# Editorial: Novel Drugs Targeting the Microenvironment and the Epigenetic Changes in Hematopoietic Malignancies

Diana Gulei, Ciprian Tomuleasa, Liren Qian, Cristina Bagacean, Carlo M Croce, Gabriel Ghiaur

► To cite this version:

Diana Gulei, Ciprian Tomuleasa, Liren Qian, Cristina Bagacean, Carlo M Croce, et al. Editorial: Novel Drugs Targeting the Microenvironment and the Epigenetic Changes in Hematopoietic Malignancies. Frontiers in Pharmacology, 2020, 11, 10.3389/fphar.2020.614614. [https://doi.org/10.3389/fphar.2020.614614](https://doi.org/10.3389/fphar.2020.614614)

HAL Id: hal-05228400

https://hal.univ-brest.fr/hal-05228400v1

Submitted on 28 Aug 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>
<figure><img src="image_2.png" /></figure>

Check for
updates

# Editorial: Novel Drugs Targeting the Microenvironment and the Epigenetic Changes in Hematopoietic Malignancies

Diana Gulei¹, Ciprian Tomuleasa²,³*, Liren Qian⁴, Cristina Bagacean⁵,⁶, Carlo M. Croce⁷ and Gabriel Ghiaur⁸

¹Medfuture Research Center for Advanced Medicine, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj Napoca, Romania, ²Department of Hematology, Ion Chiricuta Clinical Cancer Center, Cluj Napoca, Romania, ³Department of Hematology, Medfuture Research Center for Advanced Medicine, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj Napoca, Romania, ⁴Department of Hematology, The Sixth Medical Center, Chinese PLA General Hospital, Beijing, China, ⁵INSERM UMR1227, B lymphocytes and autoimmunity, University of Brest, Brest, France, ⁶Service d'Hématologie, Centre Hospitalier Régional et Universitaire de Brest, Brest, France, ⁷Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University, Columbus, OH, United States, ⁸Department of Leukemia, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, MD, United States

**Keywords:** tumor microenvironment, epigenetic changes, hematological malignances, methylation, pharmacology

## Editorial on the Research Article

### Novel Drugs Targeting the Microenvironment and the Epigenetic Changes in Hematopoietic Malignancies

**OPEN ACCESS**

Edited and reviewed by:
Olivier Feron,
Université catholique de Louvain,
Belgium

*Correspondence:
Ciprian Tomuleasa
ciprian.tomuleasa@umfcluj.ro

**Specialty section:**
This article was submitted to Pharmacology of Anti-Cancer Drugs, a section of the journal Frontiers in Pharmacology

**Received:** 06 October 2020
**Accepted:** 26 October 2020
**Published:** 10 December 2020

**Citation:** Gulei D, Tomuleasa C, Qian L, Bagacean C, Croce CM and Ghiaur G (2020) Editorial: Novel Drugs Targeting the Microenvironment and the Epigenetic Changes in Hematopoietic Malignancies. *Front. Pharmacol.* 11:614614. doi: 10.3389/fphar.2020.614614

Starting with the first definition of epigenetics “to understand how the genotypes of evolving organisms can respond to the environment in a more co-ordinated fashion” originated in the research of Conrad Hal Waddington (1942) until current days, the field of epigenetics has evolved greatly (Dimopoulos and Gronbaek, 2019). We are now aware not only of the substantial contribution of the epigenomic patterns in development and homeostasis, but also of the profound implications of epigenetic alteration in disease pathogenesis (Stahl et al., 2016). Hematological malignancies light the way and provided proof-of-concept not only for the unraveling the role of epigenetic alterations in disease, but also for correcting these alterations and the clinical development of novel therapies (DNA hypomethylating agents and histone deacetylase inhibitors) for patients with myelodysplastic syndromes (MDS) and acute myeloid leukemias (AML). Large scale studies of cancer cells show an epigenetic drift toward global hypomethylation with enhances chromosomal instability or intensified hypermethylation at CpG islands within the promoter of tumor suppressor genes and sustained tumorigenesis (Eden et al., 2003; Herman and Baylin, 2003; Karpf and Matsui, 2005; Esteller, 2008). On top of this, further research has shown that epigenetic mechanisms have deep implications for the establishment of cancer permissive microenvironments (Maio et al., 2015). The deploy of epigenetic alterations has been shown to hijack the mechanisms of immune surveillance in order to escape the antitumor immune responses (Cao and Yan, 2020). In this sense, by remodeling the tumor microenvironment, a combination between immunotherapy and epigenetic agents may provide clinical benefit for patients with incomplete responses to immunomodulatory agents (Villanueva et al., 2020). In addition, efforts are undertaken to understand the role of epigenetic alterations and tumor microenvironment in reshaping the metabolic fitness and chemoresistance of cancer cells (Carrer and Wellen, 2015; Forte et al., 2019). There is increasing evidence that the tumor
microenvironment is essential for maintaining malignant hematopoiesis. Since stromal elements (i.e., cancer-associated fibroblast, endothelial cells and other) do not exhibit somatic mutations, they are likely to be corrupted by the malignant cells via epigenetic driven events (Sylvestre et al., 2020). To this point, mesenchymal stromal cells from AML show focal points of DNA hypermethylation, but also global hypomethylation compared to their normal counterparts (von der Heide et al., 2017). Therefore, epigenetic therapy could benefit patients with hematological malignancies not only due to reprogramming the cancer cells, but also by rescuing the tumor microenvironment.

The Research Topic entitled *Novel Drugs Targeting the Microenvironment and the Epigenetic Changes in Hematopoietic Malignancies* covers recent advancements in our understanding of the role of the microenvironment in hematological malignancies. To this end, response to epigenetic drugs are presented within a cohort of juvenile myelomonocytic leukemia (JMML) cases that were molecularly annotated via targeted next generation sequencing (NSG). Treatment with 5-Azacytidine was well tolerated and had effective results in both *de novo* JMML and relapsed patients (Marcu et al., 2020). The authors are highlighting the paramount role of microenvironment not only in disease progression and treatment response, but also in the outcomes of bone marrow transplantation in these patients. These data emphasize the importance of establishing a healthy substrate for normal hematopoiesis in patients with MDS undergoing bone marrow transplantation. The article is expending on the alterations that intervene in cancer associated stromal cells and how different therapies, including epigenetic agents can modulate the malignant environment (Teodorescu et al., 2020). The heterogeneity of the tumor microenvironment within AML is discussed with a focus on how unique immune profiles can serve as a surrogate distinct prognosis profiles for patients with hematological malignancies. Whether or not these changes are related to genetic and epigenetic events remains to be discussed (Antohe et al., 2020). The concept of minimal residual disease (MRD) in oncological hematology is presented within this research topic (Radu et al., 2020). In addition, DNA methylation patterns detected via revolutionary surface-enhanced Raman spectroscopy (SERS) are used as quantifiable biomarkers of circulating tumor cells in liquid biopsies (Turcas et al., 2020).

Although the critical influence of the epigenetic landscape on cancer cells survival and development has been recognized, so is its role in the establishment of supportive tumor environments. Nevertheless, the heterogeneous clinical response of hematological malignancies patients to epigenetic therapy suggests a complex relation between epigenetics and cellular behavior. Perhaps the newly emerging field of epitranscriptomis may provide the missing link between modulation of gene expression and the malignant phenotype. To this end, N<sup>6</sup>-methyladenosine (m<sup>6</sup>A) is the most common non-genetic alteration in mRNAs. M<sup>6</sup>A impacts RNA metabolism and thus, mediates aberrant gene expression seen in disease development (Chen et al., 2019). RNA methylation is mediated by m<sup>6</sup>A methyltransferases, removed by

demethylases and identified by m6A binding proteins, all of them recognized as “writers,” “erasers,” and “readers” respectively (Lan et al., 2019). The mechanism of RNA methylation in solid and hematological tumors is in its early years, without comprehensive clarification, and whatever this mechanism can surpass epigenetic changes is unknown. m<sup>6</sup>A enhances the translation of PTEN, BCL2, and c-MYC in AML (Vu et al., 2017), where YTHDF2 (m<sup>6</sup>A binding proteins) increases the expression of Tal1 (Li et al., 2018). On top, FMR1 (protein from the m<sup>6</sup>A binding complex) can bind multiple mRNAs to impair their translation and function (Edupuganti et al., 2017). However, how the entire RNA methylation machinery is functioning in cancer is still unknown; available data are showing distinct expression profiles of various “writers,” “erasers” and “readers” between cancer patients and distinct global m<sup>6</sup>A methylation profiles (Chen et al., 2019). The heterogeneity of these molecular profiles is demonstrating that RNA methylation is a dynamic process that can shift toward malignant favoring mechanisms, including during epigenetic treatment. Therefore, hematological patients that are non-responders to demethylating agents could be characterized by a dominant RNA methylation profile that favors the cancer phenotype or could present compensatory feedback mechanisms at the level of RNA to impede the modifications from the DNA induced by epigenetic therapy. Wide screening of different markers from the RNA methylation machinery could predict the eligible patients for epigenetic treatment, while analysis of the molecular background of the non-responder patients could offer new insights into the mechanisms of dynamic RNA methylation in cancer.

## AUTHOR CONTRIBUTIONS

All authors listed have made a substantial, direct, and intellectual contribution to the work and approved it for publication.

## FUNDING

DG and CT are supported by 3 grants from the Romanian Ministry of Research and Innovation: Postdoctoral Research Projects 2020-2022 - grant number PN-III-P1-1.1-PD-2019-0805, contract number PD 122/2020); CCCDI-UEFISCDI, Project No. PN-III-P4-ID-PCCF-2016-0112 within PNCDI III, as well as by awarded for Young Research Teams 2020-2022 (Grant No. PN-III-P1-1.1-TE-2019-0271), as well as by an international collaborative grant of the European Economic Space between Romania and Iceland 2020-2022 (Grant No. 19-COP-0031). GG is funded by K08 HL127269 (GG), R03 HL145226 (GG), P01CA225618 (GG), and P30 CA006973. LQ is funded by a grant from the National Natural Science Foundation of China (Grant No. 81800180) and the National Young Elite Scientists Sponsorship Program by the China Association for Science and Technology (Grant No. 17-JCJQ-QT-032).
REFERENCES

Antohe, I., Dascalescu, A., Danaila, C., Titieanu, A., Zlei, M., Ivanov, I., et al. (2020). B7-Positive and B7-negative acute myeloid leukemias display distinct T cell maturation profiles, immune checkpoint receptor expression, and European leukemia net risk profiles. *Front. Oncol.* 10, 264. doi:10.3389/fonc.2020.00264

Cao, J., and Yan, Q. (2020). Cancer epigenetics, tumor immunity, and immunotherapy. *Trends Cancer.* 6 (7), 580–592. doi:10.1016/j.trecan.2020.02.003

Carrer, A., and Wellen, K. E. (2015). Metabolism and epigenetics: a link cancer cells exploit. *Curr. Opin. Biotechnol.* 34, 23–29. doi:10.1016/j.copbio.2014.11.012

Chen, X.-Y., Zhang, J., and Zhu, J.-S. 2019). The role of m6A RNA methylation in human cancer. *Mol. Cancer* 18 (1), 103. doi:10.1186/s12943-019-1033-z

Dimopoulos, K., and Gronbaek, K. (2019). Epigenetic therapy in hematological cancers. *APMIS* 127 (5), 316–328. doi:10.1111/apm.12906

Eden, A., Gaudet, F., Waghmare, A., and Jaenisch, R. (2003). Chromosomal instability and tumors promoted by DNA hypomethylation. *Science* 300 (5618), 455. doi:10.1126/science.1083557

Edupuganti, R. R., Geiger, S., Lindeboom, R. G. H., Shi, H., Hsu, P. J., Lu, Z., et al. (2017). N(6)-methyladenosine (m(6)A) recruits and repels proteins to regulate mRNA homeostasis. *Nat. Struct. Mol. Biol.* 24 (10), 870–878. doi:10.1038/nsmb.3462

Esteller, M. (2008). Epigenetics in cancer. *N. Engl. J. Med.* 358 (11), 1148–1159. doi:10.1056/NEJMra072067

Forte, D., Krause, D. S., Andreeff, M., Bonnet, D., and Mendez-Ferrer, S. (2019). Updates on the hematologic tumor microenvironment and its therapeutic targeting. *Haematologica* 104 (10), 1928–1934. doi:10.3324/haematol.2018.195396

Herman, J. G., and Baylin, S. B. (2003). Gene silencing in cancer in association with promoter hypermethylation. *N. Engl. J. Med.* 349 (21), 2042–2054. doi:10.1056/NEJMra023075

Karpf, A. R., and Matsui, S. (2005). Genetic disruption of cytosine DNA methyltransferase enzymes induces chromosomal instability in human cancer cells. *Cancer Res.* 65 (19), 8635–8639. doi:10.1158/0008-5472.CAN-05-1961

Lan, Q., Liu, P. Y., Haase, J., Bell, J. L., Huttelmaier, S., and Liu, T. (2019). The critical role of RNA m(6)A methylation in cancer. *Cancer Res.* 79 (7), 1285–1292. doi:10.1158/0008-5472.CAN-18-2965

Li, Z., Qian, P., Shao, W., Shi, H., He, X. C., Gogol, M., et al. (2018). Suppression of m(6)A reader Ythdf2 promotes hematopoietic stem cell expansion. *Cell Res.* 28 (9), 904–917. doi:10.1038/s41422-018-0072-0

Maio, M., Covre, A., Fratta, E., Di Giacomo, A. M., Taverna, P., Natali, P. G., et al. (2015). Molecular pathways: at the crossroads of cancer epigenetics and immunotherapy. *Clin. Cancer Res.* 21 (18), 4040–4047. doi:10.1158/1078-0432.CCR-14-2914

Marcu, A., Colita, A., Radu, L. E., Jercan, C. G., Bica, A. M., Asan, M., et al. (2020). Single-center experience with epigenetic treatment for juvenile myelomonocytic leukemia. *Front. Oncol.* 10, 484. doi:10.3389/fonc.2020.00484

Radu, L. E., Colita, A., Pasca, S., Tomuleasa, C., Popa, C., Serban, C., et al. (2020). Day 15 and day 33 minimal residual disease assessment for acute lymphoblastic leukemia patients treated according to the BFM ALL IC 2009 protocol: single-center experience of 133 cases. *Front. Oncol.* 10, 923. doi:10.3389/fonc.2020.00923

Stahl, M., Kohrman, N., Gore, S. D., Kim, T. K., Zeidan, A. M., and Prebet, T. (2016). Epigenetics in cancer: a hematological perspective. *PLoS Genet.* 12 (10), e1006193. doi:10.1371/journal.pgen.1006193

Sylvestre, M., Tarte, K., and Roulois, D. (2020). Epigenetic mechanisms driving tumor supportive microenvironment differentiation and function: a role in cancer therapy?. *Epigenomics* 12 (2), 157–169. doi:10.2217/epi-2019-0165

Teodorescu, P., Pasca, S., Dima, D., Tomuleasa, C., and Ghiaur, G. (2020). Targeting the microenvironment in MDS: the final frontier. *Front. Pharmacol.* 11, 1044. doi:10.3389/fphar.2020.01044

Turcas, C., Moisoiu, V., Stefancu, A., Jurj, A., Iancu, S. D., Teodorescu, P., et al. (2020). SERS-based assessment of MRD in acute promyelocytic leukemia?. *Front Oncol* 10, 1024. doi:10.3389/fonc.2020.01024

Villanueva, L., Alvarez-Errico, D., and Esteller, M. (2020). The contribution of epigenetics to cancer immunotherapy. *Trends Immunol.* 41 (8), 676–691. doi:10.1016/j.it.2020.06.002

von der Heide, E. K., Neumann, M., Vosberg, S., James, A. R., Schroeder, M. P., Ortiz-Tanchez, J., et al. (2017). Molecular alterations in bone marrow mesenchymal stromal cells derived from acute myeloid leukemia patients. *Leukemia* 31 (5), 1069–1078. doi:10.1038/leu.2016.324

Vu, L. P., Pickering, B. F., Cheng, Y., Zaccara, S., Nguyen, D., Minuesa, G., et al. (2017). The N(6)-methyladenosine (m(6)A)-forming enzyme METTL3 controls myeloid differentiation of normal hematopoietic and leukemia cells. *Nat. Med.* 23 (11), 1369–1376. doi:10.1038/nm.4416

**Conflict of Interest:** The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Copyright © 2020 Gulei, Tomuleasa, Qian, Bagacean, Croce and Ghiaur. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.