CD146, an epithelial-mesenchymal transition inducer, is associated with triple-negative breast cancer

Inhibition of Notch1 reverses EMT and chemoresistance to cisplatin via direct downregulation of MCAM in triple-negative breast cancer cells

Resistance to chemotherapy continues to be a critical issue in the clinical therapy of triple-negative breast cancer (TNBC). Epithelial-mesenchymal transition (EMT) is thought to contribute to chemoresistance in several cancer types, including breast cancer. Identification of the key signaling pathway that regulates the EMT program and contributes to chemoresistance in TNBC will provide a novel strategy to overcome chemoresistance in this subtype of cancer. Herein, we demonstrate that Notch1 positively associates with melanoma cell adhesion molecule (MCAM), a unique EMT activator, in TNBC tissue samples both at mRNA and protein levels. High expression of Notch1 and MCAM both predicts a poor survival in basal-like/TNBC patients, particularly in those treated with chemotherapy. The expression of Notch1 and MCAM in MDA-MB-231 cells gradually increases in a time-dependent manner when exposing to low dose cisplatin. Moreover, the expressions of Notch1 and MCAM in cisplatin-resistant MDA-MB-231 cells are significantly higher than wild-type counterparts. Notch1 promotes EMT and chemoresistance, as well as invasion and proliferation of TNBC cells via direct activating MCAM promoter. Inhibition of Notch1 significantly downregulates MCAM expression, resulting in the reversion of EMT and chemoresistance to cisplatin in TNBC cells. Our study reveals the regulatory mechanism of the Notch1 pathway and MCAM in TNBC and suggesting that targeting the Notch1/MCAM axis, in conjunction with conventional chemotherapies, might be a potential avenue to enhance the therapeutic efficacy for patients with TNBC.

Comparison of skeletal and soft tissue pericytes identifies CXCR4+ bone forming mural cells in human tissues

Human osteogenic progenitors are not precisely defined, being primarily studied as heterogeneous multipotent cell populations and termed mesenchymal stem cells (MSCs). Notably, select human pericytes can develop into bone-forming osteoblasts. Here, we sought to define the differentiation potential of CD146⁺ human pericytes from skeletal and soft tissue sources, with the underlying goal of defining cell surface markers that typify an osteoblastogenic pericyte. CD146⁺CD31^-CD45^- pericytes were derived by fluorescence-activated cell sorting from human periosteum, adipose, or dermal tissue. Periosteal CD146⁺CD31^-CD45^- cells retained canonical features of pericytes/MSC. Periosteal pericytes demonstrated a striking tendency to undergo osteoblastogenesis in vitro and skeletogenesis in vivo, while soft tissue pericytes did not readily. Transcriptome analysis revealed higher CXCR4 signaling among periosteal pericytes in comparison to their soft tissue counterparts, and CXCR4 chemical inhibition abrogated ectopic ossification by periosteal pericytes. Conversely, enrichment of CXCR4⁺ pericytes or stromal cells identified an osteoblastic/non-adipocytic precursor cell. In sum, human skeletal and soft tissue pericytes differ in their basal abilities to form bone. Diversity exists in soft tissue pericytes, however, and CXCR4⁺ pericytes represent an osteoblastogenic, non-adipocytic cell precursor. Indeed, enrichment for CXCR4-expressing stromal cells is a potential new tactic for skeletal tissue engineering.

ImmunoPET: Concept, Design, and Applications

Immuno-positron emission tomography (immunoPET) is a paradigm-shifting molecular imaging modality combining the superior targeting specificity of monoclonal antibody (mAb) and the inherent sensitivity of PET technique. A variety of radionuclides and mAbs have been exploited to develop immunoPET probes, which has been driven by the development and optimization of radiochemistry and conjugation strategies. In addition, tumor-targeting vectors with a short circulation time (e.g., Nanobody) or with an enhanced binding affinity (e.g., bispecific antibody) are being used to design novel immunoPET probes. Accordingly, several immunoPET probes, such as 89Zr-Df-pertuzumab and 89Zr-atezolizumab, have been successfully translated for clinical use. By noninvasively and dynamically revealing the expression of heterogeneous tumor antigens, immunoPET imaging is gradually changing the theranostic landscape of several types of malignancies. ImmunoPET is the method of choice for imaging specific tumor markers, immune cells, immune checkpoints, and inflammatory processes. Furthermore, the integration of immunoPET imaging in antibody drug development is of substantial significance because it provides pivotal information regarding antibody targeting abilities and distribution profiles. Herein, we present the latest immunoPET imaging strategies and their preclinical and clinical applications. We also emphasize current conjugation strategies that can be leveraged to develop next-generation immunoPET probes. Lastly, we discuss practical considerations to tune the development and translation of immunoPET imaging strategies.

Survivin expression as an independent predictor of overall survival in malignant peritoneal mesothelioma

Malignant peritoneal mesothelioma (MPeM) is an incurable cancer strongly associated with asbestos exposure and characterised by poor prognosis. The aim of the present study was to elucidate the prognostic and predictive value of CD146 and survivin expression in MPeM. Diagnostic biopsies from 60 patients with MPeM were collected and analysed for CD146, survivin and Ki-67 expression using immunohistochemistry. Complete clinical and follow-up information was obtained from patients' records. CD146 was expressed in 31/60 MPeM specimens and survivin in 34/60 specimens, with both expression levels being significantly associated with the Ki-67 labelling index (Ki-67LI). Kaplan-Meier and univariate Cox regression analyses revealed that a lower peritoneal cancer index (PCI), tumour-directed treatment, stage I, lower Ki-67LI and lower CD146 and survivin expression had a statistically positive effect on overall survival (OS). Cox regression analysis revealed that PCI [hazard ratio (HR)=1.99; 95% CI, 1.04–3.83; P=0.038], survivin (HR=1.47; 95% CI, 1.03–2.10; P=0.034) and treatment protocol including intraperitoneal chemotherapy (HR=0.28; 95% CI, 0.14–0.57; P=0.013) and systemic chemotherapy (HR=0.13; 95% CI, 0.04–0.42; P=0.013) retained independent prognostic significance for OS. All of these were included in the nomogram. Calibration curves showed good agreement between nomogram-predicted and observed survival. The C-index of the nomogram for predicting OS was 0.77. A lower PCI, intraperitoneal chemotherapy, systemic chemotherapy and a lower level of survivin were powerful prognostic markers in patients with MPeM. The proposed nomogram provides individual survival prediction for patients with MPeM.

The Blood Circulating Rare Cell Population. What is it and What is it Good For?

Blood contains a diverse cell population of low concentration hematopoietic as well as non-hematopoietic cells. The majority of such rare cells may be bone marrow-derived progenitor and stem cells. This paucity of circulating rare cells, in particular in the peripheral circulation, has led many to believe that bone marrow as well as other organ-related cell egress into the circulation is a response to pathological conditions. Little is known about this, though an increasing body of literature can be found suggesting commonness of certain rare cell types in the peripheral blood under physiological conditions. Thus, the isolation and detection of circulating rare cells appears to be merely a technological problem. Knowledge about rare cell types that may circulate the blood stream will help to advance the field of cell-based liquid biopsy by supporting inter-platform comparability, making use of biological correct cutoffs and “mining” new biomarkers and combinations thereof in clinical diagnosis and therapy. Therefore, this review intends to lay ground for a comprehensive analysis of the peripheral blood rare cell population given the necessity to target a broader range of cell types for improved biomarker performance in cell-based liquid biopsy.

Intratumoral Gene Electrotransfer of Plasmid DNA Encoding shRNA against Melanoma Cell Adhesion Molecule Radiosensitizes Tumors by Antivascular Effects and Activation of an Immune Response

In this study, radiotherapy was combined with the gene electrotransfer (GET) of plasmid encoding shRNA against melanoma cell adhesion molecule (pMCAM) with dual action, which was a vascular-targeted effect mediated by the silencing of MCAM and an immunological effect mediated by the presence of plasmid DNA in the cytosol-activating DNA sensors. The effects and underlying mechanisms of therapy were evaluated in more immunogenic B16F10 melanoma and less immunogenic TS/A carcinoma. The silencing of MCAM potentiated the effect of irradiation (IR) in both tumor models. Combined therapy resulted in 81% complete responses (CR) in melanoma and 27% CR in carcinoma. Moreover, after the secondary challenge of cured mice, 59% of mice were resistant to challenge with melanoma cells, and none were resistant to carcinoma. Combined therapy reduced the number of blood vessels; induced hypoxia, apoptosis, and necrosis; and reduced cell proliferation in both tumor models. In addition, the significant increase of infiltrating immune cells was observed in both tumor models but more so in melanoma, where the expression of IL-12 and TNF-α was determined as well. Our results indicate that the combined therapy exerts both antiangiogenic and immune responses that contribute to the antitumor effect. However, tumor immunological status is crucial for a sufficient immune system contribution to the overall antitumor effect.

Tracking extracellular vesicle phenotypic changes enables treatment monitoring in melanoma

Monitoring targeted therapy in real time for cancer patients could provide vital information about the development of drug resistance and improve therapeutic outcomes. Extracellular vesicles (EVs) have recently emerged as a promising cancer biomarker, and EV phenotyping shows high potential for monitoring treatment responses. Here, we demonstrate the feasibility of monitoring patient treatment responses based on the plasma EV phenotypic evolution using a multiplex EV phenotype analyzer chip (EPAC). EPAC incorporates the nanomixing-enhanced microchip and the multiplex surface-enhanced Raman scattering (SERS) nanotag system for direct EV phenotyping without EV enrichment. In a preclinical model, we observe the EV phenotypic heterogeneity and different phenotypic responses to the treatment. Furthermore, we successfully detect cancer-specific EV phenotypes from melanoma patient plasma. We longitudinally monitor the EV phenotypic evolution of eight melanoma patients receiving targeted therapy and find specific EV profiles involved in the development of drug resistance, reflecting the potential of EV phenotyping for monitoring treatment responses.

Aurora B induces epithelial-mesenchymal transition by stabilizing Snail1 to promote basal-like breast cancer metastasis

Aurora B is a serine/threonine kinase that has been implicated in regulating cell proliferation in distinct cancers, including breast cancer. Here we show that Aurora B expression is elevated in basal-like breast cancer (BLBC) compared with other breast cancer subtypes. This high level of expression seems to correlate with poor metastasis-free survival and relapse-free survival in affected patients. Mechanistically, we show that elevated Aurora B expression in breast cancer cells activates AKT/GSK3β to stabilize Snail1 protein, a master regulator of epithelial-mesenchymal transition (EMT), leading to EMT induction in a kinase-dependent manner. Conversely, Aurora B knock down by short-hairpin RNAs (shRNAs) suppresses AKT/GSK3β/Snail1 signaling, reverses EMT and reduces breast cancer metastatic potential in vitro and in vivo. Finally, we identified a specific OCT4 phosphorylation site (T343) responsible for mediating Aurora B-induced AKT/GSK3β/Snail1 signaling and EMT that could be attenuated by Aurora B kinase inhibitor treatment. These findings support that Aurora B induces EMT to promote breast cancer metastasis via OCT4/AKT/GSK3β/Snail1 signaling. Pharmacologic Aurora B inhibition might be a potential effective treatment for breast cancer patients with metastatic disease.

The GEF-H1/PKD3 signaling pathway promotes the maintenance of triple-negative breast cancer stem cells

Protein kinase D3 (PKD3) is upregulated in triple-negative breast cancer (TNBC) and associated with cell proliferation and metastasis development but its precise pro-oncogenic function is unknown. Here we show that PKD3 is required for the maintenance of the TNBC stem cell population. The depletion of PKD3 in MDA-MB-231 cells reduced the cancer stem cell frequency in vitro and tumor initiation potential in vivo. We further provide evidence that the RhoGEF GEF-H1 is upstream of PKD3 activation in TNBC stem cells. Most importantly, pharmacological PKD inhibition in combination with paclitaxel synergistically decreased oncosphere and colony formation efficiency in vitro and tumor recurrence in vivo. Based on our results we propose that targeting the GEF-H1/PKD3 signaling pathway in combination with chemotherapy might provide an effective therapeutic option for TNBC.

CD146 T cells in lung cancer: its function, detection, and clinical implications as a biomarker and therapeutic target

CD146 alternatively called melanoma cell adhesion molecule (MCAM), is a biomarker and therapeutic target of clinical significance. It is found on different cells including the endothelial cells and lymphocytes which participate in heterotypic and homotypic ligand-receptor. This review concentrated on the CD146 expression T cells (or lymphocytes) centering on Treg in lung cancer. Here, we have also considered the vigorous investigation of CD146 mainly acknowledged new roles, essential mechanisms and clinical implications of CD146 in cancer. CD146 has progressively become a significant molecule, particularly recognized as a novel biomarker, prognosis and therapy for cancer. Hence, targeting CD146 expression by utilization of methanol extracts of Calotropis procera leaf may be useful for the treatment of carcinogenesis.

CD146-mediated acquisition of stemness phenotype enhances tumour invasion and metastasis after EGFR-TKI resistance in lung cancer

INTRODUCTION

Tumours are more likely to metastasize after the development of resistance to EGFR-TKIs. CD146 is a multifunctional molecule and is implicated in tumour invasion and metastasis; however, its role in lung cancer has not been clearly established.

OBJECTIVE

Here, we aimed to explore the relationship between CD146 pathway and stem cell phenotype after EGFR-TKI resistance in lung cancer.

METHODS

EGFR-TKI-resistant cell lines were established by exposing parental cells to erlotinib/gefitinib. The CD146 level was measured by a western blot, RT-PCR and immunocytochemistry fluorescent. Cell migration was examined by the transwell assay and the scratch assay. Stemness phenotype genes were evaluated by RT-PCR and stem cell phenotype was observed by the microsphere formation assay.

RESULTS

CD146 and stemness phenotype genes increased while β-catenin decreased in acquired EGFR-TKI-resistant cell lines. CD146's over-expression induced the up-regulation of stemness-related genes and was inversely correlated with the β-catenin expression, which further increased the migration capability of resistant cancer cells. CD146's knockdown suppressed cell migration and stemness phenotype.

CONCLUSIONS

CD146 molecule contributes to the stemness phenotype and migration in EGFR-TKI-resistant cells. CD146 might be a potential therapeutic target for EGFR-TKI-resistant lung cancer or metastasis prevention.

Critical role of the MCAM-ETV4 axis triggered by extracellular S100A8/A9 in breast cancer aggressiveness

Metastatic breast cancer is the leading cause of cancer-associated death in women. The progression of this fatal disease is associated with inflammatory responses that promote cancer cell growth and dissemination, eventually leading to a reduction of overall survival. However, the mechanism(s) of the inflammation-boosted cancer progression remains unclear. In this study, we found for the first time that an extracellular cytokine, S100A8/A9, accelerates breast cancer growth and metastasis upon binding to a cell surface receptor, melanoma cell adhesion molecule (MCAM). Our molecular analyses revealed an important role of ETS translocation variant 4 (ETV4), which is significantly activated in the region downstream of MCAM upon S100A8/A9 stimulation, in breast cancer progression in vitro as well as in vivo. The MCAM-mediated activation of ETV4 induced a mobile phenotype called epithelial-mesenchymal transition (EMT) in cells, since we found that ETV4 transcriptionally upregulates ZEB1, a strong EMT inducer, at a very high level. In contrast, downregulation of either MCAM or ETV4 repressed EMT, resulting in greatly weakened tumor growth and lung metastasis. Overall, our results revealed that ETV4 is a novel transcription factor regulated by the S100A8/A9-MCAM axis, which leads to EMT through ZEB1 and thereby to metastasis in breast cancer cells. Thus, therapeutic strategies based on our findings might improve patient outcomes.

Therapeutic Targeting of CD146/MCAM Reduces Bone Metastasis in Prostate Cancer

Prostate Cancer is the most common cancer and the second leading cause of cancer-related death in males. When prostate cancer acquires castration resistance, incurable metastases, primarily in the bone, occur. The aim of this study is to test the applicability of targeting melanoma cell adhesion molecule (MCAM; CD146) with a mAb for the treatment of lytic prostate cancer bone metastasis. We evaluated the effect of targeting MCAM using in vivo preclinical bone metastasis models and an in vitro bone niche coculture system. We utilized FACS, cell proliferation assays, and gene expression profiling to study the phenotype and function of MCAM knockdown in vitro and in vivo. To demonstrate the impact of MCAM targeting and therapeutic applicability, we employed an anti-MCAM mAb in vivo. MCAM is elevated in prostate cancer metastases resistant to androgen ablation. Treatment with DHT showed MCAM upregulation upon castration. We investigated the function of MCAM in a direct coculture model of human prostate cancer cells with human osteoblasts and found that there is a reduced influence of human osteoblasts on human prostate cancer cells in which MCAM has been knocked down. Furthermore, we observed a strongly reduced formation of osteolytic lesions upon bone inoculation of MCAM-depleted human prostate cancer cells in animal model of prostate cancer bone metastasis. This phenotype is supported by RNA sequencing (RNA-seq) analysis. Importantly, in vivo administration of an anti-MCAM human mAb reduced the tumor growth and lytic lesions. These results highlight the functional role for MCAM in the development of lytic bone metastasis and suggest that MCAM is a potential therapeutic target in prostate cancer bone metastasis. IMPLICATIONS: This study highlights the functional application of an anti-MCAM mAb to target prostate cancer bone metastasis.

Clinical significance of melanoma cell adhesion molecule CD146 and VEGFA expression in epithelial ovarian cancer

Ovarian cancer is the fifth most common type of cancer in females; however, its asymptomatic progression and the lack of an efficient screening strategy leads to late diagnosis. The present study aimed to investigate the expression levels of cluster of differentiation (CD)146 and vascular endothelial growth factor A (VEGFA) in epithelial ovarian cancer, and their clinical significance. A total of 52 ovarian samples were tested, of which 22 were from patients with epithelial ovarian cancer and 30 were from non-cancer patients. The relative gene expression of CD146 and VEGFA was quantified using reverse transcription-quantitative polymerase chain reaction analysis. Western blotting was used to determine the protein expression levels. The relative gene expression levels of CD146 and VEGFA in tumor tissues were significantly increased compared with the control (4.92±0.44 vs. 1.05±0.06 and 3.08±0.17 vs. 1.06±0.07, P<0.01). The protein expression levels of CD146 and VEGFA in tumor tissue were also significantly increased compared with the control (0.70±0.02 vs. 0.41±0.07 and 0.54±0.01 vs. 0.26±0.01, P<0.01). There was a positive correlation between the expression levels of CD146 and VEGFA genes (r=0.78) and between the two proteins (r=0.69). Dot density frequency analysis indicated that CD146 and VEGFA were specifically present in tumor tissues. In conclusion, CD146 and VEGFA are co-overexpressed in ovarian cancer; their potential as tumor biomarkers or therapeutic targets for the treatment of ovarian cancer requires further investigation.

CD146 promotes migration and proliferation in pulmonary large cell neuroendocrine carcinoma cell lines

Dysregulated expression of the cell surface protein, CD146, has been implicated in various types of cancer in humans, including in lung cancer. The present study aimed to clarify the mechanism underlying abnormal CD146 expression in human pulmonary large cell neuroendocrine carcinoma (LCNEC) cell lines (NCI-H460 and NCI-H810). The functions of CD146 were investigated by measuring cell migration and viability following CD146 knockdown or overexpression via small interference RNA and plasmid transfection. The findings demonstrated that decreased protein expression of CD146 could inhibit migration and viability in LCNEC cells. Furthermore, CD146 was determined to influence the expression of epithelial-mesenchymal transition markers (epithelial cadherin, vimentin and Snail) and promoted AKT phosphorylation. The present results imply CD146 may function in the migration and proliferation of pulmonary LCNEC cells.

Targeted imaging and inhibition of triple-negative breast cancer metastases by a PDGFRβ aptamer

While the overall mortality for breast cancer has recently declined, management of triple-negative breast cancer (TNBC) is still challenging because of its aggressive clinical behavior and the lack of targeted therapies. Genomic profiling studies highlighted the high level of heterogeneity of this cancer, which comprises different subtypes with unique phenotypes and response to treatment. Platelet-derived growth factor receptor β (PDGFRβ) is an established mesenchymal/stem cell-specific marker in human glioblastoma and, as recently suggested, it may uniquely mark breast cancer cells with stem-like characteristics and/or that have undergone epithelial-mesenchymal transition.

Methods: Immunohistochemical analysis for PDGFRβ expression was performed on a human TNBC tissue microarray. Functional assays were conducted on mesenchymal-like TNBC cells to investigate the effect of a previously validated PDGFRβ aptamer on invasive cell growth in three-dimensional culture conditions, migration, invasion and tube formation. The aptamer was labeled with a near-infrared (NIR) dye and its binding specificity to PDGFRβ was assessed both in vitro (confocal microscopy and flow cytometry analyses) and in vivo (fluorescence molecular tomography in mice bearing TNBC xenografts). A mouse model of TNBC lung metastases formation was established and NIR-labeled PDGFRβ aptamer was used to detect lung metastases in mice untreated or intravenously injected with unlabeled aptamer.

Results: Here, we present novel data showing that tumor cell expression of PDGFRβ identifies a subgroup of mesenchymal tumors with invasive and stem-like phenotype, and propose a previously unappreciated role for PDGFRβ in driving TNBC cell invasiveness and metastases formation. We show that the PDGFRβ aptamer blocked invasive growth and migration/invasion of mesenchymal TNBC cell lines and prevented TNBC lung metastases formation. Further, upon NIR-labeling, the aptamer specifically bound to TNBC xenografts and detected lung metastases.

Conclusions: We propose PDGFRβ as a reliable biomarker of a subgroup of mesenchymal TNBCs with invasive and stem-like phenotype as well as the use of the PDGFRβ aptamer as a high efficacious tool for imaging and suppression of TNBC lung metastases. This study will allow for the significant expansion of the current repertoire of strategies for managing patients with more aggressive TNBC.

Establishment and characterization of three stable Basal/HER2-positive breast cancer cell lines derived from Chinese breast carcinoma with identical missense mutations in the DNA-binding domain of TP53

Background

Basal/human epidermal growth factor receptor (HER)2-positive (HER2+) breast cancer is resistant to monoclonal antibody (herceptin) treatment. There are currently only three basal/HER2+ breast cancer cell lines available, but they are not from Chinese populations.

Methods

Three immortalized cell lines (ZJU-0327, ZJU-0725, and ZJU-1127) were established from invasive ductal breast carcinoma tissue of two patients treated by surgical resection at our center. The cell lines were characterized in terms of histology, therapeutic response, and biomarker expression. Their tumorigenic potential was evaluated in an athymic nude (BALB/C nu) mouse xenograft model. Cell authentication testing by the techniques of short tandem repeat.

Results

ZJU-0327, ZJU-0725, and ZJU-1127 cell lines were maintained for more than 110 passages in vitro. The cells grew as monolayers; showed typical epithelial morphology and ultrastructure; were polyploid; had doubling times of 18, 57.5, and 18 h, respectively; had a near-tetraploid (ZJU-0327 and ZJU-1127) or aneuploid (ZJU-0725) karyotype with structural aberrations and tumor protein 53 mutation; insensitive to chemotherapeutic drugs and/or radiation; show high invasiveness and tumorigenicity in mice; and had no mycoplasma contamination. The cell lines were basal/HER2+, expressed cluster of differentiation, and were associated with poor prognosis. Cell authentication testing by the American Type Culture Collection confirmed the human origin of the cell lines, which did not match those in existing databases.

Conclusions

The three novel basal/HER2+ breast cancer cell lines recapitulating the malignant characteristics of the parent tumor's, and can be useful for clarifying the molecular pathogenesis of basal/HER2+ breast cancer.

Epithelial-mesenchymal transition induced PAI-1 is associated with prognosis of triple-negative breast cancer patients

Epithelial-mesenchymal transition (EMT) is a key developmental program in which epithelial cells lose polarity and become mesenchymal cells, and that is often activated during cancer invasion and metastasis. Triple negative breast cancer (TNBC) patients have a relatively aggressive biological behavior with a high risk of distant recurrence and metastasis. Here, we stimulated TNBC cells to undergo EMT, and detected the protein expression profiles of the protein secretion. High-throughput data showed that EMT could promote TNBC cells to secret PAI-1. We found that TNBC-secreted PAI-1 could increase cell growth, migration and invasion, and the expression of EMT markers in the TNBC cell lines and xenograft PAI-1-/- mice model. Using a tissues microarray of 165 TNBC patients and published breast cancer database, we found PAI-1 expression was significantly elevated in the breast cancer tissues, comparing with the normal adjacent tissues and was associated with prognosis of patients with TNBC. Taken together, our results suggests an important role of PAI-1 in the EMT process of TNBC cells and illustrates the great potential of developing PAI-1-targeting therapy for clinical TNBC patients.

CD146 mediates an E-cadherin-to-N-cadherin switch during TGF-β signaling-induced epithelial-mesenchymal transition

Cadherin switch is an initiating factor of epithelial-mesenchymal transition (EMT) and is intimately correlated with cancer metastatic potential; however, its underlying mechanisms remain unclear. Here, using a transforming growth factor-β (TGF-β)-induced EMT model, we provide explicit evidence that CD146, with elevated expression and activity in a variety of cancers, is a key factor involved in the cadherin switch. We show that CD146 can be induced by TGF-β signaling. Moreover, CD146 expression is positively correlated with the activation levels of STAT3/Twist and ERK pathways. Transcriptional response of the CD146/STAT3/Twist cascade inhibits E-cadherin expression, whereas the CD146/ERK cascade enhances N-cadherin expression. CD146 overexpression also significantly promotes EMT in both mouse embryonic fibroblasts (MEFs) and ovarian cancer cells. Clinically, ovarian cancer patients with detectable CD146 expression had a significantly lower survival rate than that of patients without CD146 expression. Furthermore, CD146-deficient MEFs exhibited decreased motility as a result of reversion in this cadherin switch, strongly suggesting that targeting CD146 is a potential strategy for cancer treatment. Therefore, CD146-mediated regulation of the E-cadherin-to-N-cadherin switch provides an insight into the general mechanisms of EMT as well as cancer metastasis.

Dendrosomal nanocurcumin and exogenous p53 can act synergistically to elicit anticancer effects on breast cancer cells

Triple-negative breast cancer (TNBC) constitutes an important histological subtype of breast cancer with a highly metastatic phenotype. The aim of the current study was to investigate the possible synergism between dendrosomal nanocurcumin (DNC) and exogenously delivered p53 in producing anticancer effects on a TNBC cell line. MTT assay was exploited to determine the viability of MDA-MB-231 cells against DNC and measure the impact of p53 overexpresssion on DNC-related cytotoxicity. Annexin-V/PI staining followed by flow cytometry and wound healing assay were used to evaluate the effects of DNC and exogenous p53, alone and in combination, on apoptosis induction and migratory capacity of MDA-MB-231 cells, respectively. Also, quantitative real-time PCR was applied to analyze the transcript levels of EMT- and metastasis-associated genes. Cell viability measurements demonstrated that DNC suppresses the proliferation of MDA-MB-231 cells in a time- and dose-dependent mode and exogenous p53 elevates the sensitivity of cells to DNC-mediated cytotoxic effects. Apoptosis and wound healing assays indicated that combination treatment with DNC and exogenous p53 leads to significantly increased apoptosis and decreased migration of breast cancer cells, compared with single treatment. The results of gene expression analysis highlighted the high potency of combination strategy to significantly reduce the expression of ZEB1 and BMI1 transcript levels. Altogether, our findings reveal that DNC and exogenous p53 act in a synergistic manner to elicit anticancer effects on MDA-MB-231 breast cancer cells. Therefore, our combination approach might be considered as a promising strategy for the development of new therapeutic modalities against breast cancer.

The Prevalence of CD146 Expression in Breast Cancer Subtypes and Its Relation to Outcome

CD146, involved in epithelial-to-mesenchymal transition (EMT), might affect cancer aggressiveness. We here investigated the prevalence of CD146 expression in breast cancer subtypes, its relation to prognosis, the relation between CD146 and EMT and the outcome to tamoxifen. Primary breast cancer tissues from 1342 patients were available for this retrospective study and immunohistochemically stained for CD146. For survival analyses, pure prognosis was studied by only including lymph-node negative patients who did not receive (neo)adjuvant systemic treatment (n = 551). 11% of the tumors showed CD146 expression. CD146 expression was most prevalent in triple-negative cases (64%, p < 0.001). In univariable analysis, CD146 expression was a prognostic factor for both metastasis-free survival (MFS) (p = 0.020) and overall survival (OS) (p = 0.037), but not in multivariable analysis (including age, tumor size, grade, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and Ki-67). No correlation between CD146 and EMT nor difference in outcome to first-line tamoxifen was seen. In this large series, our data showed that CD146 is present in primary breast cancer and is a pure prognostic factor for MFS and OS in breast cancer patients. We did not see an association between CD146 expression and EMT nor on outcome to tamoxifen.

Targeting autophagic cancer stem-cells to reverse chemoresistance in human triple negative breast cancer

There is growing evidence for the role of cancer stem-cells in drug resistance, but with few in situ studies on human tumor samples to decipher the mechanisms by which they resist anticancer agents.Triple negative breast cancer (TNBC) is the most severe sub-type of breast cancer, occurring in younger women and associated with poor prognosis even when treated at a localized stage.We investigated here the relationship between complete pathological response after chemotherapy and breast cancer stem-cell characteristics in pre-treatment biopsies of 78 women with triple negative breast carcinoma (TNBC).We found that chemoresistance was associated with large numbers of breast cancer stem-cells, and that these cancer stem-cells were neither proliferative nor apoptotic, but in an autophagic state related to hypoxia. Using relevant pharmacological models of patient-derived TNBC xenografts, we further investigated the role of autophagy in chemoresistance of breast cancer stem-cells. We demonstrated that hypoxia increased drug resistance of autophagic TNBC stem-cells, and showed that molecular or chemical inhibition of autophagic pathway was able to reverse chemoresistance.Our results support breast cancer stem-cell evaluation in pre-treatment biopsies of TNBC patients, and the need for further research on autophagy inhibition to reverse resistance to chemotherapy.

MDA-9/Syntenin (SDCBP) modulates small GTPases RhoA and Cdc42 via transforming growth factor β1 to enhance epithelial-mesenchymal transition in breast cancer

Epithelial-mesenchymal transition (EMT) is one of the decisive steps regulating cancer invasion and metastasis. However, the molecular mechanisms underlying this transition require further clarification. MDA-9/syntenin (SDCBP) expression is elevated in breast cancer patient samples as well as cultured breast cancer cells. Silencing expression of MDA-9 in mesenchymal metastatic breast cancer cells triggered a change in cell morphology in both 2D- and 3D-cultures to a more epithelial-like phenotype, along with changes in EMT markers, cytoskeletal rearrangement and decreased invasion. Conversely, over expressing MDA-9 in epithelial non-metastatic breast cancer cells instigated a change in morphology to a more mesenchymal phenotype with corresponding changes in EMT markers, cytoskeletal rearrangement and an increase in invasion. We also found that MDA-9 upregulated active levels of known modulators of EMT, the small GTPases RhoA and Cdc42, via TGFβ1. Reintroducing TGFβ1 in MDA-9 silenced cells restored active RhoA and cdc42 levels, modulated cytoskeletal rearrangement and increased invasion. We further determined that MDA-9 interacts with TGFβ1 via its PDZ1 domain. Finally, in vivo studies demonstrated that silencing the expression of MDA-9 resulted in decreased lung metastasis and TGFβ1 re-expression partially restored lung metastases. Our findings provide evidence for the relevance of MDA-9 in mediating EMT in breast cancer and support the potential of MDA-9 as a therapeutic target against metastatic disease.

Gelatin Nanoparticle-Coated Silicon Beads for Density-Selective Capture and Release of Heterogeneous Circulating Tumor Cells with High Purity

Background: Circulating tumor cells (CTCs) are a burgeoning topic in cancer biomarker discovery research with minimal invasive blood draws. CTCs can be used as potential biomarkers for disease prognosis, early cancer diagnosis and pharmacodynamics. However, the extremely low abundance of CTCs limits their clinical utility because of technical challenges such as the isolation and subsequent detailed molecular and functional characterization of rare CTCs from patient blood samples.

Methods: In this study, we present a novel density gradient centrifugation method employing biodegradable gelatin nanoparticles coated on silicon beads for the isolation, release, and downstream analysis of CTCs from colorectal and breast cancer patients.

Results: Using clinical patient/spiked samples, we demonstrate that this method has significant CTC-capture efficiency (>80%) and purity (>85%), high CTC release efficiency (94%) and viability (92.5%). We also demonstrate the unparalleled robustness of our method in downstream CTC analyses such as the detection of PIK3CA mutations.

Conclusion: The efficiency and versatility of the multifunctional density microbeads approach provides new opportunities for personalized cancer diagnostics and treatments.

Chamaejasmine B Induces the Anergy of Vascular Endothelial Cells to VEGFA Pro-angiogenic Signal by Autophagic Regulation of VEGFR2 in Breast Cancer

The neovascularization functions essentially for malignant upgrading and predicts poor prognosis in multiple cancers, which make it the highly effective strategy for clinical treatment. Unfortunately, the known anti-angiogenic therapies show low effectiveness against breast cancer. Recently, rebalancing the pro-angiogenic property in microenvironment shows great advantages and attracts increasing attention for breast cancer treatment. Herein, we for the first time reported that Chamaejasmine B (ICJ), extracted from Stellera chamaejasme L., possessed potent anti-angiogenic effect in breast cancer. By Transwell, tube formation and aortic-ring assays, ICJ efficiently suppressed the neovascularization potential in tumor-HUVEC co-culture model. In Matrigel plug assay, the efficacy of ICJ was further identified in vivo. Mechanistically, with little influence on HUVEC apoptosis, ICJ obviously induced autophagy as proved by the elevated LC3I/II ratio, dotted distribution of LC3 and upregulated Beclin-1. Moreover, by associating with LC3 and in turn, inhibiting the level of VEGFR2, the anti-angiogenesis efficacy was closely dependent on the initiation of autophagy. Above results proved that, by attenuating the pro-angiogenic communication through VEGFR2, ICJ is a novel angiogenic inhibitor and will be a promising supplement for anti-angiogenic chemotherapy for breast cancer.

Reduced CD146 expression promotes tumorigenesis and cancer stemness in colorectal cancer through activating Wnt/β-catenin signaling

Cancer stemness drives tumor progression and drug resistance, representing a challenge to cancer eradication. Compelling evidence indicates that cancer cells can reenter the stem cell state due to the reprogramming of self-renewal machinery. Here, we show that CD146 knockdown induces stem cell properties in colorectal cancer (CRC) cells through activating canonical Wnt signaling. shRNA-mediated CD146 knockdown in CRC cells facilitates tumor initiation in serial xenotransplantation experiments. Moreover, upon CD146 knockdown, CRC cells show elevated expression of specific cancer stem cell (CSC) markers, increased sphere and clone formation as well as drug resistance in vitro. Mechanistically, our findings provide evidence that CD146 expression negatively correlates with canonical Wnt/β-catenin activity in CRC cell lines and primary CRC specimens. Knockdown of CD146 results in inhibition of NF-κB/p65-initiated GSK-3β expression, subsequently promoting nuclear translocation and activation of β-catenin, and as a consequence restoring stem cell phenotypes in differentiated CRC cells. Together, our data strongly suggest that CD146 functions as a suppressor of tumorigenesis and cancer stemness in CRC through inactivating the canonical Wnt/β-catenin cascade. Our findings provide important insights into stem cell plasticity and the multifunctional role of CD146 in CRC progression.

Therapeutic and Diagnostic Antibodies to CD146: Thirty Years of Research on Its Potential for Detection and Treatment of Tumors

CD146 (MCAM, MUC18, S-Endo1) is a transmembrane glycoprotein belonging to both CAM and mucin families. It exists as different splice variants and is cleaved from the membrane by metalloproteases to generate a soluble form. CD146 is expressed by numerous cancer cells as well as being one of the numerous proteins expressed by the vascular endothelium. It has also been identified on smooth muscle cells, pericytes, and some immune cells. This protein was initially described as an actor involved in tumor growth and metastatic dissemination processes. Some recent works highlighted the role of CD146 in angiogenesis. Interestingly, this knowledge allowed the development of therapeutic and diagnostic tools specifically targeting the different CD146 variants. The first anti-CD146 antibody designed to study the function of this molecule, MUC18, was described by the Pr. J.P. Jonhson in 1987. In this review, we will discuss the 30 following years of research focused on the detection, study, and blocking of this protein in physiological and pathological processes.

Identification of differentially expressed genes regulated by molecular signature in breast cancer-associated fibroblasts by bioinformatics analysis

OBJECTIVE

Breast cancer is a severe risk to public health and has adequately convoluted pathogenesis. Therefore, the description of key molecular markers and pathways is of much importance for clarifying the molecular mechanism of breast cancer-associated fibroblasts initiation and progression. Breast cancer-associated fibroblasts gene expression dataset was downloaded from Gene Expression Omnibus database.

METHODS

A total of nine samples, including three normal fibroblasts, three granulin-stimulated fibroblasts and three cancer-associated fibroblasts samples, were used to identify differentially expressed genes (DEGs) between normal fibroblasts, granulin-stimulated fibroblasts and cancer-associated fibroblasts samples. The gene ontology (GO) and pathway enrichment analysis was performed, and protein-protein interaction (PPI) network of the DEGs was constructed by NetworkAnalyst software.

RESULTS

Totally, 190 DEGs were identified, including 66 up-regulated and 124 down-regulated genes. GO analysis results showed that up-regulated DEGs were significantly enriched in biological processes (BP), including cell-cell signalling and negative regulation of cell proliferation; molecular function (MF), including insulin-like growth factor II binding and insulin-like growth factor I binding; cellular component (CC), including insulin-like growth factor binding protein complex and integral component of plasma membrane; the down-regulated DEGs were significantly enriched in BP, including cell adhesion and extracellular matrix organization; MF, including N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase activity and calcium ion binding; CC, including extracellular space and extracellular matrix. WIKIPATHWAYS analysis showed the up-regulated DEGs were enriched in myometrial relaxation and contraction pathways. WIKIPATHWAYS, REACTOME, PID_NCI and KEGG pathway analysis showed the down-regulated DEGs were enriched endochondral ossification, TGF beta signalling pathway, integrin cell surface interactions, beta1 integrin cell surface interactions, malaria and glycosaminoglycan biosynthesis-chondroitin sulfate/dermatan sulphate. The top 5 up-regulated hub genes, CDKN2A, MME, PBX1, IGFBP3, and TFAP2C and top 5 down-regulated hub genes VCAM1, KRT18, TGM2, ACTA2, and STAMBP were identified from the PPI network, and subnetworks revealed these genes were involved in significant pathways, including myometrial relaxation and contraction pathways, integrin cell surface interactions, beta1 integrin cell surface interaction. Besides, the target hsa-mirs for DEGs were identified. hsa-mir-759, hsa-mir-4446-5p, hsa-mir-219a-1-3p and hsa-mir-26a-5p were important miRNAs in this study.

CONCLUSIONS

We pinpoint important key genes and pathways closely related with breast cancer-associated fibroblasts initiation and progression by a series of bioinformatics analysis on DEGs. These screened genes and pathways provided for a more detailed molecular mechanism underlying breast cancer-associated fibroblasts occurrence and progression, holding promise for acting as molecular markers and probable therapeutic targets.

High-throughput flow cytometry screening of human hepatocellular carcinoma reveals CD146 to be a novel marker of tumor-initiating cells

Hepatocellular carcinoma (HCC) remains a common and lethal cancer. Cancer stem cells, or tumor-initiating cells (TICs), are thought to contribute to the pathogenesis of HCC, but remain to be fully characterized. Unbiased screens of primary human HCC cells for the identification of novel HCC TIC markers have not been reported. We conducted high-throughput flow cytometry (HT-FC) profiling to characterize the expression of 375 CD antigens on tumor cells from 10 different human HCC samples. We selected 91 of these for further analysis based on HT-FC data that showed consistent expression in discrete, rare, sortable populations of HCC cells. Nine of these CD antigens demonstrated significantly increased expression in the EpCAM⁺ stem/progenitor fraction of a human HCC cell line and were further evaluated in primary human HCC tissues from 30 different patients. Of the nine tested, only CD146 demonstrated significantly increased expression in HCC tumor tissue as compared with matched adjacent non-tumor liver tissue. CD146⁺CD31⁻CD45⁻ cells purified from HCC tumors and cell lines demonstrated a unique phenotype distinct from mesenchymal stem cells. As compared with other tumor cell fractions, CD146⁺CD31⁻CD45⁻ cells showed significantly increased colony-forming capacity in vitro, consistent with TICs. This study demonstrates that HT-FC screening can be successfully applied to primary human HCC and reveals CD146 to be a novel TIC marker in this disease.

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Unbiased screens of human HCC cells for novel TIC markers have not been reported.

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A high-throughput flow cytometry screen of human HCC cells was successfully performed .

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Candidate TIC markers were further evaluated by RT-PCR and functional assays.

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Of candidates tested, only CD146 expression was significantly increased in HCC tissues.

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CD146⁺ cells had increased colony-forming capacity, consistent with a TIC phenotype.

ImmunoPET Imaging of CD146 in Murine Models of Intrapulmonary Metastasis of Non-Small Cell Lung Cancer

CD146 has been identified as an excellent biomarker for lung cancer as its overexpression in solid tumors has been linked to disease progression, invasion, and metastasis. Previously, our group described a positive correlation between ⁶⁴Cu-labeled YY146 uptake and increased expression of CD146 in six human lung cancer cell lines using subcutaneous tumor models. In this study, we investigate a monoclonal antibody called YY146 for immunoPET imaging of CD146 in two intrapulmonary metastasis models of non-small cell lung cancer (NSCLC). The binding and immunoreactivity of the tracer were assessed by in vitro assays. Radiolabeling of YY146 with positron emitting Cu-64 (⁶⁴Cu-NOTA-YY146) enabled PET imaging of intrapulmonary metastasis. Mice were intravenously injected with two million tumor cells, and CT imaging was used to verify the presence of lung metastases. ⁶⁴Cu-NOTA-YY146 was injected into tumor-bearing mice, and animals were subjected to PET/CT imaging at 4, 24, and 48 h postinjection. Both the average and maximum lung PET signal intensities were quantified and compared between high and low CD146-expressing metastases. Further validation was accomplished through immunofluorescence imaging of resected tissues with CD31 and CD146. In flow cytometry, YY146 revealed strong binding to CD146 in H460 cells due to its high expression with minimal binding to CD146-low expressing H358 cells. Both YY146 and NOTA-YY146 showed similar binding, suggesting that NOTA conjugation did not elicit any negative effects on its binding affinity. Imaging of ⁶⁴Cu-NOTA-YY146 in H460 tumor-bearing mice revealed rapid, persistent, and highly specific tracer accumulation. Uptake of ⁶⁴Cu-NOTA-YY146 in the whole lung was calculated for H460 and H358 as 7.43 ± 0.38 and 3.95 ± 0.47% ID/g at 48 h postinjection (n = 4, p < 0.05), and the maximum lung signals were determined to be 13.85 ± 1.07 (H460) and 6.08 ± 0.73% ID/g (H358) at equivalent time points (n = 4, p < 0.05). To ensure the specificity of the tracer, a nonspecific antibody was injected into H460 tumor-bearing mice. Ex vivo biodistribution and immunofluorescence imaging validated the PET findings. In summary, ⁶⁴Cu-NOTA-YY146 allowed for successful imaging of CD146-expressing intrapulmonary metastases of NSCLC in mice. This preliminary study provides evidence supporting the future clinical utilization of ⁶⁴Cu-NOTA-YY146 for possible treatment monitoring of CD146-targeted therapy or improving patient stratification.

The histone demethylase KDM3A, and its downstream target MCAM, promote Ewing Sarcoma cell migration and metastasis

Ewing Sarcoma is the second most common solid pediatric malignant neoplasm of bone and soft tissue. Driven by EWS/Ets, or rarely variant, oncogenic fusions, Ewing Sarcoma is a biologically and clinically aggressive disease with a high propensity for metastasis. However, the mechanisms underpinning Ewing Sarcoma metastasis are currently not well understood. In the present study, we identify and characterize a novel metastasis-promotional pathway in Ewing Sarcoma, involving the histone demethylase KDM3A, previously identified by our laboratory as a new cancer-promoting gene in this disease. Using global gene expression profiling, we show that KDM3A positively regulates genes and pathways implicated in cell migration and metastasis, and demonstrate, using functional assays, that KDM3A promotes migration in vitro and experimental, post-intravasation, metastasis in vivo. We further identify the melanoma cell adhesion molecule (MCAM) as a novel KDM3A target gene in Ewing Sarcoma, and an important effector of KDM3A pro-metastatic action. Specifically, we demonstrate that MCAM depletion, like KDM3A depletion, inhibits cell migration in vitro and experimental metastasis in vivo, and that MCAM partially rescues impaired migration due to KDM3A knock-down. Mechanistically, we show that KDM3A regulates MCAM expression both through a direct mechanism, involving modulation of H3K9 methylation at the MCAM promoter, and an indirect mechanism, via the Ets1 transcription factor. Finally, we identify an association between high MCAM levels in patient tumors and poor survival, in two different Ewing Sarcoma clinical cohorts. Taken together, our studies uncover a new metastasis-promoting pathway in Ewing Sarcoma, with therapeutically targetable components.

MCAM Mediates Chemoresistance in Small-Cell Lung Cancer via the PI3K/AKT/SOX2 Signaling Pathway

Despite favorable responses to initial therapy, small-cell lung cancer (SCLC) relapse occurs within a year and exhibits resistance to multiple drugs. Because of limited accessibility of patient tissues for research purposes, SCLC patient-derived xenografts (PDX) have provided the best opportunity to address this limitation. Here, we sought to identify novel mechanisms involved in SCLC chemoresistance. Through in-depth proteomic profiling, we identified MCAM as a markedly upregulated surface receptor in chemoresistant SCLC cell lines and in chemoresistant PDX compared with matched treatment-naïve tumors. MCAM depletion in chemoresistant cells reduced cell proliferation and reduced the IC₅₀ inhibitory concentration of chemotherapeutic drugs in vitro This MCAM-mediated sensitization to chemotherapy occurred via SOX2-dependent upregulation of mitochondrial 37S ribosomal protein 1/ATP-binding cassette subfamily C member 1 (MRP1/ABCC1) and the PI3/AKT pathway. Metabolomic profiling revealed that MCAM modulated lactate production in chemoresistant cells that exhibit a distinct metabolic phenotype characterized by low oxidative phosphorylation. Our results suggest that MCAM may serve as a novel therapeutic target to overcome chemoresistance in SCLC. Cancer Res; 77(16); 4414-25. ©2017 AACR.

The signalling receptor MCAM coordinates apical-basal polarity and planar cell polarity during morphogenesis

The apical-basal (AB) polarity and planar cell polarity (PCP) provide an animal cell population with different phenotypes during morphogenesis. However, how cells couple these two patterning systems remains unclear. Here we provide in vivo evidence that melanoma cell adhesion molecule (MCAM) coordinates AB polarity-driven lumenogenesis and c-Jun N-terminal kinase (JNK)/PCP-dependent ciliogenesis. We identify that MCAM is an independent receptor of fibroblast growth factor 4 (FGF4), a membrane anchor of phospholipase C-γ (PLC-γ), an immediate upstream receptor of nuclear factor of activated T-cells (NFAT) and a constitutive activator of JNK. We find that MCAM-mediated vesicular trafficking towards FGF4, while generating a priority-grade transcriptional response of NFAT determines lumenogenesis. We demonstrate that MCAM plays indispensable roles in ciliogenesis through activating JNK independently of FGF signals. Furthermore, mcam-deficient zebrafish and Xenopus exhibit a global defect in left-right (LR) asymmetric establishment as a result of morphogenetic failure of their LR organizers. Therefore, MCAM coordination of AB polarity and PCP provides insight into the general mechanisms of morphogenesis.

Immunohistochemical Expression of MCAM/CD146 in Canine Melanoma

MCAM/CD146 (melanoma cell adhesion molecule/CD146) is a transmembrane immunoglobulin superfamily cell adhesion molecule involved in transendothelial migration and signal transduction. It is expressed in melanoma, squamous cell carcinoma, prostatic, ovarian, cervical and endometrial cancers and promotes tumour growth, angiogenesis and metastasis. Melanoma is the most common malignant oral tumour of dogs and also arises in the skin, nail bed and footpad. The aim of this study was to investigate the immunohistochemical expression of MCAM/CD146 in 51 canine melanomas, including oral, cutaneous and ocular tumours. Seventeen of the 51 (33.3%) cases were negative, eight (15.7%) were weakly positive, seven (13.7%) were moderately positive and 19 (37.3%) were strongly positive. MCAM/CD146 was expressed by both oral and cutaneous melanomas; however, the intensity and the extent of the immunoreactivity was higher in oral (P = 0.009) than in cutaneous tumours (P = 0.058). Most ocular melanomas did not express MCAM/CD146 (P = 0.256). Expression of MCAM/CD146 by canine melanomas may suggest the molecule as a target for treatment, especially in oral melanomas.

Polyethylenimine-dermatan sulfate complex, a bioactive biomaterial with unique toxicity to CD146-positive cancer cells

We report unique bioactivity of a polycation-polyanion complex with potential utility for cancer therapy. A complex of disulfide-crosslinked polyethyleneimine (CLPEI), a polycation used for gene complexation, and dermatan sulfate (DS), an anionic polysaccharide to shield excessive cationic charge of the former, has toxicity to a specific group of cancer cell lines, including B16-F10 murine melanoma, A375SM human melanoma, and PC-3 human prostate cancer cells. These CLPEI-DS-sensitive cells express CD146, which binds to the complex via interaction with DS. There is a positive correlation between toxicity and intracellular level of CLPEI, indicating that the CLPEI-DS-sensitivity is attributable to the increased cellular uptake of CLPEI mediated by the DS-CD146 interactions. In vitro studies show that CLPEI-DS complex causes G₀/G₁ phase arrest and apoptotic cell death. In syngeneic and allograft models of B16-F10 melanoma, CLPEI-DS complex administered with a sub-toxic level of doxorubicin potentiates the chemotherapeutic effect of the drug by loosening tumor tissues. Given the unique toxicity, CLPEI-DS complex may be a useful carrier of gene or chemotherapeutics for the therapy of CD146-positive cancers.

METCAM/MUC18 promoted tumorigenesis of human breast cancer SK-BR-3 cells in a dosage-specific manner

OBJECTIVE

Overexpression of METCAM/MUC18, an immunoglobulin-like cell-adhesion molecule, promotes tumorigenesis and progression of human breast cancer cells. We also observed an intriguing phenomenon that a high-expressing SK-BR-3 clone manifested a transient tumor suppression effect in vivo. The purpose of this study was to understand if this was caused by clonal variation, METCAM/MUC18-dosage effect, or the number of cells injected.

MATERIALS AND METHODS

Several G418-resistant clones of SK-BR-3, expressing different levels of METCAM/MUC18, were obtained for testing effects of human METCAM/MUC18 on in vitro motility, invasiveness, and anchorage-independent colony formation (in vitro tumorigenicity) and in vivo tumorigenesis in female Balb/C athymic nude mice. Tumor sections were made for histology and immunohistochemistry analyses, and tumor lysates for Western blot analysis to determine the effects of human METCAM/MUC18 expression on levels of various downstream effectors.

RESULTS

METCAM/MUC18 promoted in vitro motility, invasiveness, and in vitro tumorigenicity of SK-BR-3 cells in a dosage-specific manner. Overexpression of METCAM/MUC18 could promote in vivo tumorigenesis of SK-BR-3 cells even when one tenth of the previously used cell number (5 × 10(5)) was injected and in vivo tumorigenesis of SK-BR-3 cells was directly proportional to the dosage of the protein. The previously observed transient tumor suppression effect from the same clone was no longer observed. The downstream effector, such as phospho-AKT/AKT ratio, was elevated in the tumors.

CONCLUSION

Transient suppression observed previously in the clone was caused by injection of a high cell number (2 × 10(6)-5 × 10(6)). METCAM/MUC18 positively promotes tumorigenesis of SK-BR-3 cells by increasing the survival and proliferation pathway.

Nestin and cluster of differentiation 146 expression in breast cancer: Predicting early recurrence by targeting metastasis?

The purpose of this study was to investigate the relationship between the expression of stem-cell markers nestin and cluster of differentiation 146 with clinicopathological characteristics in breast cancer and to determine whether a prognostic impact of nestin and CD146 expression exists regarding occurrence of disease relapse in breast cancer. A total of 141 patients who were histologically diagnosed with breast cancer and underwent radical operations from November 2006 to October 2013 in Laiko General Hospital, National and Kapodistrian University of Athens, were enrolled in the study. CD146 and nestin protein expression were evaluated using immunohistochemistry. Nestin expression was observed in 18.4% (26/141) of the cases, while CD146 expression was observed in 35.5% (50/141) of the cases. Nestin expression is significantly higher in younger patients with breast cancer. Nestin and CD146 expression were not correlated with the tumor size and the presence of lymph node metastasis. On the contrary, a significantly higher expression of nestin and CD146 was observed with triple-negative cancers (p < 0.0001 for both markers), low differentiated tumors (p = 0.021 for nestin and p = 0.008 for CD146), and increased Ki-67 expression (p = 0.007 for nestin and p < 0.0001 for CD146). The nestin-positive group of patients and the CD146-positive group of patients presented significantly higher rates of disease recurrence (log-rank test, p = 0.022 for nestin and p = 0.003 for CD146) with a distant metastasis, 30 months after the primary treatment. CD146 but not nestin, however, predicted independently (p = 0.047) disease recurrence. Nestin and CD146 are expressed in breast cancer cells with highly aggressive potency. They might contribute to disease relapse in breast cancer by activating the epithelial-mesenchymal transition pathway and assist tumor neovascularization.

MCAM/CD146 promotes tamoxifen resistance in breast cancer cells through induction of epithelial-mesenchymal transition, decreased ERα expression and AKT activation

Tamoxifen resistance presents a prominent clinical challenge in endocrine therapy for hormone sensitive breast cancer. However, the underlying mechanisms that contribute to tamoxifen resistance are not fully understood. In this study, we established a tamoxifen resistant MCF-7 cell line (MCF-7-Tam-R) by continuously incubating MCF-7 cells with 4-OH-tamoxifen. We found that melanoma cell adhesion molecule (MCAM/CD146), a unique epithelial-to-mesenchymal transition (EMT) inducer, was significantly up-regulated at both mRNA and protein levels in MCF-7-Tam-R cells compared to parental MCF-7 cells. Mechanistic research demonstrated that MCAM promotes tamoxifen resistance by transcriptionally suppressing ERα expression and activating the AKT pathway, followed by induction of EMT. Elevated MCAM expression was inversely correlated with recurrence-free and distant metastasis-free survival in a cohort of 4142 patients with breast cancer derived from a public database, particularly in the subgroup only treated with tamoxifen. These results demonstrate a novel function of MCAM in conferring tamoxifen resistance in breast cancer. Targeting MCAM might be a promising therapeutic strategy to overcome tamoxifen resistance in breast cancer patients.

Lovastatin Reduces Stemness via Epigenetic Reprograming of BMP2 and GATA2 in Human Endometrium and Endometriosis

OBJECTIVE

The stem cell theory in the endometriosis provides an advanced avenue of targeting these cells as a novel therapy to eliminate endometriosis. In this regard, studies showed that lovastatin alters the cells from a stem-like state to more differentiated condition and reduces stemness. The aim of this study was to investigate whether lovastatin treatment could influence expression and methylation patterns of genes regulating differentiation of endometrial mesenchymal stem cells (eMSCs) such as BMP2, GATA2 and RUNX2 as well as eMSCs markers.

MATERIALS AND METHODS

In this experimental investigation, MSCs were isolated from endometrial and endometriotic tissues and treated with lovastatin and decitabin. To investigate the osteogenic and adipogenic differentiation of eMSCs treated with the different concentration of lovastatin and decitabin, BMP2, RUNX2 and GATA2 expressions were measured by real-time polymerase chain reaction (PCR). To determine involvement of DNA methylation in BMP2 and GATA2 gene regulations of eMSCs, we used quantitative Methylation Specific PCR (qMSP) for evaluation of the BMP2 promoter status and differentially methylated region of GATA2 exon 4.

RESULTS

In the present study, treatment with lovastatin increased expression of BMP2 and RUNX2 and induced BMP2 promoter demethylation. We also demonstrated that lovastatin treatment down-regulated GATA2 expression via inducing methylation. In addition, the results indicated that CD146 cell marker was decreased to 53% in response to lovastatin treatment compared to untreated group.

CONCLUSION

These findings indicated that lovastatin treatment could increase the differentiation of eMSCs toward osteogenic and adiogenic lineages, while it decreased expression of eMSCs markers and subsequently reduced the stemness.

Inhibiting CD146 by its Monoclonal Antibody AA98 Improves Radiosensitivity of Cervical Cancer Cells

Background

Cervical cancer is one of the major causes of cancer death of females worldwide. Radiotherapy is considered effective for cervical cancer treatment, but the low radiosensitivity found in some cases severely affects therapeutic outcomes. This study aimed to reveal the role of CD146, an important adhesion molecule facilitating tumor angiogenesis, in regulating radiosensitivity of cervical cancer cells.

Material/Methods

CD146 protein expression was compared in normal cells, cervical cancer cells with lower radiosensitivity, and cervical cancer cells with higher sensitivity from cervical squamous cell carcinoma patients. Anti-CD146 monoclonal antibody AA98 was used to inhibit CD146 in human cervical cancer SiHa cells with relatively low radiosensitivity, and then the cell survival and apoptosis changes after radiation were detected by colony formation assay and flow cytometry.

Results

CD146 protein was significantly up-regulated in cervical cancer cells (P<0.001), especially in cancer cells with lower radiosensitivity. The SiHa cells treated with AA98 showed more obvious inhibition in cell survival (P<0.05) and promotion in cell apoptosis (P<0.01) after radiation, compared to the untreated cells. More dramatic changes in apoptotic factors Caspase 3 and Bcl-XL were also detected in AA98-treated cells.

Conclusions

These results indicate that inhibiting CD146 improves the effect of radiation in suppressing SiHa cells. This study shows the potential of CD146 as a target for increasing radiosensitivity of cervical cancer cells, which might allow improvement in treatment outcome in cervical cancer. Further studies are necessary for understanding the detailed mechanism of CD146 in regulating radiosensitivity.

NUMB negatively regulates the epithelial-mesenchymal transition of triple-negative breast cancer by antagonizing Notch signaling

Triple-negative breast cancer (TNBC), an aggressive subtype of breast cancer with higher rates of early relapse and metastasis, is frequently associated with aberrant activation of epithelial-mesenchymal transition (EMT). Nonetheless, how EMT is initiated and regulated during TNBC progression is not well understood. Here, we report that NUMB is a negative regulator of EMT in both human mammary epithelial cells and breast cancer cells. Reduced NUMB expression was significantly associated with elevated EMT in TNBC. Conversely, overexpression of NUMB strongly attenuated the EMT program and metastasis of TNBC cell lines. Interestingly, we showed that NUMB employs different molecular mechanisms to regulate EMT. In normal mammary epithelial cells and breast cancer cells expressing wild-type p53, NUMB suppressed EMT by stabilizing p53. However, in TNBC cells, loss of NUMB facilitated the EMT program by activating Notch signaling. Consistent with these findings, low NUMB expression and high Notch activity were significantly correlated with the TNBC subtype in patients. Collectively, these findings reveal novel molecular mechanisms of NUMB in the regulation of breast tumor EMT, especially in TNBC.

Anti-Metastatic and Anti-Invasion Effects of a Specific Anti-MUC18 scFv Antibody on Breast Cancer Cells

Breast cancer is the most common malignancy in women. Altered expression of MUC18, a cell surface receptor, and its interaction with Wnt-5a as its ligand, affects the motility and invasiveness of breast cancer cells. In this study, we explored the Wnt-5a binding site and designed an antigenic epitope on the MUC18 receptor using in silico methods. A specific single-chain variable fragment (scFv) was isolated against the epitope by several panning processes. The binding ability of the scFv to the related epitope was evaluated in ELISA and flow cytometry. The inhibitory effects of the selected scFv on MUC18 positive cell line, MDA-MB231, was assessed by migration and invasion assays. The results demonstrated isolation of specific scFv with frequency of 40 % which showed significant binding with the epitope in both ELISA and fluorescence-activated cell sorting (FACS) analyses. The antibody inhibited the migration (76 %) and invasion (67 %) of MUC18 positive cell line. The results suggest the specific anti-MUC18 scFv as an effective antibody for breast cancer immunotherapy.

Ectopic expression of MCAM/MUC18 increases in vitro motility and invasiveness, but decreases in vivo tumorigenesis and metastasis of a mouse melanoma K1735-9 subline in a syngeneic mouse model

Ectopic expression of MCAM/MUC18, a cell adhesion molecule in the immunoglobulin-like gene superfamily, induces two moMCAM/MUC18-minus, non-metastatic mouse melanoma K1735 sublines, K3 (tumor⁺/met^low) and K10 (tumor^-/met^low), to metastasize to lungs in a syngeneic C3H mouse model. In this report, we extended investigation of effects of moMCAM/MUC18 expression on tumorigenesis and metastasis in another lowly metastatic, however highly tumorigenic moMCAM/MUC18-minus mouse melanoma K1735 subline, K9 (tumor⁺⁺⁺/met^low). We transfected this subline with the moMCAM/MUC18 cDNA, selected for G418-resistant clones with different expression levels of moMCAM/MUC18, and used them for testing effects of MCAM/MUC18 expression on in vitro growth rate, motility, and invasiveness, in vivo subcutaneous tumor growth, and pulmonary metastasis in syngeneic C3H brown mice. Similar to K3 and K10 cells, increased expression of MCAM/MUC18 in K9 cells did not significantly affect in vitro growth rate, but increased in vitro motility and invasiveness. Surprisingly, increased expression of MCAM/MUC18 in K9 cells decreased their induction of tumorigenesis and suppressed their establishment of pulmonary nodules in syngeneic C3H brown mice. We concluded that increased MCAM/MUC18 expression in K9 subline increased in vitro epithelial-to-mesenchymal transition; however, it suppressed in vivo tumorigenicity and metastasis. Thus MCAM/MUC18 acts as a tumor and metastasis suppressor for the K9 subline, different from its role in other K1735 sublines, K3 and K10. Different intrinsic co-factors in different K1735 sublines, which modulate the functions of MCAM/MUC18 in the cells that interact differently to the tumor microenvironment, may render sublines manifest differently in tumorigenicity and metastasis in vivo.

MINDEC-An Enhanced Negative Depletion Strategy for Circulating Tumour Cell Enrichment

Most current methods of circulating tumour cell (CTC) enrichment target the epithelial protein EpCAM, which is commonly expressed in adenocarcinoma cells. However, such methods will not recover the fraction of CTCs that have a non-epithelial phenotype due to epithelial–mesenchymal transition. For phenotype-independent CTC enrichment, we developed a new enhanced negative depletion strategy—termed MINDEC—that is based on multi-marker (CD45, CD16, CD19, CD163, and CD235a/GYPA) depletion of blood cells rather than targeted enrichment of CTCs. Here we validated the performance of MINDEC using epithelial and mesenchymal cancer cell lines, demonstrating a mean recovery of 82 ± 10%, high depletion (437 ± 350 residual white blood cells (WBCs)/mL peripheral blood), linearity between spiked and recovered cells (correlation coefficient: r = 0.995), and a low detection limit (≥1 cell recovered in all four replicates spiked with 3 cells). For clinical validation of this method, we enumerated CTCs in peripheral blood samples from patients with metastatic pancreatic cancer, detecting CTCs in 15 of 21 blood samples (71%) from 9 patients. The promising performance of the MINDEC enrichment strategy in our study encourages validation in larger clinical trials.

ImmunoPET for assessing the differential uptake of a CD146-specific monoclonal antibody in lung cancer

PURPOSE

Overexpression of CD146 in solid tumors has been linked to disease progression, invasion, and metastasis. We describe the generation of a ⁶⁴Cu-labeled CD146-specific antibody and its use for quantitative immunoPET imaging of CD146 expression in six lung cancer models.

METHODS

The anti-CD146 antibody (YY146) was conjugated to 1,4,7-triazacyclononane-triacetic acid (NOTA) and radiolabeled with ⁶⁴Cu. CD146 expression was evaluated in six human lung cancer cell lines (A549, NCI-H358, NCI-H522, HCC4006, H23, and NCI-H460) by flow cytometry and quantitative western blot studies. The biodistribution and tumor uptake of ⁶⁴Cu-NOTA-YY146 was assessed by sequential PET imaging in athymic nude mice bearing subcutaneous lung cancer xenografts. The correlation between CD146 expression and tumor uptake of ⁶⁴Cu-NOTA-YY146 was evaluated by graphical software while ex vivo biodistribution and immunohistochemistry studies were performed to validate the accuracy of PET data and spatial expression of CD146.

RESULTS

Flow cytometry and western blot studies showed similar findings with H460 and H23 cells showing high levels of expression of CD146. Small differences in CD146 expression levels were found among A549, H4006, H522, and H358 cells. Tumor uptake of ⁶⁴Cu-NOTA-YY146 was highest in CD146-expressing H460 and H23 tumors, peaking at 20.1 ± 2.86 and 11.6 ± 2.34 %ID/g at 48 h after injection (n = 4). Tumor uptake was lowest in the H522 model (4.1 ± 0.98 %ID/g at 48 h after injection; n = 4), while H4006, A549 and H358 exhibited similar uptake of ⁶⁴Cu-NOTA-YY146. A positive correlation was found between tumor uptake of ⁶⁴Cu-NOTA-YY146 (%ID/g) and relative CD146 expression (r ² = 0.98, p < 0.01). Ex vivo biodistribution confirmed the accuracy of the PET data.

CONCLUSION

The strong correlation between tumor uptake of ⁶⁴Cu-NOTA-YY146 and CD146 expression demonstrates the potential use of this radiotracer for imaging tumors that elicit varying levels of CD146. In the future, this tool may promote enhanced monitoring of therapeutic response and improved patient stratification.

Generation of stem cell-based bioartificial anterior cruciate ligament (ACL) grafts for effective ACL rupture repair

In the present study, we combined stem cell technology with a non-absorbable biomaterial for the reconstruction of the ruptured ACL. Towards this purpose, multipotential stromal cells derived either from subcutaneous human adipose tissue (hAT-MSCs) or from induced pluripotent stem cells (iPSCs) generated from human foreskin fibroblasts (hiPSC-MSCs) were cultured on the biomaterial for 21days in vitro to generate a 3D bioartifical ACL graft. Stem cell differentiation towards bone and ligament at the ends and central part of the biomaterial was selectively induced using either BMP-2/FGF-2 or TGF-β/FGF-2 combinations, respectively. The bioartificial ACL graft was subsequently implanted in a swine ACL rupture model in place of the surgically removed normal ACL. Four months post-implantation, the tissue engineered ACL graft generated an ACL-like tissue exhibiting morphological and biochemical characteristics resembling those of normal ACL.