Dual combination therapy targeting DR5 and EMMPRIN in pancreatic adenocarcinoma

Novel Antibody Exerts Antitumor Effect through Downregulation of CD147 and Activation of Multiple Stress Signals

CD147 is an immunoglobulin-like receptor that is highly expressed in various cancers and involved in the growth, metastasis, and activation of inflammatory pathways via interactions with various functional molecules, such as integrins, CD44, and monocarboxylate transporters. Through screening of CD147-targeting antibodies with antitumor efficacy, we discovered a novel rat monoclonal antibody ^#147D. This humanized IgG4-formatted antibody, h4^#147D, showed potent antitumor efficacy in xenograft mouse models harboring the human PDAC cell line MIA PaCa-2, HCC cell line Hep G2, and CML cell line KU812, which featured low sensitivity to the corresponding standard-of-care drugs (gemcitabine, sorafenib, and imatinib, respectively). An analysis of tumor cells derived from MIA PaCa-2 xenograft mice treated with h4^#147D revealed that cell surface expression of CD147 and its binding partners, including CD44 and integrin α3β1/α6β1, was significantly reduced by h4^#147D. Inhibition of focal adhesion kinase (FAK), activation of multiple stress responsible signal proteins such as c-JunN-terminal kinase (JNK) and mitogen-activated protein kinase p38 (p38MAPK), and expression of SMAD4, as well as activation of caspase-3 were obviously observed in the tumor cells, suggesting that h4^#147D induced tumor shrinkage by inducing multiple stress responsible signals. These results suggest that the anti-CD147 antibody h4^#147D offers promise as a new antibody drug candidate.

Therapeutic anti-CD147 antibody sensitizes cells to chemoradiotherapy via targeting pancreatic cancer stem cells

We have previously demonstrated that anti-CD44s H4C4 or liposomal-delivered STAT3 inhibitor FLLL32 sensitized pancreatic cancer cells to radiotherapy through the elimination or inhibition of cancer stem cells (CSCs) and that HAb18G/CD147 promoted STAT3-mediated pancreatic tumor development by forming a signaling complex with CD44s. In this paper, we therefore explored whether anti-CD147 HAb18IgG sensitized pancreatic cancer cells to chemoradiotherapy via the targeting of CSCs. We tested the influence of HAb18IgG on the sensitivity of pancreatic cancer cells to chemoradiotherapy by clonogenic and MTT assays and on pancreatic CSCs by colony and sphere formation assays, flow cytometry, quantitative real-time RT-PCR (qRT-PCR) and stem cell transcription factors PCR array analysis. Changes in CD147 signaling were examined by immunoblot and reporter assays. We found that HAb18IgG sensitized pancreatic cancer cells to chemoradiotherapy by dose-dependently decreasing colony and sphere formation. Furthermore, HAb18IgG reduced the pancreatic CSC subpopulation and the expression of stem cell transcription factors OCT4, SOX2 and NANOG. Mechanistically, HAb18IgG inhibited CSCs by blocking CD44s-pSTAT3 signaling. The present findings indicated the promising therapeutic role of anti-CD147 HAb18IgG in suppressing pancreatic tumor initiation and overcoming post-chemoradiotherapy recurrence through the direct targeting of CSCs.

A Novel Imaging Biomarker Extracted from Fluorescence Microscopic Imaging of TRA-8/DR5 Oligomers Predicts TRA-8 Therapeutic Efficacy in Breast and Pancreatic Cancer Mouse Models

PURPOSE

The aim of the study was to develop a reliable quantitative imaging biomarker from fluorescence microscopic imaging of TRA-8/death receptor 5 (DR5) oligomer to predict TRA-8 therapeutic efficacy in human breast and pancreatic cancer mouse models.

PROCEDURES

Two breast (2LMP, SUM159) and two pancreatic (MIA PaCa-2, PANC1) cancer cell lines were used. 10(5) cells per cell line were placed in a culture dish and treated with Cy5.5-labeled TRA-8 overnight in vitro. Three fluorescence microphotographs (×20) were acquired from randomly selected areas, and about 300 cells were analyzed per cell line. Two-dimensional (2D) fluorescence signal distribution of Cy5.5-TRA-8 on each cell was measured. Gaussian curve fitting to the distribution was determined by the least square regression method, and the coefficient of determination (R (2)) of the fitting was found. In addition, two features of the best fitting Gaussian curve such as peak amplitude and the volume under the curve (VUC) were retrieved. A novel image biomarker was extracted by correlating the combination of R (2) value, peak amplitude, and the VUC with the logarithmic values of the half maximal inhibitory concentrations (IC50) of TRA-8 for the four cell lines or the percentage of tumor growth inhibition (%TGI) at a week of TRA-8 treatment in animal models.

RESULTS

Cy5.5-TRA-8 binding to DR5 receptors resulted in an oligomer on each cell membrane, and its fluorescence signal distribution followed Gaussian curve. Peak amplitude of fluorescence signal in the oligomeric region, R (2) value of the Gaussian fitting, and the VUC in TRA-8-sensitive cells were significantly higher than those in resistant cells (p < 0.05). The novel imaging biomarker was significantly correlated with either log10(IC50) or %TGI (p < 0.001).

CONCLUSION

The imaging biomarker extracted from the cellular distribution pattern of Cy5.5-TRA-8 may serve as a predictive biomarker of TRA-8 therapy for cancer patients.

TRAIL mediated signaling in pancreatic cancer

Research over the years has progressively shown substantial broadening of the tumor necrosis factor alpha- related apoptosis-inducing ligand (TRAIL)-mediated signaling landscape. Increasingly it is being realized that pancreatic cancer is a multifaceted and genomically complex disease. Suppression of tumor suppressors, overexpression of oncogenes, epigenetic silencing, and loss of apoptosis are some of the extensively studied underlying mechanisms. Rapidly accumulating in vitro and in vivo evidence has started to shed light on the resistance mechanisms in pancreatic cancer cells. More interestingly a recent research has opened new horizons of miRNA regulation by DR5 in pancreatic cancer cells. It has been shown that DR5 interacts with the core microprocessor components Drosha and DGCR8, thus impairing processing of primary let-7. Xenografting DR5 silenced pancreatic cancer cells in SCID-mice indicated that there was notable suppression of tumor growth. There is a paradigm shift in our current understanding of TRAIL mediated signaling in pancreatic cancer cells that is now adding new layers of concepts into the existing scientific evidence. In this review we have attempted to provide an overview of recent advances in TRAIL mediated signaling in pancreatic cancer as evidenced byfindings of in vitro and in vivo analyses. Furthermore, we discuss nanotechnological advances with emphasis on PEG-TRAIL and four-arm PEG cross-linked hyaluronic acid (HA) hydrogels to improve availability of TRAIL at target sites.

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.

SPARC-Independent Delivery of Nab-Paclitaxel without Depleting Tumor Stroma in Patient-Derived Pancreatic Cancer Xenografts

The study goal was to examine the relationship between nab-paclitaxel delivery and SPARC (secreted protein acidic and rich in cysteine) expression in pancreatic tumor xenografts and to determine the antistromal effect of nab-paclitaxel, which may affect tumor vascular perfusion. SPARC-positive and -negative mice bearing Panc02 tumor xenografts (n = 5-6/group) were injected with IRDye 800CW (IR800)-labeled nab-paclitaxel. After 24 hours, tumors were collected and stained with DL650-labeled anti-SPARC antibody, and the correlation between nab-paclitaxel and SPARC distributions was examined. Eight groups of mice bearing either Panc039 or Panc198 patient-derived xenografts (PDX; 4 groups/model, 5 animals/group) were untreated (served as control) or treated with gemcitabine (100 mg/kg body weight, i.p., twice per week), nab-paclitaxel (30 mg/kg body weight, i.v., for 5 consecutive days), and these agents in combination, respectively, for 3 weeks, and tumor volume and perfusion changes were assessed using T2-weighted MRI and dynamic contrast-enhanced (DCE) MRI, respectively. All tumors were collected and stained with Masson's Trichrome Stain, followed by a blinded comparative analysis of tumor stroma density. IR800-nab-paclitaxel was mainly distributed in tumor stromal tissue, but nab-paclitaxel and SPARC distributions were minimally correlated in either SPARC-positive or -negative animals. Nab-paclitaxel treatment neither decreased tumor stroma nor increased tumor vascular perfusion in either PDX model when compared with control groups. These data suggest that the specific tumor delivery of nab-paclitaxel is not directly related to SPARC expression, and nab-paclitaxel does not deplete tumor stroma in general. Mol Cancer Ther; 15(4); 680-8. ©2016 AACR.

Combination therapy with anti-DR5 antibody and tamoxifen for triple negative breast cancer

TRA-8, a monoclonal antibody targeting death receptor, has demonstrated high therapeutic effect for triple negative breast cancer (TNBC) in preclinical models. Tamoxifen, the standard of care for ERα-positive breast cancer, induces apoptosis via ERβ, which commonly presents in TNBC cells. The current study investigates the combination effects of TRA-8 and tamoxifen for TNBC. In vitro assays were implemented with two ERβ-positive TNBC cell lines, SUM159 and 2LMP, and in vivo therapy studies were followed using orthotopic breast tumor mouse models. IC50 of tamoxifen for SUM159 and 2LMP were 29 μM and 38 μM, respectively. Synergy between TRA-8 (0-1000 ng/mL) and tamoxifen (20 μM) was observed for both the cell lines. Tamoxifen (400 mg/kg diet) markedly suppressed the growth of SUM159 tumors for 6 weeks after therapy initiation, but it did not induce antitumor effect for 2LMP tumors. TRA-8 (0.1 mg, weekly, i.p.) successfully arrested the growth of both SUM159 and 2LMP tumors during therapy, but an antagonistic effect was observed when tamoxifen was combined. TRA-8 uptake into tumors was not changed by tamoxifen treatment. Histological analysis confirmed that caspase-3 activation induced by TRA-8 was significantly decreased when tamoxifen was used in combination. In conclusion, our findings suggest that the combined use of TRA-8 and tamoxifen may cause antagonistic effects for TNBC patients.

Dynamic contrast enhanced magnetic resonance imaging of an orthotopic pancreatic cancer mouse model

Dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) has been limitedly used for orthotopic pancreatic tumor xenografts due to severe respiratory motion artifact in the abdominal area. Orthotopic tumor models offer advantages over subcutaneous ones, because those can reflect the primary tumor microenvironment affecting blood supply, neovascularization, and tumor cell invasion. We have recently established a protocol of DCE-MRI of orthotopic pancreatic tumor xenografts in mouse models by securing tumors with an orthogonally bent plastic board to prevent motion transfer from the chest region during imaging. The pressure by this board was localized on the abdominal area, and has not resulted in respiratory difficulty of the animals. This article demonstrates the detailed procedure of orthotopic pancreatic tumor modeling using small animals and DCE-MRI of the tumor xenografts. Quantification method of pharmacokinetic parameters in DCE-MRI is also introduced. The procedure described in this article will assist investigators to apply DCE-MRI for orthotopic gastrointestinal cancer mouse models.

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.

Quantitative perfusion- and diffusion-weighted magnetic resonance imaging of gastrointestinal cancers treated with multikinase inhibitors: a pilot study

BACKGROUND

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) are often used to detect the early response of solid tumors to an effective therapy. The early changes in intratumoral physiological parameters measured by DCE-MRI/DWI have been evaluated as surrogate biomarkers allowing a tailored treatment for the individual patient.

METHODS

Patients with newly diagnosed, biopsy-proven, treatment-naïve gastrointestinal stromal tumor (GIST) or hepatocellular carcinoma (HCC) were enrolled prospectively after institutional review board (IRB)-approved informed consent (5 patients per tumor type). Patients with GIST were treated with sunitinib over 6 weeks. DCE-MRI/DWI was applied before therapy (baseline imaging) and at 2 and 6 weeks after therapy initiation. Patients with HCC were treated with radiation during the first 2 weeks and then with sorafenib for the next 6 weeks. DCE-MRI/DWI was applied in all patients with HCC before and after radiation therapy and at the end of sorafenib therapy. Tumor volume, perfusion parameters (K (trans), the forward volume-transfer constant, and k ep, the reverse reflux-rate constant) and the apparent diffusion coefficient (ADC) were measured.

RESULTS

During 2 weeks of sunitinib therapy, GIST volume, K (trans), and k ep decreased 32 ± 13, 45 ± 24, and 42 ± 15%, respectively, whereas ADC increased 76 ± 24%. After 6 weeks of sunitinib therapy, GIST volume, K (trans), and k ep decreased 56 ± 7, 70 ± 7, and 50 ± 12%, respectively, whereas ADC increased 85 ± 33%. After completion of radiation therapy, HCC volume, K (trans), and k ep decreased 34 ± 14, 35 ± 12, and 4 ± 21%, respectively, but ADC increased 21 ± 9%. During the entire 10-week therapeutic period, HCC volume, K (trans), and k ep decreased 65 ± 15, 40 ± 9, and 26 ± 2%, respectively, whereas ADC increased 28 ± 10%.

CONCLUSION

DCE-MRI/DWI can measure the perfusion and diffusion changes in GISTs or HCCs treated with multikinase inhibitors.

Antitumor efficacy of α-solanine against pancreatic cancer in vitro and in vivo

α-solanine, a steroidal glycoalkaloid in potato, was found to have proliferation-inhibiting and apoptosis-promoting effect on multiple cancer cells, such as clone, liver, melanoma cancer cells. However, the antitumor efficacy of α-solanine on pancreatic cancer has not been fully evaluated. In this study, we inquired into the anti-carcinogenic effect of α-solanine against human pancreatic cancer cells. In the present study, we investigated the anti-carcinogenic effect of α-solanine against human pancreatic cancer cells. In vitro, α-solanine inhibited proliferation of PANC-1, sw1990, MIA PaCa-2 cells in a dose-dependent manner, as well as cell migration and invasion with atoxic doses. The expression of MMP-2/9, extracellular inducer of matrix metalloproteinase (EMMPRIN), CD44, eNOS and E-cadherin were suppressed by α-solanine in PANC-1 cells. Moreover, significantly decreased vascular endothelial growth factor (VEGF) expression and tube formation of endothelial cells were discerned following α-solanine treatment. Suppressed phosphorylation of Akt, mTOR, and Stat3, and strengthen phosphorylation of β-catenin was found, along with markedly decreased tran-nuclear of NF-κB, β-catenin and TCF-1. Following the administration of α-solanine (6 µg/g for 2 weeks) in xenograft model, tumor volume and weight were decreased by 61% and 43% (p<0.05) respectively, showing decreased MMP-2/9, PCNA and VEGF expression. In conclusion, α-solanine showed beneficial effects on pancreatic cancer in vitro and in vivo, which may via suppressing the pathway proliferation, angiogenesis and metastasis.

SELDI-TOF analysis of glioblastoma cyst fluid is an approach for assessing cellular protein expression

OBJECTIVES

In about 10% of glioblastoma patients, preoperative MRI discloses the presence of tumor cysts. Whereas the impact of cystic appearance on prognosis has been discussed extensively, only little is known about the tumor cyst fluid. In this study, we tested the feasibility of the surface enhanced laser desorption ionization time of flight (SELDI-TOF) technique to detect cyst fluid proteins.

METHODS

Cyst fluid was collected from 21 glioblastoma patients for SELDI-TOF analysis and compared to control cerebrospinal fluids from 15 patients with spinal stenosis. Resulting protein peaks with significant differences between groups were further described, using the molecular weight in an internet search of protein databases and publications. Two potential cyst fluid proteins, basigin and ferritin light chain, were selected for immunohistological detection in the histologic slides of the patients, metallothionein (MT) served as negative control.

RESULTS

As supposed from the results of the SELDI-TOF analysis, basigin and ferritin were detected immunohistochemically in the cyst wall, whereas MT was more equally distributed between the cyst wall and the surrounding tumor tissue. Median survival time of the patients was 20 months (range 2 to 102 months) and correlated with age, but not with expression of the three proteins.

DISCUSSION

The SELDI-TOF approach reveals a number of proteins, potentially present in glioblastoma cyst fluid. Identification of these proteins in tumor cells may help understand the pathogenetic pathways and the prognostic value of cystic changes.

Genetic and molecular alterations in pancreatic cancer: implications for personalized medicine

Recent advances in human genomics and biotechnologies have profound impacts on medical research and clinical practice. Individual genomic information, including DNA sequences and gene expression profiles, can be used for prediction, prevention, diagnosis, and treatment for many complex diseases. Personalized medicine attempts to tailor medical care to individual patients by incorporating their genomic information. In a case of pancreatic cancer, the fourth leading cause of cancer death in the United States, alteration in many genes as well as molecular profiles in blood, pancreas tissue, and pancreas juice has recently been discovered to be closely associated with tumorigenesis or prognosis of the cancer. This review aims to summarize recent advances of important genes, proteins, and microRNAs that play a critical role in the pathogenesis of pancreatic cancer, and to provide implications for personalized medicine in pancreatic cancer.

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.

Multispectral Imaging

The field of anatomic pathology has changed significantly over the last decades and, as a result of the technological developments in molecular pathology and genetics, has had increasing pressures put on it to become quantitative and to provide more information about protein expression on a cellular level in tissue sections. Multispectral imaging (MSI) has a long history as an advanced imaging modality and has been used for over a decade now in pathology to improve quantitative accuracy, enable the analysis of multicolor immunohistochemistry, and drastically reduce the impact of contrast-robbing tissue autofluorescence common in formalin-fixed, paraffin-embedded tissues. When combined with advanced software for the automated segmentation of different tissue morphologies (eg, tumor vs stroma) and cellular and subcellular segmentation, MSI can enable the per-cell quantitation of many markers simultaneously. This article covers the role that MSI has played in anatomic pathology in the analysis of formalin-fixed, paraffin-embedded tissue sections, discusses the technological aspects of why MSI has been adopted, and provides a review of the literature of the application of MSI in anatomic pathology.

Reduced CD147 expression is linked to ERG fusion-positive prostate cancers but lacks substantial impact on PSA recurrence in patients treated by radical prostatectomy

The extracellular matrix metalloproteinase inducer CD147 has been suggested as a prognostic marker in prostate cancer. CD147 expression was analyzed by immunohistochemistry on a tissue microarray containing 11,152 prostate cancer specimens. Results were compared to tumor phenotype, biochemical recurrence, ERG status and deletions on PTEN, 3p13, 6q15 and 5q21. CD147 expression was strong in benign prostatic glands and often reduced in prostate cancers. CD147 immunostaining was found in 71.7% of 7628 interpretable cases. CD147 staining was considered strong in 34.6%, moderate in 24.3% and weak in 12.8% of cancers while 28.3% did not show any CD147 reactivity. Reduced CD147 staining was strongly associated with both TMPRSS2-ERG-rearrangement and ERG expression (p<0.0001 each). Within the subgroups of ERG positive and negative cancers, deletions of PTEN, 3p13, 6q15 and 5q21 were unrelated to the CD147 expression status. Decreased CD147 expression was significantly linked to high preoperative PSA values, high Gleason grade, advanced tumor stage (p<0.0001 each), and positive lymph node involvement (p=0.0026) in all cancers. There was a marginal, but statistically significant, association of reduced CD147 expression with early biochemical recurrence (p=0.0296). The significant reduction of CD147 expression in ERG positive prostate cancer provides further evidence for marked biological differences between "fusion type" and "non-fusion type" prostate cancer. Despite a weak association with PSA recurrence, CD147 cannot be considered a relevant prognostic biomarker.

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.

Diffusion weighted imaging evaluated the early therapy effect of tamoxifen in an MNU-induced mammary cancer rat model

Purpose

To assess the optimal time point of diffusion-weighted imaging (DWI) for early prognosis of breast cancer following tamoxifen therapy using a methylnitrosourea (MNU)-induced ER-positive breast-cancer model.

Methods

Two groups of Sprague-Dawley rats (n = 15 for group 1; n = 10 for group 2) were used. All animals (50 days old) were intravenously injected with MNU (50 mg/kg body weight) to induce ER-positive mammary tumors. When tumors were approximately 2 cm in diameter, DWI was performed on days 0, 3, and 7, and intratumoral apparent diffusion coefficient (ADC) values were measured. Therapy started on day 0 with tamoxifen (10 mg/kg diet) and continued for 4 weeks for group 1, but only 1 week for group 2, while tumor volume was measured by caliper twice weekly. All animals of group 2 were euthanized on day 7 after imaging, and Ki-67, TUNEL, ERα, and ERβ staining were performed on tumor tissue.

Results

DW images of MNU-induced mammary tumors were successfully obtained with minimal motion artifact. For group 1, ADC change for 3 days after therapy initiation (ADC_3D) was significantly correlated with tumor-volume change until day 11, but the significant correlation between ADC change for 7 days (ADC_7D) and the tumor-volume change was observed until day 18. Similarly, for group 2, either ADC_7D or ADC_3D was significantly correlated with the tumor-volume change, but the higher significance was observed for ADC_7D. Furthermore, ADC_7D was significantly correlated with apoptotic (TUNEL stained), proliferative (Ki-67 stained), and ERβ-positive cell densities, but ADC_3D was not significantly correlated with any of those.

Conclusions

ADC_7D might be a more reliable surrogate imaging biomarker than ADC_3D to assess effectiveness of tamoxifen therapy for ER-positive breast cancer, which may enable personalized treatment. The significant correlation between ADC_7D and ERβ-positive cell density suggests that ERβ may play an important role as a therapeutic indicator of tamoxifen.