Diagnosis and management of primary umbilical melanoma with omphalitis features

We report on a 62-year-old Chinese male patient who presented with a pigmented lesion in the umbilical area and who was treated for omphalitis in a local hospital for 1 month. Biopsy pathological examination revealed that the lesion was a melanoma. The Breslow depth was estimated at 3 mm, and Clark's level was IV. Ultrasonography showed no suspicious pathological lymph nodes, and no metastases were detected in the lung, liver or brain through CT scans. Reexcision was performed with lateral marginsd >2 cm from the original scar down to the peritoneum, including the umbilicus, round ligament of the liver and urachus. No adjuvant therapy was suggested, and the patient was still alive without recurrences or metastases after 36 months.

Creating an artificial two-dimensional Skyrmion crystal by nanopatterning

A Skyrmion crystal typically arises from helical spin structures induced by the Dzyaloshinskii-Moriya interaction. Experimentally its physical exploration has been impeded because it is a rarity and is found only within a narrow temperature and magnetic field range. We present a method for the assembly of a two-dimensional Skyrmion crystal based upon a combination of a perpendicularly magnetized film and nanopatterned arrays of magnetic vortices that are geometrically confined within nanodisks. The practical feasibility of the method is validated by micromagnetic simulations and computed Skyrmion number per unit cell. We also quantify a wide range in temperature and field strength over which the Skyrmion crystal can be stabilized without the need for any intrinsic Dzyaloshinskii-Moriya interactions, which otherwise is needed to underpin the arrangement as is the case in the very few known Skyrmion crystal cases. Thus, our suggested scheme involves a qualitative breakthrough that comes with a substantial quantitative advance.

Pt magnetic polarization on Y3Fe5O12 and magnetotransport characteristics

Thin Pt films on an yttrium iron garnet (YIG = Y(3)Fe(5)O(12)) show ferromagneticlike transport properties, which may impact the functionality of Pt in spin current detection, but do not provide direct quantitative information on the Pt magnetization. We report magnetic x-ray magnetic circular dichroism measurements of YIG/Pt(1.5 nm) showing an average Pt moment of 0.054 μ(B) at 300 K and 0.076 μ(B) at 20 K. This observation indicates strong proximity effects and induced magnetic ordering in Pt on magnetic insulators and their contribution to the spin-related measurements should not be neglected. The transport characteristics also suggest considerable modifications in the Pt electronic structure due to magnetic ordering.

Biodegradable and redox-responsive chitosan/poly(L-aspartic acid) submicron capsules for transmucosal delivery of proteins and peptides

The development of peptides and proteins is hampered by their rapid clearance in liver and other body tissues by proteolytic enzymes, so these drugs are difficult to administer except for the injection. Here, we designed and fabricated a novel biodegradable and redox-responsive submicron capsules through the layer-by-layer technique with poly(L-aspartic acid) and chitosan for transmucosal delivery of proteins and peptides. TEM graphs reveal that the intact submicron capsules were obtained and the shell of submicron capsules was about 40 nm. The mucoadhesion test indicates that the adsorption amount of the mucin could achieve up to 96.2 μg per 2 mg. The cell viability test shows that all types of submicron capsules had good cytocompatibility and the cell viability was above 90 %. As a drug model, the insulin could be loaded in the submicron capsules, and the loading efficiency was about 5 %. The release amount of insulin could be regulated by the levels of GSH. Therefore, the mucoadhesive submicron capsules as vehicles have a potential for the mucosal delivery (e.g. nasal and buccal) of therapeutic peptide and protein drugs.

Secondary degeneration detected by combining voxel-based morphometry and tract-based spatial statistics in subcortical strokes with different outcomes in hand function

BACKGROUND AND PURPOSE

Secondary degeneration of the pyramidal tract after focal motor pathway stroke has been observed by diffusion tensor imaging. However, the relationships between outcomes in hand function and secondary degeneration in widespread regions are not well understood. For the first time, we investigated the differences of secondary degeneration across the whole brain between subgroups of patients with stroke.

MATERIALS AND METHODS

We selected 23 patients who had a subcortical stroke in the left motor pathway and displayed only motor deficits. The patients were divided into 2 subgroups: CPH (11 patients) and PPH (12 patients). Twelve healthy controls matched for age and handedness were also recruited. We used both optimized VBM and TBSS to explore differences of FA across the whole brain between CPH and PPH. Furthermore, ROI analysis was carried out in the identified regions detected by VBM analysis to further quantify the degree of secondary degeneration in the CPH and PPH and compare these with healthy controls.

RESULTS

Compared with PPH, FA was significantly decreased in the CPH in widespread regions of the motor system remote from the primary lesion, including the ipsilesional brain stem, medial frontal gyrus, precentral gyrus, superior temporal gyrus, supplementary motor area, and contralesional postcentral gyrus. In addition, FA within these identified regions correlated with Fugl-Meyer Assessment scores (hand+wrist).

CONCLUSIONS

This study suggests a potential biomarker for outcome differences in hand function after subcortical stroke.

The characteristics of Th1/Th2 cytokine receptors on monocytes in untreated patients of long term nonprogressor or chronic HIV infection

Monocytes/macrophages play crucial roles in immunity to microorganisms and are one of the important targets for human immunodeficiency virus (HIV) infection. The phenotypes and function of monocytes in HIV-infected patients were poorly determined. We herein detected the expression of Th1/Th2 cytokine receptors on monocyte subsets in the untreated HIV-infected patients of either long term nonprogressor (LTNP) or chronic infection (CHI). CD14(+)CD16(-) monocytes were significantly increased and CD14(+)CD16(+) monocytes were reduced in patients of LTNP or CHI compared with healthy control. IL-6R expression on CD14(+)CD16(-) monocytes were decreased in patients of LTNP or CHI, whereas IL-4R and IL-10R expression on both CD14(+)CD16(-) and CD14(+)CD16(+) monocyte subsets were increased in patients with LTNP or CHI, as determined by flow cytometry and real time PCR assays. The decreased IL-6R expression and enhanced IL-4R and IL-10R expression were also observed on CD4(+) T cells of these patients, indicating that these changes in monocytes are not cell-specific. CD14(+)CD16(-) monocytes of HIV-infected patients produced less TNF-α and IL-1β but identical levels of IL-6, and IL-12 as the control after IFN-γ/LPS stimulation. However, in the presence of IL-4 or IL10, CD14(+)CD16(-) monocytes of HIV-infected patients produced more TNF-α, IL-6, IL-12 or Il-1β after IFN-γ/LPS stimulation than the healthy control, supporting the impaired IL-4R and IL-10R signal pathways in patients with LTNP and CHI. Therefore, our present study offered the basic information for the Th1/Th2 cytokine receptor expression and function on monocyte subsets in untreated HIV-infected individuals.

Down-regulation of TCF21 is associated with poor survival in clear cell renal cell carcinoma

Transcription factor 21 (TCF21) has been identified as a candidate tumor suppressor at 6q23-q24 that is epigenetically inactivated in many types of human cancers. We recently found that TCF21 methylation level was significantly increased in clear cell renal cell carcinoma (ccRCC). The purpose of this study was to investigate the prognostic impact of TCF21 expression in ccRCC and analyze the relationship between TCF21 expression and methylation level. We used real-time PCR and immunohistochemical staining to detect the expression of TCF21, and used methylation specific-PCR (MS-PCR) to determine the methylation status of TCF21 in ccRCC samples and cell line 786-O. The results showed that TCF21 expression level in ccRCC samples was significantly lower than in normal adjacent tissue samples (NAT samples). The Kaplan-Meier survival analysis demonstrated that TCF21 was a significant prognosticator of cancer-specific survival (p=0.001). Furthermore, the DNA demethylating agent 5'-azacytidine restored part of TCF21 expression by suppressing TCF21 methylation in 786-O. The methylation level of TCF21 in ccRCC samples was much higher than in NAT samples. These results suggest that the expression of TCF21 was an independent prognostic factor for poor survival in patients with ccRCC. Aberrant methylation was an important reason for the down-regulation the expression of TCF21, and may be associated with tumorigenesis in ccRCC.

Protective effect of the nitric oxide pathway in L-citrulline renal ischaemia-reperfusion injury in rats

To observe the protective effects of L-citrulline on the renal I/R injury and elucidate the mechanisms involved, 48 rats were randomized into eight groups: Group 1: sham operated; Group 2: I/R (45 min renal ischaemia and 24 h reperfusion); Group 3: I/R + L-citrulline (300 mg/kg, i.g.); Group 4: I/R + L-citrulline (600 mg/kg, i.g.); Group 5: I/R + L-citrulline (900 mg/kg, i.g.); Group 6: I/R + normal saline (NS, i.g.); Group 7: I/R + N sup ω nitro-L-arginine ester (L-NAME, 20 mg/kg, i.p.); Group 8: I/R + L-citrulline (900 mg/kg, i.g.) + L-NAME (20 mg/ kg, i.p.). At the end of the reperfusion period, serum was collected and the kidneys underwent histological and biochemical examinations. Our results showed that pre-treatment with L-citrulline (300, 600, and 900 mg/kg) significantly ameliorated the renal injury caused by I/R. Moreover, L-citrulline prevented induction of lipid peroxidation and increased the activity of superoxide dismutase and the levels of glutathione and nitric oxide. The I/R-induced decreases in total nitric oxide synthase activity, inducible nitric oxide activity, constitutive nitric oxide activity and endothelial nitric oxide protein expression in the renal cortex were significantly prevented. However, the L-citrulline-mediated protection was significantly antagonized by co-administration of L-NAME. These results suggested that L-citrulline administration exhibited significant protection against renal I/R injury. This protective effect, at least in part, via up-regulation of the endothelial nitric oxide protein expression and constitutive nitric oxide synthase activity, maintained production of nitric oxide at the basal level.

Potential metabolite markers of schizophrenia

Schizophrenia is a severe mental disorder that affects 0.5-1% of the population worldwide. Current diagnostic methods are based on psychiatric interviews, which are subjective in nature. The lack of disease biomarkers to support objective laboratory tests has been a long-standing bottleneck in the clinical diagnosis and evaluation of schizophrenia. Here we report a global metabolic profiling study involving 112 schizophrenic patients and 110 healthy subjects, who were divided into a training set and a test set, designed to identify metabolite markers. A panel of serum markers consisting of glycerate, eicosenoic acid, β-hydroxybutyrate, pyruvate and cystine was identified as an effective diagnostic tool, achieving an area under the receiver operating characteristic curve (AUC) of 0.945 in the training samples (62 patients and 62 controls) and 0.895 in the test samples (50 patients and 48 controls). Furthermore, a composite panel by the addition of urine β-hydroxybutyrate to the serum panel achieved a more satisfactory accuracy, which reached an AUC of 1 in both the training set and the test set. Multiple fatty acids and ketone bodies were found significantly (P<0.01) elevated in both the serum and urine of patients, suggesting an upregulated fatty acid catabolism, presumably resulting from an insufficiency of glucose supply in the brains of schizophrenia patients.

Abstract P5-01-16: Value of ultrasonography appearance of breast mass in prediction of histologic type

Objective to determine the relationship of sonographic features to the histological typing and grading of breast mass.

Methods: 292 breast masses were prospectively evaluated with ultrasonography. Sonographic features included irregular shape, microlobulation, spiculated margin, halo, posterior attenuation, microcalcification, ductal distortion. Lesion morphology was analyzed and correlated with histopathologic results, which included tumor typing and grading. Then we make a retrospective analysis and evaluation of patients scanned completely by qualitative and semi-quantitative methods. All patients have signed the informed consent form before the test, together with the recognition of the Ethics Committee.

Resuls: Among these masses, there are breast cancer accounted for 45.89% (134/292), A rounded or lobular mass was strongly associated with ductal carcinoma in situ(DCIS), poorly differential invasive ductal carcinoma(IDC), or some of the specific invasive cancer. Mastitis accounted for 8.22% (24/292), fibroadenoma accounted for 43.84% (128/292), and phyllodes tumor accounted for 2.05% (6/292). In 134 breast cancer cases, 92.70% (127/134)have obviously sonographic features with justled growth was found around the turmor with lamellar necrosis in different extents and lympholeukocytic infiltration, microlobulation, speculated margin, halo, posterior attenuation, microcalcification, ductal distortion, with justled growth was found around the turmor, neoplastic cell array showed as massive nest, patchy and satin ribbon structure, and the membrane of tumor cells was unsharpness with less cytoplasma, round or oval nucleus, great heteromorphism, higher karyoplasmic ratio and common nuclear mitotic figures. Other 7 cases with fibrous tissue hyperplasia under microscope show a regular shape. In fibroadenoma, phyllodes tumor and mastitis team, they shows unobviously sonographic features and the cell morphology contrast with breast cancer are quite different.

Conclusions:Ultrasonography appearance of breast masses is related to pathologic characteristics and can be a predictor of histopathologic pattern preoperatively.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-01-16.

Abstract P5-03-06: Bisphenol A and mammary stem cells: implications in breast cancer susceptibility

It has been speculated that the increasing incidence of breast cancer might be linked to the increased exposure to environmental synthetic estrogens, such as bisphenol A (BPA), which is a most pervasive chemical in modern life as a component of polycarbonate plastics and epoxy resins used widely for food and beverage containers and dental sealants. Perinatal exposure to low, environmentally relevant doses of BPA in rodents resulted in the induction of pre-neoplastic ductal hyperplasia, carcinoma in situ, and increased susceptibility to tumorigenesis. However, the underlying mechanism for these observations is unclear. The murine mammary stem cells (MaSCs) are present in fetal mammary rudiments and could be the putative targets for BPA-induced tumorigenesis. More recently, MaSCs of different lineages have been matched with different subtypes of breast cancer by their specific gene-expression signatures. We thus hypothesize that mammary gland exposed to BPA at a susceptible window may lead to its susceptibility to tumorigenesis through a MaSC and/or stem cell niche mediated mechanism. To test this hypothesis, we exposed 21-day old Balb/C mice to BPA by gavage at 25 µg/kg/day during puberty for 3 weeks, and then isolated primary mammary cells at different time points (6-week, 2 and 4-month) for MaSC quantification using an in vitro mammosphere formation and 3D-ECM sphere differentiation assay as well as the in vivo cleared mammary fat pad regeneration assay. Our findings indicate that low dose BPA exposure at puberty can accelerate puberty onset, increase lateral branches and hyperplasia in adult mammary glands. Further, a single oral dose of DMBA at 30 mg/kg administrated at 2-month old resulted in a 2.4-fold increase in hyperplasia of mammary glands harvested at 4-month old when compared with BPA treated group without DMBA. Most significantly, puberty BPA exposure increased luminal MaSCs during gland development and this resulted in an increase of luminal cells in adult glands. In addition, puberty BPA exposure also altered basal MaSCs in such a way that regenerated glands from these basal MaSCs yielded higher preneoplastic lesion than control basal MaSCs, indicating puberty BPA exposure render basal MaSCs more susceptible to transformation. We also found significant increase of gene expression in steroid hormonal receptors (e.g. ERs and PR) in the stromal compartment (or stem cell niche), which suggest that the changes we observed above for the luminal and basal MaSCs may be caused indirectly through altered stromal environment upon BPA exposure during early life stage. Future studies are necessary to differentiate the effect of BPA exposure on MaSCs or the MaSC niche. In conclusion, our study showed that BPA-induced morphogenesis changes in mammary gland had a stem cell origin. More importantly, our findings suggest that BPA-induced susceptibility of mammary glands to tumorigenesis may also have a stem cell origin.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-03-06.

Abstract P5-04-04: Significance of PELP1/HDAC2/microRNA-200 regulatory network in EMT and metastasis of breast cancer

Tumor metastasis remains a significant clinical problem and is the leading cause of death among breast cancer patients. Estrogen receptor (ER)-coregulators play an essential role in cancer progression and metastatic tumors express increased levels of coregulators. Proline glutamic acid rich protein (PELP1) is an ER coregulator, its expression is upregulated during breast cancer progression to metastasis and is an independent prognostic predictor of shorter survival of breast cancer patients. MicroRNA (miR) mediated regulation of tumorigenesis is emerging as a new paradigm in cancer biology and widespread misexpression of miRs has been reported in breast cancer. The objective of this study is to examine the mechanism and therapeutic significance of PELP1 regulation of miRs leading to breast cancer metastasis. We have used both ER+ve (ZR75, MCF7) and ER-ve (MDAMB231, MDAMB468) models that either stably overexpress PELP1 or PELP1shRNA. Boyden chamber, and invasion assays demonstrated that PELP1 down regulation significantly affect migration of both ER+ve and ER-ve cells. Epithelial to Mesenchymal Transition (EMT) real time qPCR Array studies identified PELP1 modulate expression of EMT genes Snail, Twist, ZEB1, ZEB2, Vimentin and MMPs. Importantly, whole genome microRNA array analysis using PELP1 model cells revealed that miR200a and miR141 were significantly upregulated in cells expressing PELP1-shRNA compared to control cells. Accordingly, over expression of PELP1 in low metastatic model cells decreased expression of miR200a and miR141. PELP1 regulation of miRs was further confirmed by ZEB1 and ZEB2 3′ UTR luciferase reporter assays. ChIP analysis revealed recruitment of PELP1 to the proximal promoter region of miR-200a and miR141 and promoter reporter assays further confirmed PELP1 regulation of miRs. Interestingly, PELP1 down regulated expression of miR200a and miR141 by promoting repressive chromatin modifications via HDAC2. Supporting this, HDAC inhibitors reversed PELP1 driven repressive effects. Further, ectopic expression of miR200a and miR141 mimetic decreased PELP1 mediated invasion/metastatic functions. Prognostic significance of PELP1-miRNA axis was determined using Tissue micro-array (TMA) and in situ hybridization (ISH assays) of Locked Nucleic Acid (LNA™)-based microarray approach in 102 human breast tumors. To test therapeutic potential in vivo, we have generated ZR-PELP1- and MCF7-PELP1-shMIMIC of miR200a and miR141 stable cells. In vitro gene expression and Boyden chamber assays using these model cells revealed that shMIMIC of miR200a and miR141 reversed PELP1 mediated alterations in gene expression and reduced PELP1 driven migration/invasion. Proof of principle studies using IVIS imaging of nude mice based assays of GFP-Luc labeled cells demonstrated therapeutic efficacy of miRIDIAN shMIMIC of miR200a and miR141 on PELP1 driven in vivo metastasis. Collectively, these novel findings demonstrate for the first time a previously unknown role for PELP1 in epigenetically controlling the functions of tumor metastasis suppressor miR-200a and miR141. These results suggest that PELP1-miR axis may be crucial stimulus for promoting EMT and breast cancer metastasis. This study is funded by NIH T32CA148724 Postdoc Fellowship Grant.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-04-04.

Abstract P4-03-12: diagnostic value and clinical significance of integrin αvβ3 in breast mass

Background: Integrins are cell adhesion molecules that widely exists in cell surface, it is a hetero-dimeric protein bound non-covalently by α, β subunit. It plays the role of mediation during interaction of the αvβ3 and the corresponding receptor in signal transduction pathway, integrin αvβ3 is much richer in the surface of neovascular endothelial cells and tumor cells, while poor in the blood vessels and normal tissues. Therefore, it plays an important role in a variety of malignant tumors of the occurrence, development and metastasis processes. We find tumors constituted with neovascularization earlier by marker of integrin αvβ3.

Materials & Methods: We give patients who consider as breast mass intravenous injection of99mTc-3PRGD2 as a tracer preoperatively by SPECT/CT imaging and treat with surgery within a week, then make pathological examination with tumor tissues removed by needle biopsy. Then we make a retrospective analysis and evaluation of patients scanned completely by qualitative and semi-quantitative methods. All patients have signed the informed consent form before the test, together with the recognition of the Ethics Committee.

Results: From December 2011 to May 2012, a total of 245 patients were scanned and operated with clear paraffin pathological diagnosis by intravenous injection of99mTc −3PRGD2. Among them, a total of 106 patients (167 developing lesions) were positive with radionuclide imaging results, 139 patients were negative. Diseases of 106 patients are divided into four series: breast cancer, inflammation mastitis, phyllodes tumor and partly with fibroadenoma. They have in common that there is a clear flow signal in and around lesions by color Doppler ultrasound.

Discussion: After study on 245 patients, we created a molecular imaging tool to show expression of integration αvβ3 in order to assess tumor angiogenesis. Integrin αvβ3 plays an important role in physiological and pathological processes of malignant tumor, such as inflammation, tumor angiogenesis, invasion and metastasis etc. Therefore, its high expression is easy to find in cancer, mastitis, most of the phyllodes tumor and part of fiber adenoma with peripheral lesions. For patients with clear imaging, we make comprehensive analysis based on their ultrasound, mammography, MRI or CT results, which can generally contributes to the early diagnosis of disease in clinical. The detection of sentinel lymph node should be avoided for the patients with axillary lymph node imaging, who are clearly diagnosed as breast carcinoma with axillary lymph node metastases. These peptides are not only tumor receptor-targeted imaging agents with potential clinical value, but also laid a solid foundation for further development of receptor-targeted radionuclide therapy to solid tumors. The method marked with high expression of integrin αvβ3 in the tumor vascular endothelial cells by99mTc-3PRGD2 and SPECT/CT imaging mode has a broad prospect in the early diagnosis of tumor, lesion detection and efficacy evaluation. In the future, we may also find the new imaging agent with more accuracy and specificity. We believe that there will be more and more breast cancer patients benefit from the technology development of ECT/CT examination.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-03-12.

Abstract P5-03-04: Effect of aging on the function and transformation of murine mammary stem cells

Epidemiological studies have shown that the risk of getting breast cancer progressively increases with age. A woman is 100 times more susceptible to develop breast cancer in her 60s than in her 20s. A better understanding of altered cellular and molecular mechanisms leading to the development of sporadic breast cancers as a result of aging are urgently needed for its prevention and treatment in growing population of older women. Recent research implicated that adult mammary stem cells (MaSCs) might be responsible for the initiation and progression of certain types of breast cancer. But no studies have been reported on how lifelong exposure of MaSCs to endogenous and environmental stresses during aging compromises their self-renewal and differentiation function and predispose them to neoplastic transformation either spontaneously or after carcinogen exposure. In our study, we have investigated the effect of progressive aging and carcinogen exposure on MaSC number and function in a murine model. The FACS isolated MaSC enriched basal cells, characterized by their immunophenotype (Lin−CD49fhighCD24med) were utilized to evaluate MaSC frequency and function during aging by in vitro mammosphere formation and 3D-ECM sphere differentiation assay as well as by in vivo cleared mammary fat pad transplantation (IVT). The results of our study showed that the percentage of MaSCs analyzed by both FACS profile and in vitro assays, increased steadily with increasing age observed at 2, 7, 17 and 25 month-old C57BL/6 mice. Subsequent IVT using mammosphers or 3D structures formed by young (4 months) and old MaSCs (28 months) derived from C57BL/6 mice showed similar in vivo functional mammary gland regenerative capacity indicating similar self-renewal/differentiation ability between young and old MaSCs. However, we found that the regenerated glands from old MaSCs had significantly higher number of spontaneous pre-neoplastic lesions (52.0%) than those from young MaSCs (18.3%). Significantly, MaSC frequency was also increased by the in vivo exposure of a carcinogen, N-Methyl-N-Nitrosourea (MNU, 25 mg/kg body weight, once a week for three consecutive weeks), in old mice with no effect on total mammary cell number. Furthermore, the old MaSCs expanded by MNU treatment were still capable of in vivo regeneration with similar success rate as that of normal old MaSCs. But, we observed increased frequency of hyperplasia and dysplasia in the regenerated glands initiated by MNU treated old MaSC. Our results indicate that MaSCs might be the precursors of preneoplastic lesions and old MaSCs appear to be predisposed to premalignant transformation, which is enhanced by the exposure to a DNA damaging agent.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-03-04.

Abstract P2-04-07: Modeling orthotopic and metastatic progression of mammary tumors to evaluate the efficacy of TGF-β inhibitors in a pre-clinical setting

Preclinical models are elemental in understanding drug efficacy and safety in vivo. Many existing models of breast cancer metastasis use immune compromised animals and do not effectively characterize the differential stages of metastasis. Transforming growth factor-β (TGF-β) has been shown to be a major contributor in epithelial-mesenchymal transition and enhances various steps during metastasis.

The aim of this study is to develop mouse models of tumor metastasis using murine mammary cells in a syngeneic background. This will help illustrate the effect of TGF-β inhibitors on metastasis in an immune competent environment, and also allow determining the optimal time of drug administration. We demonstrate that TGF-β signaling has differential effects on a pair of murine mammary cell lines derived from PyMT tumors in C57Bl/6 mice. These cell lines represent luminal (Py 230) and basal (Py 8119) epithelial cell populations in the tumor. In vitro characterization revealed differences in viability, motility, and transcriptional and translational activation of Smad. Py 230 (clonal luminal) cells are growth inhibited and exhibit epithelial-mesenchymal transition on treatment with TGF-β, whereas Py 8119 (basal cells) are non-responsive to both effects. Furthermore, intra cardiac injections were performed using luciferase-GFP labeled PyMT cells in syngeneic background and animals were treated with either placebo or TβRI-KI (kinase inhibitor for TGF-β receptor I). Results from Py 8119 cell injections showed that TβRI-KI treatment enhanced bone and brain metastases. Further results will shed light on the effect of TβRI-KI during specific stages of metastasis progression.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P2-04-07.

Abstract P1-05-18: Determining the molecular mechanism of the breast cancer-induced brain metastasis and a role of a novel pan-TGF-β inhibitor as a potential therapy for brain metastasis in a mouse xenograft model

Breast cancer (BCa) is the most common malignant disease in women in the U.S. Nearly 20% of patients with advanced BCa are eventually diagnosed with brain lesions, which is a devastating complication in patients with BCa over-expressing EGF receptor family members including Her2 positive and triple negative breast cancer. It is the most feared complication of BCa in part because are not capable of significantly treating the BCa-induced brain metastases due to the inability of the available treatment regimens to effectively penetrate the blood brain barrier (BBB) and also due to our limited knowledge on cellular and molecular mechanisms that drive the homing to and growth in the brain of BCa cells. Therefore, there is a need of efficient model system that can significantly contribute towards our understanding of different factors from both host and tumor leading to brain metastasis. We have recently isolated a novel BCa cell line B6TC that was generated through fusion between human BCa, MDA-MB-231 and ZR-75-1 cells in mouse bone marrow. This B6TC cell line showed higher propensity to metastasize to brain than its parental cells when inoculated through intracardiac injection in female athymic nude mice. In order to generate a highly brain metastatic breast cancer model for mechanistic research, we subjected the B6TC cells through four rounds of selection for cells that were capable of trans-endothelial cell invasion to obtain cells that could invade through BBB. This in vitro selected cell line was further subjected through three rounds of in vivo selection for cells that were capable of metastasizing to the brain and the cells after third round selection was named N3LR, which has the highest potential to cause brain metastasis. In searching for genes and pathways that may contribute to the increased brain metastasis of N3-LR cell with microarray analysis, we found that the transforming growth factor-beta (TGFβ) signaling pathway is upregulated in N3-LR cell in comparison with B6TC cell, in addition to the EGF and prostaglandin signaling pathways that have been reported to be associated with brain metastatic breast cancer cells. Functional comparison also showed that N3-LR cell was more migratory than B6TC cell and more responsive to TGFβ-induced phosphorylation of Smad3 as well as migration, suggesting that TGFβ signaling may contribute to the increased brain metastatic potential. We next investigated whether metastatic tumor growth in the brain microenvironment can be inhibited by systemic administration of a potent pan-TGFβ inhibitor, BGERII- a recombinant fusion protein containing the endoglin domain of betaglycan (BGE) and the extracellular domain of RII. The animals were inoculated intracardically with N3LR, the most potent subline of highly metastatic B6TC cells, and were then treated with vehicle or BGERII systemically via i.p. injection right after the inoculation. After three weeks, the BGERII treated group showed lower brain metastasis incidence and tumor burden as detected by whole mouse bioluminescence and GFP imaging. Further analyses to understand the underlying molecular and regulatory mechanism of brain metastasis and its intervention in our mouse model is underway for the discovery of novel molecularly targeted drugs to prevent and eradicate BCa metastasis initiation, progression and recurrence.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-05-18.