Integrin-associated transcriptional characteristics of circulating tumor cells in breast cancer patients.

Background: Integrins enable cell communication with the basal membrane and extracellular matrix, activating signaling pathways and facilitating intracellular changes. Integrins in circulating tumor cells (CTCs) play a significant role in apoptosis evasion and anchor-independent survival. However, the link between CTCs expressing different integrin subunits, their transcriptional profile and, therefore, their functional activity with respect to metastatic potential remains unclear. Methods: Single-cell RNA sequencing of CD45-negative cell fraction of breast cancer patients was performed. All CTCs were divided into nine groups according to their integrin profile. Results: СTCs without the gene expression of integrins or with the expression of non-complementary α and ß subunits that cannot form heterodimers prevailed. Only about 15% of CTCs expressed integrin subunits which can form heterodimers. The transcriptional profile of CTCs appeared to be associated with the spectrum of expressed integrins. The lowest potential activity was observed in CTCs without integrin expression, while the highest frequency of expression of tumor progression-related genes, namely genes of stemness, epithelial-mesenchymal transition (EMT), invasion, proinflammatory chemokines and cytokines as well as laminin subunits, were observed in CTCs co-expressing ITGA6 and ITGB4. Validation on the protein level revealed that the median of integrin ß4+ CTCs was higher in patients with more aggressive molecular subtypes as well as in metastatic breast cancer patients. One can expect that CTCs with ITGA6 and ITGB4 expression will have pronounced metastatic potencies manifesting in expression of EMT and stemness-related genes, as well as potential ability to produce chemokine/proinflammatory cytokines and laminins.

Spatial Heterogeneity of Integrins and Their Ligands in Primary Breast Tumors.

BACKGROUND: The diversity of cell-cell interactions in different regions of a tumor reflects the functional heterogeneity of cancer, which poses challenges in early diagnosis, selection of treatment strategies, and prognosis of breast cancer. Cancer cells interact with each other to form different morphological structures in the tumor and stromal host cells via integrins. The objective of this study was to characterize the morphological and spatial heterogeneity of primary breast tumors in the context of expression profiles of integrins and their ligands. METHODS: We studied spatial transcriptomics using the 10X Visium approach and the Niche Interactions and Communication Heterogeneity in Extracellular Signaling (NICHES) algorithm to map ligand-receptor signaling pathways and visualize the heterogeneity of signaling archetypes in tumor clusters. RESULTS: Cluster analysis of the expression profiles of tumor spots from the samples indicated pronounced inter-tumoral heterogeneity. Integrin-ligand functional clusters were associated with intratumoral heterogeneity, which was manifested by the presence of several morphological loci as observed in histological tumor samples. Inter-tumoral heterogeneity was manifested by a different number of functional clusters, ranging from 2 to 9 for each tumor sample. The main characteristic of these clusters was the significant predominance of non-complementary integrin subunits. Of the 42 functional integrin-ligand pairs in 21 clusters of five samples, 41 pairs occurred only once. The exception was the laminin subunit alpha-5 (LAMA5)-integrin beta 4 (ITGB4) pair, which was detected in two clusters of different samples. CONCLUSIONS: The spatial heterogeneity of integrin-ligand expression clusters in breast cancer contributes significantly to the functional heterogeneity of the tumor, which sets the stage for many scenarios of parenchymatous-stromal relationships, some of which may be effective in the emergence of metastasizing tumor seed cells. The intra- and inter-tumoral spatio-functional heterogeneity of the tumor tissue that we discovered may largely explain why it is difficult to achieve success in most patients with breast cancer using any therapeutic strategy targeting one molecule of the vast array, regardless of the importance of its pathogenetic significance.

The Association of Integrins ß3, ß4, and αVß5 on Exosomes, CTCs and Tumor Cells with Localization of Distant Metastasis in Breast Cancer Patients.

Integrins are cell adhesion receptors, which play a role in breast cancer invasion, angiogenesis, and metastasis. Moreover, it has been shown that exosomal integrins provide organotropic metastasis in a mouse model. In our study, we aimed to investigate the expression of integrins ß3, ß4, and αVß5 on exosomes and tumor cells (circulating tumor cells and primary tumor) and their association with the localization of distant metastasis. We confirmed the association of exosomal integrin ß4 with lung metastasis in breast cancer patients. However, we were unable to evaluate the role of integrin ß3 in brain metastasis due to the rarity of this localization. We established no association of exosomal integrin αVß5 with liver metastasis in our cohort of breast cancer patients. The further evaluation of ß3, ß4, and αVß5 integrin expression on CTCs revealed an association of integrin ß4 and αVß5 with liver, but not the lung metastases. Integrin ß4 in the primary tumor was associated with liver metastasis. Furthermore, an in-depth analysis of phenotypic characteristics of ß4+ tumor cells revealed a significantly increased proportion of E-cadherin+ and CD44+CD24- cells in patients with liver metastases compared to patients with lung or no distant metastases.

LIMCH1 as a New Potential Metastasis Predictor in Breast Cancer.

BACKGROUND AND OBJECTIVE: High LIMCH1 expression in lung and renal cancer is determined as a favorable prognostic factor. However, prognostic value of LIMCH1 expression in breast cancer has not been studied yet. Therefore, this study was performed to determine the prognostic value of LIMCH1 expression in breast cancer patients. METHODS: This retrospective study included 89 patients with invasive breast carcinoma of no special type. These patients referred to  Cancer Research Institute of Tomsk National Research Medical Center from 2007 to 2018. LIMCH1 protein expression in tumor cells was detected by immunohistochemical analysis in this study. Statistical analysis was done to investigate the possible relationship between LIMCH1 protein expression and clinicopathological parameters, risk of metastasis, distant metastasis free survival, and overall survival. RESULTS: IHC analysis of breast cancer tissue samples revealed that LIMHC1 protein expression was found in 29.2% (26/89) of the cases. Lymph node and distant metastases were more frequent in patients with LIMCH1 protein expression. LIMCH1 protein expression increased the risk of distant metastasis based on our findings. LIMCH1 protein affected metastatic-free survival regardless of the T, as well as other clinical and pathological parameters (p=0.0146, HR=3.2058 (1.26; 8.17)). Moreover, LIMCH1 protein expression was associated with worse overall survival (p=0.0071, HR=2.73 (1.28; 5.85)) in our breast cancer patients. CONCLUSION: LIMCH1 protein expression was associate with metastases development, providing prognostic stratification. In breast cancer, LIMCH1 protein expression was found as an unfavorable prognostic factor of distant metastasis-free survival based on our findings.

The Novel Association of Early Apoptotic Circulating Tumor Cells with Treatment Outcomes in Breast Cancer Patients.

Stemness and epithelial-mesenchymal plasticity are widely studied in the circulating tumor cells of breast cancer patients because the roles of both processes in tumor progression are well established. An important property that should be taken into account is the ability of CTCs to disseminate, particularly the viability and apoptotic states of circulating tumor cells (CTCs). Recent data demonstrate that apoptosis reversal promotes the formation of stem-like tumor cells with pronounced potential for dissemination. Our study focused on the association between different apoptotic states of CTCs with short- and long-term treatment outcomes. We evaluated the association of viable CTCs, CTCs with early features of apoptosis, and end-stage apoptosis/necrosis CTCs with clinicopathological parameters of breast cancer patients. We found that the proportion of circulating tumor cells with features of early apoptosis is a perspective prognosticator of metastasis-free survival, which also correlates with the neoadjuvant chemotherapy response in breast cancer patients. Moreover, we establish that apoptotic CTCs are associated with the poor response to neoadjuvant chemotherapy, and metastasis-free survival expressed at least two stemness markers, CD44 and CD133.

Tumor Properties Mediate the Relationship between Peripheral Blood Monocytes and Tumor-Associated Macrophages in Breast Cancer.

In cancer patients, circulating monocytes show functional alterations. Since monocytes are precursors of tumor-associated macrophages (TAMs), TAMs ensuring tumor viability are potentially replenished through the recruitment of monocytes with specific properties. We demonstrated that locoregional metastasis and circulating factors, such as CD45-EpCAM + CD44 + CD24-/low circulating tumor cells, and serum MCP-1 and HMGB1 were statistically associated with modulation of the monocyte features in breast cancer patients. The count of circulating CD45-EpCAM + cells correlated with CD68+, CD163 + monocyte in blood, and with density of CD68 + TAM in breast cancer tumors. Overall, the relationship between monocytes and TAMs is mediated by the tumor in breast cancer patients.

Premalignant Changes in the Bronchial Epithelium Are Prognostic Factors of Distant Metastasis in Non-Small Cell Lung Cancer Patients.

BACKGROUND: The study assessed the possibility of dividing patients into groups based on the assessment of morphological changes in the epithelium of small-caliber bronchi located near the primary tumor in order to predict high and low risks of distant metastasis of non-small cell lung cancer. METHODS: In 171 patients with non-small cell lung cancer (T1-4N0-3M0) in small-caliber bronchi taken at a distance of 3-5 cm from the tumor, various variants of morphological changes in the bronchial epithelium (basal cell hyperplasia (BCH), squamous cell metaplasia (SM), and dysplasia (D)) were assessed. Long-term results of treatment, namely, distant metastasis, were assessed after 2 and 5 years. RESULTS: During the follow-up period, distant metastases were found in 35.1% (60/171) of patients. Most often, they were observed in patients of the high-risk group: BCH+SM-D- (51.6%, 40/95) and BCH-SM+D+ (54.4%, 6/11). Less often, distant metastases were observed in low-risk group patients: BCH+SM+D- (6.7%, 3/45) and BCH-SM-D- (10.0%, 2/20). Tumor size, grade, and stage were significant predictors of metastasis only in the high-risk group. The 5-year metastasis-free survival was better in the low-risk group of distant metastases. CONCLUSIONS: Isolated BCH or dysplasia in small bronchi distant from foci of tumor is associated with a high-risk distant metastasis and less 5-year metastasis-free survival.

Heterogeneous Manifestations of Epithelial-Mesenchymal Plasticity of Circulating Tumor Cells in Breast Cancer Patients.

To date, there is indisputable evidence of significant CTC heterogeneity in carcinomas, in particular breast cancer. The heterogeneity of CTCs is manifested in the key characteristics of tumor cells related to metastatic progression - stemness and epithelial-mesenchymal (EMT) plasticity. It is still not clear what markers can characterize the phenomenon of EMT plasticity in the range from epithelial to mesenchymal phenotypes. In this article we examine the manifestations of EMT plasticity in the CTCs in breast cancer. The prospective study included 39 patients with invasive carcinoma of no special type. CTC phenotypes were determined by flow cytometry before any type of treatment. EMT features of CTC were assessed using antibodies against CD45, CD326 (EpCam), CD325 (N-cadherin), CK7, Snail, and Vimentin. Circulating tumor cells in breast cancer are characterized by pronounced heterogeneity of EMT manifestations. The results of the study indicate that the majority of heterogeneous CTC phenotypes (22 out of 24 detectable) exhibit epithelial-mesenchymal plasticity. The variability of EMT manifestations does not prevent intravasation. Co-expression of EpCAM and CK7, regardless of the variant of co-expression of Snail, N-cadherin, and Vimentin, are associated with a low number of CTCs. Intrapersonal heterogeneity is manifested by the detection of several CTC phenotypes in each patient. Interpersonal heterogeneity is manifested by various combinations of CTC phenotypes in patients (from 1 to 17 phenotypes).

Prognosis of Different Types of Non-Small Cell Lung Cancer Progression: Current State and Perspectives.

Despite advances in diagnostics and therapy of non-small cell lung cancer (NSCLC), the problem of prognosis and prevention of tumor progression is still highly important. Even if NSCLC is diagnosed in the early stages, almost a quarter of patients develop relapse; most of them die from recurrent disease. A large number of different markers have been proposed to predict the risk of NSCLC progression; however, none of them are used in clinical practice. It is obvious that this situation is related to the economic and methodological complexity of the proposed markers and/or their insufficient efficiency due to a lack of effective study models and tumor heterogeneity. Another reason may be that potential markers are developed for NSCLC progression in general, which is represented by at least four pathogenetically-distinct processes: synchronous lymph node metastasis, local, regional, and distant recurrence. In this review, we summarize data from published literature on clinicopathological, genetic, and molecular factors associated with different types of NSCLC progression and emphasize challenges and approaches to developing prognostic factors. In conclusion, we highlight the importance of further studies to reveal molecular mechanisms of NSCLC progression and the need for differential analysis of markers of local, regional, and distant recurrences for disease prognosis.

The Activity of KIF14, Mieap, and EZR in a New Type of the Invasive Component, Torpedo-Like Structures, Predetermines the Metastatic Potential of Breast Cancer.

Intratumor morphological heterogeneity reflects patterns of invasive growth and is an indicator of the metastatic potential of breast cancer. In this study, we used this heterogeneity to identify molecules associated with breast cancer invasion and metastasis. The gene expression microarray data were used to identify genes differentially expressed between solid, trabecular, and other morphological arrangements of tumor cells. Immunohistochemistry was applied to evaluate the association of the selected proteins with metastasis. RNA-sequencing was performed to analyze the molecular makeup of metastatic tumor cells. High frequency of metastases and decreased metastasis-free survival were detected in patients either with positive expression of KIF14 or Mieap or negative expression of EZR at the tips of the torpedo-like structures in breast cancers. KIF14- and Mieap-positive and EZR-negative cells were mainly detected in the torpedo-like structures of the same breast tumors; however, their transcriptomic features differed. KIF14-positive cells showed a significant upregulation of genes involved in ether lipid metabolism. Mieap-positive cells were enriched in genes involved in mitophagy. EZR-negative cells displayed upregulated genes associated with phagocytosis and the chemokine-mediated signaling pathway. In conclusion, the positive expression of KIF14 and Mieap and negative expression of EZR at the tips of the torpedo-like structures are associated with breast cancer metastasis.

Heterogeneity of Stemlike Circulating Tumor Cells in Invasive Breast Cancer.

The presence of stem and epithelial-mesenchymal-transition (EMT) features in circulating tumor cells (CTCs) determines their invasiveness, adaptability to the microenvironment, and resistance to proapoptotic signals and chemotherapy. It also allows them to fulfil the role of metastatic "seeds". We evaluated the heterogeneity of stem CTCs by their CD44, ALDH1, and CD133 expression depending on N-cadherin expression in breast-cancer patients. A total of 38 female patients were selected for this study. CTC phenotypes were determined by flow cytometry before any type of treatment. Multiplex immunofluorescence was used for the evaluation of tumor-cell heterogeneity in primary lesions. In patients who had CD44-CD24- CTCs, a subset of cells with the expression of other stem-cell markers (CD133 and ALDH1) were detected. Expression of CD133 and/or ALDH1 may be associated with expression of N-cadherin: all populations of N-cadherin+ CTCs demonstrate stem features; in the absence of N-cadherin expression, true nonstem (CD44-CD24-CD133-ALDH1-) cells are found. The heterogeneity of stem marker expression in CTCs was observed regardless of N-cadherin expression. In our study, stromal cell-derived factor-1 (SDF-1) receptor expression in CTCs did not depend on stemlike traits, but was instead associated with N-cadherin expression. Subpopulations of tumor cells, detected both in tumors and blood, were identified. Breast cancer was characterized by pronounced interpersonal and intrapersonal heterogeneity of CTCs by the presence and combination of various stem features and N-cadherin expression. To complete the characterization of stemlike features of CTCs, we suggest the simultaneous use of the three stem markers.

Single Tumor Cells With Epithelial-Like Morphology Are Associated With Breast Cancer Metastasis.

Introduction: The identification of tumor cells that can be potential metastatic seeds would reach two key aims-prognosis of metastasis risk and appointment of the optimal adjuvant therapy to prevent metastatic disease. Single tumor cells (STCs) located out of multicellular structures can most likely demonstrate features that are needed to initiate metastasis. Methods: One-hundred-and-thirty-five patients with invasive breast carcinoma of no special type have been enrolled. Molecular subtypes of breast cancer were categorized according to St. Gallen recommendations. Hematoxylin and eosin staining was used to identify STCs with epithelial-like morphology (eSTCs) in breast tumors. Immunofluorescence staining was applied to evaluate stemness and epithelial-mesenchymal transition (EMT) in STCs. The correlation between STCs and recurrence and metastasis-free survival (MFS) was performed using the Kaplan-Meier method and the log-rank test. Results: Distant metastasis was more frequent in eSTC-positive than eSTC-negative patients (28.0% vs. 9.4%, p = 0.007). When tumor types were analyzed separately, distant metastasis tended to be more frequent in eSTC-positive than eSTC-negative patients for HER2-positive cancer [75.0% (3/4) vs. 12.5% (1/8), p = 0.066]. In luminal A [22.7% (5/22) vs. 10.0% (3/30), p = 0.259], luminal B [21.1% (4/19) vs. 6.7% (2/30), p = 0.189], and triple-negative [40.0% (2/5) vs. 11.8% (2/17), p = 0.209] cancers, distance metastasis was not associated with eSTCs. Median MFS was not reached in eSTC-positive and eSTC-negative patients. eSTC-positive patients had a higher risk of breast cancer metastasis [hazard ratio (HR) 3.57, 95% confidence interval (CI): 1.46-8.71; p = 0.001]. When tumor types were analyzed separately, a higher risk of breast cancer metastasis occurred only in HER2-positive patients (HR 8.49, 95% CI: 1.29-55.59; p = 0.016). Immunofluorescence analysis revealed mesenchymal-like STCs (mSTCs) and inter- and intra-tumor heterogeneity in STCs. There were breast tumors with either eSTCs or mSTCs and tumors with both types of STCs. Both eSTCs and mSTCs were represented by cells with different stem and/or EMT phenotypes. Conclusions: STCs with epithelial-like morphology contribute to breast cancer metastasis and represent an attractive model for studying mechanisms of metastatic seeding. The assessment of STCs in histological sections of breast tumors can be a simple and effective method for the prediction of metastasis risk.

SI-CLP inhibits the growth of mouse mammary adenocarcinoma by preventing recruitment of tumor-associated macrophages.

Chitinase-like proteins (CLP) are chitin-binding proteins that lack chitin hydrolyzing activity, but possess cytokine-like and growth factor-like properties, and play crucial role in intercellular crosstalk. Both human and mice express two members of CLP family: YKL-40 and stabilin-1 interacting chitinase-like protein (SI-CLP). Despite numerous reports indicating the role of YKL-40 in the support of angiogenesis, tumor cell proliferation, invasion and metastasis, the role of its structurally related protein SI-CLP in cancer was not reported. Using gain-of-function approach, we demonstrate in the current study that the expression of recombinant SI-CLP in mouse TS/A mammary adenocarcinoma cells results in significant and persistent inhibition of in vivo tumor growth. Using quantitative immunohistochemistry, we show that on the cellular level this phenomenon is associated with reduced infiltration of tumor-associated macrophages (TAMs), CD4+ and FoxP3+ cells in SI-CLP expressing tumors. Gene expression analysis in TAM isolated from SI-CLP-expressing and control tumors demonstrated that SI-CLP does not affect macrophage phenotype. However, SI-CLP significantly inhibited migration of murine bone-marrow derived macrophages and human primary monocytes toward monocyte-recruiting chemokine CCL2 produced in the tumor microenvironment (TME). Mechanistically, SI-CLP did not affect CCL2/CCR2 interaction, but suppressed cytoskeletal rearrangements in response to CCL2. Altogether, our data indicate that SI-CLP functions as a tumor growth inhibitor in mouse breast cancer by altering cellular composition of TME and blocking cytokine-induced TAM recruitment. Taking into consideration weak to absent expression of SI-CLP in human breast cancer, it can be considered as a therapeutic protein to block TAM-mediated support of breast tumor growth.

Markers of Cancer Cell Invasion: Are They Good Enough?

Invasion, or directed migration of tumor cells into adjacent tissues, is one of the hallmarks of cancer and the first step towards metastasis. Penetrating to adjacent tissues, tumor cells form the so-called invasive front/edge. The cellular plasticity afforded by different kinds of phenotypic transitions (epithelial-mesenchymal, collective-amoeboid, mesenchymal-amoeboid, and vice versa) significantly contributes to the diversity of cancer cell invasion patterns and mechanisms. Nevertheless, despite the advances in the understanding of invasion, it is problematic to identify tumor cells with the motile phenotype in cancer tissue specimens due to the absence of reliable and acceptable molecular markers. In this review, we summarize the current information about molecules such as extracellular matrix components, factors of epithelial-mesenchymal transition, proteases, cell adhesion, and actin cytoskeleton proteins involved in cell migration and invasion that could be used as invasive markers and discuss their advantages and limitations. Based on the reviewed data, we conclude that future studies focused on the identification of specific invasive markers should use new models one of which may be the intratumor morphological heterogeneity in breast cancer reflecting different patterns of cancer cell invasion.

Mechanisms behind prometastatic changes induced by neoadjuvant chemotherapy in the breast cancer microenvironment.

Chemotherapy, along with surgery and radiotherapy, is a key treatment option for malignant tumors. Neoadjuvant chemotherapy (NACT) reduces the tumor size and enables total tumor resection. In addition, NACT is believed to be more effective in destroying micrometastases than the same chemotherapy performed after surgery. To date, various NACT regimens have been tested and implemented, which provide a favorable outcome in primary tumors and reduce the risk of progression. However, there is increasing evidence of the NACT ability to increase the risk of cancer progression. This review discusses potential mechanisms by which NACT promotes distant metastasis of breast cancer through changes in the microenvironment of tumor cells. We describe prometastatic NACT-mediated changes in angiogenesis, immuno-inflammatory reactions in the stroma, intravasation, and amount of circulating tumor cells. The role of NACT-related cellular stress in cancer metastasis is also discussed.

Tumor-associated macrophages in human breast cancer produce new monocyte attracting and pro-angiogenic factor YKL-39 indicative for increased metastasis after neoadjuvant chemotherapy.

In breast cancer, the tumor microenvironment plays a critical role in the tumor progression and responses to therapy. Tumor-associated macrophages (TAMs) are major innate immune cells in tumor microenvironment that regulate intratumoral immunity and angiogenesis by secretion of cytokines, growth factors as well as chitinase-like proteins (CLPs), that combine properties of cytokines and growth factors. YKL-39 is a chitinase-like protein found in human and absent in rodents, and its expression in TAMs and role in breast cancer progression was not studied to date. Here for the first time we demonstrate that YKL-39 is expressed on TAMs, predominantly positive for stabilin-1, but not by malignant cells or other stromal cells in human breast cancer. TGF-beta in combination with IL-4, but not IL-4 alone was responsible of the stimulation of the production of YKL-39 in human primary macrophages. Mechanistically, stabilin-1 directly interacted with YKL-39 and acted as sorting receptor for targeting YKL-39 into the secretory pathway. Functionally, purified YKL-39 acted as a strong chemotactic factor for primary human monocytes, and induced angiogenesis in vitro. Elevated levels of YKL-39 expression in tumors after neoadjuvant chemotherapy (NAC) were predictive for increased risk of distant metastasis and for poor response to NAC in patients with nonspecific invasive breast carcinoma. Our findings suggest YKL-39 as a novel therapeutic target, and blocking of its activity can be combined with NAC in order to reduce the risk of metastasis in breast cancer patients.

The effect of neoadjuvant chemotherapy on the correlation of tumor-associated macrophages with CD31 and LYVE-1.

Angiogenesis and lymphangiogenesis play a crucial role in tumor growth, invasion and metastasis. Tumor-associated macrophages (TAM) induce both angiogenesis and lymphangiogenesis in mouse breast cancer models and positively correlate with these processes in human breast cancer patients. Neoadjuvant chemotherapy (NAC) is a widely used therapeutic option for cancer treatment. However, the effect of NAC on the distribution of TAM within intratumoral compartments and their correlation with angiogenesis and lymphangiogenesis remained unknown. In the present study we analyzed the effect of NAC on the distribution of CD68+ and stabilin-1+ TAM in five functionally distinct areas of human breast cancer and their correlations with microvessel density (MVD) and lymphatic microvessel density (LMVD), identified by CD31 and LYVE1, respectively. We found that NAC enhances blood vessel density in soft fibrous stroma and in coarse fibrous stroma. Without NAC the amount of CD68+ TAM in gaps of ductal tumor structures positively correlate with CD31+ microvessel density in soft fibrous stroma. NAC had enhancing effect on the amount of CD68+ TAM but not stabilin-1+ TAM in soft fibrous stroma. However, no correlation between TAM and CD31+ microvessel density was identified after NAC. NAC did not enhance the lymphatic microvessel density. But after NAC stabilin-1 expressing subpopulation of TAM positively correlated with expression of LYVE-1. We hypothesized that CD68+ TAM can support tumor angiogenesis primarily before NAC, while stabilin-1+ TAM can contribute to the maintenance of lymphatic microvessel density after NAC.

Predictive value of vascular endothelial growth factor receptor type 2 in triple-negative breast cancer patients treated with neoadjuvant chemotherapy.

The identification of informative biomarkers that could predict the treatment response is particularly important in the triple-negative (TN) breast cancer, which is characterized by biological diversity. The aim of this study was to investigate the impact of vascular endothelial growth factor receptor (VEGFR2) expression and its gene polymorphisms on pathologic complete response (pCR) to neoadjuvant chemotherapy (NCT) in Russian patients with TN breast cancer. We performed a retrospective analysis of 70 women with operable TN breast cancer, who underwent NCT with 5-fluorouracil, adriamycin, and cyclophosphamide (FAC) or cyclophosphamide, adriamycin, and capecitabine (CAX) between 2007 and 2013. VEGFR2 expression was evaluated before NCT by immunohistochemistry. TaqMan SNP assays were used for genotyping KDR - 604T>C (rs2071559) and KDR 1192G>A (rs2305948) polymorphisms. The pCR was used as an end-point in the treatment efficacy analysis. In the univariate analysis, the pCR rate was strongly associated with young age (P = 0.004), high Ki67 expression (P = 0.012), lymph node negativity (P = 0.023) as well as with positive VEGFR2 expression (P = 0.019) and the CAX regimen (P = 0.005). In the multivariate analysis, only patient's age (P = 0.005) and pre-NCT VEGFR2 expression (P = 0.048) remained significant predictors of pCR. The pCR rate was higher in the CAX-treated patients than that in the FAC-treated patients (P = 0.005). Our results revealed that - 604TT genotype of rs2071559 and age < 50 years were correlated with a pCR in the CAX-treated patients. VEGFR2 expression in pre-NCT tumors and KDR gene polymorphism can be considered as additional predictive molecular markers of pCR in Russian TN breast cancer patients treated with NCT.

Development of Novel Monoclonal Antibodies for Evaluation of Transmembrane Prostate Androgen-Induced Protein 1 (TMEPAI) Expression Patterns in Gastric Cancer.

Transmembrane prostate androgen-induced protein 1 (TMEPAI) is a single-span membrane protein, functionally involved in transforming growth factor beta signaling pathway. The particular protein presented in cells in three isoforms, which differs in the length of the soluble N-terminal extracellular domain, making it challenging for the immunochemical recognition. By using quantitative real-time polymerase chain reaction, we identified significant upregulation of PMEPA1 gene expression in malignant tissues of patients with gastric adenocarcinoma. The main part of commercially available anti-TMEPAI antibodies are having polyclonal nature or not suitable for immunocytochemical localization of target protein in tissue specimens. Hence, we decide to generate a set of novel rat monoclonal antibodies (mAb) directed against conservative C-terminal cytoplasmic epitope. Immunoblotting analysis showed that monoclonal antibodies, 2E1, 6C6, and 10A7 were able to recognize specifically target protein in transiently transfected HEK293T and CHO-K1 cells. Especially established mAb, named 10A7, showed the excellent binding ability to target protein in immunohistochemistry. By using developed antibodies, we observed pronounced expression of TMEPAI in normal gastric epithelial cells while tumor cells from gastric adenomas, and adenocarcinoma samples were mostly negative for target protein expression. Also, we found that gastric epithelium cells lose the TMEPAI expression concurrently with severe dysplasia progression, which probably caused by a mechanism involving specific microRNA.

Clinically relevant morphological structures in breast cancer represent transcriptionally distinct tumor cell populations with varied degrees of epithelial-mesenchymal transition and CD44+CD24- stemness.

Intratumor morphological heterogeneity in breast cancer is represented by different morphological structures (tubular, alveolar, solid, trabecular, and discrete) and contributes to poor prognosis; however, the mechanisms involved remain unclear. In this study, we performed 3D imaging, laser microdissection-assisted array comparative genomic hybridization and gene expression microarray analysis of different morphological structures and examined their association with the standard immunohistochemistry scorings and CD44+CD24- cancer stem cells. We found that the intratumor morphological heterogeneity is not associated with chromosomal aberrations. By contrast, morphological structures were characterized by specific gene expression profiles and signaling pathways and significantly differed in progesterone receptor and Ki-67 expression. Most importantly, we observed significant differences between structures in the number of expressed genes of the epithelial and mesenchymal phenotypes and the association with cancer invasion pathways. Tubular (tube-shaped) and alveolar (spheroid-shaped) structures were transcriptionally similar and demonstrated co-expression of epithelial and mesenchymal markers. Solid (large shapeless) structures retained epithelial features but demonstrated an increase in mesenchymal traits and collective cell migration hallmarks. Mesenchymal genes and cancer invasion pathways, as well as Ki-67 expression, were enriched in trabecular (one/two rows of tumor cells) and discrete groups (single cells and/or arrangements of 2-5 cells). Surprisingly, the number of CD44+CD24- cells was found to be the lowest in discrete groups and the highest in alveolar and solid structures. Overall, our findings indicate the association of intratumor morphological heterogeneity in breast cancer with the epithelial-mesenchymal transition and CD44+CD24- stemness and the appeal of this heterogeneity as a model for the study of cancer invasion.