Publications by authors named "Goran Landberg"

142 Publications

Tumor co-expression of progranulin and sortilin as a prognostic biomarker in breast cancer.

BMC Cancer 2021 Feb 22;21(1):185. Epub 2021 Feb 22.

Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Center for Cancer Research, Sahlgrenska Academy, University of Gothenburg, Box 425, Medicinaregatan 1G, SE-13 90, Gothenburg, Sweden.

Background: The growth factor progranulin has been implicated in numerous biological processes such as wound healing, inflammation and progressive tumorigenesis. Both progranulin and its receptor sortilin are known to be highly expressed in subgroups of breast cancer and have been associated with various clinical properties including tamoxifen resistance. Recent data further suggest that progranulin, via its receptor sortilin, drives breast cancer stem cell propagation in vitro and increases metastasis formation in an in vivo breast cancer xenograft model. In this retrospective biomarker analysis, we aimed to determine whether tumor co-expression of progranulin and sortilin has prognostic and treatment predictive values for breast cancer patients.

Methods: We explored how co-expression of progranulin and sortilin was associated with established clinical markers by analyzing a tissue microarray including 560 randomized premenopausal breast cancer patients receiving either 2 years of tamoxifen treatment or no adjuvant treatment, with a median follow-up time of 28 years. Breast cancer-specific survival was analyzed using Kaplan-Meier and Cox Proportional Hazards regression models to assess the prognostic and predictive value of progranulin and sortilin in relation to known clinical markers.

Results: Co-expression of progranulin and sortilin was observed in 20% of the breast cancer samples. In untreated patients, prognostic considerations could be detailed separately from treatment prediction and the high progranulin and sortilin expressing subgroup was significantly associated with breast cancer-specific death in multivariable analyses (HR=2.188, CI: 1.317-3.637, p=0.003) along with tumor size, high tumor grade and lymph node positivity. When comparing the untreated patients with tamoxifen treated patients in the ERα positive subgroup, co-expression of progranulin and sortilin was not linked to tamoxifen resistance.

Conclusion: Data suggest that co-expression of progranulin and its receptor sortilin is a novel prognostic biomarker combination identifying a highly malignant subgroup of breast cancer. Importantly, this subpopulation could potentially be targeted with anti-sortilin based therapies.
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http://dx.doi.org/10.1186/s12885-021-07854-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7898426PMC
February 2021

Breast cancer patient-derived scaffolds as a tool to monitor chemotherapy responses in human tumor microenvironments.

J Cell Physiol 2021 Jun 23;236(6):4709-4724. Epub 2020 Dec 23.

Department of Laboratory Medicine, Sahlgrenska Center for Cancer Research, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.

Breast cancer is a heterogeneous disease where the tumor microenvironment, including extracellular components, plays a crucial role in tumor progression, potentially modulating treatment response. Different approaches have been used to develop three-dimensional models able to recapitulate the complexity of the extracellular matrix. Here, we use cell-free patient-derived scaffolds (PDSs) generated from breast cancer samples that were recellularized with cancer cell lines as an in vivo-like culture system for drug testing. We show that PDS cultured MCF7 cancer cells increased their resistance against the front-line chemotherapy drugs 5-fluorouracil, doxorubicin and paclitaxel in comparison to traditional two-dimensional cell cultures. The gene expression of the environmentally adapted cancer cells was modulated in different ways depending on the drug and the concentration used. High doses of doxorubicin reduced cancer stem cell features, whereas 5-fluorouracil increased stemness and decreased the proliferative phenotype. By using PDSs repopulated with other breast cancer cell lines, T-47D and MDA-MB-231, we observed both general and cell line specific drug responses. In summary, PDSs can be used to examine the extracellular matrix influence on cancer drug responses and for testing novel compounds in in vivo-like microenvironments.
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http://dx.doi.org/10.1002/jcp.30191DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8049042PMC
June 2021

Patient-derived scaffolds as a model of colorectal cancer.

Cancer Med 2021 Feb 23;10(3):867-882. Epub 2020 Dec 23.

Sahlgrenska Center for Cancer Research, Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.

Background: Colorectal cancer is the second most common cause of cancer-related death worldwide and standardized therapies often fail to treat the more aggressive and progressive types of colorectal cancer. Tumor cell heterogeneity and influence from the surrounding tumor microenvironment (TME) contribute to the complexity of the disease and large variability in clinical outcomes.

Methods: To model the heterogeneous nature of colorectal cancer, we used patient-derived scaffolds (PDS), which were obtained via decellularization of surgically resected tumor material, as a growth substrate for standardized cell lines.

Results: After confirmation of native cell absence and validation of the structural and compositional integrity of the matrix, 89 colorectal PDS were repopulated with colon cancer cell line HT29. After 3 weeks of PDS culture, HT29 cells varied their gene and protein expression profiles considerably compared to 2D-grown HT29 cells. Markers associated with proliferation were consistently decreased, while markers associated with pluripotency were increased in PDS-grown cells compared to their 2D counterparts. When comparing the PDS-induced changes in HT29 cells with clinically relevant tumor information from individual patients, we observed significant associations between stemness/pluripotency markers and tumor location, and between epithelial-to-mesenchymal transition (EMT) markers and cancer mortality. Kaplan-Meier analysis revealed that low PDS-induced EMT correlated with worse cancer-specific survival.

Conclusions: The colorectal PDS model can be used as a simplified personalized tool that can potentially reveal important diagnostic and pathophysiological information related to the TME.
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http://dx.doi.org/10.1002/cam4.3668DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7897946PMC
February 2021

The mevalonate precursor enzyme HMGCS1 is a novel marker and key mediator of cancer stem cell enrichment in luminal and basal models of breast cancer.

PLoS One 2020 21;15(7):e0236187. Epub 2020 Jul 21.

Sahlgrenska Cancer Center, Department of Laboratory Medicine, Gothenburg, Sweden.

The definitive characterization of common cancer stem cell (CSCs) subpopulations in breast cancer subtypes with distinct genotypic and phenotypic features remains an ongoing challenge. In this study, we have used a non-biased genome wide screening approach to identify transcriptional networks that may be specific to the CSC subpopulations in both luminal and basal breast cancer subtypes. In depth studies of three CSC-enriched breast cancer cell lines representing various subtypes of breast cancer revealed a striking hyperactivation of the mevalonate metabolic pathway in comparison to control cells. The upregulation of metabolic networks is a key feature of tumour cells securing growth and proliferative capabilities and dysregulated mevalonate metabolism has been associated with tumour malignancy and cellular transformation in breast cancer. Furthermore, accumulating evidence suggests that Simvastatin therapy, a mevalonate pathway inhibitor, could affect breast cancer progression and reduce breast cancer recurrence. When detailing the mevalonate pathway in breast cancer using a single-cell qPCR, we identified the mevalonate precursor enzyme, HMGCS1, as a specific marker of CSC-enriched subpopulations within both luminal and basal tumour subtypes. Down-regulation of HMGCS1 also decreased the CSC fraction and function in various model systems, suggesting that HMGCS1 is essential for CSC-activities in breast cancer in general. These data was supported by strong associations between HMGCS1 expression and aggressive features, such as high tumour grade, p53 mutations as well as ER-negativity in lymph node positive breast cancer. Importantly, loss of HMGCS1 also had a much more pronounced effect on CSC-activities compared to treatment with standard doses of Simvastatin. Taken together, this study highlights HMGCS1 as a potential gatekeeper for dysregulated mevalonate metabolism important for CSC-features in both luminal and basal breast cancer subtypes. Pharmacological inhibition of HMGCS1 could therefore be a superior novel treatment approach for breast cancer patients via additional CSC blocking functions.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0236187PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7373278PMC
September 2020

Characterization of cell-free breast cancer patient-derived scaffolds using liquid chromatography-mass spectrometry/mass spectrometry data and RNA sequencing data.

Data Brief 2020 Aug 16;31:105860. Epub 2020 Jun 16.

Department of Laboratory medicine, Institute of Biomedicine, Sahlgrenska Academy, Sahlgrenska Cancer Center, University of Gothenburg, SE-41390 Gothenburg, Sweden.

Patient-derived scaffolds (PDSs) generated from primary breast cancer tumors can be used to model the tumor microenvironment . Patient-derived scaffolds are generated by repeated detergent washing, removing all cells. Here, we analyzed the protein composition of 15 decellularized PDSs using liquid chromatography-mass spectrometry/mass spectrometry. One hundred forty-three proteins were detected and their relative abundance was calculated using a reference sample generated from all PDSs. We performed heatmap analysis of all the detected proteins to display their expression patterns across different PDSs together with pathway enrichment analysis to reveal which processes that were connected to PDS protein composition. This protein dataset together with clinical information is useful to investigators studying the microenvironment of breast cancers. Further, after repopulating PDSs with either MCF7 or MDA-MB-231 cells, we quantified their gene expression profiles using RNA sequencing. These data were also compared to cells cultured in conventional 2D conditions, as well as to cells cultured as xenografts in immune-deficient mice. We investigated the overlap of genes regulated between these different culture conditions and performed pathway enrichment analysis of genes regulated by both PDS and xenograft cultures compared to 2D in both cell lines to describe common processes associated with both culture conditions. Apart from our described analyses of these systems, these data are useful when comparing different experimental model systems. Downstream data analyses and interpretations can be found in the research article "Patient-derived scaffolds uncover breast cancer promoting properties of the microenvironment" [1].
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http://dx.doi.org/10.1016/j.dib.2020.105860DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7327418PMC
August 2020

Patient-derived scaffolds uncover breast cancer promoting properties of the microenvironment.

Biomaterials 2020 03 23;235:119705. Epub 2019 Dec 23.

Department of Laboratory Medicine, Institute of Biomedicine, Sahlgrenska Academy, Sahlgrenska Cancer Center, University of Gothenburg, SE-41390, Gothenburg, Sweden; Wallenberg Center for Molecular and Translational Medicine, University of Gothenburg, SE-41390, Gothenburg, Sweden; Department of Clinical Genetics and Genomics, Sahlgrenska University Hospital, SE-41390, Gothenburg, Sweden. Electronic address:

Tumor cells interact with the microenvironment that specifically supports and promotes tumor development. Key components in the tumor environment have been linked to various aggressive cancer features and can further influence the presence of subpopulations of cancer cells with specific functions, including cancer stem cells and migratory cells. To model and further understand the influence of specific microenvironments we have developed an experimental platform using cell-free patient-derived scaffolds (PDSs) from primary breast cancers infiltrated with standardized breast cancer cell lines. This PDS culture system induced a series of orchestrated changes in differentiation, epithelial-mesenchymal transition, stemness and proliferation of the cancer cell population, where an increased cancer stem cell pool was confirmed using functional assays. Furthermore, global gene expression profiling showed that PDS cultures were similar to xenograft cultures. Mass spectrometry analyses of cell-free PDSs identified subgroups based on their protein composition that were linked to clinical properties, including tumor grade. Finally, we observed that an induction of epithelial-mesenchymal transition-related genes in cancer cells growing on the PDSs were significantly associated with clinical disease recurrences in breast cancer patients. Patient-derived scaffolds thus mimics in vivo-like growth conditions and uncovers unique information about the malignancy-inducing properties of tumor microenvironment.
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http://dx.doi.org/10.1016/j.biomaterials.2019.119705DOI Listing
March 2020

Breast cancer stromal clotting activation (Tissue Factor and thrombin): A pre-invasive phenomena that is prognostic in invasion.

Cancer Med 2020 03 21;9(5):1768-1778. Epub 2020 Jan 21.

Faculty of Biology, Medicine and Health, Division of Cancer Sciences, School of Medical Sciences, Manchester Cancer Research Centre, University of Manchester, Manchester, UK.

Background: Tumor stroma, of which fibroblasts are the most abundant cell, resembles a non-healing wound, where a procoagulant environment creates a permissive milieu for cancer growth. We aimed to determine if tumor expression of coagulation factors (procoagulant phenotype), and systemic hypercoagulability, occur at the preinvasive (ductal carcinoma in situ; DCIS) stage and correlate with breast cancer subtype, disease-free survival (DFS), and overall survival (OS).

Methods: In a prospective cohort of early breast cancer (DCIS, n = 76; invasive, n = 248) tumor, normal breast and plasma were examined. Fibroblast and epithelial expression of Tissue Factor (TF), thrombin, PAR1, PAR2, and plasma thrombin-antithrombin (TAT) and D-dimer were correlated with clinicopathological data, and 5-year survival.

Results: Fibroblast expression of TF, thrombin, and PAR1 was increased in DCIS and invasive cancer compared to normal breast fibroblasts (P ≤ .003, all). Fibroblast TF, thrombin, PAR1, and PAR2 was increased in cancers with high Ki67, high grade, ER- (vs ER+), and HER2+ (vs HER2-) (all P < .05). On univariate analysis, fibroblast TF expression was inversely associated with DFS (P = .04) and OS (P = .02). D-dimer was higher in node positive (507 (CI: 411-625) ng/mL, n = 68) vs negative patients (428 (CI: 387-472) ng/mL, n = 171, P = .004) and inversely associated with OS (P = .047). On multivariate analysis, plasma TAT was associated with reduced OS (HR 3.26, CI 1.16-3.1, P = .02), with a high plasma TAT (≥3.2 ng/mL) associated with > 3-fold mortality risk compared to low TAT.

Conclusion: This demonstrates procoagulant phenotypic changes occur in fibroblasts at the preinvasive stage. Fibroblast procoagulant phenotype is associated with aggressive breast cancer subtypes and reduced survival. Coagulation may be a therapeutic target in breast cancer.
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http://dx.doi.org/10.1002/cam4.2748DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7050075PMC
March 2020

Identification of Breast Cancer Stem Cell Related Genes Using Functional Cellular Assays Combined With Single-Cell RNA Sequencing in MDA-MB-231 Cells.

Front Genet 2019 22;10:500. Epub 2019 May 22.

Department of Pathology and Genetics, Institute of Biomedicine, Sahlgrenska Cancer Center, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.

Breast cancer tumors display different cellular phenotypes. A growing body of evidence points toward a population of cancer stem cells (CSCs) that is important for metastasis and treatment resistance, although the characteristics of these cells are incomplete. We used mammosphere formation assay and label-retention assay as functional cellular approaches to enrich for cells with different degree of CSC properties in the breast cancer cell line MDA-MB-231 and performed single-cell RNA sequencing. We clustered the cells based on their gene expression profiles and identified three subpopulations, including a CSC-like population. The cell clustering into these subpopulations overlapped with the cellular enrichment approach applied. To molecularly define these groups, we identified genes differentially expressed between the three subpopulations which could be matched to enriched gene sets. We also investigated the transition process from CSC-like cells into more differentiated cell states. In the CSC population we found 14 significantly upregulated genes. Some of these potential breast CSC markers are associated to reported stem cell properties and clinical survival data, but further experimental validation is needed to confirm their cellular functions. Detailed characterization of CSCs improve our understanding of mechanisms for tumor progression and contribute to the identification of new treatment targets.
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http://dx.doi.org/10.3389/fgene.2019.00500DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6541172PMC
May 2019

Hypoxia-induced secretion stimulates breast cancer stem cell regulatory signalling pathways.

Mol Oncol 2019 08 26;13(8):1693-1705. Epub 2019 Jun 26.

Department of Pathology and Genetics, Institute of Biomedicine, Sahlgrenska Cancer Center, University of Gothenburg, Sweden.

It is well known that tumour cells are dependent on communication with the tumour microenvironment. Previously, it has been shown that hypoxia (HX) induces pronounced, diverse and direct effects on cancer stem cell (CSC) qualities in different breast cancer subtypes. Here, we describe the mechanism by which HX-induced secretion influences the spreading of CSCs. Conditioned media (CM) from estrogen receptor (ER)-α-positive hypoxic breast cancer cell cultures increased the fraction of CSCs compared to normal growth conditions, as determined using sets of CSC assays and model systems. In contrast, media from ERα-negative hypoxic cell cultures instead decreased this key subpopulation of cancer cells. Further, there was a striking overrepresentation of JAK-STAT-associated cytokines in both the ERα-positive and ERα-negative linked hypoxic responses as determined by a protein screen of the CM. JAK-STAT inhibitors and knockdown experiments further supported the hypothesis that this pathway is critical for the CSC-activating and CSC-inactivating effects induced by hypoxic secretion. We also observed that the interleukin-6-JAK2-STAT3 axis was specifically central for the ERα-negative hypoxic behaviour. Our results underline the importance of considering breast cancer subtypes in treatments targeting JAK-STAT or HX-associated processes and indicate that HX is not only a confined tumour biological event, but also influences key tumour properties in widespread normoxic microenvironments.
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http://dx.doi.org/10.1002/1878-0261.12500DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6670019PMC
August 2019

JAK-STAT signalling controls cancer stem cell properties including chemotherapy resistance in myxoid liposarcoma.

Int J Cancer 2019 07 29;145(2):435-449. Epub 2019 Jan 29.

Sahlgrenska Cancer Center, Department of Pathology and Genetics, Institute of Biomedicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden.

Myxoid liposarcoma (MLS) shows extensive intratumoural heterogeneity with distinct subpopulations of tumour cells. Despite improved survival of MLS patients, existing therapies have shortcomings as they fail to target all tumour cells. The nature of chemotherapy-resistant cells in MLS remains unknown. Here, we show that MLS cell lines contained subpopulations of cells that can form spheres, efflux Hoechst dye and resist doxorubicin, all properties attributed to cancer stem cells (CSCs). By single-cell gene expression, western blot, phospho-kinase array, immunoprecipitation, immunohistochemistry, flow cytometry and microarray analysis we showed that a subset of MLS cells expressed JAK-STAT genes with active signalling. JAK1/2 inhibition via ruxolitinib decreased, while stimulation with LIF increased, phosphorylation of STAT3 and the number of cells with CSC properties indicating that JAK-STAT signalling controlled the number of cells with CSC features. We also show that phosphorylated STAT3 interacted with the SWI/SNF complex. We conclude that MLS contains JAK-STAT-regulated subpopulations of cells with CSC features. Combined doxorubicin and ruxolitinib treatment targeted both proliferating cells as well as cells with CSC features, providing new means to circumvent chemotherapy resistance in treatment of MLS patients.
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http://dx.doi.org/10.1002/ijc.32123DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6590236PMC
July 2019

Sortilin inhibition limits secretion-induced progranulin-dependent breast cancer progression and cancer stem cell expansion.

Breast Cancer Res 2018 11 20;20(1):137. Epub 2018 Nov 20.

Department of Pathology and Genetics, Institute of Biomedicine, Sahlgrenska Cancer Center, University of Gothenburg, Gothenburg, Sweden.

Background: Cancer progression is influenced by genetic aberrations in the cancer cell population as well as by other factors including the microenvironment present within a tumour. Direct interactions between various cell types as well as cellular signalling via secreted cytokines can drive key tumourigenic properties associated with disease progression and treatment resistance. Also, cancer stem cell functions are influenced by the microenvironment. This challenging subset of cells has been linked to malignant properties. Within a screen, using in vivo like growth conditions, we identified progranulin as a highly secreted cytokine affecting cancer stem cells in breast cancer. This cytokine is known to play a role in numerous biological and tumour-related processes including therapy resistance in a range of cancer types.

Methods: Different in vitro and in vivo relevant conditions were used to validate breast cancer stem cell expansion mediated by progranulin and its receptor sortilin. Small interfering ribonucleic acid (siRNA) and pharmacological inhibition of sortilin were used to elucidate the role of sortilin as a functional receptor during progranulin-induced breast cancer stem cell propagation, both in vitro and in vivo, using breast cancer xenograft models. In addition, single-cell gene expression profiling as well as a Sox2 reporter breast cancer cell line were used to validate the role of dedifferentiation mediated by progranulin.

Results: In various in vivo-like screening assays, progranulin was identified as a potent cancer stem cell activator, highly secreted in ERα-negative breast cancer as well as in ERα-positive breast cancer under hypoxic adaptation. Progranulin exposure caused dedifferentiation as well as increased proliferation of the cancer stem cell pool, a process that was shown to be dependent on its receptor sortilin. Subcutaneous injections of progranulin or its active domain (GRN A) induced lung metastases in breast cancer xenograft models, supporting a major role for progranulin in cancer progression. Importantly, an orally bioavailable small molecule (AF38469) targeting sortilin, blocked GRN A-induced lung metastases and prevented cancer cell infiltration of the skin.

Conclusion: The collective results suggest that sortilin targeting represents a potential novel breast cancer therapy approach inhibiting tumour progression driven by secretion and microenvironmental influences.
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http://dx.doi.org/10.1186/s13058-018-1060-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6245804PMC
November 2018

Identification of inhibitors regulating cell proliferation and FUS-DDIT3 expression in myxoid liposarcoma using combined DNA, mRNA, and protein analyses.

Lab Invest 2018 07 27;98(7):957-967. Epub 2018 Mar 27.

Sahlgrenska Cancer Center, Department of Pathology and Genetics, Institute of Biomedicine, Sahlgrenska Academy at University of Gothenburg, Medicinaregatan 1F, 413 90, Gothenburg, Sweden.

FUS-DDIT3 belongs to the FET (FUS, EWSR1, and TAF15) family of fusion oncogenes, which collectively are considered to be key players in tumor development. Even though over 90% of all myxoid liposarcomas (MLS) have a FUS-DDIT3 gene fusion, there is limited understanding of the signaling pathways that regulate its expression. In order to study cell proliferation and FUS-DDIT3 regulation at mRNA and protein levels, we first developed a direct cell lysis approach that allows DNA, mRNA, and protein to be analyzed in the same sample using quantitative PCR, reverse transcription quantitative qPCR and proximity ligation assay, respectively. We screened 70 well-characterized kinase inhibitors and determined their effects on cell proliferation and expression of FUS-DDIT3 and FUS at both mRNA and protein levels in the MLS 402-91 cell line, where twelve selected inhibitors were evaluated further in two additional MLS cell lines. Both FUS-DDIT3 and FUS mRNA expression correlated with cell proliferation and both transcripts were co-regulated in most conditions, indicating that the common 5' FUS promotor is important in transcriptional regulation. In contrast, FUS-DDIT3 and FUS protein levels displayed more cell line dependent expression. Furthermore, most JAK inhibitors caused FUS-DDIT3 downregulation at both mRNA and protein levels. In conclusion, defining factors that regulate FUS-DDIT3 expression opens new means to understand MLS development at the molecular level.
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http://dx.doi.org/10.1038/s41374-018-0046-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6070472PMC
July 2018

Cellular organization and molecular differentiation model of breast cancer-associated fibroblasts.

Mol Cancer 2017 04 3;16(1):73. Epub 2017 Apr 3.

Department of Pathology, Sahlgrenska Cancer Center, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.

Background: The role of cancer-associated fibroblasts (CAFs) during tumour progression is obscured by the inherently complex, heterotypic nature of fibroblast cells and behaviours in various subtypes of malignancies. Therefore, we sought to identify distinct fibroblast subpopulations at the single-cell level.

Methods: Using single-cell quantitative PCR as a powerful tool to study heterogeneity and rare cell events, in a high-throughput manner a panel of gene targets are run simultaneously on transcripts isolated from single cells obtained by fluorescence-activated cell sort. Assessment of cells with stem-like characteristics was attained by anchorage-independent, anoikis-resistant culture.

Results: Single-cell analysis of fibroblasts and their tumour-activated counterparts demonstrated molecularly distinct cell types defined by differential expression of characteristic mesenchymal and fibroblast activation markers. Identified subpopulations presented overlapping gene expression patterns indicating transitional molecular states during fibroblast differentiation. Using single-cell resolution data we generated a molecular differentiation model which enabled the classification of patient-derived fibroblasts, validating our modelling approach. Remarkably, a subset of fibroblasts displayed expression of pluripotency markers, which was enriched for in non-adherent conditions. Yet the ability to form single-cell derived spheres was generally reduced in CAFs and upon fibroblast activation through TGFβ1 ligand and cancer cell-secreted factors. Hence, our data imply the existence of putative stem/progenitor cells as a physiological feature of undifferentiated fibroblasts.

Conclusions: Within this comprehensive study we have identified distinct and intersecting molecular profiles defining fibroblast activation states and propose that underlying cellular heterogeneity, fibroblasts are hierarchically organized. Understanding the molecular make-up of cellular organization and differentiation routes will facilitate the discovery of more specific markers for stromal subtypes and targets for anti-stromal therapies.
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http://dx.doi.org/10.1186/s12943-017-0642-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5376683PMC
April 2017

Cell Cycle and Cell Size Dependent Gene Expression Reveals Distinct Subpopulations at Single-Cell Level.

Front Genet 2017 25;8. Epub 2017 Jan 25.

Department of Pathology and Genetics, Sahlgrenska Cancer Center, Institute of Biomedicine, University of Gothenburg Gothenburg, Sweden.

Cell proliferation includes a series of events that is tightly regulated by several checkpoints and layers of control mechanisms. Most studies have been performed on large cell populations, but detailed understanding of cell dynamics and heterogeneity requires single-cell analysis. Here, we used quantitative real-time PCR, profiling the expression of 93 genes in single-cells from three different cell lines. Individual unsynchronized cells from three different cell lines were collected in different cell cycle phases (G0/G1 - S - G2/M) with variable cell sizes. We found that the total transcript level per cell and the expression of most individual genes correlated with progression through the cell cycle, but not with cell size. By applying the random forests algorithm, a supervised machine learning approach, we show how a multi-gene signature that classifies individual cells into their correct cell cycle phase and cell size can be generated. To identify the most predictive genes we used a variable selection strategy. Detailed analysis of cell cycle predictive genes allowed us to define subpopulations with distinct gene expression profiles and to calculate a cell cycle index that illustrates the transition of cells between cell cycle phases. In conclusion, we provide useful experimental approaches and bioinformatics to identify informative and predictive genes at the single-cell level, which opens up new means to describe and understand cell proliferation and subpopulation dynamics.
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http://dx.doi.org/10.3389/fgene.2017.00001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5263129PMC
January 2017

High expression of stromal PDGFRβ is associated with reduced benefit of tamoxifen in breast cancer.

J Pathol Clin Res 2017 Jan 14;3(1):38-43. Epub 2016 Sep 14.

Department of Oncology-Pathology Cancer Center Karolinska, Karolinska Institutet Stockholm Sweden.

Cancer-associated fibroblasts (CAFs) regulate tumour growth, metastasis and response to treatment. Recent studies indicate the existence of functionally distinct CAF subsets. Suggested mechanisms whereby CAFs can impact on treatment response include paracrine signalling affecting cancer cell drug sensitivity and effects on tumour drug uptake. PDGFRβ is an important regulator of fibroblasts. Experimental studies have linked PDGFRβ-positive fibroblasts to metastasis and also to reduced tumour drug uptake. This study has investigated the potential role of PDGFRβ-positive fibroblasts in response to adjuvant tamoxifen treatment of breast cancer. Analyses of two breast cancer collections from randomised studies analysing adjuvant tamoxifen treatment in early breast cancer demonstrated significant benefit of tamoxifen in the group with low stromal PDGFRβ, which was not observed in the group with high stromal PDGFRβ. In general terms these findings provide novel evidence, derived from analyses of randomised clinical studies, of response-predictive capacity of a marker-defined subset of CAFs and, more specifically, identify stromal PDGFRβ as a marker related to tamoxifen benefit in early breast cancer.
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http://dx.doi.org/10.1002/cjp2.56DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5259559PMC
January 2017

Tissue Factor promotes breast cancer stem cell activity in vitro.

Oncotarget 2017 Apr;8(16):25915-25927

The University of Manchester, Manchester Academic Health Science Centre, Department of Academic Surgery, University Hospital of South Manchester, Manchester, UK.

Cancer stem cells (CSCs) are a subpopulation of cells that can self-renew and initiate tumours. The clotting-initiating protein Tissue Factor (TF) promotes metastasis and may be overexpressed in cancer cells with increased CSC activity. We sought to determine whether TF promotes breast CSC activity in vitro using human breast cancer cell lines. TF expression was compared in anoikis-resistant (CSC-enriched) and unselected cells. In cells sorted into of TF-expressing and TF-negative (FACS), and in cells transfected to knockdown TF (siRNA) and overexpress TF (cDNA), CSC activity was compared by (i) mammosphere forming efficiency (MFE) (ii) holoclone colony formation (Hc) and (iii) ALDH1 activity. TF expression was increased in anoikis-resistant and high ALDH1-activity T47D cells compared to unselected cells. FACS sorted TF-expressing T47Ds and TF-overexpressing MCF7s had increased CSC activity compared to TF-low cells. TF siRNA cells (MDAMB231,T47D) had reduced CSC activity compared to control cells. FVIIa increased MFE and ALDH1 in a dose-dependent manner (MDAMB231, T47D). The effects of FVIIa on MFE were abrogated by TF siRNA (T47D). Breast CSCs (in vitro) demonstrate increased activity when selected for high TF expression, when induced to overexpress TF, and when stimulated (with FVIIa). Targeting the TF pathway in vivo may abrogate CSC activity.
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http://dx.doi.org/10.18632/oncotarget.13928DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5432226PMC
April 2017

Lipid Heterogeneity Resulting from Fatty Acid Processing in the Human Breast Cancer Microenvironment Identified by GCIB-ToF-SIMS Imaging.

Anal Chem 2016 12 9;88(23):11946-11954. Epub 2016 Nov 9.

Department of Chemistry and Molecular Biology, University of Gothenburg , Gothenburg 412 96, Sweden.

Breast cancer is an umbrella term used to describe a collection of different diseases with broad inter- and intratumor heterogeneity. Understanding this variation is critical in order to develop, and precisely prescribe, new treatments. Changes in the lipid metabolism of cancerous cells can provide important indications as to the metabolic state of the cells but are difficult to investigate with conventional histological methods. Due to the introduction of new higher energy (40 kV) gas cluster ion beams (GCIBs), time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging is now capable of providing information on the distribution of hundreds of molecular species simultaneously on a cellular to subcellular scale. GCIB-ToF-SIMS was used to elucidate changes in lipid composition in nine breast cancer biopsy samples. Improved molecular signal generation by the GCIB produced location-specific information that revealed elevated levels of essential lipids to be related to inflammatory cells in the stroma, while cancerous areas were dominated by nonessential fatty acids and a variety of phosphatidylinositol species with further in-tumor variety arising from decreased desaturase activity. These changes in lipid composition due to different enzyme activity are seemingly independent of oxygen availability and can be linked to favorable cell membrane properties for either proliferation/invasion or drug resistance/survival.
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http://dx.doi.org/10.1021/acs.analchem.6b03884DOI Listing
December 2016

Naphthalene Derivatives from the Roots of Pentas parvifolia and Pentas bussei.

J Nat Prod 2016 09 12;79(9):2181-7. Epub 2016 Aug 12.

Department of Chemistry and Molecular Biology, University of Gothenburg , SE-412 96 Gothenburg, Sweden.

The phytochemical investigation of the CH2Cl2/MeOH (1:1) extract of the roots of Pentas parvifolia led to the isolation of three new naphthalenes, parvinaphthols A (1), B (2), and C (3), two known anthraquinones, and five known naphthalene derivatives. Similar investigation of the roots of Pentas bussei afforded a new polycyclic naphthalene, busseihydroquinone E (4), a new 2,2'-binaphthralenyl-1,1'-dione, busseihydroquinone F (5), and five known naphthalenes. All purified metabolites were characterized by NMR and MS data analyses, whereas the absolute configurations of 3 and 4 were determined by single-crystal X-ray diffraction studies. The E-geometry of compound 5 was supported by DFT-based chemical shift calculations. Compounds 2-4 showed marginal cytotoxicity against the MDA-MB-231 human triple-negative breast cancer cell line with IC50 values ranging from 62.3 to 129.6 μM.
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http://dx.doi.org/10.1021/acs.jnatprod.6b00178DOI Listing
September 2016

Identification of Distinct Breast Cancer Stem Cell Populations Based on Single-Cell Analyses of Functionally Enriched Stem and Progenitor Pools.

Stem Cell Reports 2016 Jan;6(1):121-36

Department of Pathology, Institute of Biomedicine, Sahlgrenska Cancer Center, Sahlgrenska Academy, University of Gothenburg, 40530 Gothenburg, Sweden. Electronic address:

The identification of breast cancer cell subpopulations featuring truly malignant stem cell qualities is a challenge due to the complexity of the disease and lack of general markers. By combining extensive single-cell gene expression profiling with three functional strategies for cancer stem cell enrichment including anchorage-independent culture, hypoxia, and analyses of low-proliferative, label-retaining cells derived from mammospheres, we identified distinct stem cell clusters in breast cancer. Estrogen receptor (ER)α+ tumors featured a clear hierarchical organization with switch-like and gradual transitions between different clusters, illustrating how breast cancer cells transfer between discrete differentiation states in a sequential manner. ERα- breast cancer showed less prominent clustering but shared a quiescent cancer stem cell pool with ERα+ cancer. The cellular organization model was supported by single-cell data from primary tumors. The findings allow us to understand the organization of breast cancers at the single-cell level, thereby permitting better identification and targeting of cancer stem cells.
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http://dx.doi.org/10.1016/j.stemcr.2015.12.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4719187PMC
January 2016

An Endothelial Gene Signature Score Predicts Poor Outcome in Patients with Endocrine-Treated, Low Genomic Grade Breast Tumors.

Clin Cancer Res 2016 05 14;22(10):2417-26. Epub 2016 Jan 14.

Department of Oncology and Pathology, Karolinska Institutet and University Hospital, Stockholm, Sweden.

Purpose: The ability of vascular genes to provide treatment predictive information in breast cancer patients remains unclear. As such, we assessed the expression of genes representative of normal endothelial microvasculature (MV) in relation to treatment-specific patient subgroups.

Experimental Design: We used expression data from 993 breast tumors to assess 57 MV genes (summarized to yield an MV score) as well as the genomic grade index (GGI) and PAM50 signatures. MV score was compared with CD31 staining by correlation and gene ontology (GO) analysis, along with clinicopathologic characteristics and PAM50 subtypes. Uni-, multivariate, and/or t-test analyses were performed in all and treatment-specific subgroups, along with a clinical trial cohort of patients with metastatic breast cancer, seven of whom received antiangiogenic therapy.

Results: MV score did not correlate with microvessel density (correlation = 0.096), but displayed enrichment for angiogenic GO terms, and was lower in Luminal B tumors. In endocrine-treated patients, a high MV score was associated with decreased risk of metastasis [HR 0.58; 95% confidence interval (CI), 0.38-0.89], even after adjusting for histologic grade, but not GGI or PAM50. Subgroup analysis showed the prognostic strength of the MV score resided in low genomic grade tumors and MV score was significantly increased in metastatic breast tumors after treatment with sunitinib + docetaxel (P = 0.031).

Conclusions: MV score identifies two groups of better and worse survival in low-risk endocrine-treated breast cancer patients. We also show normalization of tumor vasculature on a transcriptional level in response to an angiogenic inhibitor in human breast cancer samples. Clin Cancer Res; 22(10); 2417-26. ©2016 AACR.
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http://dx.doi.org/10.1158/1078-0432.CCR-15-1691DOI Listing
May 2016

Phytoconstituents with Radical Scavenging and Cytotoxic Activities from .

Diseases 2016 Jan 15;4(1). Epub 2016 Jan 15.

Department of Chemistry and Molecular Biology, University of Gothenburg, Gothenburg SE-412 96, Sweden.

As part of our search for natural products having antioxidant and anticancer properties, the phytochemical investigation of (Ebenaceae), a plant belonging to a genus widely used in East African traditional medicine, was carried out. From its stem and root barks the new naphthoquinone 8,8'-oxo-biplumbagin () was isolated along with the known tetralones -isoshinanolone () and -isoshinanolone (), and the naphthoquinones plumbagin () and 3,3'-biplumbagin (). Compounds , , and showed cytotoxicity (IC 520-82.1 μM) against MDA-MB-231 breast cancer cells. Moderate to low cytotoxicity was observed for the hexane, dichloromethane, and methanol extracts of the root bark (IC 16.1, 29.7 and > 100 μg/mL, respectively), and for the methanol extract of the stem bark (IC 59.6 μg/mL). The radical scavenging activity of the isolated constituents (-) was evaluated on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The applicability of the crude extracts and of the isolated constituents for controlling degenerative diseases is discussed.
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http://dx.doi.org/10.3390/diseases4010003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5456303PMC
January 2016

CAF-specific markers: role of the TGFβ pathway.

Oncoscience 2015 21;2(10):835-6. Epub 2015 Aug 21.

Sahlgrenska Cancer Center, Gothenburg University, Sweden.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4671944PMC
http://dx.doi.org/10.18632/oncoscience.209DOI Listing
December 2015

Rotenoids, Flavonoids, and Chalcones from the Root Bark of Millettia usaramensis.

J Nat Prod 2015 Dec 14;78(12):2932-9. Epub 2015 Dec 14.

Department of Chemistry, University of Nairobi , P.O. Box 30197-00100, Nairobi, Kenya.

Five new compounds, 4-O-geranylisoliquiritigenin (1), 12-dihydrousararotenoid B (2), 12-dihydrousararotenoid C (3), 4'-O-geranyl-7-hydroxyflavanone (4), and 4'-O-geranyl-7-hydroxydihydroflavanol (5), along with 12 known natural products (6-17) were isolated from the CH2Cl2/MeOH (1:1) extract of the root bark of Millettia usaramensis ssp. usaramensis by chromatographic separation. The purified metabolites were identified by NMR spectroscopic and mass spectrometric analyses, whereas their absolute configurations were established on the basis of chiroptical data and in some cases also by X-ray crystallography. The crude extract was moderately active (IC50 = 11.63 μg/mL) against the ER-negative MDB-MB-231 human breast cancer cell line, and accordingly compounds 6, 8, 9, 10, 12, and 16 also showed moderate to low cytotoxic activities (IC50 25.7-207.2 μM). The new natural product 1 exhibited antiplasmodial activity with IC50 values of 3.7 and 5.3 μM against the chloroquine-sensitive 3D7 and the chloroquine-resistant Dd2 Plasmodium falciparum strains, respectively, and was also cytotoxic to the HEK293 cell line.
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http://dx.doi.org/10.1021/acs.jnatprod.5b00581DOI Listing
December 2015

Anti-estrogen Resistance in Human Breast Tumors Is Driven by JAG1-NOTCH4-Dependent Cancer Stem Cell Activity.

Cell Rep 2015 Sep 17;12(12):1968-77. Epub 2015 Sep 17.

Breast Cancer Now Research Unit, Institute of Cancer Sciences, University of Manchester, Wilmslow Road, Manchester M20 4BX, UK. Electronic address:

Breast cancers (BCs) typically express estrogen receptors (ERs) but frequently exhibit de novo or acquired resistance to hormonal therapies. Here, we show that short-term treatment with the anti-estrogens tamoxifen or fulvestrant decrease cell proliferation but increase BC stem cell (BCSC) activity through JAG1-NOTCH4 receptor activation both in patient-derived samples and xenograft (PDX) tumors. In support of this mechanism, we demonstrate that high ALDH1 predicts resistance in women treated with tamoxifen and that a NOTCH4/HES/HEY gene signature predicts for a poor response/prognosis in 2 ER+ patient cohorts. Targeting of NOTCH4 reverses the increase in Notch and BCSC activity induced by anti-estrogens. Importantly, in PDX tumors with acquired tamoxifen resistance, NOTCH4 inhibition reduced BCSC activity. Thus, we establish that BCSC and NOTCH4 activities predict both de novo and acquired tamoxifen resistance and that combining endocrine therapy with targeting JAG1-NOTCH4 overcomes resistance in human breast cancers.
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http://dx.doi.org/10.1016/j.celrep.2015.08.050DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4594158PMC
September 2015

N-Cinnamoyltetraketide Derivatives from the Leaves of Toussaintia orientalis.

J Nat Prod 2015 Aug 27;78(8):2045-50. Epub 2015 Jul 27.

Department of Chemistry and Molecular Biology, University of Gothenburg , Gothenburg SE-412 96, Sweden.

Seven N-cinnamoyltetraketides (1-7), including the new Z-toussaintine E (2), toussaintine F (6), and toussaintine G (7), were isolated from the methanol extract of the leaves of Toussaintia orientalis using column chromatography and HPLC. The configurations of E-toussaintine E (1) and toussaintines A (3) and D (5) are revised based on single-crystal X-ray diffraction data from racemic crystals. Both the crude methanol extract and the isolated constituents exhibit antimycobacterial activities (MIC 83.3-107.7 μM) against the H37Rv strain of Mycobacterium tuberculosis. Compounds 1, 3, 4, and 5 are cytotoxic (ED50 15.3-105.7 μM) against the MDA-MB-231 triple negative aggressive breast cancer cell line.
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http://dx.doi.org/10.1021/acs.jnatprod.5b00356DOI Listing
August 2015

Properties of targeted preamplification in DNA and cDNA quantification.

Expert Rev Mol Diagn 2015 1;15(8):1085-100. Epub 2015 Jul 1.

Sahlgrenska Cancer Center, Department of Pathology, Sahlgrenska Academy at University of Gothenburg, Box 425, 40530 Gothenburg, Sweden.

Objective: Quantification of small molecule numbers often requires preamplification to generate enough copies for accurate downstream enumerations. Here, we studied experimental parameters in targeted preamplification and their effects on downstream quantitative real-time PCR (qPCR).

Methods: To evaluate different strategies, we monitored the preamplification reaction in real-time using SYBR Green detection chemistry followed by melting curve analysis. Furthermore, individual targets were evaluated by qPCR.

Result: The preamplification reaction performed best when a large number of primer pairs was included in the primer pool. In addition, preamplification efficiency, reproducibility and specificity were found to depend on the number of template molecules present, primer concentration, annealing time and annealing temperature. The amount of nonspecific PCR products could also be reduced about 1000-fold using bovine serum albumin, glycerol and formamide in the preamplification.

Conclusion: On the basis of our findings, we provide recommendations how to perform robust and highly accurate targeted preamplification in combination with qPCR or next-generation sequencing.
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http://dx.doi.org/10.1586/14737159.2015.1057124DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4673511PMC
April 2016

Monocytes and macrophages, implications for breast cancer migration and stem cell-like activity and treatment.

Oncotarget 2015 Jun;6(16):14687-99

Breakthrough Breast Cancer Unit, Institute of Cancer Sciences, Paterson Institute for Cancer Research, University of Manchester, Manchester, UK.

Macrophages are a major cellular constituent of the tumour stroma and contribute to breast cancer prognosis. The precise role and treatment strategies to target macrophages remain elusive. As macrophage infiltration is associated with poor prognosis and high grade tumours we used the THP-1 cell line to model monocyte-macrophage differentiation in co-culture with four breast cancer cell lines (MCF7, T47D, MDA-MB-231, MDA-MB-468) to model in vivo cellular interactions. Polarisation into M1 and M2 subtypes was confirmed by specific cell marker expression of ROS and HLA-DR, respectively. Co-culture with all types of macrophage increased migration of ER-positive breast cancer cell lines, while M2-macrophages increased mammosphere formation, compared to M1-macrophages, in all breast cancer cells lines. Treatment of cells with Zoledronate in co-culture reduced the "pro-tumourigenic" effects (increased mammospheres/migration) exerted by macrophages. Direct treatment of breast cancer cells in homotypic culture was unable to reduce migration or mammosphere formation.Macrophages promote "pro-tumourigenic" cellular characteristics of breast cancer cell migration and stem cell activity. Zoledronate targets macrophages within the microenvironment which in turn, reduces the "pro-tumourigenic" characteristics of breast cancer cells. Zoledronate offers an exciting new treatment strategy for both primary and metastatic breast cancer.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4546497PMC
http://dx.doi.org/10.18632/oncotarget.4189DOI Listing
June 2015

Early diagnostic value of Bcl-3 localization in colorectal cancer.

BMC Cancer 2015 May 1;15:341. Epub 2015 May 1.

Department of Laboratory Medicine, Translational Cancer Research, Division of Molecular Tumour Pathology, Lund University, Medicon Village, Building 404:A3, 223 83, Lund, Sweden.

Background: B-cell leukemia 3 (Bcl-3) is a member of the inhibitor of κB family, which regulates a wide range of biological processes by functioning as a transcriptional activator or as a repressor of target genes. Elevated expression, sustained nuclear accumulation, and uncontrolled activation of Bcl-3 causes increased cellular proliferation or survival, dependent on the tissue and type of stimuli.

Methods: We retrospectively reviewed patients who were diagnosed with colorectal cancer at Skåne University Hospital in Malmö between 1st of January 1990 and 31st of December 1991. Bcl-3 localization in colorectal cancer was assessed by immunohistochemistry on tissue microarray and freshly isolated colon from patients. Correlation between Bcl-3 localization and clinicopathological parameters of the cohort were evaluated using the Spearman rank-order correlation coefficient. In addition, Bcl-3 expression and localization in colon adenocarcinoma cells were analysed by western blot, immunohistochemistry and subcellular fractionation separately.

Results: We found that Bcl-3 was mainly localized in the cytoplasm in the tumour tissue isolated from colon cancer patients. Normal colon samples from the same patients showed Bcl-3 localization in the nucleus. In three out of six colon cancer cell lines, we detected elevated levels of Bcl-3. In these cell lines Bcl-3 was accumulated in the cytosol. We confirmed these findings by analysing Bcl-3 localization in a colon tissue micro array consisting of 270 cases. In these samples Bcl-3 localization correlated with the proliferation marker Ki-67, but not with the apoptotic marker Caspase 3.

Conclusion: These findings indicate that analysis of the subcellular localization of Bcl-3 could be a potential-early diagnostic marker in colon cancer.
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http://dx.doi.org/10.1186/s12885-015-1342-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4434567PMC
May 2015

Loss of TGFβ Receptor Type 2 Expression Impairs Estrogen Response and Confers Tamoxifen Resistance.

Cancer Res 2015 Apr;75(7):1457-69

Sahlgrenska Cancer Center, Gothenburg University, Gothenburg, Sweden. Molecular Pathology, Breakthrough Breast Cancer Research Unit, University of Manchester, United Kingdom.

One third of the patients with estrogen receptor α (ERα)-positive breast cancer who are treated with the antiestrogen tamoxifen will either not respond to initial therapy or will develop drug resistance. Endocrine response involves crosstalk between ERα and TGFβ signaling, such that tamoxifen nonresponsiveness or resistance in breast cancer might involve aberrant TGFβ signaling. In this study, we analyzed TGFβ receptor type 2 (TGFBR2) expression and correlated it with ERα status and phosphorylation in a cohort of 564 patients who had been randomized to tamoxifen or no-adjuvant treatment for invasive breast carcinoma. We also evaluated an additional four independent genetic datasets in invasive breast cancer. In all the cohorts we analyzed, we documented an association of low TGFBR2 protein and mRNA expression with tamoxifen resistance. Functional investigations confirmed that cell cycle or apoptosis responses to estrogen or tamoxifen in ERα-positive breast cancer cells were impaired by TGFBR2 silencing, as was ERα phosphorylation, tamoxifen-induced transcriptional activation of TGFβ, and upregulation of the multidrug resistance protein ABCG2. Acquisition of low TGFBR2 expression as a contributing factor to endocrine resistance was validated prospectively in a tamoxifen-resistant cell line generated by long-term drug treatment. Collectively, our results established a central contribution of TGFβ signaling in endocrine resistance in breast cancer and offered evidence that TGFBR2 can serve as an independent biomarker to predict treatment outcomes in ERα-positive forms of this disease.
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http://dx.doi.org/10.1158/0008-5472.CAN-14-1583DOI Listing
April 2015

Selenium Accumulating Leafy Vegetables Are a Potential Source of Functional Foods.

Int J Food Sci 2015 10;2015:549676. Epub 2015 Dec 10.

Chemistry Department, College of Natural and Applied Sciences, University of Dar es Salaam, P.O. Box 35061, Dar es Salaam, Tanzania.

Selenium deficiency in humans has been associated with various diseases, the risks of which can be reduced through dietary supplementation. Selenium accumulating plants may provide a beneficial nutrient for avoiding such illnesses. Thus, leafy vegetables such as Amaranthus hybridus, Amaranthus sp., Cucurbita maxima, Ipomoea batatas, Solanum villosum, Solanum scabrum, and Vigna unguiculata were explored for their capabilities to accumulate selenium when grown on selenium enriched soil and for use as a potential source of selenium enriched functional foods. Their selenium contents were determined by spectrophotometry using the complex of 3,3'-diaminobenzidine hydrochloride (DABH) as a chromogen. The mean concentrations in the leaves were found to range from 7.90 ± 0.40 to 1.95 ± 0.12 μg/g dry weight (DW), with C. maxima accumulating the most selenium. In stems, the accumulated selenium content ranged from 1.12 ± 0.10 μg/g in Amaranthus sp. to 5.35 ± 0.78 μg/g DW in C. maxima and was hence significantly different (P < 0.01). The cancer cell line MDA-MB-231 was used in cytotoxicity assays to determine the anticancer potential of these extracts. With exception of S. scabrum and S. villosum, no cytotoxicity was detected for the selenium enriched vegetable extracts up to 100 μg/mL concentration. Hence, following careful evaluation the studied vegetables may be considered as selenium enriched functional foods.
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http://dx.doi.org/10.1155/2015/549676DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4756630PMC
March 2016