Abstract
Over the past years, we synthesized a series of new molecules that are hybrids of spirocyclic ketones as complexity-bearing cores with bi- and ter-phenyls as privileged fragments. Some of these newly-shaped small molecules showed antiproliferative, pro-apoptotic and differentiating activity in leukemia cell lines. In the present study, to investigate more in depth the mechanisms of action of these molecules, the protein expression profiles of K562 cells treated with or without the compounds IND_S1, MEL_T1, IND_S7 and MEL_S3 were analyzed using two-dimensional gel electrophoresis coupled with mass spectrometry. Proteome comparisons revealed several differentially expressed proteins, mainly related to cellular metabolism, chaperone activity, cytoskeletal organization and RNA biogenesis. The major results were validated by Western blot and qPCR. To attempt integrating findings into a cellular signaling context, proteomic data were explored using MetaCore. Network analysis highlighted relevant relationships between the identified proteins and additional potential effectors. Notably, qPCR validation of central hubs showed that the compound MEL_S3 induced high mRNA levels of the transcriptional factors EGR1 and HNF4-alpha; the latter to our knowledge is reported here for the first time to be present in K562 cells. Consistently with the known EGR1 involvement in the regulation of differentiation along megakaryocyte lineage, MEL_S3-treated leukemia cells showed a marked expression of glycoprotein IIb/IIIa (CD41) and glycoprotein Ib (CD42), two important cell markers in megakaryocytic differentiation, together with morphological aspects of megakaryoblasts and megakaryocytes.
Highlights
Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by increased proliferation of the granulocytic cell line
To identify the proteins whose expression was responsive to the synthetic small molecules IND_S1, MEL_T1, IND_S7 and MEL_S3, protein extracts from K562 cells grown for 24 h in the presence or absence of 30 mM of each compound were subjected to a 2-DE-based analysis
Principal Component Analysis (PCA) was applied to the entire 2-DE dataset to disclose differences in the protein patterns of K562 cells exposed to the four synthetic small molecules
Summary
Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by increased proliferation of the granulocytic cell line. Imatinib binds to and stabilizes the inactive form of BCR-ABL, blocking its autophosphorylation and downstream kinase activity This induces hematologic, cytogenetic and molecular response in the majority of CML patients, through inhibition of proliferation and triggering of apoptosis of BCR-ABL-expressing cells. Clinical resistance develops frequently, in accelerated phase and blastic crisis of CML This has led to the development of second-generation BCR-ABL-targeting molecules, that have been proved to be effective in most imatinibresistant BCR-ABL-positive leukemias [3,4,5]. TKIs are ineffective in patients who undergo blastic transformation, and unable to eradicate CML at the stem cell level, underscoring the need to pursue novel therapeutic strategies [6,8] In this regard, differentiation induction therapy has attracted universal attention as a promising approach to treat leukemia by turning abnormal cells back to differentiate and cease proliferation. Research efforts are geared towards targeting signaling pathways that are chronically activated and critical for transformation of leukemia cells, for example by manipulating the transcription factors that govern the differentiation and lineage commitment of hematopoietic progenitors [8,10,11]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call