title: Exosomes Secreted by Apoptosis-Resistant Acute Myeloid Leukemia (AML) Blasts Harbor Regulatory Network Proteins Potentially Involved in Antagonism of Apoptosis.
abstract: Expression of apoptosis-regulating proteins (B-cell CLL/lymphoma 2 - BCL-2, Myeloid Cell Leukemia 1 - MCL-1, BCL-2 like 1 - BCL-X and BCL-2-associated X protein - BAX) in acute myeloid leukemia (AML) blasts at diagnosis is associated with disease-free survival. We previously found that the initially high apoptosis-resistance of AML cells decreased after therapy, while regaining high levels at relapse. Herein, we further explored this aspect of dynamic apoptosis regulation in AML. First, we showed that the intraindividualex vivoapoptosis-related profiles of normal lymphocytes and AML blasts within the bone marrow of AML patients were highly correlated. The expression values of apoptosis-regulating proteins were far beyond healthy control lymphocytes, which implicates the influence of microenvironmental factors. Second, we demonstrated that apoptosis-resistant primary AML blasts, as opposed to apoptosis-sensitive cells, were able to up-regulate BCL-2 expression in sensitive AML blasts in contact cultures (p= 0.0067 andp= 1.0, respectively). Using secretome proteomics, we identified novel proteins possibly engaged in apoptosis regulation. Intriguingly, this analysis revealed that major functional protein clusters engaged in global gene regulation, including mRNA splicing, protein translation, and chromatin remodeling, were more abundant (p= 4.01E-06) in secretomes of apoptosis-resistant AML. These findings were confirmed by subsequent extracellular vesicle proteomics. Finally, confocal-microscopy-based colocalization studies show that splicing factors-containing vesicles secreted by high AAI cells are taken up by low AAI cells. The current results constitute the first comprehensive analysis of proteins released by apoptosis-resistant and sensitive primary AML cells. Together, the data point to vesicle-mediated release of global gene regulatory protein clusters as a plausible novel mechanism of induction of apoptosis resistance. Deciphering the modes of communication between apoptosis-resistant blasts may in perspective lead to the discovery of prognostic tools and development of novel therapeutic interventions, aimed at limiting or overcoming therapy resistance.
authors.affiliation: From the ‡Dept. of Pediatric Oncology/Hematology, §Dept. of Hematology.
authors.forename: Anna
authors.initials: A
authors.lastname: Wojtuszkiewicz
authors.affiliation: §Dept. of Hematology.
authors.forename: Gerrit J
authors.initials: GJ
authors.lastname: Schuurhuis
authors.affiliation: §Dept. of Hematology.
authors.forename: Floortje L
authors.initials: FL
authors.lastname: Kessler
authors.affiliation: ¶OncoProteomics Laboratory, Dept. of Medical Oncology.
authors.forename: Sander R
authors.initials: SR
authors.lastname: Piersma
authors.affiliation: ¶OncoProteomics Laboratory, Dept. of Medical Oncology.
authors.forename: Jaco C
authors.initials: JC
authors.lastname: Knol
authors.affiliation: ¶OncoProteomics Laboratory, Dept. of Medical Oncology.
authors.forename: Thang V
authors.initials: TV
authors.lastname: Pham
authors.affiliation: ‖Dept. of Rheumatology, VUmc-Cancer Center Amsterdam, VU University Medical Center, De Boelelaan 1117, 1081HV Amsterdam, The Netherlands;
authors.forename: Gerrit
authors.initials: G
authors.lastname: Jansen
authors.affiliation: **Dept. of Physiology, ICaR-VU, VU University Medical Center, De Boelelaan 1117, 1081HV Amsterdam, The Netherlands;
authors.forename: René J P
authors.initials: RJ
authors.lastname: Musters
authors.affiliation: §Dept. of Hematology.
authors.forename: Johan
authors.initials: J
authors.lastname: van Meerloo
authors.affiliation: ‡‡Dept. of Biology, Fred Wyszkowski Cancer Research Laboratory, Faculty of Biology, Technion-Israel, Institute of Technology, Haifa 3200003, Israel.
authors.forename: Yehuda G
authors.initials: YG
authors.lastname: Assaraf
authors.affiliation: From the ‡Dept. of Pediatric Oncology/Hematology.
authors.forename: Gertjan J L
authors.initials: GJ
authors.lastname: Kaspers
authors.affiliation: §Dept. of Hematology.
authors.forename: Sonja
authors.initials: S
authors.lastname: Zweegman
authors.affiliation: From the ‡Dept. of Pediatric Oncology/Hematology, §Dept. of Hematology.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Cloos
authors.affiliation: ¶OncoProteomics Laboratory, Dept. of Medical Oncology, c.jimenez@vumc.nl.
authors.forename: Connie R
authors.initials: CR
authors.lastname: Jimenez
mesh_terms: D017209:Apoptosis; D001854:Bone Marrow Cells / Q000166:cytology / Q000473:pathology; D019008:Drug Resistance, Neoplasm; D055354:Exosomes / Q000378:metabolism*; D015972:Gene Expression Regulation, Neoplastic; D053263:Gene Regulatory Networks; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000378:metabolism / Q000473:pathology*; D020543:Proteome / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D020543:Proteome