E-cadherin Receptor Research Articles

Relation between the expression of E-cadherin, p53,c-erb-B2 (HER-2/neu) and steroid receptors (ER, PgR) in invasive ductal breast carcinoma with axillary lymph node metastases

Objective : This study explores the correlation between the expression of E-cadherin, p53 tumor suppressor gene, c-erb-B2 (HER-2/neu) and steroid receptors (ER, PgR) in invasive ductal breast carcinoma with axillary lymph node metastases. Patients and Methods : We have investigated tumor samples from sixty patients with invasive ductal breast carcinoma. 30 of the patients had axillary lymph node metastases and 30 had no axillary lymph node metastases. Tumor tissues of these patients were evaluated by immunohistochemistry for E-cadherin, p53, c-erb-B2 (HER-2/neu) and steroid receptors (ER, PgR). Results : E-cadherin staining was not expressed in 39 patients (65%) with invasive ductal breast carcinoma. ER, PgR, p53, and c-erb-B2 signals were positive in 36 (60%), 26 (43.3%), 33 (55%), and 29 (48.3%) of the patients, respectively. PgR and c-erb-B2 expression was associated with lymph node metastases (p=0.009, p=0.001, respectively). No association was found between the reduced E-cadherin protein and age. The presence of E-cadherin was associated with axillary lymph node metastases and p53 (p<0.009, p<0.001, respectively). Conclusion : We found that, the p53 protein may play a role in regulation of E-cadherin protein expression in invasive ductal breast carcinomas with axillary lymph node metastases. Keywords : Breast carcinoma, E-cadherin, p53, c-erb-B2, ER, PgR, Metastases

Are bilateral breast cancers and breast cancers coexisting with ovarian cancer different from solitary tumors? A pair-matched immunohistochemical analysis aimed at intrinsic tumor phenotype.

Patients with bilateral breast cancer (BBC) and breast-ovarian cancer syndrome (BOCS) constitute populations potentially enriched for molecular defects involved in the pathomechanisms of these malignancies. The aim of our study was to compare tumor morphology and expression of estrogen and progesterone receptor, HER2, Ki67, cytokeratin 5/6, E-cadherin, vimentin and epidermal growth factor receptor in tissue microarrays from 199 tumors from BBC or BOCS patients and 199 age-matched solitary tumors. Compared to controls, BBC and BOCS considered jointly had lower incidence of DCIS, lower expression of PgR and HER2, and higher expression of Ki67 and vimentin. BOCS tumors were of higher grade, had lower expression of ER and PgR and higher expression of Ki67, CK5/6, vimentin and EGFR. BBC had less DCIS component, lower HER2 expression and higher Ki67 expression. Metachronous BBC (mBBC) had lower expression of ER, PgR and HER2, and higher expression of Ki67 and vimentin. Synchronous BBC (sBBC) had less DCIS component, higher expression of ER, and lower expression of CK5/6, EGFR and E-cadherin. BBC and breast cancers in BOCS differ in many aspects from solitary tumors. BBC are a heterogeneous group of tumors, differing between sBBC and mBBC. mBBC phenotype shares many features with BOCS tumors.

Activin A balance regulates epithelial invasiveness and tumorigenesis

Activin A (Act A) is a member of the TGFβ superfamily. Act A and TGFβ have multiple common downstream targets and have been described to merge in their intracellular signaling cascades and function. We have previously demonstrated that coordinated loss of E-cadherin and TGFβ receptor II (TβRII) results in epithelial cell invasion. When grown in three-dimensional organotypic reconstruct cultures, esophageal keratinocytes expressing dominant-negative mutants of E-cadherin and TβRII showed activated Smad2 in the absence of functional TβRII. However, we could show that increased levels of Act A secretion was able to induce Smad2 phosphorylation. Growth factor secretion can activate autocrine and paracrine signaling, which affects crosstalk between the epithelial compartment and the surrounding microenvironment. We show that treatment with the Act A antagonist Follistatin or with a neutralizing Act A antibody can increase cell invasion in organotypic cultures in a fibroblast- and MMP-dependent manner. Similarly, suppression of Act A with shRNA increases cell invasion and tumorigenesis in vivo. Therefore, we conclude that maintaining a delicate balance of Act A expression is critical for homeostasis in the esophageal microenvironment.

Utility of Oncotype DX risk assessment in patients with invasive lobular carcinoma (ILC).

28 Background: Oncotype DX (Genomic Health, Redwood City, CA) is a breast cancer assay that uses reverse transcriptase polymerase chain reaction (RT-PCR) to measure gene expression in paraffin-embedded tumor tissue, which correlates with recurrence risk. This test is used to guide chemotherapy decisions in patients with estrogen receptor-positive breast cancer. Invasive lobular carcinoma (ILC) is a distinct histologic subtype, inherently estrogen receptor rich, that has not been the unique focus of prior studies validating Oncotype DX. The study purpose was to determine if there are certain features of ILC that predict uniformly low Oncotype DX Recurrence Scores (RS) such that Oncotype DX testing may be unnecessary, saving patients time and financial resources. Methods: A search was conducted of all ILC cases having Oncotype DX testing in our hospital pathology database. The Oncotype DX RS, histologic tumor characteristics (including subtype and grade), immunohistochemical (IHC) analyses of estrogen receptor (ER)/progesterone receptor (PR) percent (by image analysis), E-cadherin expression, and Ki-67 levels were obtained for each case. Discriminant analysis was used to test the hypothesis that tumors classified as low or high risk based on the Oncotype DX RS would differ significantly on a linear combination of selected variables. Results: From 2006 to 2013, 158 cases of ILC having Oncotype DX testing were identified; 90 low risk (RS &lt;18), 66 intermediate risk (RS 18 – 30) and 2 high risk (RS &gt; 30). Discriminant analysis showed that PR% followed by Ki-67 provided the greatest contribution to discriminating between low versus high RS. A subset of 57 cases (~ 36%) with predicted probabilities &gt; 86% for either low or high RS yielded 96.5% correct classification, 92.3% sensitivity, and 97.7% specificity. Conclusions: Our analytical model may be useful in predicting high versus low recurrence risk in some patients with ILC. If validated, this provides a faster and less expensive alternative to Oncotype DX testing in certain patients with ILC.

Neuroendocrine differentiation in breast carcinoma with osteoclast-like giant cells. Report of a case and review of the literature

Osteoclast-like giant cells (OGCs) may occur in several types of breast carcinomas (BS). Neuroendocrine differentiation may be present in BS but, associated with OGCs, neuroendocrine differentiation has been rarely reported. A case of invasive ductal carcinoma with OGCs and neuroendocrine differentiation diagnosed by fine needle cytology (FNC) is described. A 72-year-old woman with a nodular lesion of the right breast underwent to fine-needle cytology (FNC) The smears showed a dissociated cell population of monomorphous, mononucleated atypical cells with interspersed multinucleated giant cells osteoclast-like. The mononuclear cell component showed plasmacytoid features and frequent vacuoles of secretion. Immunostaining (IHC) performed on cell block sections showed oestrogen receptor positivity in the mononucleated cells and OGCs positivity for LCA and CD68. Histologically the tumour showed cell nests or cords separated by thin fibrovascular septa. The neoplastic cells were monomorphic, with round-oval nuclei, granular chromatin and evident nucleoli. The cytoplasm was indistinct and eosinophilic, finely granular, often containing eosinophilic globules that were positive at the PAS and mucicarmine stainings. Numerous non-neoplastic OGCs were also detected in the interstitial septa. The ICH showed positivity of the tumoral cells for E-Cadherin, oestrogen and progesterone receptors and c-ErbB2 negativity. Mitotic index was inconspicuous with a low Ki67 positivity rate (<10%). OCGs were CD68 and LCA positive. IHC also showed strong positivity for the chromogranin and synaptophysin. A diagnosis of invasive ductal BC with OGCs and neuroendocrine differentiation was performed. The expression of chromogranin and synaptophysin was then retrospectively assessed on CB sections too. The identification of OGCs component on breast FNA samples is not difficult, depending on a good sampling only. On contrary, the neuroendocrine differentiation still represents still a challenge in breast FNC.

Loss of expression and aberrant methylation of the CDH1 (E-cadherin) gene in breast cancer patients from Kashmir.

Aberrant promoter hypermethylation has been recognized in human breast carcinogenesis as a frequent molecular alteration associated with the loss of expression of a number of key regulatory genes and may serve as a biomarker. The E-cadherin gene (CDH1), mapping at chromosome 16q22, is an intercellular adhesion molecule in epithelial cells, which plays an important role in establishing and maintaining intercellular connections. The aim of our study was to assess the methylation pattern of CDH1 and to correlate it with the expression of E-cadherin, clinicopathological parameters and hormone receptor status in breast cancer patients of Kashmir. Methylation specific PCR (MSP) was used to determine the methylation status of CDH1 in 128 invasive ductal carcinomas (IDCs) paired with the corresponding normal tissue samples. Immunohistochemistry was used to study the expression of E-cadherin, ER and PR. CDH1 hypermethylation was detected in 57.8% of cases and 14.8% of normal adjacent controls. Reduced levels of E-cadherin protein were observed in 71.9% of our samples. Loss of E-cadherin expression was significantly associated with the CDH1 promoter region methylation (p<0.05, OR=3.48, CI: 1.55-7.79). Hypermethylation of CDH1 was significantly associated with age at diagnosis (p=0.030), tumor size (p=0.008), tumor grade (p=0.024) and rate of node positivity or metastasis (p=0.043). Our preliminary findings suggest that abnormal CDH1 methylation occurs in high frequencies in infiltrating breast cancers associated with a decrease in E-cadherin expression. We found significant differences in tumor-related CDH1 gene methylation patterns relevant to tumor grade, tumor size, nodal involvement and age at diagnosis of breast tumors, which could be extended in future to provide diagnostic and prognostic information.

Unusual Patterns of Endometrial Carcinoma Including MELF and its Relation to Epithelial Mesenchymal Transition

Although most of Dr Scully's research addressed diseases of the ovary, about 10% of his published manuscripts focused on endometrial lesions, most often consisting of observations about unusual types or deceptive patterns of endometrial carcinoma that had not previously been described, or lesions for which the behavior had been unknown. He characterized and clarified the entity of clear cell carcinoma of the endometrium, and wrote about endometrial carcinomas with argyrophil, oxyphil, and giant cells, and those simulating microglandular hyperplasia of the cervix, as well as uterine papillary serous, squamous cell, and small cell carcinoma,. He provided a useful classification of precancers of the endometrium and also emphasized the relationship between estrogens and the development of some forms of uterine carcinoma. This article addresses the importance of his careful observations, focusing primarily on the potential relationship of 1 pattern of endometrial carcinoma that he described which has areas of microcystic, elongated, fragmented glands (MELF), frequently accompanied by a fibromyxoid or inflammatory stroma, to the recently described concept of epithelial mesenchymal transition. Endometrioid carcinomas with MELF frequently display a variety of immunohistochemical changes including reduced expression of E-cadherin, B-catenin, estrogen and progesterone receptors, Ki67, and overexpression of fascin, galactin-3, cyclin D1, and p16, as might be expected with epithelial mesenchymal transition. Additional studies will be needed to explain the significance of epithelial mesenchymal transition that occurs in carcinomas with regions of MELF.

ID2 predicts poor prognosis in breast cancer, especially in triple-negative breast cancer, and inhibits E-cadherin expression.

BackgroundInhibitors of DNA-binding (ID) proteins are known as important modulators in the regulation of cell proliferation and differentiation. This study sought to investigate the prognostic value of ID proteins in breast cancer.MethodsThe prognostic role of ID proteins in human breast cancer was investigated in 250 breast cancers, via tissue microarrays. The messenger (m)RNA and protein levels of E-cadherin were examined by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blotting, in cells overexpressing IDs. Dual-luciferase report assay was used to investigate the potential mechanism, and a migration assay was performed to investigate the influence of IDs on cell migratory activity.ResultsThe survival analysis with Kaplan–Meier and Cox regression showed that ID2 expression level, which correlated with estrogen receptor status and E-cadherin abundance, served as an independent prognostic factor for disease-free survival (DFS) (P=0.013). The prognostic value of ID2 for DFS was most significant in triple-negative breast cancer patients (P=0.009). We also found that ID2 was negatively correlated with E-cadherin expression by correlation analysis (P=0.020, Pearson’s R=−0.155). Subsequently, we explored the biological rationale and uncovered that the enforced expression of ID proteins could suppress E-cadherin expression significantly, thus increasing the migration ability of mammary epithelial cells. Then using a combination of ID2 and E-cadherin expression, the patients were classified into four subgroups with different DFS (P=0.023).ConclusionThe overexpression of ID2 can be used as a prognostic marker in breast cancer patients, especially in triple-negative breast cancer patients. ID proteins were still, unexpectedly, revealed to inhibit E-cadherin abundance.

English

Prostate cancer (PC) is the most common malignant tumor in men. Early identification of prostate cancer may result in improved cure rates and increased life expectancies. Gleason score and clinical range at the time of diagnosis are important factors to predict prognosis and outcome after therapy but additional accurate and reliable biomarkers are warranted. Few biomarkers of prostate cancer have been successfully implemented and used in clinical practice. In this study, we sought to determine the expression of E-cadherin, beta-catenin and human epidermal receptor (HER2) in biopsy specimens of prostate cancer with perineural invasion, and correlate them with Gleason score in order to verify the relationship between those markers and prostate cancer process. Our study demonstrated abnormal expression of E-cadherin, beta-catenin and HER2. On the other hand, our results showed no correlation between Gleason score and the expression of those markers in invasive prostate cancer tissues. Other different biomarkers remain to be identified, that potentially could improve the evaluation of prognostic of the patient. Key words: Biomarkers, biopsy specimens, Gleason score, perineural invasion, prostate cancer.

Cystic Rete Ovarii and Uterine Tube Adenoma in a Rabbit

ABSTRACTA 6-year-old female rabbit was presented to a veterinary clinic, and the result of ultrasound examination suggested a tumor in the uterine tube. Subsequently, both ovaries and uterus were surgically removed. In gross, a single large cyst in the right ovary and enlargement of the left uterine tube were observed. Histological examination revealed that the cyst had developed in the hilus of the ovary and was lined by single-layered cuboidal cells. In the left uterine tube, a tumor composed of epithelial cells arranged in tubular structures and pleomorphic cells between the tubular structures was observed. Immunohistochemically, the epithelial cells of the cyst were positive for pan-cytokeratin, cytokeratin 18, CD10, E-cadherin, calretinin and estrogen receptor; the tumor cells of the left uterine tube were positive for pan-cytokeratin, cytokeratin 18, E-cadherin, vimentin, calretinin and estrogen receptor. From these results, the cyst was diagnosed as cystic rete ovarii, and the tumor was diagnosed as adenoma of the uterine tube. This case is the first to demonstrate cystic rete ovarii and uterine tube adenoma in rabbits.

Nephrogenic adenoma of the urinary tract: clinical, histological, and immunohistochemical characteristics

Nephrogenic adenoma is a benign condition of the urinary tract resulting from the displacement and seeding of renal tubular cells from the renal pelvis to the urethra. A retrospective series of 134 cases collected from four hospitals in three different countries was analyzed in this study. Recorded clinical data included age and sex, topography, urological antecedents, coexistent lesions, and follow-up. Cytonuclear and architectural features were reviewed, and PAX-8, p63, PSMA, S100A1, CEA, EMA, CD117, cannabinoid receptor CB1, AMACR, E-cadherin, and CD10 antibodies were included in an immunohistochemical panel. Males predominated (105 M/29 F) with an average age of 66 years (range, 14-96). Urothelial carcinoma was the most frequent clinical antecedent (43.2 %) and also the most common coexisting lesion (14 %). Tubular architecture was the most frequent pattern detected (40 %) although most cases showed a mixed pattern (45.5 %). Deep infiltrative growth into the muscularis propria occurred in two cases. EMA and PAX-8 were expressed in 100 % of nephrogenic adenomas, while E-cadherin reactivity was observed in 66.6 % of cases, cannabinoid receptor CB1 in 25 %, CD10 in 13.6 %, CD117 in 4.1 %, and AMACR in 2.7 %. For the rest of the antigens, no reactivity was found. The average time lapse between the pathological antecedent and the discovery of a nephrogenic adenoma was 32 months. We conclude that nephrogenic adenoma displays a broad spectrum of histological features that may mimic malignancy. In our experience, CB1 immunostaining adds a further argument in favor of a renal origin of this lesion. The combination of PAX-8+, p63-, and EMA + distinguishes nephrogenic adenoma from urothelial and prostate carcinoma, its most frequent malignant look-alikes.

Production of biofilm by Listeria monocytogenes in different materials and temperatures

Listeria monocytogenes, considered as one of the most important foodborne pathogens, is easily found on surfaces, particularly in the form of a biofilm. Biofilms are aggregates of cells that facilitate the persistence of these pathogens in food processing environments conferring resistance to the processes of cleaning and may cause contamination of food during processing, thus, representing a danger to public health. Little is known about the dynamics of the formation and regulation of biofilm production in L. monocytogenes, but several authors reported that the luxS gene may be a precursor in this process. In addition, the product of the inlA gene is responsible for facilitating the entry of the microorganism into epithelial cells that express the receptor E-cadherin, also participates in surface attachment. Thus, 32 strains of L. monocytogenes isolated from different foods (milk and vegetables) and from food processing environments were analyzed for the presence of these genes and their ability to form biofilms on three different surfaces often used in the food industry and retail (polystyrene, glass and stainless steel) at different temperatures (4, 20 and 30 °C). All strains had the ilnA gene and 25 out of 32 strains (78.1%) were positive for the presence of the luxS gene, but all strains produced biofilm in at least one of the temperatures and materials tested. This suggests that genes in addition to luxS may participate in this process, but were not the decisive factors for biofilm formation. The bacteria adhered better to hydrophilic surfaces (stainless steel and glass) than to hydrophobic ones (polystyrene), since at 20 °C for 24 h, 30 (93.8%) and 26 (81.3%) produced biofilm in stainless steel and glass, respectively, and just 2 (6.2%) in polystyrene. The incubation time seemed to be an important factor in the process of biofilm formation, mainly at 35 °C for 48 h, because the results showed a decrease from 30 (93.8%) to 20 (62.5%) and from 27 (84.4%) to 12 (37.5%), on stainless steel and glass, respectively, although this was not significant (p = 0.3847). We conclude that L. monocytogenes is capable of forming biofilm on different surfaces independent of temperature, but the surface composition may be important factor for a faster development of biofilm.

Murinization of Internalin Extends Its Receptor Repertoire, Altering Listeria monocytogenes Cell Tropism and Host Responses

Listeria monocytogenes (Lm) is an invasive foodborne pathogen that leads to severe central nervous system and maternal-fetal infections. Lm ability to actively cross the intestinal barrier is one of its key pathogenic properties. Lm crosses the intestinal epithelium upon the interaction of its surface protein internalin (InlA) with its host receptor E-cadherin (Ecad). InlA-Ecad interaction is species-specific, does not occur in wild-type mice, but does in transgenic mice expressing human Ecad and knock-in mice expressing humanized mouse Ecad. To study listeriosis in wild-type mice, InlA has been “murinized” to interact with mouse Ecad. Here, we demonstrate that, unexpectedly, murinized InlA (InlAm) mediates not only Ecad-dependent internalization, but also N-cadherin-dependent internalization. Consequently, InlAm-expressing Lm targets not only goblet cells expressing luminally-accessible Ecad, as does Lm in humanized mice, but also targets villous M cells, which express luminally-accessible N-cadherin. This aberrant Lm portal of entry results in enhanced innate immune responses and intestinal barrier damage, both of which are not observed in wild-type Lm-infected humanized mice. Murinization of InlA therefore not only extends the host range of Lm, but also broadens its receptor repertoire, providing Lm with artifactual pathogenic properties. These results challenge the relevance of using InlAm-expressing Lm to study human listeriosis and in vivo host responses to this human pathogen.

Abstract 335: A genetic mouse model of head-and-neck squamous cell carcinoma using targeted deletion of E-cadherin and TGFβ receptor II.

Abstract We previously observed that 70% of esophageal tumors demonstrated coordinated loss of E-cadherin and TGFβRII. When grown in three-dimensional organotypic reconstruct cultures, cells lacking E-cadherin and TGFβRII demonstrate fibroblast-dependent invasion into the underlying matrix. Therefore, we hypothesized that coordinated loss of CDH1 (E-cadherin) and TGFBR2 (TGFβRII) will induce tumorigenesis in vivo. We developed a mouse model targeting CDH1 and TGFBR2 loss in the oral-esophageal epithelium using the Epstein-Barr virus L2 promoter, ED-L2. For spatio-temporal control of CDH1- and TGFBR2 gene expression, we also generated an inducible mouse model using Cre-ERT(tam) under the control of the keratin 14 promoter. Few mouse models focusing on genetic alterations of oral and head-and-neck cancer exist. We show that the loss of E-cadherin and TGFβ receptor II without carcinogen treatment is sufficient to induce invasive HNSCC and forestomach tumors. Double knock-out animals succumb to the disease between 1 and 1.5 years of age and show invasive tumors in the oral cavity and tongue, as well as the forestomach. Advanced tumors metastasize to the lung. The tumors are characterized by Ki67-positive and p63-positive staining and show disruption of adherens junctions with loss of β-catenin and mislocalisation of p120 to the cytoplasm. Additional genetic modifications frequently described for HNSCC are the upregulation of c-myc and cyclin D1. We could show that the oral mouse tumors are positive for these markers allowing us to conclude that this animal model recapitulates HNSCC at the pathologic and molecular levels. Furthermore, the forestomach is an extension of the squamous epithelium of the esophagus in the mouse. Known genetic alterations causing esophageal squamous cancer are amplification of EGFR, cyclin D1 and mutations in p53 in addition to the loss of E-cadherin and TGFβRII. The analysis of the forestomach tumors recapitulates these events in the mouse model as a result of CDH1 and TGFBR2 loss. This tumor model will provide us with a unique tool for testing therapeutic approaches. Citation Format: Thomas Andl, Gregoire F. Le Bras, Nicole F. Richards, Gillian L. Allison, M. Kay Washington, R. Katie Lee, Claudia D. Andl. A genetic mouse model of head-and-neck squamous cell carcinoma using targeted deletion of E-cadherin and TGFβ receptor II. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 335. doi:10.1158/1538-7445.AM2013-335

Abstract 2247: Ganoderma lucidum (Reishi) downregulates key proteins overexpressed in IBC and chemosensitizes EGFR-overexpressing cells to erlotinib.

Abstract Inflammatory Breast Cancer (IBC) is a unique and aggressive cancer where tumor spheroids invade the dermal lymphatics causing the inflammatory phenotype. IBC cell lines and human tissues overexpress plasma membrane proteins such as E-cadherin and Epidermal Growth Factor Receptor (EGFR), which are associated with maintaining tumor spheroid integrity, increased IBC tumor growth rate, invasion and metastasis. Since IBC tumor cell emboli are more efficient at forming metastases and are more resistant to chemo and radiotherapy than single cells, it seems feasible to prevent IBC with a compound that has the ability to disintegrate the cell spheroids. Our published data shows that the medicinal mushroom, Ganoderma lucidum (Reishi), inhibits IBC progression via disintegration of tumor spheroids. Thus, we aimed to investigate Reishi's in vitro and in vivo therapeutic potential in IBC, focusing on the regulation of E-cadherin and EGFR and its contribution to the IBC cellular response when treated with the EGFR Tyrosine Kinase Inhibitor (TKI), erlotinib (commercially known as Tarceva®). Herein, we show that Reishi downregulates E-cadherin and EGFR abundance in vitro, significantly reduces tumor growth by 58%, and downregulates in vivo EGFR, and E-cadherin protein expression. Moreover, a synergistic effect is observed when erlotinib and Reishi are used simultaneously after 72 hours of treatment. Since Reishi downregulates the expression of E-cadherin and EGFR, our subsequent investigations will focus on the identification of PM proteins using stable isotope labeling with amino acids in cell culture (SILAC). Our results provide evidence that Reishi downregulates key proteins overexpressed in IBC, and chemosensitizes IBC cells to erlotinib therapy, highlighting its anti-IBC-therapeutic potential. This project was sponsored by Title V PPOHA US Dept of Education #P031M105050 to UCC, NIH/RCMI #2G12RR003035 to UCC, NIH/INBRE #5P20RR016470 to UPR/UCC, NIH/NCRR #U54RR026139 to UPR/UCC, and a research donation from the Commonwealth of Puerto Rico to UCC-Centro Universitario de Medicina Integral y Complementaria (CUMIC) / MMM. Citation Format: Ivette Suarez-Arroyo, Raysa Rosario-Acevedo, Alexandra Aguilar-Pérez, Luis A. Cubano, Michelle M. Martínez-Montemayor. Ganoderma lucidum (Reishi) downregulates key proteins overexpressed in IBC and chemosensitizes EGFR-overexpressing cells to erlotinib. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2247. doi:10.1158/1538-7445.AM2013-2247

Host pathogen interactions: new lessons from Listeria monocytogenes

Listeria monocytogenes is a bacterial pathogen that hijacks different host cell components at different stages of the infection. The talk will focus on the invasion process which involves two receptors E‐cadherin and the receptor tyrosine kinase Met. Interactions of the bacteria with the receptors activate a series of molecular events that lead to entry. We will show in particular how we discovered the unexpected key role of clathrin in the actin rearrangements used for entry, what are the main actors involved in clathrin recruitment and in the connection of clathrin to actin. A complete picture is emerging from RNAi screens which will be discussed. In addition, we will show how the study of Listeria entry into cells has helped discovering a so far not described role for clathrin in cell cell junctions formation.

Cell surface changes in theCandida albicansmitochondrial mutantgoa1Δ are associated with reduced recognition by innate immune cells

We have previously characterized several fungal-specific proteins from the human pathogen Candida albicans that either encode subunits of mitochondria Complex I (CI) of the electron transport chain (ETC) or regulate CI activity (Goa1p). Herein, the role of energy production and cell wall gene expression is investigated in the mitochondria mutant goa1Δ. We show that downregulation of cell wall-encoding genes in the goa1Δ results in sensitivity to cell wall inhibitors such as Congo red and Calcofluor white, reduced phagocytosis by a macrophage cell line, reduced recognition by macrophage receptors, and decreased expression of cytokines such as IL-6, IL-10 and IFN-γ. In spite of the reduced recognition by macrophages, the goa1Δ is still killed to the same extent as control strains. We also demonstrate that expression of the epithelial cell receptors E-cadherin and EGFR is also reduced in the presence of goa1Δ. Together, our data demonstrate the importance of mitochondria in the expression of cell wall biomolecules and the interaction of C. albicans with innate immune and epithelial cells. Our underlying premise is thatmitochondrial proteins such as Goa1p and other fungal-specific mitochondrial proteins regulate critical functions in cell growth and in virulence. As such, they remain as valid drug targets for antifungal drug discovery.

Imbalance of desmoplastic stromal cell numbers drives aggressive cancer processes

Epithelial tissues have sparse stroma, in contrast to their corresponding tumours. The effect of cancer cells on stromal cells is well recognized. Increasingly, stromal components, such as endothelial and immune cells, are considered indispensable for cancer progression. The role of desmoplastic stroma, in contrast, is poorly understood. Targeting such cellular components within the tumour is attractive. Recent evidence strongly points towards a dynamic stromal cell participation in cancer progression that impacts patient prognosis. The role of specific desmoplastic stromal cells, such as stellate cells and myofibroblasts in pancreatic, oesophageal and skin cancers, was studied in bio-engineered, physiomimetic organotypic cultures and by regression analysis. For pancreatic cancer, the maximal effect on increasing cancer cell proliferation and invasion, as well as decreasing cancer cell apoptosis, occurs when stromal (pancreatic stellate cells) cells constitute the majority of the cellular population (maximal effect at a stromal cell proportion of 0.66-0.83), accompanied by change in expression of key molecules such as E-cadherin and β-catenin. Gene-expression microarrays, across three tumour types, indicate that stromal cells consistently and significantly alter global cancer cell functions such as cell cycle, cell-cell signalling, cell movement, cell death and inflammatory response. However, these changes are mediated through cancer type-specific alteration of expression, with very few common targets across tumour types. As highlighted by these in vitro data, the reciprocal relationship of E-cadherin and polymeric immunoglobulin receptor (PIGR) expression in cancer cells could be shown, in vivo, to be dependent on the stromal content of human pancreatic cancer. These studies demonstrate that context-specific cancer-stroma crosstalk requires to be precisely defined for effective therapeutic targeting. These data may be relevant to non-malignant processes where epithelial cells interact with stromal cells, such as chronic inflammatory and fibrotic conditions.

Improved Therapeutic Effect against Leukemia by a Combination of the Histone Methyltransferase Inhibitor Chaetocin and the Histone Deacetylase Inhibitor Trichostatin A

SUV39H1 is a histone 3 lysine 9 (H3K9)-specific methyltransferase that is important for heterochromatin formation and the regulation of gene expression. Chaetocin specifically inhibits SUV39H1, resulted in H3K9 methylation reduction as well as reactivation of silenced genes in cancer cells. Histone deacetylase (HDAC) inhibitors inhibit deacetylases and accumulate high levels of acetylation lead to cell cycle arrest and apoptosis. In this study, we demonstrated that treatment with chaetocin enhanced apoptosis in human leukemia HL60, KG1, Kasumi, K562, and THP1 cells. In addition, chaetocin induced the expression of cyclin-dependent kinase inhibitor 2B (p15), E-cadherin (CDH1) and frizzled family receptor 9 (FZD9) through depletion of SUV39H1 and reduced H3K9 methylation in their promoters. Co-treatment with chaetocin and HDAC inhibitor trichostatin A (TSA) dramatically increased apoptosis and produced greater activation of genes. Furthermore, this combined treatment significantly increased loss of SUV39H1 and reduced histone H3K9 trimethylation responses accompanied by increased acetylation. Importantly, co-treatment with chaetocin and TSA produced potent antileukemic effects in leukemia cells derived from patients. These in vitro findings suggest that combination therapy with SUV39H1 and HDAC inhibitors may be of potential value in the treatment of leukemia.

Signaling pathway through the inhibitory receptor E-cadherin in epidermal γδ T cells

Signaling pathway through the inhibitory receptor E-cadherin in epidermal γδ T cells