Extracelluar matrix metalloproteinase as a novel target for pancreatic cancer therapy

Tenascin-C expression is significantly associated with the progression and prognosis in gastric GISTs

Tenascin-C (TNC), an extracellular matrix glycoprotein, has been implicated in progression of various types of cancer. However, few reports exist on TNC expression in gastrointestinal stromal tumors (GISTs). We here attempted to investigate the expression pattern and prognostic significance of TNC in gastric GISTs. We studied TNC expression in 122 gastric GISTs tissue samples by immunohistochemistry, and examined the correlations of TNC expression with clinicopathological parameters and survival of gastric GISTs. The TNC-high expression was observed in 30 (24.6%) of 122 of gastric GISTs. The high levels of TNC expression in gastric GISTs was significantly associated with tumor size (P < .001), multivisceral resection (P = .006), metastasis at initial diagnosis (P = .006), mitotic count (P = .002) and NIH risk classification (P = .015). The TNC mRNA and protein levels were found to significantly downregulated in tumors without progression compared to those tumors which occurred tumor progression during the follow-up period (P < .05). As for the prognostic analysis, it revealed that tumor size, mitotic count, surgical margins, multivisceral resection, and TNC expression were independent predictors of PFS for gastric GISTs (P < .05). The overexpression of TNC may be as a possible marker for the metastatic potential of gastric GISTs patients.

212Pb-Labeled Antibody 225.28 Targeted to Chondroitin Sulfate Proteoglycan 4 for Triple-Negative Breast Cancer Therapy in Mouse Models

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with a poor prognosis. There is a clinical need for effective, targeted therapy strategies that destroy both differentiated TNBC cells and TNBC cancer initiating cells (CICs), as the latter are implicated in the metastasis and recurrence of TNBC. Chondroitin sulfate proteoglycan 4 (CSPG4) is overexpressed on differentiated tumor cells and CICs obtained from TNBC patient specimens, suggesting that CSPG4 may be a clinically relevant target for the imaging and therapy of TNBC. The purpose of this study was to determine whether α-particle radioimmunotherapy (RIT) targeting TNBC cells using the CSPG4-specific monoclonal antibody (mAb) 225.28 as a carrier was effective at eliminating TNBC tumors in preclinical models. To this end, mAb 225.28 labeled with ²¹²Pb (²¹²Pb-225.28) as a source of α-particles for RIT was used for in vitro Scatchard assays and clonogenic survival assays with human TNBC cells (SUM159 and 2LMP) grown as adherent cells or non-adherent CIC-enriched mammospheres. Immune-deficient mice bearing orthotopic SUM159 or 2LMP xenografts were injected i.v. with the targeted (225.28) or irrelevant isotype-matched control (F3-C25) mAbs, labeled with ^99mTc, ¹²⁵I, or ²¹²Pb for in vivo imaging, biodistribution, or tumor growth inhibition studies. ²¹²Pb-225.28 bound to adherent SUM159 and 2LMP cells and to CICs from SUM159 and 2LMP mammospheres with a mean affinity of 0.5 nM. Nearly ten times more binding sites per cell were present on SUM159 cells and CICs compared with 2LMP cells. ²¹²Pb-225.28 was six to seven times more effective than ²¹²Pb-F3-C25 at inhibiting SUM159 cell and CIC clonogenic survival (p < 0.05). Radiolabeled mAb 225.28 showed significantly higher uptake than radiolabeled mAb F3-C25 in SUM159 and 2LMP xenografts (p < 0.05), and the uptake of ²¹²Pb-225.28 in TNBC xenografts was correlated with target epitope expression. ²¹²Pb-225.28 caused dose-dependent growth inhibition of SUM159 xenografts; 0.30 MBq ²¹²Pb-225.28 was significantly more effective than 0.33 MBq ²¹²Pb-F3-C25 at inhibiting tumor growth (p < 0.01). These results suggest that CSPG4-specific ²¹²Pb-225.28 is a useful reagent for RIT of CSPG4-expressing tumors, including metastatic TNBC.

212Pb-labeled B7-H3-targeting antibody for pancreatic cancer therapy in mouse models

INTRODUCTION

We recently validated monoclonal antibody (mAb) 376.96 as an effective carrier for targeted α-particle radioimmunotherapy (RIT) with ²¹²Pb in ovarian cancer mouse models. In this study, we tested the binding of radiolabeled mAb 376.96 to human pancreatic ductal adenocarcinoma (PDAC) cells and localization in xenografts in immune-deficient mice and evaluated ²¹²Pb-labeled 376.96 (²¹²Pb-376.96) for PDAC therapy.

METHODS

In vitro Scatchard assays assessed the specific binding of ²¹²Pb-376.96 to human PDAC3 adherent differentiated cells and non-adherent cancer initiating cells (CICs) dissociated from tumorspheres. In vitro clonogenic assays were used to measure the proliferation of adherent PDAC3 cells and CIC-enriched tumorspheres treated with ²¹²Pb-376.96 or the irrelevant isotype-matched ²¹²Pb-F3-C25. Mice bearing patient derived pancreatic cancer Panc039 xenografts were i.v. injected with 0.17-0.70 MBq ²¹²Pb-376.96 or isotype control ²¹²Pb-F3-C25, and used for biodistribution and tumor growth inhibition studies. Mice bearing orthotopic PDAC3 xenografts were i.v. co-injected with ^99mTc-376.96 and ¹²⁵I-F3-C25 and used for biodistribution studies.

RESULTS

²¹²Pb-376.96 specifically bound to PDAC3 adherent and dissociated tumorsphere CICs; K_d values averaged 9.0 and 21.7 nM, respectively, with 10⁴-10⁵ binding sites/cell. ²¹²Pb-376.96 inhibited the clonogenic survival of PDAC3 cells or CICs dissociated from tumorspheres 3-6 times more effectively than isotype-matched control ²¹²Pb-F3-C25. Panc039 s.c. tumors showed significantly higher uptake of ²¹²Pb-376.96 (14.0 ± 2.1% ID/g) compared to ²¹²Pb-F3-C25 (6.5 ± 0.9% ID/g, p < .001) at 24 h after dosing. Orthotopic PDAC3 tumors showed significantly higher uptake of ^99mTc-376.96 (6.4 ± 1.8% ID/g) compared to ¹²⁵I-F3-C25 (3.9 ± 0.9% ID/g, p < .05) at 24 h after dosing. Panc039 tumor growth was significantly inhibited by ²¹²Pb-376.96 compared to ²¹²Pb-F3-C25 or non-treated control tumors (p < .05).

CONCLUSION

Our results provide evidence for the efficacy of B7-H3 targeted RIT against preclinical models of pancreatic ductal adenocarcinoma (PDAC) and support future studies with ²¹²Pb-376.96 in combination with chemotherapy to potentiate efficacy against PDAC.

Characterizing the detection threshold for optical imaging in surgical oncology

BACKGROUND AND OBJECTIVES

Optical imaging to guide cancer resections is rapidly transitioning into the operating room. However, the sensitivity of this technique to detect subclinical disease is yet characterized. The purpose of this study was to determine the minimum range of cancer cells that can be detected by antibody-based fluorescence imaging.

METHODS

2LMP (breast), COLO-205 (colon), MiaPaca-2 (pancreas), and SCC-1 (head and neck) cells incubated in vitro with cetuximab-IRDye800CW (dose range 8.6-86 nM) were implanted subcutaneously in mice (n = 3 mice, 5 tumors/mouse). Following incubation with 8.6 × 10^-2  µM of cetuximab-IRDye800CW in vitro, serial dilutions of each cell type (1 × 10³ -1 × 10⁶ ) were implanted subcutaneously (n = 3, 5 tumors/mouse). Tumors were imaged with Pearl Impulse and Xenogen IVIS 100 imaging systems. Scatchard analysis was performed to determine receptor density and kinetics for each cell line.

RESULTS

Under conditions of minimal cetuximab-IRDye800CW exposure to low cellular quantity, closed-field fluorescence imaging theoretically detected a minimum of 4.2 × 10⁴ -9.5 × 10⁴ 2LMP cells, 1.9 × 10⁵ -4.5 × 10⁵ MiaPaca-2 cells, and 2.4 × 10⁴ -6.7 × 10⁴ SCC-1 cells; COLO-205 cells could not be identified. Higher EGFR-mediated uptake of cetuximab correlated with sensitivity of detection.

CONCLUSION

This study supports the clinical utility of cetuximab-IRDye800CW to sensitively localize subclinical disease in the surgical setting.

B7-H3-targeted 212Pb radioimmunotherapy of ovarian cancer in preclinical models

INTRODUCTION

Novel therapies that effectively kill both differentiated cancer cells and cancer initiating cells (CICs), which are implicated in causing chemotherapy-resistance and disease recurrence, are needed to reduce the morbidity and mortality of ovarian cancer. These studies used monoclonal antibody (mAb) 376.96, which recognizes a B7-H3 epitope expressed on ovarian cancer cells and CICs, as a carrier molecule for targeted α-particle radioimmunotherapy (RIT) in preclinical models of human ovarian cancer.

METHODS

mAb 376.96 was conjugated to the chelate 2-(4-isothiocyanotobenzyl)-1,4,7,10-tetraaza-1,4,7,10-tetra-(2-carbamoylmethyl)-cyclododecane (TCMC) and radiolabeled with ²¹²Pb, a source of α-particles. In vitro Scatchard assays determined the specific binding of ²¹²Pb-376.96 to adherent differentiated or non-adherent CIC-enriched ES-2 and A2780cp20 ovarian cancer cells. Adherent ovarian cancer cells and non-adherent CIC-enriched tumorspheres treated in vitro with ²¹²Pb-376.96 or the irrelevant isotype-matched ²¹²Pb-F3-C25 were assessed for clonogenic survival. Mice bearing i.p. ES-2 or A2780cp20 xenografts were injected i.p. with 0.17-0.70MBq ²¹²Pb-376.96 or ²¹²Pb-F3-C25 and were used for in vivo imaging, ex vivo biodistribution, and therapeutic survival studies.

RESULTS

²¹²Pb-376.96 was obtained in high yield and purity (>98%); K_d values ranged from 10.6-26.6nM for ovarian cancer cells, with 10⁴-10⁵ binding sites/cell. ²¹²Pb-376.96 inhibited the clonogenic survival of ovarian cancer cells up to 40 times more effectively than isotype-matched control ²¹²Pb-F3-C25; combining ²¹²Pb-376.96 with carboplatin significantly decreased clonogenic survival compared to either agent alone. In vivo imaging and biodistribution analysis 24h after i.p. injection of ²¹²Pb-376.96 showed high peritoneal retention and tumor tissue accumulation (28.7% ID/g in ES-2 ascites, 73.1% ID/g in A2780cp20 tumors); normal tissues showed lower and comparable uptake for ²¹²Pb-376.96 and ²¹²Pb-F3-C25. Tumor-bearing mice treated with ²¹²Pb-376.96 alone or combined with carboplatin survived 2-3 times longer than mice treated with ²¹²Pb-F3-C25 or non-treated controls.

CONCLUSION

These results support additional RIT studies with ²¹²Pb-376.96 for future evaluation in patients with ovarian cancer.

Selecting Targets for Tumor Imaging: An Overview of Cancer-Associated Membrane Proteins

Tumor targeting is a booming business: The global therapeutic monoclonal antibody market accounted for more than $78 billion in 2012 and is expanding exponentially. Tumors can be targeted with an extensive arsenal of monoclonal antibodies, ligand proteins, peptides, RNAs, and small molecules. In addition to therapeutic targeting, some of these compounds can also be applied for tumor visualization before or during surgery, after conjugation with radionuclides and/or near-infrared fluorescent dyes. The majority of these tumor-targeting compounds are directed against cell membrane-bound proteins. Various categories of targetable membrane-bound proteins, such as anchoring proteins, receptors, enzymes, and transporter proteins, exist. The functions and biological characteristics of these proteins determine their location and distribution on the cell membrane, making them more, or less, accessible, and therefore, it is important to understand these features. In this review, we evaluate the characteristics of cancer-associated membrane proteins and discuss their overall usability for cancer targeting, especially focusing on imaging applications.

Bioorthogonal labeling cell-surface proteins expressed in pancreatic cancer cells to identify potential diagnostic/therapeutic biomarkers

To develop new diagnostic and therapeutic tools to specifically target pancreatic tumors, it is necessary to identify cell-surface proteins that may serve as potential tumor-specific targets. In this study we used an azido-labeled bioorthogonal chemical reporter to metabolically label N-linked glycoproteins on the surface of pancreatic cancer cell lines to identify potential targets that may be exploited for detection and/or treatment of pancreatic cancer. Labeled glycoproteins were tagged with biotin using click chemistry, purified by streptavidin-coupled magnetic beads, separated by gel electrophoresis, and identified by liquid chromatography-tandem mass spectrometry (MS). MS/MS analysis of peptides from 3 cell lines revealed 954 unique proteins enriched in the azido sugar samples relative to control sugar samples. A comparison of the proteins identified in each sample indicated 20% of these proteins were present in 2 cell lines (193 of 954) and 17 of the proteins were found in all 3 cell lines. Five of the 17 proteins identified in all 3 cell lines have not been previously reported to be expressed in pancreatic cancer; thus indicating that novel cell-surface proteins can be revealed through glycoprotein profiling. Western analysis of one of these glycoproteins, ecto-5'-nucleotidase (NT5E), revealed it is expressed in 8 out of 8 pancreatic cancer cell lines examined. Further, immunohistochemical analysis of human pancreatic tissues indicates NT5E is significantly overexpressed in pancreatic tumors compared to normal pancreas. Thus, we have demonstrated that metabolic labeling with bioorthogonal chemical reporters can be used to selectively enrich and identify novel cell-surface glycoproteins expressed in pancreatic ductal adenocarcinomas.

Modulation, bioinformatic screening, and assessment of small molecular peptides targeting the vascular endothelial growth factor receptor

Vascular endothelial growth factor (VEGF) and VEGF receptor (VEGFR) are important factors in tumor growth and metastasis. Molecular probes or drugs designed to target VEGF/VEGFR interactions are crucial in tumor molecular imaging and targeted therapy. Bioinformatic methods enable molecular design based on the structure of bio-macromolecules and their interactions. This study was aimed to identify tumor-targeting small-molecule peptides with high affinity for VEGFR using bioinformatics screening. The VEGFR extracellular immunoglobulin-like modules Ig1–Ig3 were used as the target to systematically alter the primary peptide sequence of VEGF_125–136. Molecular docking and surface functional group interaction methods were combined in an in silico screen for polypeptides, which in theory, would have higher affinities for VEGFR. In vitro receptor competition binding assays were used to assess the affinity of the putative VEGFR-binding polypeptides. Rhodamine-conjugated peptides were used to label and visualize peptide-binding sites on A549 cells. Using bioinformatic screening, we identified 20 polypeptides with potentially higher affinity for VEGFR. The polypeptides were capable of inhibiting the binding of ¹²⁵I-VEGF to VEGFR in a dose-dependent manner. The IC₅₀ values of QKRKRKKSRKKH and RKRKRKKSRYIVLS (80 and 185 nmol/L, respectively) were significantly lower than that of VEGF_125–136 (464 nmol/L); thus, the affinity of these peptides for VEGFR was 6- and 2.5-fold higher, respectively, than that of VEGF_125–136. Rhodamine labeling of A549 cells revealed peptide binding mainly on the plasma membrane and in the cytoplasm. Bioinformatic approaches hold promise for the development of molecular imaging probes. Using this approach, we designed two peptides that showed higher affinity toward VEGFR. These polypeptides may be used as molecular probes or drugs targeting VEGFR, which can be utilized in molecular imaging and targeted therapy of certain tumors.

Dynamic contrast-enhanced MRI evaluates the early response of human head and neck tumor xenografts following anti-EMMPRIN therapy with cisplatin or irradiation

PURPOSE

To assess the early therapeutic effects of anti-EMMPRIN (extracellular matrix metalloprotease inducer) antibody with/without cisplatin or X-ray radiation in head and neck cancer mouse models using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).

MATERIALS AND METHODS

Mice bearing SCC1 (or OSC19) tumor xenografts were treated with anti-EMMPRIN antibody, radiation, cisplatin, or anti-EMMPRIN antibody plus cisplatin (or radiation) for a week (n = 4-5 per group). DCE-MRI was carried out on a 9.4T small animal MR scanner on days 0, 3, and 7, and K(trans) values were averaged in a 0.5-mm-thick peripheral tumor region. Ki67 and CD31 staining were implemented for all tumors after imaging.

RESULTS

The K(trans) changes of SCC1 and OSC19 tumors treated with anti-EMMPRIN antibody for 3 days were -18 ± 8% and 4 ± 7%, respectively, which were significantly lower than those of control groups (39 ± 5% and 45 ± 7%; P = 0.0025 and 0.0220, respectively). When cisplatin was added, those were -42 ± 9% and -44 ± 9%, respectively, and with radiation, -45 ± 9% and -27 ± 10%, respectively, which were also significantly lower than those of control groups (P < 0.0001 for all four comparisons). In the eight groups untreated (served as control) or treated with anti-EMMPRIN antibody with/without cisplatin or radiation, the mean K(trans) change for 3 days was significantly correlated with the mean tumor volume change for 7 days (r = 0.74, P = 0.0346), Ki67-expressing cell density (r = 0.96, P = 0.0001), and CD31 density (r = 0.84, P = 0.0084).

CONCLUSION

DCE-MRI might be utilized to assess the early therapeutic effects of anti-EMMPRIN antibody with/without chemotherapy or radiotherapy in head and neck cancer.

Synergistic effect of nanosecond pulsed electric field combined with low-dose of pingyangmycin on salivary adenoid cystic carcinoma

Adenoid cystic carcinoma (ACC) is one of the most common malignant neoplasms in salivary glands. To evaluate the therapeutic effects of nanosecond pulsed electric field (nsPEF) combined with pingyangmycin (PYM) on salivary gland adenoid cystic carcinoma (SACC), ACC high metastatic cell line (SACC-LM) and low metastatic cell line (SACC‑83) were tested by CCK-8 assay, cell clonogenic assay, flow cytometry and Transwell assay. Extracellular matrix metalloproteinase inducer (EMMPRIN) expression was tested by western blotting to verify the synergistic mechanism of nsPEF and PYM. The results showed that nsPEF inhibited the cell proliferation of both cell lines, and the inhibitory effect was strongly associated with time and electrical field strength. Moreover, PYM combined with nsPEF may enhance the suppression effect significantly, even at a very low dose (0.01 µg/ml). The synergistic effects may contribute to the downregulation of EMMPRIN expression resulting from the application of nsPEF. For SACC, nsPEF combined with chemotherapy agents may be a valuable strategy not only to improve the treatment effect and prognosis, but also to reduce the side-effects of chemotherapy.

HAb18G/CD147 promotes pSTAT3-mediated pancreatic cancer development via CD44s

PURPOSE

Signal transducer and activator of transcription 3 (STAT3) plays a critical role in initiation and progression of pancreatic cancer. However, therapeutically targeting STAT3 has failed clinically. We previously identified HAb18G/CD147 as an effective target for cancer treatment. In this study, we aimed to investigate the potential role of HAb18G/CD147 in STAT3-involved pancreatic tumorigenesis in vitro and in vivo.

EXPERIMENTAL DESIGN

The expression of HAb18G/CD147, pSTAT3, and CD44s was determined in tissue microarrays. The tumorigenic function and molecular signaling mechanism of HAb18G/CD147 were assessed by in vitro cellular and clonogenic growth, reporter assay, immunoblot assay, immunofluorescence staining, immunoprecipitation, and in vivo tumor formation using loss or gain-of-function strategies.

RESULTS

Highly expressed HAb18G/CD147 promoted cellular and clonogenic growth in vitro and tumorigenicity in vivo. Cyclophilin A (CyPA), a ligand of CD147, stimulated STAT3 phosphorylation and its downstream genes cyclin D1/survivin through HAb18G/CD147-dependent mechanisms. HAb18G/CD147 was associated and colocalized with cancer stem cell marker CD44s in lipid rafts. The inhibitors of STAT3 and survivin, as well as CD44s neutralizing antibodies suppressed the HAb18G/CD147-induced cell growth. High HAb18G/CD147 expression in pancreatic cancer was significantly correlated with the poor tumor differentiation, and the high coexpression of HAb18G/CD147-CD44s-STAT3 associated with poor survival of patients with pancreatic cancer.

CONCLUSIONS

We identified HAb18G/CD147 as a novel upstream activator of STAT3, which interacts with CD44s and plays a critical role in the development of pancreatic cancer. The data suggest that HAb18G/CD147 could be a promising therapeutic target for highly aggressive pancreatic cancer and a surrogate marker in the STAT3-targeted molecular therapies.

Antagonistic effects of anti-EMMPRIN antibody when combined with chemotherapy against hypovascular pancreatic cancers

PURPOSE

To examine the antagonistic effects of anti-extracellular matrix metalloprotease inducer (anti-EMMPRIN) antibody when combined with chemotherapy using a hypovascular pancreatic tumor model.

PROCEDURES

Severely compromised immunodeficient mice bearing orthotopic MIA PaCa-2 tumors were used (five to six animals per group). Dynamic contrast-enhanced magnetic resonance imaging was used to examine the relationship between tumor vascularity and size. Therapy was initiated when tumors were hypovascular. Treatments included: (1) gemcitabine alone, (2) anti-EMMPRIN antibody alone, and (3) combination, each for 2 weeks. Additionally, another treatment arm included β-lapachone, an NAD(P)H/quinone 1 (NQO1) bioactivated agent. (18)F-fluoro-D-glucose-positron emission tomography/computed tomography imaging was used weekly to monitor therapeutic effects.

RESULTS

Gemcitabine or anti-EMMPRIN monotherapy significantly delayed tumor growth, but the combination therapy showed an antagonistic effect. Similarly, tumor growth was significantly suppressed by β-lapachone alone, and additive effects were noted when combined with gemcitabine, but the therapeutic efficacy was reduced when anti-EMMPRIN antibody was added.

CONCLUSIONS

Anti-EMMPRIN antibody with chemotherapy in hypovascular tumors results in antagonistic effects.

Cancer Stem Cells, EMT, and Developmental Pathway Activation in Pancreatic Tumors

Pancreatic cancer is a disease with remarkably poor patient survival rates. The frequent presence of metastases and profound chemoresistance pose a severe problem for the treatment of these tumors. Moreover, cross-talk between the tumor and the local micro-environment contributes to tumorigenicity, metastasis and chemoresistance. Compared to bulk tumor cells, cancer stem cells (CSC) have reduced sensitivity to chemotherapy. CSC are tumor cells with stem-like features that possess the ability to self-renew, but can also give rise to more differentiated progeny. CSC can be identified based on increased in vitro spheroid- or colony formation, enhanced in vivo tumor initiating potential, or expression of cell surface markers. Since CSC are thought to be required for the maintenance of a tumor cell population, these cells could possibly serve as a therapeutic target. There appears to be a causal relationship between CSC and epithelial-to-mesenchymal transition (EMT) in pancreatic tumors. The occurrence of EMT in pancreatic cancer cells is often accompanied by re-activation of developmental pathways, such as the Hedgehog, WNT, NOTCH, and Nodal/Activin pathways. Therapeutics based on CSC markers, EMT, developmental pathways, or tumor micro-environment could potentially be used to target pancreatic CSC. This may lead to a reduction of tumor growth, metastatic events, and chemoresistance in pancreatic cancer.

Dual combination therapy targeting DR5 and EMMPRIN in pancreatic adenocarcinoma

The goal of the study was to assess the efficacy of combined extracellular matrix metalloprotease inducer (EMMPRIN)- and death receptor 5 (DR5)-targeted therapy for pancreatic adenocarcinoma in orthotopic mouse models with multimodal imaging. Cytotoxicity of anti-EMMPRIN antibody and anti-DR5 antibody (TRA-8) in MIA PaCa-2 and PANC-1 cell lines was measured by ATPlite assay in vitro. The distributions of Cy5.5-labeled TRA-8 and Cy3-labeled anti-EMMPRIN antibody in the 2 cell lines were analyzed by fluorescence imaging in vitro. Groups 1 to 12 of severe combined immunodeficient mice bearing orthotopic MIA PaCa-2 (groups 1-8) or PANC-1 (groups 9-12) tumors were used for in vivo studies. Dynamic contrast-enhanced-MRI was applied in group 1 (untreated) or group 2 (anti-EMMPRIN antibody). The tumor uptake of Tc-99m-labeled TRA-8 was measured in group 3 (untreated) and group 4 (anti-EMMPRIN antibody). Positron emission tomography/computed tomography imaging with (18)F-FDG was applied in groups 5 to 12. Groups 5 to 8 (or groups 9 to 12) were untreated or treated with anti-EMMPRIN antibody, TRA-8, and combination, respectively. TRA-8 showed high killing efficacy for both MIA PaCa-2 and PANC-1 cells in vitro, but additional anti-EMMPRIN treatment did not improve the cytotoxicity. Cy5.5-TRA-8 formed cellular caps in both the cell lines, whereas the maximum signal intensity was correlated with TRA-8 cytotoxicity. Anti-EMMPRIN therapy significantly enhanced the tumor delivery of the MR contrast agent, but not Tc-99m-TRA-8. Tumor growth was significantly suppressed by the combination therapy, and the additive effect of the combination was shown in both MIA PaCa-2 and PANC-1 tumor models.