Exploratory analysis of the effect of taselisib on downstream pathway modulation and correlation with tumor response in ER-positive/HER2-negative early-stage breast cancer from the LORELEI trial.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. 1050-1050 ◽  
Author(s):  
Paolo Nuciforo ◽  
Dominik Hlauschek ◽  
Cristina Saura ◽  
Evandro de Azambuja ◽  
Roberta Fasani ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Early Stage ◽  
Objective Response ◽  
Wild Type ◽  
Cycle Arrest ◽  
Er Positive ◽  
A Cell ◽  
Tumor Biopsies ◽  
Clinical Trial Information

1050 Background: Taselisib (T) is an oral, potent, selective inhibitor of Class I PI3-kinase with enhanced activity against PIK3CA mutant cancer cells. Results from the LORELEI trial have demonstrated a significant improvement in ORR (objective response rate) by centrally assessed magnetic resonance imaging in all randomized patients as well as in the PIK3CA mutant (MT) cohort treated with neoadjuvant T plus letrozole (L) compared to placebo (P) plus L. Here we present the results of exploratory analyses of selected pathway-related phosphoproteins. Methods: Baseline (BL) and week3 (W3) tumor biopsies were obtained from 334 patients enrolled in the trial. Phosphoproteins (pAKT, pPRAS40 and pS6) were analyzed by IHC. BL levels as well as changes from BL to W3 were correlated with response assessed either by ORR or cell cycle arrest (Ki67 at W3 < 2.7%). Results: In the overall population, BL phosphoproteins levels were similar between the T and P arms. Higher pAKT (p < 0.001) and pPRAS40 (p = 0.004) levels were observed in MT vs wild-type (WT), whereas the opposite result was found for pS6 (p = 0.03). Treatment-induced absolute changes of phosphoproteins adjusted for BL levels were not significantly different between the T and P arms in the overall population, except for pPRAS40 with higher decrease in the T arm (p = 0.014). After stratification for PIK3CA genotype, a significantly greater decrease in expression levels was observed for pPRAS40 (p < 0.001) and pS6 (p = 0.020) in MT tumors treated with T. The treatment effects were not significantly different in the WT population. A trend for an association between decrease in pS6 levels at W3 and improved ORR was observed in the MT (p = 0.08) and T (p = 0.09) subgroups. The magnitude of pS6 suppression at W3 was higher in tumors achieving a cell cycle arrest in the MT/T subgroup (biserial correlation = -0.473). Conclusions: Exploratory analyses of phosphoproteins showed bioactivity of taselisib as indicated by downstream pathway suppression. Translational research aiming to integrate these results with additional exploratory biomarkers data is currently ongoing. Clinical trial information: NCT02273973.

scholarly journals CRISPR/Cas9 treatment causes extended TP53-dependent cell cycle arrest in human cells

2020 ◽  
Vol 48 (16) ◽  
pp. 9067-9081
Author(s):  
Jonathan M Geisinger ◽  
Tim Stearns
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Cell Cycle Progression ◽  
Target Sequence ◽  
Wild Type ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
Dependent Cell ◽  
A Cell

Abstract While the mechanism of CRISPR/Cas9 cleavage is understood, the basis for the large variation in mutant recovery for a given target sequence between cell lines is much less clear. We hypothesized that this variation may be due to differences in how the DNA damage response affects cell cycle progression. We used incorporation of EdU as a marker of cell cycle progression to analyze the response of several human cell lines to CRISPR/Cas9 treatment with a single guide directed to a unique locus. Cell lines with functionally wild-type TP53 exhibited higher levels of cell cycle arrest compared to lines without. Chemical inhibition of TP53 protein combined with TP53 and RB1 transcript silencing alleviated induced arrest in TP53+/+ cells. Using dCas9, we determined this arrest is driven in part by Cas9 binding to DNA. Additionally, wild-type Cas9 induced fewer 53BP1 foci in TP53+/+ cells compared to TP53−/− cells and DD-Cas9, suggesting that differences in break sensing are responsible for cell cycle arrest variation. We conclude that CRISPR/Cas9 treatment induces a cell cycle arrest dependent on functional TP53 as well as Cas9 DNA binding and cleavage. Our findings suggest that transient inhibition of TP53 may increase genome editing recovery in primary and TP53+/+ cell lines.

scholarly journals CRISPR/Cas9 Treatment Causes Extended TP53-Dependent Cell Cycle Arrest In Human Cells

2019 ◽  
Author(s):  
Jonathan M. Geisinger ◽  
Tim Stearns
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Cell Cycle Progression ◽  
Target Sequence ◽  
Wild Type ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
Dependent Cell ◽  
A Cell

ABSTRACTWhile the mechanism of CRISPR/Cas9 cleavage is understood, the large variation in mutant recovery for a given target sequence between cell lines is much less clear. We hypothesized that this variation may be due to differences in how the DNA damage response affects cell cycle progression. We used incorporation of EdU as a marker of cell cycle progression to analyze the response of several human cell lines to CRISPR/Cas9 treatment with a single guide directed to a unique locus. Cell lines with functionally wild-type TP53 exhibited higher levels of cell cycle arrest compared to lines without. Chemical inhibition of TP53 protein combined with TP53 and RB1 transcript silencing alleviated induced arrest in TP53+/+ cells. This arrest is driven in part by Cas9 binding to DNA. Additionally, wild-type Cas9 induced fewer 53BP1 foci in TP53+/+ cells compared to TP53−/− cells, suggesting that differences in break sensing are responsible for cell cycle arrest variation. We conclude that CRISPR/Cas9 treatment induces a cell cycle arrest dependent on functional TP53 as well as Cas9 DNA binding and cleavage. Our findings suggest that transient inhibition of TP53 may increase genome editing efficiency in primary and TP53+/+ cell lines.

scholarly journals Proteotoxic Stress Induces a Cell-Cycle Arrest by Stimulating Lon to Degrade the Replication Initiator DnaA

Cell ◽  
2013 ◽  
Vol 154 (3) ◽  
pp. 623-636 ◽  
Author(s):  
Kristina Jonas ◽  
Jing Liu ◽  
Peter Chien ◽  
Michael T. Laub
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Proteotoxic Stress ◽  
Cycle Arrest ◽  
A Cell ◽  
Replication Initiator

scholarly journals Effect of Piceatannol on Cell Cycle Progression in Prostate Cancer Cells (P05-005-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Larissa Kido ◽  
Eun-Ryeong Hahm ◽  
Valeria Cagnon ◽  
Mário Maróstica ◽  
Shivendra Singh
Keyword(s):  
Prostate Cancer ◽  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Cell Cycle Progression ◽  
Cell Cycle Distribution ◽  
Mutant P53 ◽  
Wild Type ◽  
Cycle Progression ◽  
Cycle Arrest

Abstract Objectives Piceatannol (PIC) is a polyphenolic and resveratrol analog that is found in many vegetables consumed by humans. Like resveratrol, PIC has beneficial effects on health due to its anti-inflammatory, anti-oxidative and anti-proliferative features. However, the molecular targets of PIC in prostate cancer (PCa), which is the second most common cancer in men worldwide, are still poorly understood. Preventing cancer through dietary sources is a promising strategy to control diseases. Therefore, the aim of present study was to investigate the molecular mechanistic of actions of PIC in PCa cell lines with different genetic background common to human prostate cancer. Methods Human PCa cell lines (PC-3, 22Rv1, LNCaP, and VCaP) were treated with different doses of PIC (5–40 µM) and used for cell viability assay, measurement of total free fatty acids (FFA) and lactate, and cell cycle distribution. Results PIC treatment dose- and time-dependently reduced viability in PC-3 (androgen-independent, PTEN null, p53 null) and VCaP cells (androgen-responsive, wild-type PTEN, mutant p53). Because metabolic alterations, such as increased glucose and lipid metabolism are implicated in pathogenesis of in PCa, we tested if PIC could affect these pathways. Results from lactate and total free fatty acid assays in VCaP, 22Rv1 (castration-resistant, wild-type PTEN, mutant p53), and LNCaP (androgen-responsive, PTEN null, wild-type p53) revealed no effect of PIC on these metabolisms. However, PIC treatment delayed cell cycle progression in G0/G1 phase concomitant with the induction of apoptosis in both LNCaP and 22Rv1 cells, suggesting that growth inhibitory effect of PIC in PCa is associated with cell cycle arrest and apoptotic cell death at least LNCaP and 22Rv1 cells. Conclusions While PIC treatment does not alter lipid or glucose metabolism, cell cycle arrest and apoptosis induction are likely important in anti-cancer effects of PIC. Funding Sources São Paulo Research Foundation (2018/09793-7).

scholarly journals Co-expression of murine double minute 2 siRNA and wild-type p53 induces G1 cell cycle arrest in H1299 cells

2017 ◽  
Vol 16 (6) ◽  
pp. 9137-9142
Author(s):  
Long Liu ◽  
Ping Zhang ◽  
Hua Guo ◽  
Xinyu Tang ◽  
Lianqin Liu ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Wild Type ◽  
Cycle Arrest ◽  
Double Minute ◽  
G1 Cell Cycle Arrest ◽  
Murine Double Minute ◽  
Wild Type P53

scholarly journals The Fanconi anemia complementation group C protein corrects DNA interstrand cross-link-specific apoptosis in HSC536N cells

Blood ◽  
1996 ◽  
Vol 88 (6) ◽  
pp. 2298-2305 ◽  
Author(s):  
UK Marathi ◽  
SR Howell ◽  
RA Ashmun ◽  
TP Brent
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Fanconi Anemia ◽  
Complementation Group ◽  
Cross Linking ◽  
Wild Type ◽  
Cross Link ◽  
Cycle Arrest ◽  
Protein Functions ◽  
Induced Apoptosis

Fanconi anemia (FA) cells are hypersensitive to cytotoxicity, cell cycle arrest, and chromosomal aberrations induced by DNA cross-linking agents, such as mitomycin C (MMC) and nitrogen mustard (HN2). Although MMC hypersensitivity is complemented in a subset of FA cells (complementation group C [FA-C]) by wild-type FAC cDNA, the cytoprotective mechanism is unknown. In the current study, we tested the hypothesis that FAC protein functions in the suppression of DNA interstand cross-link (ISC)-induced cell cycle arrest and apoptosis. Comparison of HN2-induced cell cycle arrest and apoptosis with those of its non-cross-linking analogs, diethylaminoethyl chloride and 2- dimethylaminoethyl chloride, delineated the DNA ISC specificity of FAC- mediated cytoprotection. Overexpression of wild-type FAC cDNA in FA-C lymphoblasts (HSC536N cell line) prevented HN2-induced growth inhibition, G2 arrest, and DNA fragmentation that is characteristic of apoptosis. In contrast cytoprotection was not conferred against the effects of the non-cross-linking mustards. Our data show that DNA ISCs induce apoptosis more potently than do DNA monoadducts and suggest that FAC suppresses specifically DNA ISC-induced apoptosis in the G2 phase of the cell cycle.

scholarly journals Mitochondrial DNA Damage Initiates a Cell Cycle Arrest by a Chk2-associated Mechanism in Mammalian Cells

2009 ◽  
Vol 284 (52) ◽  
pp. 36191-36201 ◽  
Author(s):  
Christopher A. Koczor ◽  
Inna N. Shokolenko ◽  
Amy K. Boyd ◽  
Shawn P. Balk ◽  
Glenn L. Wilson ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Mitochondrial Dna ◽  
Cell Cycle Arrest ◽  
Mammalian Cells ◽  
Mitochondrial Dna Damage ◽  
Cycle Arrest ◽  
A Cell
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