PXD035007-1

PXD035007 is an original dataset announced via ProteomeXchange.

Title	Endoxifen Downregulates AKT Phosphorylation Through Protein Kinase C Beta 1 in ER+/HER2- Breast Cancer
Description	In phase I/II clinical trials, Z-endoxifen demonstrated substantial oral bioavailability and promising antitumor activity in endocrine-refractory estrogen-receptor positive breast cancer (ER+ BC) and other solid tumors, with plasma concentrations reportedly as high as 5 �M. Therefore, we explored the potential mechanisms of Z-endoxifen antitumor activity that extends beyond ERα inhibition. In estrogen unstimulated aromatase-expressing ER+/human epidermal growth factor 2 receptor negative (HER2-) MCF7AC1 BC cells, Z-endoxifen at 5 �M, but not ER�-targeting 0.01 and 0.1 �M concentrations inhibited growth and induced apoptosis, suggesting an ERα-independent effect. Utilizing an unbiased mass spectrometry approach, we explored Z-endoxifen effects on other signaling pathways. Z-endoxifen at 5 µM profoundly altered the phosphoproteome with minimal impact on total proteome. Computational analysis revealed Protein kinase C beta (PKC�) and AKT1 as the prevalent upstream kinases for Z-endoxifen-downregulated protein phosphorylations. Notably, in ER+/HER2- BC models, Z-endoxifen at 5 �M attenuated AKTSer473 and AKT substrates in vitro in the presence of insulin and PKC agonist PMA and in vivo. Further, Z-endoxifen inhibited PKC�1 kinase activity compared to other PKC isoforms in vitro and bound to PKCβ1. While PMA stimulated PKC�1Ser661 phosphorylation correlated with AKTSer473 and AKT substrate phosphorylation, Z-endoxifen at 5 �M uniquely blocked these effects and induced PKCβ1 protein degradation. siRNA-mediated PKC�1 knockdown attenuated AKTSer473 phosphorylation, suggesting PKCβ1-mediated suppression of AKT signaling by Z-endoxifen. Further, Z-endoxifen at 5 �M replicates the pan-AKT inhibitor MK-2206 effects on apoptosis. These findings implicate PKCβ1 as a novel Z-endoxifen substrate responsible for suppressing AKT signaling and inducing apoptosis in breast cancer.
HostingRepository	PRIDE
AnnounceDate	2024-01-26
AnnouncementXML	Submission_2024-01-26_06:54:01.430.xml
DigitalObjectIdentifier	https://dx.doi.org/10.6019/PXD035007
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Supported dataset by repository
PrimarySubmitter	Akhilesh Pandey
SpeciesList	scientific name: Homo sapiens (Human); NCBI TaxID: 9606;
ModificationList	phosphorylated residue; acetylated residue; monohydroxylated residue; iodoacetamide derivatized residue
Instrument	Orbitrap Fusion Lumos

Revision	Datetime	Status	ChangeLog Entry
0	2022-06-30 03:18:06	ID requested
⏵ 1	2024-01-26 06:54:02	announced
2	2024-10-22 06:25:44	announced	2024-10-22: Updated project metadata.

Jayaraman S, Wu X, Kalari KR, Tang X, Kuffel MJ, Bruinsma ES, Jalali S, Peterson KL, Correia C, Kudgus RA, Kaufmann SH, Renuse S, Ingle JN, Reid JM, Ames MM, Fields AP, Schellenberg MJ, Hawse JR, Pandey A, Goetz MP, + breast cancer. NPJ Breast Cancer, 9(1):101(2023) [pubmed]

10.1038/s41523-023-00606-2;

10.6019/PXD035007;

submitter keyword: breast cancer,Endoxifen, Mass Spectrometry, PKC-beta-1, AKT, Apoptosis, Phosphoproteome

Akhilesh Pandey
contact affiliation	Laboratory Medicine and Pathology Mayo Clinic USA
contact email	pandey.akhilesh@mayo.edu
lab head
Akhilesh Pandey
contact affiliation	Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905
contact email	pandey.akhilesh@mayo.edu
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD035007
     1. Label: PRIDE project
     2. Name: Endoxifen Downregulates AKT Phosphorylation Through Protein Kinase C Beta 1 in ER+/HER2- Breast Cancer