which an significant difference of biological characteristics was observed between the cancer stem cells and non-cancer stem cells. And CD133 is considered to be cancer stem cell marker. So there may be significant differences in CD133- positive cells and CD133-negative cells. The aim of this study is to isolate CD133+ cells and CD133- cells from lung cancer cell line A549, explore their biological characteristics and screen the metastasis-related genes.
METHODS: MACS was applied to isolate CD133+ cells and CD133- cells from human lung cancer cell line A549. To observe the formation of sphere, CD133+ cells and CD133- cells were cultured in serum-free DMEM-F12 medium (containing EGF, bFGF) in vitro. The colony formatting efficiency of CD133+ cells, CD133- cells and cells without sorting was tested by colony-forming assay. The differentiation of sphere was induced by culturing in DMEM-F12 medium (containing serum). The metastasis-related genes (84 genes) of CD133+ cells and CD133- cells were detected by using DNA microarray. Immunohistochemistry was used to detect the expression of CD133 protein in Human lung cancer tissue.
RESULTS: CD133+ cells formed sphere in serum-free DMEM-F12 medium,while the CD133- cells failed to form sphere. The rates of CD133+ cell colony formation (57.1%) was significantly higher than that of CD133- cells (3.3%). Sphere (CD133+/CK7-) was induced to differentiate, and CK7 expression was found in differentiated cells. The expression levels of 19 metastasis-related genes from CD133+ cells and CD133- cells were significant different. Little CD133 positive cells which distributing around the cancer nests were found in lung cancer tissue. The expression of CD133 was not related to tumor types, cell differentiation or TNM stage.
CONCLUSIONS: CD133+ cells exhibit the characteristics of cancer stem cells. The difference of metastasis-related gene expression levels was discovered between CD133+ cells and CD133- cells. CD82 plays an important role in mechanism of tumor metastasis.

Wang W, Yang ZL, Liu JQ, et al.
Overexpression of MTA1 and loss of KAI-1 and KiSS-1 expressions are associated with invasion, metastasis, and poor-prognosis of gallbladder adenocarcinoma.
Tumori. 2014 Nov-Dec; 100(6):667-74 [PubMed] Related Publications
AIMS AND BACKGROUND: Over 90% of patients with gallbladder cancer have invasion and/or metastasis when they are diagnosed at the clinic. Such patients usually have an extremely poor prognosis. The molecular mechanism responsible for the high prevalence of invasion and metastasis remains unknown.
METHODS: We investigated the expression of two metastasis-suppression genes--KAI-1 and KiSS-1--and a metastasis-associated gene--MTA1--in 108 adenocarcinomas, 15 gallbladder polyps, 35 chronic cholecystitis tissues, and 46 peritumoral tissues using in situ hybridization or immunohistochemistry.
RESULTS: We demonstrated that positive MTA1 expression was significantly higher whereas positive expressions of KAI-1 and KiSS-1 genes were significantly lower in gallbladder adenocarcinoma than in peritumoral tissues, polyps, and chronic cholecystitis. Positive MTA1 expression was significantly lower, but positive KAI-1 and KiSS-1 expressions were significantly higher in cases with well-differentiated adenocarcinoma, smaller tumor mass, no metastasis of lymph node, and no invasion of regional tissues than in cases having poorly differentiated adenocarcinoma, larger tumor mass, metastasis and invasion. Univariate Kaplan-Meier analysis showed that increased expression of MTA1 and lowered expression of KAI-1 and KiSS-1 were significantly associated with decreased overall survival. Cox regression analysis showed that tumor mass, lymph node metastasis, invasion, and MTA1 expression levels negatively correlated with survival.
CONCLUSIONS: Our study suggested that KAI-1, KiSS-1, and MTA1 might be important biological markers involved in the carcinogenesis, metastasis, and invasion of gallbladder adenocarcinoma, but MTA1 is an independent factor of prognosis.

Zhang QH, Yao YL, Wu XY, et al.
Anti-miR-362-3p Inhibits Migration and Invasion of Human Gastric Cancer Cells by Its Target CD82.
Dig Dis Sci. 2015; 60(7):1967-76 [PubMed] Related Publications
AIM: This study was to investigate the effects and mechanisms of miR-362-3p on regulation of gastric cancer (GC) cell metastasis potential.
METHODS: We detected miR-362-3p level in GC and adjacent normal tissues and investigated the relationship with clinicopathological factors. Next, we analyzed the level of miR-362-3p expression and CD82 in different differentiated GC cells compared with a normal gastric mucosa cell by RT-PCR and Western blot. Dual-luciferase reporter assay and Western blot confirmed a direct interaction between miR-362-3p and CD82 3'UTR. After miR-362-3p and CD82 were silenced in GC cells, we compared the transfected GC cells migration and invasion capacity by transwell assay. In addition, we detected the effects on cells angiogenesis by tube formation assay. Western blot was used to detect the impact of CD82 and miR-362-3p on epithelial-to-mesenchymal transition markers in treated GC cells.
RESULTS: Level of miR-362-3p expression was much higher in GC cells than in normal gastric mucosa cell, and miR-362-3p expression negatively correlated with CD82 mRNA expression in these cell lines. Furthermore, miR-362-3p expression induced [corrected] GC cell metastasis capacity by suppression of CD82 expression. Level of miR-362-3p may mediate E-cadherin, N-cadherin, and vimentin expression in GC cells.
CONCLUSION: This study illuminated that downregulation of miR-362-3p along with the upregulation of CD82 in GC cells resulted in the inhibition of GC migration and invasion. Thus, our results suggested that miR-362-3p or CD82 can be exploited as a new potential target for control of GC in the future.

Hakomori SI, Handa K
GM3 and cancer.
Glycoconj J. 2015; 32(1-2):1-8 [PubMed] Related Publications
Our studies during the early 1970s showed that expression of GM3, the simplest ganglioside and an abundant animal cell membrane component, is reduced during malignant transformation of cells by oncogenic viruses. Levels of mRNA for GM3 synthase were reduced in avian and mammalian cells transformed by oncoprotein "v-Jun", and overexpression of GM3 synthase in the transformed cells caused reversion from transformed to normal cell-like phenotype. GM3 has a well-documented inhibitory effect on activation of growth factor receptors (GFRs), particularly epidermal GFR (EGFR). De-N-acetyl GM3, which is expressed in some invasive human cancer cells, has an enhancing effect on EGFR activation. The important role of the sialosyl group of GM3 was demonstrated using NEU3, a plasma membrane-associated sialidase that selectively remove sialic acids from gangliosides GM3 and GD1a and is up-regulated in many human cancer cells. GM3 is highly enriched in a type of membrane microdomain termed "glycosynapse", and forms complexes with co-localized cell signaling molecules, including Src family kinases, certain tetraspanins (e.g., CD9, CD81, CD82), integrins, and GFRs (e.g., fibroblast growth factor receptor and hepatocyte growth factor receptor c-Met). Studies by our group and others indicate that GM3 modulates cell adhesion, growth, and motility by altering molecular organization in glycosynaptic microdomains and the activation levels of co-localized signaling molecules that are involved in cancer pathogenesis.

Lee KH, Ahn EJ, Oh SJ, et al.
KITENIN promotes glioma invasiveness and progression, associated with the induction of EMT and stemness markers.
Oncotarget. 2015; 6(5):3240-53 [PubMed] Free Access to Full Article Related Publications
KITENIN (KAI1 COOH-terminal interacting tetraspanin) promotes tumor invasion and metastasis in various cancers. This study assessed the association between KITENIN expression and advanced glioma grade in patients. In vitro assays revealed that KITENIN knockdown inhibited the invasion and migration of glioma cells, whereas KITENIN overexpression promoted their invasion and migration. In orthotopic mouse tumor models, mice transplanted with KITENIN-transfected glioma cells had significantly shorter survival than mice transplanted with mock-transfected cells. Patients with low KITENIN expression showed a significantly longer progression-free survival than patients with high KITENIN expression. KITENIN induced the expression of the epithelial-mesenchymal transition (EMT) markers (N-cadherin, ZEB1, ZEB2, SNAIL and SLUG) as well as the glioma stemness markers (CD133, ALDH1 and EPH-B1). Taken together, these findings showed that high levels of KITENIN increased glioma invasiveness and progression, associated with the up-regulation of EMT and stemness markers.

Iribe Y, Kuroda N, Nagashima Y, et al.
Immunohistochemical characterization of renal tumors in patients with Birt-Hogg-Dubé syndrome.
Pathol Int. 2015; 65(3):126-32 [PubMed] Related Publications
Birt-Hogg-Dubé syndrome (BHD) is an autosomal dominant disorder associated with a germline mutation of folliculin (FLCN). The affected families are at a high risk for developing multiple renal cell carcinomas (RCC). Little is known about the immunostaining patterns of mutant FLCN-associated RCCs. We investigated 32 RCCs obtained from 17 BHD patients. The studied tumors included chromophobe RCCs (n = 15), hybrid oncocytic/chromophobe tumors (HOCT) (n = 14) and clear cell RCCs (n = 3). Almost all chromophobe RCCs and HOCTs revealed positive staining for S100A1, Ksp-cadherin and CD82. They stained either focally or diffusely for CK7, and were negative for CA-IX. All clear cell RCCs were positively stained for CA-IX and negative for CK7. These data confirmed that mutant FLCN-associated oncocytic and clear cell RCCs exhibited generally similar immunostaining patterns compared to their sporadic counterparts. Frequent positive staining for S100A1, Ksp-cadherin and CD82 in chromophobe RCCs and HOCTs indicated that these two types were relatively similar rather than distinctively different in their patterns of immunoreactivity. Characteristic peri-nuclear halos and polygonal cells with clear cytoplasm, which often misleads pathologists into the diagnosis of clear cell RCC, should be carefully examined using an immunohistochemical panel including CA-IX, Ksp-cadherin, CD82 and CK7.

Upheber S, Karle A, Miller J, et al.
Alternative splicing of KAI1 abrogates its tumor-suppressive effects on integrin αvβ3-mediated ovarian cancer biology.
Cell Signal. 2015; 27(3):652-62 [PubMed] Related Publications
Loss or downregulation of the tumor-suppressor KAI1 correlates with poor cancer patient prognosis. KAI1 functions by interacting with other proteins, including integrin cell adhesion and signaling receptors. We previously showed that KAI1 physically and functionally crosstalks with the tumor-biologically relevant integrin αvβ3, thereby suppressing ovarian cancer cell migration and proliferation. Interestingly, in metastases, a KAI1 splice variant had been identified, indicating poor patient prognosis. Thus, we here characterized differential effects of the two KAI1 proteins upon their cellular restoration. Opposite to KAI1, KAI1-splice reduced αvβ3-mediated cell adhesion, thereby inducing cell migration. This was accompanied by elevated αvβ3 levels and drastically elevated focal adhesion kinase activation, however, without any obvious colocalization with αvβ3, as observed for KAI1. Moreover, codistribution of KAI1 with the cell/cell-adhesion molecule E-cadherin was abrogated in KAI1-splice. Whereas KAI1 diminished cell proliferative activity, KAI1-splice prominently enhanced cell proliferation concomitant with elevated transcription and cell-surface expression of the epidermal growth factor receptor. Thus KAI1-splice does not only counteract the tumor-suppressive actions of KAI1, but - beyond that - promotes αvβ3-mediated biological functions in favor of tumor progression and metastasis.

Bozdogan O, Yulug IG, Vargel I, et al.
Differential expression patterns of metastasis suppressor proteins in basal cell carcinoma.
Int J Dermatol. 2015; 54(8):905-15 [PubMed] Related Publications
BACKGROUND: Basal cell carcinomas (BCCs) are common malignant skin tumors. Despite having a significant invasion capacity, they metastasize only rarely. Our aim in this study was to detect the expression patterns of the NM23-H1, NDRG1, E-cadherin, RHOGDI2, CD82/KAI1, MKK4, and AKAP12 metastasis suppressor proteins in BCCs.
METHODS: A total of 96 BCC and 10 normal skin samples were included for the immunohistochemical study. Eleven frozen BCC samples were also studied by quantitative real time polymerase chain reaction (qRT-PCR) to detect the gene expression profile.
RESULTS: NM23-H1 was strongly and diffusely expressed in all types of BCC. Significant cytoplasmic expression of NDRG1 and E-cadherin was also detected. However, AKAP12 and CD82/KAI1 expression was significantly decreased. The expressions of the other proteins were somewhere between the two extremes. Similarly, qRT-PCR analysis showed down-regulation of AKAP12 and up-regulation of NM23-H1 and NDRG1 in BCC. Morphologically aggressive BCCs showed significantly higher cytoplasmic NDRG1 expression scores and lower CD82/KAI1 scores than non-aggressive BCCs.
CONCLUSION: The relatively preserved levels of NM23-H1, NDRG1, and E-cadherin proteins may have a positive effect on the non-metastasizing features of these tumors.

Zhao B, Zhao W, Wang Y, et al.
Connexin32 regulates hepatoma cell metastasis and proliferation via the p53 and Akt pathways.
Oncotarget. 2015; 6(12):10116-33 [PubMed] Free Access to Full Article Related Publications
Hepatocellular carcinoma (HCC) progresses rapidly and is frequently associated with vascular invasion, metastasis, recurrence, and poor prognosis. The expression of connexin32 (Cx32) is frequently downregulated in HCC tissues. In this study, the role of Cx32 in HCC metastasis and proliferation was investigated. The reduction of Cx32 in HCC tissues was significantly associated with increased vascular invasion, increased tumor size, and poor survival. In vitro assays revealed that Cx32 not only suppressed the invasion and migration of HCC cells, but also repressed HCC cell proliferation. Subsequent investigations revealed that Cx32 directly enhanced the acetylation and transcriptional activity of p53, thus upregulating the expression of the tumor metastasis suppressor protein KAI1/CD82, which is a p53 target gene. Additionally, Cx32 negatively regulated the phosphorylation of Akt and the expression of the cell cycle regulation protein cyclin D1, thereby inhibiting the proliferation of HCC cells. Our in vivo nude mice model further confirmed that Cx32 is able to suppress HCC tumor growth and metastasis in nude mice. Our results imply that Cx32 downregulation contributes to the proliferation and metastasis of HCC, and the restoration of Cx32 expression may be a promising strategy for HCC therapy.

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