Cadherins and Integrins in Renal Cell Carcinoma an Immunohistochemical Study

A systematic review and meta-analysis combined with bioinformatic analysis on the predictive value of E-cadherin in patients with renal cell carcinoma

OBJECTIVES

Renal cell carcinoma (RCC) is the most common cancer of the kidney. This study aims to evaluate the potential predictive value of E-cadherin, a marker of the epithelial mesenchymal transit (EMT) process that has been associated with tumor metastasis.

METHODS

We searched PubMed, Embase, and Cochrane Library to identify prospective studies. Hazard ratios (HRs), odds ratios (ORs), and 95% confidence intervals (CIs) were summarized to validate the relationship between E-cadherin and survival and clinical characteristics. The quality of the included studies was assessed using the NOS table. Then, we analyzed genetic data and clinical characteristics from The Cancer Genome Atlas Program (TCGA) database using R language with the dplyr package for validation.

RESULTS

Including 21 articles. The analysis revealed a strong link between high E-cadherin expression and favorable prognosis (for OS, HR = 0.35, 95% CI: 0.19-0.62; for PFS, HR = 0.19, 95% CI: 0.03-0.53; for DSS, HR = 0.25, 95% CI: 0.08-0.76; for RFS, HR = 0.71, 95% CI: 0.44-1.16; for DFS, HR = 0.28, 95% CI: 0.13-0.61; for T stage, OR = 0.21, 95% CI: 0.11-0.41; for N stage, OR = 0.07, 95%CI: 0.02-0.25; for M stage, OR = 0.12, 95% CI: 0.02-0.60; for clinical stage, OR = 0.29, 95% CI: 0.18-0.47; for nuclear grade, OR = 0.23, 95% CI: 0.13-0.41; for tumor size, OR = 0.49, 95% CI: 0.26-0.92). The findings were supported by bioinformatic analysis which used TCGA RCC patient's cohort (P < 0.01).

CONCLUSION

Based on the current data, E-cadherin may predict a better prognosis in RCC patients.

Apolipoprotein L1 is a tumor suppressor in clear cell renal cell carcinoma metastasis

The 5-year survival rate of kidney cancer drops dramatically from 93% to 15% when it is metastatic. Metastasis constitutes for 30% of kidney cancer cases, in which clear cell renal cell carcinoma (ccRCC) is the most prominent subtype. By sequencing mRNA of ccRCC patient samples, we found that apolipoprotein L1 (APOL1) was highly expressed in tumors compared to their adjacent normal tissues. This gene has been previously identified in a large body of kidney disease research and was reported as a potential prognosis marker in many types of cancers. However, the molecular function of APOL1 in ccRCC, especially in metastasis, remained unknown. In this study, we modulated the expression of APOL1 in various renal cancer cell lines and analyzed their proliferative, migratory, and invasive properties. Strikingly, APOL1 overexpression suppressed ccRCC metastasis both in vitro and in vivo. We then explored the mechanism by which APOL1 alleviated ccRCC malignant progression by investigating its downstream pathways. APOL1 overexpression diminished the activity of focal adhesive molecules, Akt signaling pathways, and EMT processes. Furthermore, in the upstream, we discovered that miR-30a-3p could inhibit APOL1 expression. In conclusion, our study revealed that APOL1 play a role as a tumor suppressor in ccRCC and inhibit metastasis, which may provide novel potential therapeutic approaches for ccRCC patients.

Aberrant Expression of E-cadherin, N-cadherin, and P-cadherin in Clear Cell Renal Cell Carcinoma: Association With Adverse Clinicopathologic Factors and Poor Prognosis

OBJECTIVE

Aberrant expression of cadherins is known to be associated with tumor aggression. However, their role in clear cell renal cell carcinoma (CCRCC) is not well elucidated. This study investigated the expression of epithelial cadherin (E-cadherin), neural cadherin (N-cadherin), and placental cadherin (P-cadherin) in CCRCC, and assessed their prognostic significance and clinicopathologic association.

MATERIALS AND METHODS

We enrolled 254 patients with CCRCC who underwent radical or partial nephrectomy. E-cadherin, N-cadherin, and P-cadherin expression was evaluated by immunohistochemistry in a tissue microarray.

RESULTS

Low E-cadherin expression was associated with larger tumor size, lymphovascular invasion, higher pT stage, lymph node and distant metastasis, and higher stage. High N-cadherin expression was significantly associated with larger tumor size, higher nuclear grade, and tumor necrosis. P-cadherin expression was found to be significantly associated with higher nuclear grade, distant metastasis, and higher stage. Univariate analysis revealed that aberrant expression of the 3 cadherins was significantly related to shorter overall survival (OS). Loss of E-cadherin, high P-cadherin expression, and higher stage were independent prognostic factors for OS. For recurrence-free survival, lymphovascular invasion, high P-cadherin expression, and higher stage were independent prognostic factors. Cadherin switch was significantly associated with aggressive clinicopathologic factors and poor outcomes.

CONCLUSIONS

Aberrant expression of E-cadherin, N-cadherin, and P-cadherin was associated with adverse clinicopathologic factors and worse OS. Low E-cadherin and high P-cadherin expression were significantly associated with distant metastasis and independent prognostic factors. Therefore, cadherin expression may be used as a prognostic marker and therapeutic target, and cadherin switch plays an important role in CCRCC progression.

Low Dosed Curcumin Combined with Visible Light Exposure Inhibits Renal Cell Carcinoma Metastatic Behavior In Vitro

Recent documentation shows that a curcumin-induced growth arrest of renal cell carcinoma (RCC) cells can be amplified by visible light. This study was designed to investigate whether this strategy may also contribute to blocking metastatic progression of RCC. Low dosed curcumin (0.2 µg/mL; 0.54 µM) was applied to A498, Caki1, or KTCTL-26 cells for 1 h, followed by exposure to visible light for 5 min (400–550 nm, 5500 lx). Adhesion to human vascular endothelial cells or immobilized collagen was then evaluated. The influence of curcumin on chemotaxis and migration was also investigated, as well as curcumin induced alterations of α and β integrin expression. Curcumin without light exposure or light exposure without curcumin induced no alterations, whereas curcumin plus light significantly inhibited RCC adhesion, migration, and chemotaxis. This was associated with a distinct reduction of α3, α5, β1, and β3 integrins in all cell lines. Separate blocking of each of these integrin subtypes led to significant modification of tumor cell adhesion and chemotactic behavior. Combining low dosed curcumin with light considerably suppressed RCC binding activity and chemotactic movement and was associated with lowered integrin α and β subtypes. Therefore, curcumin combined with visible light holds promise for inhibiting metastatic processes in RCC.

Regulation of antitumor miR-144-5p targets oncogenes: Direct regulation of syndecan-3 and its clinical significance

In the human genome, miR-451a, miR-144-5p (passenger strand), and miR-144-3p (guide strand) reside in clustered microRNA (miRNA) sequences located within the 17q11.2 region. Low expression of these miRNAs is significantly associated with poor prognosis of patients with renal cell carcinoma (RCC) (miR-451a: P = .00305; miR-144-5p: P = .00128; miR-144-3p: P = 9.45 × 10-5 ). We previously reported that miR-451a acted as an antitumor miRNA in RCC cells. Involvement of the passenger strand of the miR-144 duplex in the pathogenesis of RCC is not well understood. Functional assays showed that miR-144-5p and miR-144-3p significantly reduced cancer cell migration and invasive abilities, suggesting these miRNAs acted as antitumor miRNAs in RCC cells. Analyses of miR-144-5p targets identified a total of 65 putative oncogenic targets in RCC cells. Among them, high expression levels of 9 genes (FAM64A, F2, TRIP13, ANKRD36, CENPF, NCAPG, CLEC2D, SDC3, and SEMA4B) were significantly associated with poor prognosis (P < .001). Among these targets, expression of SDC3 was directly controlled by miR-144-5p, and its expression enhanced cancer cell aggressiveness. We identified genes downstream by SDC3 regulation. Data showed that expression of 10 of the downstream genes (IL18RAP, SDC3, SH2D1A, GZMH, KIF21B, TMC8, GAB3, HLA-DPB2, PLEK, and C1QB) significantly predicted poor prognosis of the patients (P = .0064). These data indicated that the antitumor miR-144-5p/oncogenic SDC3 axis was deeply involved in RCC pathogenesis. Clustered miRNAs (miR-451a, miR-144-5p, and miR-144-3p) acted as antitumor miRNAs, and their targets were intimately involved in RCC pathogenesis.

Levels of Ve-Cadherin Increase Independently of Vegf in Preoperative Sera of Patients with Colorectal Cancer

AIMS AND BACKGROUND

Vascular endothelial cadherin (VE-cadherin) preserves the tightness of the mature vascular network as a component of endothelial adherens junctions. Vascular endothelial growth factor (VEGF) makes VE-cadherin dissociate from complexes with beta-catenin, so that endothelial cells can loosely proliferate and migrate. We searched for relationships between VEGF and VE-cadherin levels in preoperative sera of patients with colorectal cancer (CRC). We also compared VE-cadherin levels of control and preoperative CRC sera in relation to clinicopathological features.

METHODS

We measured with an ELISA kit the serum levels of the proteins in preoperative samples from 125 CRC patients and in samples from 16 healthy volunteers.

RESULTS

Serum VE-cadherin was about fourfold higher in CRC patients than in controls (P < 0.00001), with similar results being found in subgroups with different clinicopathological features versus controls. VE-cadherin was not correlated with VEGF in the entire group of CRC patients nor in the subgroups of node-positive and node-negative patients, different grades of histological differentiation (G2 or G3), extent of tumor growth (pT1+pT2 or pT3+pT4), histopathological type (adenocarcinoma or mucinous carcinoma), sex, age, and tumor site (colon or rectum). However, the serum levels of VE-cadherin and VEGF in CRC patients, which were higher than the mean values of controls, tended towards a negative correlation in node-positive patients (P = 0.078, r = -0.279).

CONCLUSIONS

VEGF and VE-cadherin seem to be independent markers of angiogenesis in CRC with no significant correlation between their serum levels.

Management of Locally Advanced Renal Cell Carcinoma

Background

Renal cell carcinoma accounts for approximately 3% of adult malignancies and over 90% of primary renal tumors. Recurrence rates for patients with locally advanced renal cell carcinoma (LARCC) remain high.

Methods

The authors review literature regarding prognostic factors, potential biomarkers, surgical strategies, and adjuvant therapy trials for patients with LARCC.

Results

Molecular tumor markers may improve existing staging systems for predicting prognosis. Surgery is the best initial treatment for most patients with clinically localized renal tumors, although complete surgical resection can be challenging for patients with large tumors, bulky regional lymph node involvement, or inferior vena cava tumor thrombus. Significant recurrence rates for patients with LARCC undergoing nephrectomy indicate the presence of undetected micrometastases at the time of surgery. Adjuvant radiation, chemotherapy, and immunotherapy have been ineffective. Other trials of adjuvant therapy are ongoing.

Conclusions

Aggressive surgical resection alone for LARCC is not sufficient to prevent disease recurrence in a significant number of patients. Adjuvant therapies are needed to improve cancer-specific survival.

Role of N-cadherin in proliferation, migration, and invasion of germ cell tumours

Germ cell tumors (GCTs) are the most common malignancies in young men. Most patients with GCT can be cured with cisplatin-based combination chemotherapy, even in metastatic disease. In case of therapy resistance, prognosis is usually poor. We investigated the potential of N-cadherin inhibition as a therapeutic strategy. We analyzed the GCT cell lines NCCIT, NTERA-2, TCam-2, and the cisplatin-resistant sublines NCCIT-R and NTERA-2R. Effects of a blocking antibody or siRNA against N-cadherin on proliferation, migration, and invasion were investigated. Mouse xenografts of GCT cell lines were analyzed by immunohistochemistry for N-cadherin expression. All investigated GCT cell lines were found to express N-cadherin protein in vitro and in vivo. Downregulation of N-cadherin in vitro leads to a significant inhibition of proliferation, migration, and invasion. N-cadherin-downregulation leads to a significantly higher level of pERK. N-cadherin-inhibition resulted in significantly higher rates of apoptotic cells in caspase-3 staining. Expression of N-cadherin is preserved in cisplatin-resistant GCT cells, pointing to an important physiological role in cell survival. N-cadherin-downregulation results in a significant decrease of proliferation, migration, and invasion and stimulates apoptosis in cisplatin-naive and resistant GCT cell lines. Therefore, targeting N-cadherin may be a promising therapeutic approach, particularly in cisplatin-resistant, therapy refractory and metastatic GCT.

Cadherin 17 is a sensitive and specific marker for metanephric adenoma

Metanephric adenoma (MA) is a rare benign renal neoplasm that shares morphologic and immunophenotypic overlap with epithelial-predominant Wilms tumor (e-WT) and with the solid variant of papillary renal cell carcinoma (s-PRCC). Cadherin 17 (CDH17) is expressed primarily in the normal intestine and digestive tract tumors and has not been detected in tumors from other sites including the kidney. We investigated the diagnostic utility of CDH17 in differentiating between MA, e-WT, and s-PRCC. Immunohistochemical analysis for CDH17, CD57, AMACR, WT-1, and CDX2 was performed on 17 e-WTs, 15 s-PRCCs, and 21 MAs and assessed on the basis of a combined score of extent and intensity. Normal adult kidney parenchyma was negative for CDH17 staining. CDH17 was expressed in the late stages of fetal kidney development at the junction of the glomerular space and proximal nephron. The majority of MAs (81%) demonstrated membranous CDH17 immunoreactivity in all components (acinar, tubular, and papillary), whereas all cases of e-WTs and s-PRCCs were negative (P<0.0001). WT-1 was negative in s-PRCC and was positive in all cases of e-WT and MA. All MAs were strongly positive for CD57; however, this marker was also moderate to strongly positive in 6 (35%) e-WTs and 2 (13%) s-PRCCs. AMACR was strongly positive in all s-PRCCs, but moderate reactivity was seen in 3 (17%) e-WTs and 2 MAs (10%). CDH17 is a sensitive (81%) and highly specific (100%) marker for MA and should be considered in the immunohistochemistry panel for distinguishing MA from its mimics.

Overexpression of integrin αv correlates with poor prognosis in colorectal cancer

AIMS

Integrin αv subunits are involved in tumour angiogenesis and tumour progression in various types of cancers. Clinical trials evaluating agents targeting integrin αv are ongoing. Integrin αv expression has been reported in several cancers in association with tumour progression or poor survival. However, no study has addressed the prognostic influence of integrin αv expression on survival of patients with colorectal cancer (CRC).

METHODS

Immunohistochemical staining of integrin αv was performed in 198 CRC samples to evaluate its prognostic significance.

RESULTS

High expression of integrin αv was observed in 58.1% (115/189) of colorectal adenocarcinoma samples, while only in 11.5% (3/26) of tubular adenoma samples and in none of normal mucosa or hyperplastic polyp samples. It was more frequently found in female patients and less frequently observed in well differentiated tumours. The proportion of cases with high expression of integrin αv showed an increasing trend with increased T stage (p=0.032), N stage (p=0.006) and TNM stage (p=0.001). Patients displaying exuberant expression of integrin αv showed shorter overall survival (p=0.001) and disease-free survival (p=0.004). Elevated integrin αv expression was an independent prognostic factor for overall survival (HR: 2.04, 95% CI 1.16 to 3.56; p=0.013) and disease-free survival (HR: 2.19, 95% CI 1.16 to 4.13; p=0.015).

CONCLUSIONS

Overexpression of integrin αv is associated with advanced T and N stage and as an independent prognostic factor in CRC.

The soluble Decoy Receptor 3 is regulated by a PI3K-dependent mechanism and promotes migration and invasion in renal cell carcinoma

Background

Overexpression of Decoy Receptor 3 (DcR3), a soluble member of the tumor necrosis factor receptor superfamily, is a common event in several types of cancer. In renal cell carcinoma (RCC), DcR3 overexpression is associated with lymph node and distant metastasis as well as a poor prognosis. However, the functional role and regulation of DcR3 expression in RCC is so far unknown.

Methods

Modulation of DcR3 expression by siRNA and ectopic gene expression, respectively, was performed in ACHN and 769-P RCC cell lines. Functional effects of a modulated DcR3 expression were analyzed with regard to migration, invasion, adhesion, clonogenicity, and proliferation. Furthermore, quantitative RT-PCR and immunoblot analyses were performed to evaluate the expression of downstream mediators of DcR3. In further experiments, luciferase assays, quantitative RT-PCR and immunoblot analyses were applied to study the regulation of DcR3 expression in RCC. Additionally, an ex vivo tissue slice culture technique combined with immunohistochemistry was used to study the regulation of DcR3 expression in human RCC specimens.

Results

Here, we show that DcR3 promotes adhesion, migration and invasiveness of RCC cells. The DcR3-dependent increase in cellular invasiveness is accompanied with an up-regulation of integrin alpha 4, matrixmetalloproteinase 7 and urokinase plasminogen activator (uPA). Further, we identified a signaling pathway regulating DcR3 expression in RCC. Using in vitro experiments as well as an ex vivo RCC tissue slice culture model, we demonstrate that expression of DcR3 is regulated in a PI3K/AKT-dependent manner involving the transcription factor nuclear factor of activated T-cells (NFAT).

Conclusions

Taken together, our results identify DcR3 as a key driver of tumor cell dissemination and suggest DcR3 as a promising target for rational therapy of RCC.

Dual inhibition of αV integrins and Src kinase activity as a combination therapy strategy for colorectal cancer

Both Src and αV integrins are important for tumor growth and angiogenesis. They are interconnected and responsible for important features of the tumor phenotype including invasiveness, metastasis, angiogenesis, and resistance to apoptosis. This study examines whether combinational inhibition of both integrin and Src pathways would exert greater antiangiogenesis and antitumor effects than either pathway alone. Using in-vitro cell culture systems, the activity of CNTO95 (Intetumumab), an αV integrin inhibitor, and dasatinib, an Src inhibitor, on proliferation, adhesion, and migration was evaluated in colon cancer cell lines, HCT-116 and RKO, as well as HUVEC cells. The antiangiogenic effect of this combinatory regimen was also tested using an in-vitro tubular network formation assay. The effects of CNTO95 and dasatinib on the activation of Src and integrin pathway signal transduction were also determined by western blotting. The combination of CNTO95 plus dasatinib inhibited adhesion, migration, and paxillin phosphorylation in both HCT-116 and RKO cells. CNTO95 and dasatinib also led to increased apoptosis of HCT-116 cells; however, similar effects were not observed in RKO cells. In addition, dual treatment of CNTO95 and dasatinib exerted enhanced effects on HUVEC cell proliferation, invasion, tubular network formation, and paxillin phosphorylation. In conclusion, our results suggest that concurrent inhibition of both the integrin and the Src pathways exert more pronounced antiangiogenic and antitumor effects than with either pathway being inhibited alone.

N-cadherin expression in malignant germ cell tumours of the testis

BACKGROUND

Testicular germ cell tumours (TGCTs) are the most common malignancy in young men aged 18-35 years. They are clinically and histologically subdivided into seminomas and non-seminomas. Cadherins are calcium-dependent transmembrane proteins of the group of adhesion proteins. They play a role in the stabilization of cell-cell contacts, the embryonic morphogenesis, in the maintenance of cell polarity and signal transduction. N-cadherin (CDH2), the neuronal cadherin, stimulates cell-cell contacts during migration and invasion of cells and is able to suppress tumour cell growth.

METHODS

Tumour tissues were acquired from 113 male patients and investigated by immunohistochemistry, as were the three TGCT cell lines NCCIT, NTERA-2 and Tcam2. A monoclonal antibody against N-cadherin was used.

RESULTS

Tumour-free testis and intratubular germ cell neoplasias (unclassified) (IGCNU) strongly expressed N-cadherin within the cytoplasm. In all seminomas investigated, N-cadherin expression displayed a membrane-bound location. In addition, the teratomas and yolk sac tumours investigated also differentially expressed N-cadherin. In contrast, no N-cadherin could be detected in any of the embryonal carcinomas and chorionic carcinomas examined. This expression pattern was also seen in the investigated mixed tumours consisting of seminomas, teratomas, and embryonal carcinoma.

CONCLUSIONS

N-cadherin expression can be used to differentiate embryonal carcinomas and chorionic carcinomas from other histological subtypes of TGCT.

N-cadherin is differentially expressed in histological subtypes of papillary renal cell carcinoma

Background

Papillary renal cell carcinoma (RCC) represents a rare tumor, which is divided, based on histological criteria, into two subtypes. In contrast to type I papillary RCC type II papillary RCC shows a worse prognosis. So far, reliable immunohistochemical markers for the distinction of these subtypes are not available.

Methods

In the present study the expression of N(neural)-, E(epithelial)-, P(placental)-, und KSP(kidney specific)-cadherin was examined in 22 papillary RCC of histological type I and 18 papillary RCC of histological type II (n = 40).

Results

All papillary RCC type II displayed a membranous expression for N-cadherin, whereas type I did not show any membranous positivity for N-cadherin. E-cadherin exhibited a stronger, but not significant, membranous as well as cytoplasmic expression in type II than in type I papillary RCC. A diagnostic relevant expression of P- and KSP-cadherin could not be demonstrated in both tumor entities.

Conclusion

Thus N-cadherin represents the first immunhistochemical marker for a clear cut differentiation between papillary RCC type I and type II and could be a target for therapy and diagnostic in the future.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2011556982761733

Valproic acid blocks adhesion of renal cell carcinoma cells to endothelium and extracellular matrix

Treatment strategies for metastatic renal cell carcinoma (RCC) have been limited due to chemotherapy and radiotherapy resistance. The development of targeted drugs has now opened novel therapeutic options. In the present study, anti-tumoral properties of the histone deacetylase inhibitor valproic acid (VPA) were tested in vitro and in vivo on pre-clinical RCC models. RCC cell lines Caki-1, KTC-26 or A498 were treated with various concentrations of VPA to evaluate tumour cell adhesion to vascular endothelial cells or to immobilized extracellular matrix proteins. In vivo tumour growth was conducted in subcutaneous xenograft mouse models. VPA was also combined with low dosed interferon-alpha (IFN-alpha) and the efficacy of the combination therapy, as opposed to VPA monotherapy, was compared. VPA significantly and dose-dependently prevented tumour cell attachment to endothelium or matrix proteins, accompanied by elevated histones H3 and H4 acetylation. VPA altered integrin-alpha and -beta subtype expression, in particular alpha(3), alpha(5) and beta(3), and blocked integrin-dependent signalling. In vivo, VPA significantly inhibited the growth of Caki-1 in subcutaneous xenografts with the 200 mg/kg being superior to the 400 mg/kg dosing schedule. VPA-IFN-alpha combination markedly enhanced the effects of VPA on RCC adhesion, and in vivo tumour growth was further reduced by the 400 mg/kg but not by the 200 mg/kg VPA dosing schedule. VPA profoundly blocked the interaction of RCC cells with endothelium and extracellular matrix and reduced tumour growth in vivo. Therefore, VPA should be considered an attractive candidate for clinical trials.

Alterations of the gene expression profile in renal cell carcinoma after treatment with the histone deacetylase-inhibitor valproic acid and interferon-alpha

PURPOSE

Renal cell carcinoma (RCC) is highly resistant to chemotherapy and unresponsive to radio- and immunotherapy. Recently, we have documented that the histone deacetylase (HDAC)-inhibitor valproic acid (VPA) in combination with low-dosed interferon (IFN)-alpha significantly inhibits RCC proliferation and adhesion in vitro and in vivo. The current study investigated the effects of these compounds on gene transcription of metastatic RCC cell line Caki-1 after 3 and 5 days exposure.

METHODS

To evaluate the gene expression profiles of the RCC cells, we performed microarray analysis using Affymetrix GeneChip. Selected significant genes were further validated by Real Time PCR.

RESULTS

Microarray revealed that VPA altered genes that are involved in cell growth, cell survival, immune response, cell motility and cell adhesion. Combination of VPA with IFN-alpha not only enhanced the effects on gene transcription but also resulted in the expression of novel genes, which were not induced by either VPA or IFN-alpha alone. Among the up-regulated genes were chemokines (CXCL10, CXCL11, CXCL16) and integrins (ITGA2, ITGA4, ITGA5, ITGA6, ITGA7). Genes encoding for adhesion molecules (NCAM1, ICAM1, VCAM1) were also modulated. Real Time PCR approved these findings.

CONCLUSION

This data provides insight into the molecular mechanism of action of the combined treatment of VPA and IFN-alpha in RCC. Implications are that the combined application of VPA and IFN-alpha may represent a more efficient alternative to existing therapy options for RCC.

CNTO 95, a fully human anti alphav integrin antibody, inhibits cell signaling, migration, invasion, and spontaneous metastasis of human breast cancer cells

CNTO 95 is a fully human monoclonal antibody that recognizes alphav integrins. Previous studies have shown that CNTO 95 exhibits both anti-tumor and anti-angiogenic activities (Trikha M et al., Int J Cancer 110:326-335, 2004). In this study we investigated the biological activities of CNTO 95 on breast tumor cells both in vitro and in vivo. In vitro treatment with CNTO 95 decreased the viability of breast tumor cells adhering to vitronectin. CNTO 95 inhibited tumor cell adhesion, migration, and invasion in vitro. CNTO 95 treatment also induced tyrosine dephosphorylation of focal adhesion kinase (FAK), and the docking protein paxillin that recruits both structural and signaling molecules to focal adhesions (Turner CE, Int J Biochem Cell Biol 30:955-959, 1998; O'Neil GM et al., Trends Cell Biol 10:111-119, 2000). These results suggest that CNTO 95 inhibits breast tumor cell growth, migration and invasion by interruption of alphav integrin mediated focal adhesions and cell motility signals. In vivo studies of CNTO 95 were conducted in an orthotopic breast tumor xenograft model. Treatment with CNTO 95 resulted in significant inhibition of both tumor growth and spontaneous metastasis of MDA-MB-231 cells to the lungs. CNTO 95 also inhibited lung metastasis in a separate experimental (tail vein injection) model of metastasis. The results presented here demonstrate the anti-tumor and anti-metastatic activities of CNTO 95 in breast cancer models and provide insight into the cellular and molecular mechanisms mediating its inhibitory effects on metastasis.

Transient down-regulation of beta1 integrin subtypes on kidney carcinoma cells is induced by mechanical contact with endothelial cell membranes

Adhesion molecules of the integrin beta1 family are thought to be involved in the malignant progression renal cell carcinoma (RCC). Still, it is not clear how they contribute to this process. Since the hematogenous phase of tumour dissemination is the rate-limiting step in the metastatic process, we explored beta1 integrin alterations on several RCC cell lines (A498, Caki1, KTC26) before and after contacting vascular endothelium in a tumour-endothelium (HUVEC) co-culture assay. Notably, alpha2, alpha3 and alpha5 integrins became down-regulated immediately after the tumour cells attached to HUVEC, followed by re-expression shortly thereafter. Integrin down-regulation on RCC cells was caused by direct contact with endothelial cells, since the isolated endothelial membrane fragments but not the cell culture supernatant contributed to the observed effects. Integrin loss was accompanied by a reduced focal adhesion kinase (FAK) expression, FAK activity and diminished binding of tumour cells to matrix proteins. Furthermore, intracellular signalling proteins RCC cells were altered in the presence of HUVEC membrane fragments, in particular 14-3-3 epsilon, ERK2, PKCdelta, PKCepsilon and RACK1, which are involved in regulating tumour cell motility. We, therefore, speculate that contact of RCC cells with the vascular endothelium converts integrin-dependent adhesion to integrin-independent cell movement. The process of dynamic integrin regulation may be an important part in tumour cell migration strategy, switching the cells from being adhesive to becoming motile and invasive.

αv Integrin-Targeted Immunoconjugates Regress Established Human Tumors in Xenograft Models

PURPOSE

Targeted delivery of cytotoxic agents to solid tumors through cell surface antigens can potentially reduce systemic toxicity and increase the efficacy of the targeted compounds. The purpose of this study was to show the feasibility of treating solid tumors by targeting alpha(v) integrins with antibody-maytansinoid conjugates and to test the relative in vivo activities of several linker-maytansinoid chemistries.

EXPERIMENTAL DESIGN

CNTO 364, CNTO 365, and CNTO 366 are targeted cytotoxic agents created by conjugating the CNTO 95 anti-alpha(v) integrin antibody with three distinct maytansinoid-linker structures. These structures were designed to have varying degrees of chemical substitution surrounding the disulfide bond linking the cytotoxic agent to the antibody. A model conjugate was shown to be specifically cytotoxic in vitro and highly active against established human tumor xenografts in immunocompromised rats. The in vivo antitumor activities of CNTO 364, CNTO 365, and CNTO 366 were compared in rat xenograft models.

RESULTS

CNTO 365, with a linker chemistry of expected intermediate stability, was shown to be substantially more active than the other two conjugates with lesser or greater substitution around the disulfide linkage.

CONCLUSION

CNTO 95-maytansinoid immunoconjugates are potent antitumor agents against alpha(v) integrin-expressing human carcinomas. These studies show for the first time the feasibility of targeting alpha(v) integrins on solid tumors with tumor-activated prodrugs. The DM4 linker-maytansinoid configuration of CNTO 365 was substantially more active in the models tested here when compared with alternative configurations with greater or lesser chemical substitution surrounding the linker.

Expression of MUC1 (EMA) and E-cadherin in renal cell carcinoma: a systematic immunohistochemical analysis of 188 cases

MUC1 (epithelial membrane antigen) is a membrane-associated mucin known to interfere with both cell-cell and cell-matrix adhesions. Overexpression has been associated with poor prognosis in a variety of cancers. We investigated the expression of MUC1 (using two different antibodies, MA695 and E29) and E-cadherin in renal cell carcinomas (137 conventional, 23 chromophobe, 20 papillary, and eight unclassified tumors) with respect to diagnostic and prognostic significance using a tissue microarray technique. Immunoreactivity was correlated with histological subtype, pT-stage, and grade using the chi2 test or the Fisher's exact test, respectively. Impact on disease-free survival was analyzed using the Kaplan-Meier method and the log-rank test. Immunoreactivity of more than 10% of cancer cells with MA695, E 29, and E-cadherin antibodies was found in 112/133 (84%), 86/133 (65%), and 7/131 (5%) conventional, 20/22 (91%), 19/22 (86%), and 21/22 (95%) chromophobe, 13/20 (65%), 8/20 (40%), and 3/20 (15%) papillary as well as 5/8 (63%), 5/8 (63%), and 4/8 (50%) unclassified carcinomas, respectively. The two different MUC1 antibodies yielded comparable staining results. A diffuse cytoplasmic staining pattern for MUC1 was found exclusively in chromophobe carcinomas, whereas conventional and papillary subtypes showed predominantly membranous staining (P<0.0001). Regarding papillary carcinomas, MUC1 was predominantly associated with type 1 (P=0.0001), and E-cadherin with type 2 (P=0.049) tumors. The cellular staining pattern of MUC1 in conventional tumors was related to pT-stage (P=0.002) and tumor grade (P=0.001): Low-stage (pT1/pT2) and grade (G1/G2) tumors showed a predominantly apical membranous staining, high-stage (pT3a/pT3b) and grade (G3/G4) tumors a predominantly circumferential membranous staining (with or without additional diffuse cytoplasmic immunoreactivity), which, in the conventional subtype, was associated with poor prognosis (P<0.0001). In conclusion, MUC1 and E-cadherin are diagnostically and prognostically useful markers in renal tumor pathology, especially when cellular staining patterns are considered.

Laminin alpha1 chain in human renal cell carcinomas and integrin-mediated adhesion of renal cell carcinoma cells to human laminin isoforms

In human tissues, the laminin (Ln) alpha1 chain shows a restricted and developmentally regulated distribution in basement membranes (BMs) of a subset of epithelial tissues, including those of renal proximal convoluted tubules. The present study investigated the distribution of the Ln alpha1 chain in renal cell carcinomas (RCCs) and oncocytomas as well as in xenografted tumours induced in nude mice with four characterized RCC cell lines. These cell lines were also used in cell adhesion studies with purified laminins. By immunohistochemistry it was found that the Ln alpha1 chain is widely present in the BMs of RCCs, all of the specimens presenting immunoreactivity. High-grade RCCs tended to contain more BM-confined and stromal immunoreactivity than low-grade tumours, none of the grade 3 (G3) carcinomas being negative and all of the metastatic specimens showing partial or overall BM immunoreactivity. Double immunolabelling experiments showed that in RCC BMs but not in vessel walls, the Ln alpha1 chain was co-distributed with Ln alpha5, beta1, and beta2 chains, implying the presence of Ln-1/Ln-3 and Ln-10/Ln-11. In papillary RCCs, the Ln alpha1 chain co-localized with Ln-5. The oncocytomas lacked immunoreactivity for the Ln alpha1 chain. Xenografted tumours induced in nude mice showed BM-like deposition of the Ln alpha1 chain. In cell adhesion studies, mouse and human Ln-1 were equally effective in promoting cell adhesion of all RCC cell lines. For each cell line, Ln-10 and Ln-10/11 were equally effective adhesive substrates, all cell lines adhering more avidly to these laminins than to mouse or human Ln-1. As judged by inhibition assays employing specific integrin antibodies, adhesion of normal human renal proximal tubular epithelial (RPTE) cells and RCC cells from a G1 tumour to human Ln-1 was mediated mainly by alpha(6)beta(1) integrin, while only the G1 RCC cells adhered to mouse Ln-1 by using alpha(6)beta(1) integrin. For adhesion to Ln-10, RPTE cells and RCC cells from a G1 tumour used an unidentified beta(1) integrin. Cells from G3 tumours mainly used an alpha(3)beta(1) integrin complex for adhesion to mouse Ln-1 and to human Ln-1 and Ln-10. For all cells, adhesion to the Ln-10/11 mixture was mediated by an unidentified integrin complex or by other adhesion molecules. These results show that laminin trimers containing the alpha1 chain are, in contrast to oncocytomas, abundant in the BMs of RCCs. This is in keeping with their suggested origin from renal proximal tubular epithelium known for its capacity to produce the Ln alpha1 chain. The results also show that RCC cells utilize complex, mainly integrin alpha(3)beta(1)- and integrin alpha(6)beta(1)-mediated, mechanisms for adhesion to laminins. The adhesion to Ln-1 changes from integrin alpha(6)beta(1) to integrin alpha(3)beta(1) upon increasing malignancy and, especially for Ln-10 and Ln-10/11, other adhesion molecules of non-integrin type may contribute to the adhesion.

Classical cadherin and catenin expression in normal myometrial tissues and uterine leiomyomas

Uterine leiomyomas are the most common benign uterine tumors in the women of reproductive age. Previous studies have suggested that uterine leiomyomas are monoclonal tumors derived from a single neoplastic myometrial cell. However, the neoplastic transformation of myometrium to leiomyomas remains to be elucidated. The classical cadherins are a gene family of integral membrane glycoproteins that mediate calcium-dependent cell-cell adhesion in a homophilic manner. These cell adhesion molecules (CAMs) have been shown to play pivotal roles in tumorigenesis. Catenins are intracellular proteins that link the cytoplasmic domains of the cadherins to the cytoskeletons to promote the biological functions of these CAMs. In this study, we compared the expression of E-, N-, and P-cadherins and alpha-, beta-, and gamma-catenins in the uterine leiomyomas and the counterparts of normal myometrium of the same patients by using semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis. Of these, E-cadherin (E-cad) was not detected in both uterine leiomyomas and myometrium, P-cadherin (P-cad) was similarly expressed in these two tissues, but N-cadherin (N-cad) mRNA and protein expression levels in uterine leiomyomas were significantly greater than those observed in the myometrium. Catenins were not differentially expressed in uterine myometrium and leiomyomas. The overexpression of N-cad in uterine leiomyomas suggests that this CAM may play a central role in the development of uterine leiomyomas.