LRP6 overexpression defines a class of breast cancer subtype and is a target for therapy.
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ABSTRACT:
SUBMITTER: Liu CC
PROVIDER: S-EPMC2841938 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:PurposeThe current study evaluated associative effects of breast cancer cells with the tumor microenvironment and its influence on tumor behavior.Experimental designFormalin-fixed, paraffin-embedded tissue and matched protein lysates were evaluated from two independent breast cancer patient datasets (TCGA and MD Anderson). Reverse-phase protein arrays (RPPA) were utilized to create a proteomics signature to define breast tumor subtypes. Expression patterns of cell lines and normal breast tissues were utilized to determine markers that were differentially expressed in stroma and cancer cells. Protein localization and stromal contents were evaluated for matched cases by imaging.ResultsA subtype of breast cancers designated "Reactive," previously identified by RPPA that was not predicted by mRNA profiling, was extensively characterized. These tumors were primarily estrogen receptor (ER)-positive/human EGF receptor (HER)2-negative, low-risk cancers as determined by enrichment of low-grade nuclei, lobular or tubular histopathology, and the luminal A subtype by PAM50. Reactive breast cancers contained high numbers of stromal cells and the highest extracellular matrix content typically without infiltration of immune cells. For ER-positive/HER2-negative cancers, the Reactive classification predicted favorable clinical outcomes in the TCGA cohort (HR, 0.36; P < 0.05).ConclusionsA protein stromal signature in breast cancers is associated with a highly differentiated phenotype. The stromal compartment content and proteins are an extended phenotype not predicted by mRNA expression that could be utilized to subclassify ER-positive/HER2-negative breast cancers. Clin Cancer Res; 22(20); 5068-78. ©2016 AACR.
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Project description:Mismatch repair (MMR) alterations are important prognostic and predictive biomarkers in a variety of cancer subtypes, including colorectal and endometrial. However, in breast cancer (BC), the distinction and clinical significance of MMR are largely unknown. This may be due in part to the fact that genetic alterations in MMR genes are rare and only seen to occur in around 3% of BCs. In the present study, we analyzed TCGA data using a multi-sample protein-protein interaction (PPI) analysis tool, Proteinarium, and showed a distinct separation between specific MMR-deficient and -intact networks in a cohort of 994 BC patients. In the PPI networks specific to MMR deficiency, highly connected clusters of histone genes were identified. We also found the distribution of MMR-deficient BC to be more prevalent in HER2-enriched and triple-negative (TN) BC subtypes compared to luminal BCs. We recommend defining MMR-deficient BC by next-generation sequencing (NGS) when any somatic mutation is detected in one of the seven MMR genes.
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Project description:The ubiquitously expressed 14-3-3 proteins are involved in numerous important cellular functions. The loss of 14-3-3sigma is a common event in breast cancer; however, the role of other 14-3-3s in breast cancer is unclear. Recently, we found that 14-3-3zeta overexpression occurs in early stage breast diseases and contributes to transformation of human mammary epithelial cells. Here, we show that 14-3-3zeta overexpression also persisted in invasive ductal carcinoma and contributed to the further progression of breast cancer. To examine the clinical effect of 14-3-3zeta overexpression in advanced stage breast cancer, we performed immunohistochemical analysis of 14-3-3zeta expression in primary breast carcinomas. 14-3-3zeta overexpression occurred in 42% of breast tumors and was determined to be an independent prognostic factor for reduced disease-free survival. 14-3-3zeta overexpression combined with ErbB2 overexpression and positive lymph node status identified a subgroup of patients at high risk for developing distant metastasis. To investigate whether 14-3-3zeta overexpression causally promotes breast cancer progression, we overexpressed 14-3-3zeta by stable transfection or reduced 14-3-3zeta expression by siRNA in cancer cell lines. Increased 14-3-3zeta expression enhanced anchorage-independent growth and inhibited stress-induced apoptosis, whereas down-regulation of 14-3-3zeta reduced anchorage-independent growth and sensitized cells to stress-induced apoptosis via the mitochondrial apoptotic pathway. Transient blockade of 14-3-3zeta expression by siRNA in cancer cells effectively reduced the onset and growth of tumor xenografts in vivo. Therefore, 14-3-3zeta overexpression is a novel molecular marker for disease recurrence in breast cancer patients and may serve as an effective therapeutic target in patients whose tumors overexpress 14-3-3zeta.
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Project description:To find new molecular targets for triple negative breast cancer (TNBC), we analyzed a large-scale drug screening dataset based on breast cancer subtypes. We discovered that BDP-9066, a specific MRCK inhibitor (MRCKi), may be an effective drug against TNBC. After confirming the efficacy and specificity of BDP-9066 against TNBC in vitro and in vivo, we further analyzed the underlying mechanism of specific activity of BDP-9066 against TNBC. Comparing the transcriptome of BDP-9066-sensitive and -resistant cells, the activation of the focal adhesion and YAP/TAZ pathway were found to play an important role in the sensitive cells. Furthermore, YAP/TAZ is indeed repressed by BDP-9066 in the sensitive cells, and active form of YAP suppresses the effects of BDP-9066. YAP/TAZ expression and activity are high in TNBC, especially the Claudin-low subtype, consistent with the expression of focal adhesion-related genes. Interestingly, NF-κB functions downstream of YAP/TAZ in TNBC cells and is suppressed by BDP-9066. Furthermore, the PI3 kinase pathway adversely affected the effects of BDP-9066 and that alpelisib, a PI3 kinase inhibitor, synergistically increased the effects of BDP-9066, in PIK3CA mutant TNBC cells. Taken together, we have shown for the first time that MRCKi can be new drugs against TNBC, particularly the Claudin-low subtype.
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Project description:Cancer cells exhibit dramatic alterations of chromatin organization at cis-regulatory elements, but the molecular basis, extent, and impact of these alterations are still being unraveled. Here, we identify extensive genome-wide modification of sites bearing the active histone mark H3K4me2 in primary human colorectal cancers, as compared with corresponding benign precursor adenomas. Modification of certain colorectal cancer sites highlighted the activity of the transcription factor CNOT3, which is known to control self-renewal of embryonic stem cells (ESC). In primary colorectal cancer cells, we observed a scattered pattern of CNOT3 expression, as might be expected for a tumor-initiating cell marker. Colorectal cancer cells exhibited nuclear and cytoplasmic expression of CNOT3, suggesting possible roles in both transcription and mRNA stability. We found that CNOT3 was bound primarily to genes whose expression was affected by CNOT3 loss, and also at sites modulated in certain types of colorectal cancers. These target genes were implicated in ESC and cancer self-renewal and fell into two distinct groups: those dependent on CNOT3 and MYC for optimal transcription and those repressed by CNOT3 binding and promoter hypermethylation. Silencing CNOT3 in colorectal cancer cells resulted in replication arrest. In clinical specimens, early-stage tumors that included >5% CNOT3+ cells exhibited a correlation to worse clinical outcomes compared with tumors with little to no CNOT3 expression. Together, our findings implicate CNOT3 in the coordination of colonic epithelial cell self-renewal, suggesting this factor as a new biomarker for molecular and prognostic classification of early-stage colorectal cancer. Cancer Res; 77(3); 766-79. ©2016 AACR.
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Project description:Breast cancer patients have benefited from the use of targeted therapies directed at specific molecular alterations. To identify additional opportunities for targeted therapy, we searched for genes with marked overexpression in subsets of tumors across a panel of breast cancer profiling studies comprising 3,200 microarray experiments. In addition to prioritizing ERBB2, we found AGTR1, the angiotensin II receptor type I, to be markedly overexpressed in 10-20% of breast cancer cases across multiple independent patient cohorts. Validation experiments confirmed that AGTR1 is highly overexpressed, in several cases more than 100-fold. AGTR1 overexpression was restricted to estrogen receptor-positive tumors and was mutually exclusive with ERBB2 overexpression across all samples. Ectopic overexpression of AGTR1 in primary mammary epithelial cells, combined with angiotensin II stimulation, led to a highly invasive phenotype that was attenuated by the AGTR1 antagonist losartan. Similarly, losartan reduced tumor growth by 30% in AGTR1-positive breast cancer xenografts. Taken together, these observations indicate that marked AGTR1 overexpression defines a subpopulation of ER-positive, ERBB2-negative breast cancer that may benefit from targeted therapy with AGTR1 antagonists, such as losartan.
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Project description:AXL is a receptor tyrosine kinase (RTK) that has been implicated in diverse tumor-promoting processes such as proliferation, migration, invasion, survival, and apoptosis. AXL therefore plays a role in cancer progression, and AXL has been implicated in a wide variety of malignancies from solid tumors to hematopoietic cancers where it is often associated with poor prognosis. In cancer, AXL has been shown to promote epithelial to mesenchymal transition (EMT), metastasis formation, drug resistance, and a role for AXL in modulation of the tumor microenvironment and immune response has been identified. In light of these activities multiple AXL inhibitors have been developed, and several of these have entered clinical trials in the U.S. In breast cancer, high levels of AXL expression have been observed. The role of AXL in cancer with a focus on therapeutic implications for breast cancer is discussed.
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Project description:Endometrial cancer is the most common female genital tract malignancy in the United States. Type I endometrial cancer is usually diagnosed at an early stage, and has a good prognosis. Type II is very aggressive, and is responsible for most uterine cancer relapses and deaths. Uterine serous adenocarcinomas (USC) constitute the majority of Type II variants. They have a higher propensity for lymph node and distant metastases. They are frequently aneuploid and associated with p53 mutations. erbB2 overexpression in USC has been described. The incidence, which is higher in African Americans, ranges from 18-80%. erbB2 overexpression was found to be associated with higher stage, chemoresistance, and worse survival. Trastuzumab a humanized mAb was approved by the FDA for treatment of breast cancers that overexpress erbB2 in combination with standard chemotherapy. Evidence of trastuzumab activity in USC has been reported in vitro, as well as in case reports of advanced and recurrent cases. Promising results were obtained in these heavily pretreated patients either with trastuzumab alone or in combination with chemotherapy. This supports the hypothesis that trastuzumab may very well be an attractive and viable treatment option for advanced stage USC tumors that overexpress the erbB2, and is worthy of further study.
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Project description:Invasive lobular carcinoma (ILC) is an understudied subtype of breast cancer that requires novel therapies in the advanced setting. To study acquired resistance to endocrine therapy in ILC, we have recently performed RNA-Sequencing on long-term estrogen deprived cell lines and identified FGFR4 overexpression as a top druggable target. Here, we show that FGFR4 expression also increases dramatically in endocrine-treated distant metastases, with an average fold change of 4.8 relative to the paired primary breast tumor for ILC, and 2.4-fold for invasive ductal carcinoma (IDC). In addition, we now report that FGFR4 hotspot mutations are enriched in metastatic breast cancer, with an additional enrichment for ILC, suggesting a multimodal selection of FGFR4 activation. These data collectively support the notion that FGFR4 is an important mediator of endocrine resistance in ILC, warranting future mechanistic studies on downstream signaling of overexpressed wild-type and mutant FGFR4.
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Project description:PURPOSE:HER2 signaling functional activity may be important to measure in addition to HER2 protein quantification when identifying patients eligible for HER2 therapies. A HER2 Signaling Function (CELx HSF) Test for HER2-negative patients uses patient's live tumor cells on a biosensor to identify patients with abnormally high HER2-related signaling (HSFs+) likely to respond to anti-HER2 therapies. METHODS:The CELx HSF test was employed to: (1) characterize the sensitivity and specificity of the test to detect abnormal levels of HER2 signaling; (2) evaluate the inhibitory effectiveness of five different anti-HER2 therapies; (3) assess the correlation between CELx HSF test detection of abnormal HER2 signaling and response to HER2 therapy using xenograft models; and (4) confirm the prevalence of abnormal HER2 signaling amongst HER2-negative breast cancer patients (HER2-/HSFs+). RESULTS:HER2-/HSFs+ breast cancer patient samples were identified and showed sensitivity to five approved anti-HER2 therapies. Xenograft studies using both HER2+ and HER2- cell lines confirmed that CELx HER2 signaling status better predicts HER2 inhibitor efficacy than HER2 receptor status. In a study of 114 HER2-negative breast tumor patient samples, 27 (23.7%; 95% CI = 17-32%) had abnormal HER2 signaling (HSFs+). A ROC curve constructed with this dataset projects the CELx HSF Test would have greater than 90% sensitivity and specificity to detect the HER2-/HSFs+ patient population. CONCLUSIONS:The CELx HSF test is a well-characterized functional biomarker assay capable of identifying dynamic HER2-driven signaling dysfunction in tumor cells from HER2-negative breast cancer patients. This test has demonstrated efficacy of various HER2 targeted therapies in live tumor cells from the HSFs+ population and correlated the test result to HER2 drug response in mouse xenograft studies. The proportion of HER2-negative breast cancer patients found to have abnormal HER2 signaling in a 114 patient sample study, 20-25%, is significant. A clinical trial to evaluate the efficacy of anti-HER2 therapies in this patient population is warranted.
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