scholarly journals Valproic Acid Regulates HR and Cell Cycle Through MUS81-pRPA2 Pathway in Response to Hydroxyurea

2021 ◽  
Vol 11 ◽  
Author(s):  
Benyu Su ◽  
David Lim ◽  
Zhujun Tian ◽  
Guochao Liu ◽  
Chenxia Ding ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Valproic Acid ◽  
Breast Cancer Cells ◽  
Tumor Burden ◽  
Checkpoint Kinases ◽  
Combined Application ◽  
Kaplan Meier ◽  
Phase Slippage ◽  
Primary Problem

Breast cancer is the primary problem threatening women’s health. The combined application of valproic acid (VPA) and hydroxyurea (HU) has a synergistic effect on killing breast cancer cells, but the molecular mechanism remains elusive. Replication protein A2 phosphorylation (pRPA2), is essential for homologous recombination (HR) repair and cell cycle. Here we showed that in response to HU, the VPA significantly decreased the tumor cells survival, and promoted S-phase slippage, which was associated with the decrease of pCHK1 and WEE1/pCDK1-mediated checkpoint kinases phosphorylation pathway and inhibited pRPA2/Rad51-mediated HR repair pathway; the mutation of pRPA2 significantly diminished the above effect, indicating that VPA-caused HU sensitization was pRPA2 dependent. It was further found that VPA and HU combination treatment also resulted in the decrease of endonuclease MUS81. After MUS81 elimination, not only the level of pRPA2 was abolished in response to HU treatment, but also VPA-caused HU sensitization was significantly down-regulated through pRPA2-mediated checkpoint kinases phosphorylation and HR repair pathways. In addition, the VPA altered the tumor microenvironment and reduced tumor burden by recruiting macrophages to tumor sites; the Kaplan-Meier analysis showed that patients with high pRPA2 expression had significantly worse survival. Overall, our findings demonstrated that VPA influences HR repair and cell cycle through down-regulating MUS81-pRPA2 pathway in response to HU treatment.

scholarly journals Valproic acid inhibits proliferation of HER2-expressing breast cancer cells by inducing cell cycle arrest and apoptosis through Hsp70 acetylation

2015 ◽  
Vol 47 (6) ◽  
pp. 2073-2081 ◽  
Author(s):  
TOSHIKI MAWATARI ◽  
ITASU NINOMIYA ◽  
MASAFUMI INOKUCHI ◽  
SHINICHI HARADA ◽  
HIRONORI HAYASHI ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Valproic Acid ◽  
Cell Cycle Arrest ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Cycle Arrest

scholarly journals Polarity Protein Par3 Sensitizes Breast Cancer to Paclitaxel by Promoting Cell Cycle Arrest.

2021 ◽  
Author(s):  
She Chen ◽  
Yannan Zhao ◽  
Huitong Peng ◽  
Limiao Liang ◽  
Yi Li ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Cancer Cells ◽  
Cell Apoptosis ◽  
Breast Cancer Cells ◽  
Brdu Incorporation ◽  
Individual Treatment ◽  
Breast Cancer Patients ◽  
Kaplan Meier

Abstract Purpose Paclitaxel, belongs to tubulin-binding agents (TBAs), showed a great efficacy against breast cancer via stabilizing microtubules. Drug resistance limits its clinical application. Here we aimed to explore a role of Polarity protein Par3 in improving paclitaxel effectiveness.Methods Breast cancer specimens from 45 patients were collected to study the relationship between Par3 expression and paclitaxel efficacy. The Kaplan–Meier method was used for survival analysis. Cell viability was measured in breast cancer cells (SK-BR-3 and T-47D) with Par3 over-expression or knockdown. The flow cytometry assays were performed to measure cell apoptosis and cell cycle. BrdU incorporation assay and Hoechst 33258 staining were performed to measure cell proliferation and cell apoptosis, respectively. Immunofluorescence was used to detect microtubule structures. Results Par3 expression is associated with good response of paclitaxel in breast cancer patients. Consistently, Par3 overexpression significantly sensitizes breast cancer cells to paclitaxel by promoting cell apoptosis and reducing cell proliferation. In Par3 overexpressing cells upon paclitaxel treatment, we observed intensified cell cycle arrests at metaphase. Further exploration showed that Par3 overexpression stabilizes microtubules of breast cancer cells in response to paclitaxel, and resists to microtubules instability induced by nocodazole, a microtubule-depolymerizing agent. Conclusion Par3 facilitates polymeric forms of tubulin and stabilizes microtubule structure, which aggravates paclitaxel-induced delay at the metaphase-anaphase transition, leading to proliferation inhibition and apoptosis of breast cancer cells. Par3 has a potential role in sensitizing breast cancer cells to paclitaxel, which may provide a more precise assessment of individual treatment and novel therapeutic targets.

scholarly journals Matrix degradation and cell proliferation are coupled to promote invasion and escape from an engineered human breast microtumor

2021 ◽  
Vol 13 (1) ◽  
pp. 17-29
Author(s):  
Emann M Rabie ◽  
Sherry X Zhang ◽  
Andreas P Kourouklis ◽  
A Nihan Kilinc ◽  
Allison K Simi ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cell Proliferation ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Type I ◽  
Matrix Degradation ◽  
Human Breast ◽  
Rate Of Invasion

Abstract Metastasis, the leading cause of mortality in cancer patients, depends upon the ability of cancer cells to invade into the extracellular matrix that surrounds the primary tumor and to escape into the vasculature. To investigate the features of the microenvironment that regulate invasion and escape, we generated solid microtumors of MDA-MB-231 human breast carcinoma cells within gels of type I collagen. The microtumors were formed at defined distances adjacent to an empty cavity, which served as an artificial vessel into which the constituent tumor cells could escape. To define the relative contributions of matrix degradation and cell proliferation on invasion and escape, we used pharmacological approaches to block the activity of matrix metalloproteinases (MMPs) or to arrest the cell cycle. We found that blocking MMP activity prevents both invasion and escape of the breast cancer cells. Surprisingly, blocking proliferation increases the rate of invasion but has no effect on that of escape. We found that arresting the cell cycle increases the expression of MMPs, consistent with the increased rate of invasion. To gain additional insight into the role of cell proliferation in the invasion process, we generated microtumors from cells that express the fluorescent ubiquitination-based cell cycle indicator. We found that the cells that initiate invasions are preferentially quiescent, whereas cell proliferation is associated with the extension of invasions. These data suggest that matrix degradation and cell proliferation are coupled during the invasion and escape of human breast cancer cells and highlight the critical role of matrix proteolysis in governing tumor phenotype.

scholarly journals Mutant p53L194F Harboring Luminal-A Breast Cancer Cells Are Refractory to Apoptosis and Cell Cycle Arrest in Response to MortaparibPlus, a Multimodal Small Molecule Inhibitor

Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 3043
Author(s):  
Ahmed Elwakeel ◽  
Anissa Nofita Sari ◽  
Jaspreet Kaur Dhanjal ◽  
Hazna Noor Meidinna ◽  
Durai Sundar ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Cancer Cells ◽  
Small Molecule ◽  
Breast Cancer Cells ◽  
Luminal A ◽  
Molecular Analyses ◽  
Cycle Arrest ◽  
Mcf 7

We previously performed a drug screening to identify a potential inhibitor of mortalin–p53 interaction. In four rounds of screenings based on the shift in mortalin immunostaining pattern from perinuclear to pan-cytoplasmic and nuclear enrichment of p53, we had identified MortaparibPlus (4-[(1E)-2-(2-phenylindol-3-yl)-1-azavinyl]-1,2,4-triazole) as a novel synthetic small molecule. In order to validate its activity and mechanism of action, we recruited Luminal-A breast cancer cells, MCF-7 (p53wild type) and T47D (p53L194F) and performed extensive biochemical and immunocytochemical analyses. Molecular analyses revealed that MortaparibPlus is capable of abrogating mortalin–p53 interaction in both MCF-7 and T47D cells. Intriguingly, upregulation of transcriptional activation function of p53 (as marked by upregulation of the p53 effector gene—p21WAF1—responsible for cell cycle arrest and apoptosis) was recorded only in MortaparibPlus-treated MCF-7 cells. On the other hand, MortaparibPlus-treated T47D cells exhibited hyperactivation of PARP1 (accumulation of PAR polymer and decrease in ATP levels) as a possible non-p53 tumor suppression program. However, these cells did not show full signs of either apoptosis or PAR-Thanatos. Molecular analyses attributed such a response to the inability of MortaparibPlus to disrupt the AIF–mortalin complexes; hence, AIF did not translocate to the nucleus to induce chromatinolysis and DNA degradation. These data suggested that the cancer cells possessing enriched levels of such complexes may not respond to MortaparibPlus. Taken together, we report the multimodal anticancer potential of MortaparibPlus that warrants further attention in laboratory and clinical studies.

scholarly journals Overexpression of β-Arrestins inhibits proliferation and motility in triple negative breast cancer cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Saber Yari Bostanabad ◽  
Senem Noyan ◽  
Bala Gur Dedeoglu ◽  
Hakan Gurdal
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cancer Cells ◽  
Cancer Cell ◽  
Breast Cancer Cells ◽  
Cell Function ◽  
Expression Profiles ◽  
Tissue Samples ◽  
Expression Levels ◽  
Cell Cycle Genes

Abstractβ-Arrestins (βArrs) are intracellular signal regulating proteins. Their expression level varies in some cancers and they have a significant impact on cancer cell function. In general, the significance of βArrs in cancer research comes from studies examining GPCR signalling. Given the diversity of different GPCR signals in cancer cell regulation, contradictory results are inevitable regarding the role of βArrs. Our approach examines the direct influence of βArrs on cellular function and gene expression profiles by changing their expression levels in breast cancer cells, MDA-MB-231 and MDA-MB-468. Reducing expression of βArr1 or βArr2 tended to increase cell proliferation and invasion whereas increasing their expression levels inhibited them. The overexpression of βArrs caused cell cycle S-phase arrest and differential expression of cell cycle genes, CDC45, BUB1, CCNB1, CCNB2, CDKN2C and reduced HER3, IGF-1R, and Snail. Regarding to the clinical relevance of our results, low expression levels of βArr1 were inversely correlated with CDC45, BUB1, CCNB1, and CCNB2 genes compared to normal tissue samples while positively correlated with poorer prognosis in breast tumours. These results indicate that βArr1 and βArr2 are significantly involved in cell cycle and anticancer signalling pathways through their influence on cell cycle genes and HER3, IGF-1R, and Snail in TNBC cells.

Steroidal aromatase inhibitors inhibit growth of hormone-dependent breast cancer cells by inducing cell cycle arrest and apoptosis

APOPTOSIS ◽  
2013 ◽  
Vol 18 (11) ◽  
pp. 1426-1436 ◽  
Author(s):  
Cristina Amaral ◽  
Carla Varela ◽  
Margarida Borges ◽  
Elisiário Tavares da Silva ◽  
Fernanda M. F. Roleira ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Cancer Cells ◽  
Aromatase Inhibitors ◽  
Breast Cancer Cells ◽  
Cycle Arrest ◽  
Steroidal Aromatase Inhibitors
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