| 1. |
- Lamb, R., et al.
(författare)
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Cell cycle regulators cyclin D1 and CDK4/6 have estrogen receptor-dependent divergent functions in breast cancer migration and stem cell-like activity
- 2013
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Ingår i: Cell Cycle. - : Informa UK Limited. - 1538-4101 .- 1551-4005. ; 12:15, s. 2384-2394
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Tidskriftsartikel (refereegranskat)abstract
- Cyclin D1 and its binding partners CDK4/6 are essential regulators of cell cycle progression and are implicated in cancer progression. Our aim was to investigate a potential regulatory role of these proteins in other essential tumor biological characteristics. Using a panel of breast cancer cell lines and primary human breast cancer samples, we have demonstrated the importance of these cell cycle regulators in both migration and stem-like cell activity. siRNA was used to target cyclin D1 and CDK4/6 expression, having opposing effects on both migration and stem-like cell activity dependent upon estrogen receptor (ER) expression. Inhibition of cyclin D1 or CDK4/6 increases or decreases migration and stem-like cell activity in ER-ve (ER-negative) and ER+ve (ER-positive) breast cancer, respectively. Furthermore, overexpressed cyclin D1 caused decreased migration and stem-like cell activity in ER-ve cells while increasing activity in ER+ve breast cancer cells. Treatment of breast cancer cells with inhibitors of cyclin D1 and CDK4/6 (Flavopiridol/PD0332991), currently in clinical trials, mimicked the effects observed with siRNA treatment. Re-expression of ER in two ER-ve cell lines was sufficient to overcome the effects of either siRNA or clinical inhibitors of cyclin D1 and CDK4/6. In conclusion, cyclin D1 and CDK4/6 have alternate roles in regulation of migration and stem-like cell activity. Furthermore, these effects are highly dependent upon expression of ER. The significance of these results adds to our general understanding of cancer biology but, most importantly, could be used diagnostically to predict treatment response to cell cycle inhibition in breast cancer.
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| 2. |
- Larsson, Anna H., et al.
(författare)
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Significant association and synergistic adverse prognostic effect of podocalyxin-like protein and epidermal growth factor receptor expression in colorectal cancer
- 2016
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Ingår i: Journal of Translational Medicine. - : BioMed Central. - 1479-5876 .- 1479-5876. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Background: Podocalyxin-like 1 (PODXL) is an anti-adhesive transmembrane protein that has been demonstrated to be an independent factor of poor prognosis in colorectal cancer (CRC). The gene encoding PODXL is located to chromosome 7, which also harbours the gene for the epidermal growth factor receptor (EGFR). The aim of this study was to examine the associations between PODXL and EGFR expression in CRC in vitro and in vivo. Methods: EGFR expression was analysed in tumours from three independent patient cohorts; cohort 1 (n = 533), cohort 2 (n = 259) and cohort 3 (n = 310), previously analysed for immunohistochemical PODXL expression and KRAS and BRAF mutations (cohort 1 and 3). Levels of EGFR and PODXL were determined by western blot in six different CRC cell lines. Results: High expression of PODXL was significantly associated with high EGFR expression (p < 0.001) in all three cohorts, and with BRAF mutation (p < 0.001) in cohort 1 and 3. High EGFR expression correlated with BRAF mutation (p < 0.001) in cohort 1. High EGFR expression was associated with adverse clinicopathological factors and independently predicted a reduced 5-year overall survival (OS) in cohort 1 (HR 1.77; 95 % CI 1.27-2.46), cohort 2 (HR 1.58; 95 % CI 1.05-2.38) and cohort 3 (HR 1.83; 95 % CI 1.19-2.81). The highest risk of death within 5 years was observed in patients with tumours displaying high expression of both EGFR and PODXL in cohort 1 and 3 (HR 1.97; 95 % CI 1.18-3.28 and HR 3.56; 95 % CI 1.75-7.22, respectively). Western blot analysis showed a uniform expression of PODXL and EGFR in all six examined CRC cell lines. Conclusions: The results from this study demonstrate that high expression of EGFR is an independent factor of poor prognosis in CRC. Moreover, strong links have been uncovered between expression of the recently proposed biomarker candidate PODXL with EGFR expression in CRC in vivo and in vitro, and with BRAF mutation in vivo. High expression of both PODXL and EGFR may also have a synergistic adverse effect on survival. These findings suggest a potential functional link in CRC between PODXL, EGFR and BRAF, all originating from chromosome 7, which may be highly relevant in the clinical setting and therefore merit future in-depth study.
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| 3. |
- Lehn, Sophie, et al.
(författare)
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A non-functional retinoblastoma tumor suppressor (RB) pathway in premenopausal breast cancer is associated with resistance to tamoxifen.
- 2011
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Ingår i: Cell Cycle. - : Informa UK Limited. - 1551-4005 .- 1538-4101. ; 10:6, s. 956-962
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Tidskriftsartikel (refereegranskat)abstract
- The retinoblastoma tumor suppressor (RB) is important for retaining cell cycle control and loss of RB function is commonly observed in various malignancies. Experimental and animal studies have shown that RB knockdown in ER+ (estrogen receptor) cell lines and xenografts leads to resistance to tamoxifen, indicating that RB-inactivation could be linked to impaired response to specific cancer treatments. To address this issue, we utilized a unique randomized trial including 500 premenopausal breast cancer patients receiving either two years of adjuvant tamoxifen treatment or no treatment after surgery, and defined the tamoxifen response in RB-subgroups. Non-functional RB tumors were defined by lack of concordance between RB-phosphorylation and proliferation, in comparison to RB-functional tumors displaying comparable RB-phosphorylation and proliferation. In the ER+ tumors harboring a functional RB pathway (N=204), patients benefited from adjuvant tamoxifen with fewer breast cancer recurrences (HR=0.53, 95% CI 0.34-0.81, P=0.003). In the small subgroup of ER+ and RB non-functional tumors there was no benefit of tamoxifen (HR=2.28, 95% CI 0.51-10.3, P=0.28). In a multivariate analysis, the interaction between status of the RB pathway and treatment was significant (P=0.010), validating that despite being a small subgroup of ER+ breast cancer, RB functional status appears to be linked to response to tamoxifen treatment. These findings are in line with earlier experimental data altogether suggesting that analyses of RB status in breast cancer have the potential to be one among other future predictive factors that needs to be analyzed in order to successfully identify patients that will benefit from tamoxifen treatment.
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| 4. |
- Lehn, Sophie
(författare)
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Cell cycle deregulation in breast cancer subgroups and effects on proliferation, migration and tamoxifen resistance
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Breast cancer is a heterogenous disease which can be divided in subgroups of distinct biology with disparate prognosis and response to treatment. The overall aim of this thesis was to delineate subgroup specific behaviour in breast cancer cells with focus on proliferation, migration and stem-like cell activity. In addition, we have studied the functional retinoblastoma tumour suppressor (RB) protein pathway and associations to tamoxifen response. Furthermore, the expression of yes-associated protein (YAP1), reported to have both oncogenic and tumour suppressive functions, was investigated in breast cancer subgroups and related to tamoxifen response. Two of the key processes in malignant behaviour, proliferation and migration, have previously been reported to act as two opposing events in a cancer cell. We found that siRNA-mediated reduction of cyclin D1, a protein expressed in the active cell cycle, resulted in a migratory increase in cell lines negative of estrogen receptor (ER) expression. Conversely, in ER positive cell lines, downregulation of cyclin D1 resulted in decreased migratory capacity and a reduced number of stem-like cells, as measured by the mammosphere assay. Two agents inhibiting the cell cycle machinery, currently undergoing clinical trials, were further evaluated. Results showed that use of these agents in ER negative cell lines increased the number of stem-like cells, whereas a decrease was observed in the ER positive cells. These results point to the disparate effects of cell cycle-targeting treatments on breast cancer cells and highlight the importance of subgroup analysis. The breast cancer therapy tamoxifen is widely used in patients with ER positive breast cancers; however resistance occurs in approximately one-third of patients. By analysing a breast cancer tumour material from a patient cohort randomised to receive tamoxifen or control treatment, we have found that a non-functional RB pathway in ER positive breast tumours was predictive of tamoxifen insensitivity. The non-functional RB pathway was however not correlated to prognosis, indicating that status of RB pathway holds purely treatment predictive information. In addition, YAP1 was analysed in the tamoxifen randomised patient cohort and tumours lacking YAP1 protein expression were correlated with resistance to tamoxifen. Furthermore, in ER negative breast tumours, higher YAP1 expression was associated with increased proliferation whereas in ER positive tumours, YAP1 was negatively correlated to proliferation and grade. In vitro experiments downregulating YAP1 resulted in increased levels of ER and progesterone receptor (PgR), indicating deregulated signalling of the ER pathway. Taken together, we have shown that the consequences of targeting cell cycle proteins may differ depending on ER expression. Furthermore, we have linked a non-functional pathway of the cell-cycle regulator RB and absent YAP1 protein expression to impaired tamoxifen response, identifying two potential biomarkers for predicting tamoxifen insensitivity.
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| 5. |
- Lehn, Sophie, et al.
(författare)
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Decreased expression of Yes-associated protein is associated with outcome in the luminal A breast cancer subgroup and with an impaired tamoxifen response
- 2014
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Ingår i: Bmc Cancer. - : Springer Science and Business Media LLC. - 1471-2407. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Background: Yes-associated protein (YAP1) is frequently reported to function as an oncogene in many types of cancer, but in breast cancer results remain controversial. We set out to clarify the role of YAP1 in breast cancer by examining gene and protein expression in subgroups of patient material and by downregulating YAP1 in vitro and studying its role in response to the widely used anti-estrogen tamoxifen. Methods: YAP1 protein intensity was scored as absent, weak, intermediate or strong in two primary breast cancer cohorts (n = 144 and n = 564) and mRNA expression of YAP1 was evaluated in a gene expression dataset (n = 1107). Recurrence-free survival was analysed using the log-rank test and Cox multivariate analysis was used to test for independence. WST-1 assay was employed to measure cell viability and a luciferase ERE (estrogen responsive element) construct was used to study the effect of tamoxifen, following downregulation of YAP1 using siRNAs. Results: In the ER+ (Estrogen Receptor a positive) subgroup of the randomised cohort, YAP1 expression was inversely correlated to histological grade and proliferation (p = 0.001 and p = 0.016, respectively) whereas in the ER-(Estrogen Receptor a negative) subgroup YAP1 expression correlated positively to proliferation (p = 0.005). Notably, low YAP1 mRNA was independently associated with decreased recurrence-free survival in the gene expression dataset, specifically for the luminal A subgroup (p < 0.001) which includes low proliferating tumours of lower grade, usually associated with a good prognosis. This subgroup specificity led us to hypothesize that YAP1 may be important for response to endocrine therapies, such as tamoxifen, extensively used for luminal A breast cancers. In a tamoxifen randomised patient material, absent YAP1 protein expression was associated with impaired tamoxifen response which was significant upon interaction analysis (p = 0.042). YAP1 downregulation resulted in increased progesterone receptor (PgR) expression and a delayed and weaker tamoxifen in support of the clinical data. Conclusions: Decreased YAP1 expression is an independent prognostic factor for recurrence in the less aggressive luminal A breast cancer subgroup, likely due to the decreased tamoxifen sensitivity conferred by YAP1 downregulation.
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| 6. |
- Lehn, Sophie, et al.
(författare)
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Down-regulation of the oncogene cyclin D1 increases migratory capacity in breast cancer and is linked to unfavorable prognostic features.
- 2010
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Ingår i: The American journal of pathology. - : Elsevier BV. - 1525-2191 .- 0002-9440. ; 177:6, s. 2886-97
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Tidskriftsartikel (refereegranskat)abstract
- The oncogene cyclin D1 is highly expressed in many breast cancers and, despite its proliferation-activating properties, it has been linked to a less malignant phenotype. To clarify this observation, we focused on two key components of malignant behavior, migration and proliferation, and observed that quiescent G(0)/G(1) cells display an increased migratory capacity compared to cycling cells. We also found that the down-regulation of cyclin D1 in actively cycling cells significantly increased migration while also decreasing proliferation. When analyzing a large set of premenopausal breast cancers, we observed an inverse proliferation-independent link between cyclin D1 and tumor size and recurrence, suggesting that this protein might abrogate infiltrative malignant behavior in vivo. Finally, gene expression analysis after cyclin D1 down-regulation by siRNA confirmed changes in processes associated with migration and enrichment of our gene set in a metastatic poor prognosis signature. This novel function of cyclin D1 illustrates the interplay between tumor proliferation and migration and may explain the attenuation of malignant behavior in breast cancers with high cyclin D1 levels.
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| 7. |
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| 8. |
- Lindström, Lisa, et al.
(författare)
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Therapeutic Targeting of Nuclear Gamma-Tubulin in RB1-negative Tumors.
- 2015
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Ingår i: Molecular Cancer Research. - 1557-3125. ; 13:7, s. 1073-1082
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Tidskriftsartikel (refereegranskat)abstract
- In addition to its cytosolic function, gamma-tubulin is a chromatin-associated protein. Reduced levels of nuclear gamma-tubulin increase the activity of E2 promoter-binding factors (E2F) and raise the levels of retinoblastoma (RB1) tumor suppressor protein. In tumor cells lacking RB1 expression, decreased gamma-tubulin levels induce cell death. Consequently, impairment of the nuclear activity of gamma-tubulin has been suggested as a strategy for targeted chemotherapy of RB1-deficient tumors; thus, tubulin inhibitors were tested to identify compounds that interfere with gamma-tubulin. Interestingly, citral increased E2F activity but impaired microtubule dynamics while citral analogs, like citral dimethyl acetal (CDA), increased E2F activity without affecting microtubules. The cytotoxic effect of CDA on tumor cells was attenuated by increased expression of either RB1 or gamma-tubulin, and increased by reduced levels of either RB1 or gamma-tubulin. Mechanistic study, in silico and in vitro, demonstrated that CDA prevents GTP binding to gamma-tubulin and suggested that the FDA approved drug dimethyl fumarate is also a gamma-tubulin inhibitor. Finally, in vivo growth of xenograft tumors carrying defects in the RB1 signaling pathway were inhibited by CDA treatment. These results demonstrate that inhibition of gamma-tubulin has the potential to specifically target tumor cells and may aid in the design of safer and more efficient chemotherapeutic regimes.
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| 9. |
- Lundgren, Katja, et al.
(författare)
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Stromal Expression of beta-Arrestin-1 Predicts Clinical Outcome and Tamoxifen Response in Breast Cancer
- 2011
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Ingår i: Journal of Molecular Diagnostics. - : American Society for Investigative Pathology (ASIP). - 1525-1578 .- 1943-7811. ; 13:3, s. 340-351
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Tidskriftsartikel (refereegranskat)abstract
- The G-protein coupled receptor associated protein beta-arrestin-1 is crucial for the regulation of numerous biological processes involved in cancer progression, such as intracellular signaling and cell motility. The encoding gene ARRB1 is harbored in the same chromosomal region as the CCND1 gene (11q13). Amplification of CCND1, frequently encountered in breast cancer, often involves coamplification of additional oncogenes, as well as deletion of distal 11q genes. We investigated the clinical relevance of beta-arrestin-1 in breast cancer and elucidated a potential link between beta-arrestin-1 expression and CCND1 amplification. beta-Arrestin-1 protein expression was evaluated in two breast cancer patient cohorts, comprising 179 patients (cohort I) and 500 patients randomized to either tamoxifen or no adjuvant treatment (cohort H). Additionally, migration after beta-arrestin-1 overexpression or silencing was monitored in two breast cancer cell lines. Overexpression of beta-arrestin-1 reduced the migratory propensity of both cell lines, whereas silencing increased migration. In cohort I, high expression of stromal beta-arrestin-1 was linked to reduced patient survival, whereas in cohort II both high and absent stromal expression predicted a poor clinical outcome. Patients exhibiting low or moderate levels of stromal beta-arrestin-1 did not benefit from tamoxifen, in contrast to patients exhibiting absent or high expression. Furthermore, CCND1 amplification was inversely correlated with tumor cell expression of beta-arrestin-1, indicating ARRB1 gene deletion in CCND1-amplified breast cancers.
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| 10. |
- Michaut, Magali, et al.
(författare)
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Integration of genomic, transcriptomic and proteomic data identifies two biologically distinct subtypes of invasive lobular breast cancer.
- 2016
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Invasive lobular carcinoma (ILC) is the second most frequently occurring histological breast cancer subtype after invasive ductal carcinoma (IDC), accounting for around 10% of all breast cancers. The molecular processes that drive the development of ILC are still largely unknown. We have performed a comprehensive genomic, transcriptomic and proteomic analysis of a large ILC patient cohort and present here an integrated molecular portrait of ILC. Mutations in CDH1 and in the PI3K pathway are the most frequent molecular alterations in ILC. We identified two main subtypes of ILCs: (i) an immune related subtype with mRNA up-regulation of PD-L1, PD-1 and CTLA-4 and greater sensitivity to DNA-damaging agents in representative cell line models; (ii) a hormone related subtype, associated with Epithelial to Mesenchymal Transition (EMT), and gain of chromosomes 1q and 8q and loss of chromosome 11q. Using the somatic mutation rate and eIF4B protein level, we identified three groups with different clinical outcomes, including a group with extremely good prognosis. We provide a comprehensive overview of the molecular alterations driving ILC and have explored links with therapy response. This molecular characterization may help to tailor treatment of ILC through the application of specific targeted, chemo- and/or immune-therapies.
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