scholarly journals Implications of TGFβ Signaling and CDK Inhibition for the Treatment of Breast Cancer

Cancers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 5343
Author(s):  
Joseph T. Decker ◽  
Jeffrey A. Ma ◽  
Lonnie D. Shea ◽  
Jacqueline S. Jeruss
Keyword(s):  
Breast Cancer ◽  
Poor Prognosis ◽  
Cell Cycle Control ◽  
Tgfβ Signaling ◽  
Cyclin Dependent Kinases ◽  
C Terminus ◽  
Smad3 Phosphorylation ◽  
Tumor Suppressive Function ◽  
Regulatory Actions

TGFβ signaling enacts tumor-suppressive functions in normal cells through promotion of several cell regulatory actions including cell-cycle control and apoptosis. Canonical TGFβ signaling proceeds through phosphorylation of the transcription factor, SMAD3, at the C-terminus of the protein. During oncogenic progression, this tumor suppressant phosphorylation of SMAD3 can be inhibited. Overexpression of cyclins D and E, and subsequent hyperactivation of cyclin-dependent kinases 2/4 (CDKs), are often observed in breast cancer, and have been associated with poor prognosis. The noncanonical phosphorylation of SMAD3 by CDKs 2 and 4 leads to the inhibition of tumor-suppressive function of SMAD3. As a result, CDK overactivation drives oncogenic progression, and can be targeted to improve clinical outcomes. This review focuses on breast cancer, and highlights advances in the understanding of CDK-mediated noncanonical SMAD3 phosphorylation. Specifically, the role of aberrant TGFβ signaling in oncogenic progression and treatment response will be examined to illustrate the potential for therapeutic discovery in the context of cyclins/CDKs and SMAD3.

Biological Role of CDK 11 and 12 in Cell Cycle and its Function in Tumorigenesis

2020 ◽  
Author(s):  
Shamim Mushtaq
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Web Of Science ◽  
The Body ◽  
Main Role ◽  
Hallmarks Of Cancer ◽  
Cyclin Dependent Kinases ◽  
Tumor Studies ◽  
Cycle Regulation

Uninhibited proliferation and abnormal cell cycle regulation are the hallmarks of cancer. The main role of cyclin dependent kinases is to regulate the cell cycle and cell proliferation. These protein kinases are frequently down regulated or up regulated in various cancers. Two CDK family members, CDK 11 and 12, have contradicting views about their roles in different cancers. For example, one study suggests that the CDK 11 isoforms, p58, inhibits growth of breast cancer whereas, the CDK 11 isoform, p110, is highly expressed in breast tumor. Studies regarding CDK 12 show variation of opinion towards different parts of the body, however there is a consensus that upregulation of cdk12 increases the risk of breast cancer. Hence, CDK 11 and CDK 12 need to be analyzed to confirm their mechanism and their role regarding therapeutics, prognostic value, and ethnicity in cancer. This article gives an outline on both CDKs of information known up to date from Medline, PubMed, Google Scholar and Web of Science search engines, which were explored and thirty relevant researches were finalized.

scholarly journals Cell cycle analysis of the activity, subcellular localization, and subunit composition of human CAK (CDK-activating kinase).

1994 ◽  
Vol 127 (2) ◽  
pp. 467-478 ◽  
Author(s):  
J P Tassan ◽  
S J Schultz ◽  
J Bartek ◽  
E A Nigg
Keyword(s):  
Cell Cycle ◽  
Somatic Cell ◽  
Cell Cycle Control ◽  
Gel Filtration ◽  
Multiprotein Complex ◽  
Cyclin Dependent Kinases ◽  
Critical Residue ◽  
Cdk Activating Kinase

The activity of cyclin-dependent kinases (cdks) depends on the phosphorylation of a residue corresponding to threonine 161 in human p34cdc2. One enzyme responsible for phosphorylating this critical residue has recently been purified from Xenopus and starfish. It was termed CAK (for cdk-activating kinase), and it was shown to contain p40MO15 as its catalytic subunit. In view of the cardinal role of cdks in cell cycle control, it is important to learn if and how CAK activity is regulated during the somatic cell cycle. Here, we report a molecular characterization of a human p40MO15 homologue and its associated CAK activity. We have cloned and sequenced a cDNA coding for human p40MO15, and raised specific polyclonal and monoclonal antibodies against the corresponding protein expressed in Escherichia coli. These tools were then used to demonstrate that p40MO15 protein expression and CAK activity are constant throughout the somatic cell cycle. Gel filtration suggests that active CAK is a multiprotein complex, and immunoprecipitation experiments identify two polypeptides of 34 and 32 kD as likely complex partners of p40MO15. The association of the three proteins is near stoichiometric and invariant throughout the cell cycle. Immunocytochemistry and biochemical enucleation experiments both demonstrate that p40MO15 is nuclear at all stages of the cell cycle (except for mitosis, when the protein redistributes throughout the cell), although the p34cdc2/cyclin B complex, one of the major purported substrates of CAK, occurs in the cytoplasm until shortly before mitosis. The absence of obvious changes in CAK activity in exponentially growing cells constitutes a surprise. It suggests that the phosphorylation state of threonine 161 in p34cdc2 (and the corresponding residue in other cdks) may be regulated primarily by the availability of the cdk/cyclin substrates, and by phosphatase(s).

scholarly journals Loss of HOXB3 promotes development of hormone receptor negative breast cancer

2020 ◽  
Author(s):  
Lizhe Zhu ◽  
Shibo Yu ◽  
Siyuan Jiang ◽  
Guanqun Ge ◽  
Yu Yan ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Western Blot ◽  
Cell Line ◽  
Hormone Receptor ◽  
Poor Prognosis ◽  
Cancer Gene ◽  
Qrt Pcr ◽  
Lower Expression ◽  
Breast Cancer Gene

Abstract BackgroundThe homobox (HOX) gene family as a transcription factor encoding a specific nuclear protein is essential for embryonic development, differentiation, and homeostasis. The role of HOXB3 protein varies in different tumors. This study aims to explore the role of the HOXB3 gene in breast cancer.MethodDifferentiated expressed genes were screened by analyzing metastatic breast cancer gene chip data in TCGA and GEO database. The function of selected HOXB3 gene was also analyzed by GEPIA, Kaplan-Meier Plotter, Breast Cancer Gene-Expression Miner and metascape. Molecular biology methods such as qRT-PCR, western blot and IF was used to verify bio-informatics findings.ResultsBoth bio-informatics analyses and western blot showed that HOXB3 was lost in breast cancer compared to normal breast tissue. Survival analysis also showed that lower expression of HOXB3 was associated with poor prognosis. Bio-informatics analyses further showed that HOXB3 was positively correlated with hormone receptors. qRT-PCR, immunofluorescence and western blot also confirmed that HOXB3 had the highest expression in the immortalized breast epithelial cell line MCF-10A, lower in luminal breast cancer cell line T47D and the lowest in triple negative breast cancer (TNBC) cell line MDA-MB-231. Metascape for GO analysis of GEO data provided possible mechanism that HOXB3 could positively regulate cell adhesion, inhibit cell proliferation and activate immune response in breast cancer, and considered that HOXB3 might cause cell malignant transformation through the above pathways.ConclusionIn summary, HOXB3 expression was decreased in breast cancer, especially in hormone receptor-negative breast cancer. The lower expression of HOXB3 was associated with poor prognosis. It might become a new biomarker to predict prognosis of breast cancer.

scholarly journals Decreased HECTD1 mRNA expression is associated with poor prognosis and enhanced mitochondrial cellular respiratory function in breast cancer

2021 ◽  
Author(s):  
Yasuaki Uemoto ◽  
Eriko Katsuta ◽  
Naoto Kondo ◽  
Yumi Wanifuchi-Endo ◽  
Takashi Fujita ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Multivariate Analysis ◽  
Protein Expression ◽  
Mrna Expression ◽  
Respiratory Function ◽  
Poor Prognosis ◽  
Prognostic Significance ◽  
Negative Regulator ◽  
Mesenchymal Transition

Abstract HECT domain E3 ubiquitin ligase 1 (HECTD1) has been reported to be a negative regulator of epithelial-mesenchymal transition and to decrease breast cancer invasion and metastasis. However, the clinical significance and detailed role of HECTD1 in breast cancer remain elusive. We investigated the role of HECTD1 in two large breast cancer cohorts using mRNA and protein expression, and bioinformatics. We examined the prognostic significance of HECTD1 by multivariate analysis. HECTD1 mRNA expression (HECTD1 expression) was lower in breast cancer compared with adjacent normal tissues. HECTD1 expression levels also differed among breast cancer subtypes. Decreased HECTD1 expression was significantly associated with aggressive tumour characteristics, including large tumour size and high histological grade. HECTD1 expression was inversely associated with mitochondrial cellular respiratory function and reactive oxygen species in breast cancer tissues. Multivariate analysis identified low HECTD1 mRNA expression level as an independent risk factor for disease-free (P = 0.009) and overall (P = 0.046) survival among breast cancer patients. There was no association of HECTD1 protein expression with mRNA expression and prognosis. HECTD1 mRNA expression is a candidate prognostic biomarker in breast cancer. The poor prognosis of patients with low HECTD1 mRNA expression may be associated with increased mitochondrial respiratory function.

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