OGT and OGA gene-edited human induced pluripotent stem cells for dissecting the functional roles of O-GlcNAcylation in hematopoiesis

Hematopoiesis continues throughout life to produce all types of blood cells from hematopoietic stem cells (HSCs). Metabolic state is a known regulator of HSC self-renewal and differentiation, but whether and how metabolic sensor O-GlcNAcylation, which can be modulated via an inhibition of its cycling enzymes O-GlcNAcase (OGA) and O-GlcNAc transferase (OGT), contributes to hematopoiesis remains largely unknown. Herein, isogenic, single-cell clones of OGA-depleted (OGAi) and OGT-depleted (OGTi) human induced pluripotent stem cells (hiPSCs) were successfully generated from the master hiPSC line MUSIi012-A, which were reprogrammed from CD34+ hematopoietic stem/progenitor cells (HSPCs) containing epigenetic memory. The established OGAi and OGTi hiPSCs exhibiting an increase or decrease in cellular O-GlcNAcylation concomitant with their loss of OGA and OGT, respectively, appeared normal in phenotype and karyotype, and retained pluripotency, although they may favor differentiation toward certain germ lineages. Upon hematopoietic differentiation through mesoderm induction and endothelial-to-hematopoietic transition, we found that OGA inhibition accelerates hiPSC commitment toward HSPCs and that disruption of O-GlcNAc homeostasis affects their commitment toward erythroid lineage. The differentiated HSPCs from all groups were capable of giving rise to all hematopoietic progenitors, thus confirming their functional characteristics. Altogether, the established single-cell clones of OGTi and OGAi hiPSCs represent a valuable platform for further dissecting the roles of O-GlcNAcylation in blood cell development at various stages and lineages of blood cells. The incomplete knockout of OGA and OGT in these hiPSCs makes them susceptible to additional manipulation, i.e., by small molecules, allowing the molecular dynamics studies of O-GlcNAcylation.

Inhibition of O-GlcNAcase Inhibits Hematopoietic and Leukemic Stem Cell Self-Renewal and Drives Dendritic Cell Differentiation via STAT3/5 Signaling

Myeloid differentiation blockage at immature and self-renewing stages is a common hallmark across all subtypes of acute myeloid leukemia (AML), despite their genetic heterogeneity. Metabolic state is an important regulator of hematopoietic stem cell (HSC) self-renewal and lineage-specific differentiation as well as several aggressive cancers. However, how O-GlcNAcylation, a nutrient-sensitive posttranslational modification of proteins, contributes to both normal myelopoiesis and AML pathogenesis remains largely unknown. Using small molecule inhibitors and the CRISPR/Cas9 system, we reveal for the first time that inhibition of either OGA or OGT, which subsequently caused an increase or decrease in cellular O-GlcNAcylation, inhibits the self-renewal and maintenance of CD34+ hematopoietic stem/progenitor cells (HSPCs) and leukemic stem/progenitor cells and drives normal and malignant myeloid differentiation. We further unveiled the distinct roles of OGA and OGT inhibition in lineage-specific differentiation. While OGT inhibition induces macrophage differentiation, OGA inhibition promotes the differentiation of both CD34+ HSPCs and AML cells into dendritic cells (DCs), in agreement with an upregulation of a multitude of genes involved in DC development and function and their ability to induce T-cell proliferation, via STAT3/5 signaling. Our novel findings provide significant basic knowledge that could be important in understanding AML pathogenesis and overcoming differentiation blockage-agnostic to the genetic background of AML. Additionally, the parallel findings in normal HSPCs may lay the groundwork for future cellular therapy as a means to improve the ex vivo differentiation of normal DCs and macrophages.

Bcl-2 Family Members Bcl-xL and Bax Cooperatively Contribute to Bortezomib Resistance in Mantle Cell Lymphoma

Mantle cell lymphoma (MCL) is an aggressive non-Hodgkin lymphoma with poor prognosis, due to the inevitable development of drug resistance. Despite being the first-in-class proteasome inhibitor for relapsed/refractory MCL, resistance to bortezomib (BTZ) in MCL patients remains a major hurdle of effective therapy, and relapse following BTZ is frequent. Understanding the mechanisms underlying BTZ resistance is, therefore, important for improving the clinical outcome and developing novel therapeutic strategies. Here, we established de novo BTZ-resistant human MCL-derived cells with the highest resistance index of 300-fold compared to parental cells. We provided compelling evidence that both Bcl-xL and Bax are key mediators in determining BTZ sensitivity in MCL cells. Overexpression of antiapoptotic Bcl-xL and depletion of proapoptotic Bax cooperatively protected MCL cells against BTZ-induced apoptosis, causing acquired BTZ resistance, likely by tilting the balance of Bcl-2 family proteins toward antiapoptotic signaling. Bioinformatics analyses suggested that high BCL2L1 (encoded Bcl-xL) and low BAX were, in part, associated with poor prognosis of MCL patients, e.g., when combined with low OGT, which regulates cellular O-GlcNAcylation. Our findings support recent strategies in small molecule drug discovery co-targeting antiapoptotic Bcl-2 family proteins using BH3 mimetics and Bax using Bax activators to overcome cancer drug resistance.

Metabolic sensor O-GlcNAcylation regulates erythroid differentiation and globin production via BCL11A

Background

Human erythropoiesis is a tightly regulated, multistep process encompassing the differentiation of hematopoietic stem cells (HSCs) toward mature erythrocytes. Cellular metabolism is an important regulator of cell fate determination during the differentiation of HSCs. However, how O-GlcNAcylation, a posttranslational modification of proteins that is an ideal metabolic sensor, contributes to the commitment of HSCs to the erythroid lineage and to the terminal erythroid differentiation has not been addressed.

Methods

Cellular O-GlcNAcylation was manipulated using small molecule inhibition or CRISPR/Cas9 manipulation of catalyzing enzyme O-GlcNAc transferase (OGT) and removing enzyme O-GlcNAcase (OGA) in two cell models of erythroid differentiation, starting from: (i) human umbilical cord blood-derived CD34⁺ hematopoietic stem/progenitor cells (HSPCs) to investigate the erythroid lineage specification and differentiation; and (ii) human-derived erythroblastic leukemia K562 cells to investigate the terminal differentiation. The functional and regulatory roles of O-GlcNAcylation in erythroid differentiation, maturation, and globin production were investigated, and downstream signaling was delineated.

Results

First, we observed that two-step inhibition of OGT and OGA, which were established from the observed dynamics of O-GlcNAc level along the course of differentiation, promotes HSPCs toward erythroid differentiation and enucleation, in agreement with an upregulation of a multitude of erythroid-associated genes. Further studies in the efficient K562 model of erythroid differentiation confirmed that OGA inhibition and subsequent hyper-O-GlcNAcylation enhance terminal erythroid differentiation and affect globin production. Mechanistically, we found that BCL11A is a key mediator of O-GlcNAc-driven erythroid differentiation and β- and α-globin production herein. Additionally, analysis of biochemical contents using synchrotron-based Fourier transform infrared (FTIR) spectroscopy showed unique metabolic fingerprints upon OGA inhibition during erythroid differentiation, supporting that metabolic reprogramming plays a part in this process.

Conclusions

The evidence presented here demonstrated the novel regulatory role of O-GlcNAc/BCL11A axis in erythroid differentiation, maturation, and globin production that could be important in understanding erythropoiesis and hematologic disorders whose etiology is related to impaired erythroid differentiation and hemoglobinopathies. Our findings may lay the groundwork for future clinical applications toward an ex vivo production of functional human reticulocytes for transfusion from renewable cell sources, i.e., HSPCs and pluripotent stem cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02954-5.

Abstract 769: Zeb-1 contributes to the development of chemotherapeutic resistance in mantle cell lymphoma

Despite progress overall in improving cancer treatments, the complete response of mantle cell lymphoma (MCL) is still limited due to the inevitable development of drug resistance. Understanding how MCL cells acquire resistance at the molecular level may be a key innovation to targeted therapy. We established a series of bortezomib (BTZ)-resistant MCL cells and performed gene/protein profiling along with metabolic fingerprinting using synchrotron-based Fourier-transform infrared spectroscopy. Zeb-1, an epithelial-mesenchymal transition-inducing transcription factor better known for promoting metastasis in solid carcinomas, was found to be aberrantly expressed in the resistant MCL cells in accordance with an excessive production of lipids. Ectopic expression of Zeb-1 in parental MCL cells rendered the cells to acquire apoptosis resistance to BTZ. Here we demonstrated, for the first time, two possible encompassing mechanisms for Zeb-1-mediated BTZ resistance: (i) Zeb-1 induces cancer stem cells, as evaluated by tumor spheres and aldehyde dehydrogenase activity; and (ii) Zeb-1 induces lipid reprograming that may interfere with cell growth and drug response. Together, our results unveil a novel role of Zeb-1 in MCL aggressiveness. These findings have a clinical significance insight to the development of chemotherapeutic resistance of MCL.

Citation Format: Sudjit Luanpitpong, Jirarat Poohadsuan, Montira Janan, Kanjana Thumanu, Yon Rojanasakul, Surapol Issaragrisil. Zeb-1 contributes to the development of chemotherapeutic resistance in mantle cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 769.

Inhibition of O-GlcNAcase Sensitizes Apoptosis and Reverses Bortezomib Resistance in Mantle Cell Lymphoma through Modification of Truncated Bid

Aberrant energy metabolism represents a hallmark of cancer and contributes to numerous aggressive behaviors of cancer cells, including cell death and survival. Despite the poor prognosis of mantle cell lymphoma (MCL), due to the inevitable development of drug resistance, metabolic reprograming of MCL cells remains an unexplored area. Posttranslational modification of proteins via O-GlcNAcylation is an ideal sensor for nutritional changes mediated by O-GlcNAc transferase (OGT) and is removed by O-GlcNAcase (OGA). Using various small-molecule inhibitors of OGT and OGA, we found for the first time that O-GlcNAcylation potentiates MCL response to bortezomib. CRISPR interference of MGEA5 (encoding OGA) validated the apoptosis sensitization by O-GlcNAcylation and OGA inhibition. To identify the potential clinical candidates, we tested MCL response to drug-like OGA inhibitor, ketoconazole, and verified that it exerts similar sensitizing effect on bortezomib-induced apoptosis. Investigations into the underlying molecular mechanisms reveal that bortezomib and ketoconazole act in concert to cause the accumulation of truncated Bid (tBid). Not only does ketoconazole potentiate tBid induction, but also increases tBid stability through O-GlcNAcylation that interferes with tBid ubiquitination and proteasomal degradation. Remarkably, ketoconazole strongly enhances bortezomib-induced apoptosis in de novo bortezomib-resistant MCL cells and in patient-derived primary cells with minimal cytotoxic effect on normal peripheral blood mononuclear cells and hepatocytes, suggesting its potential utility as a safe and effective adjuvant for MCL. Together, our findings provide novel evidence that combination of bortezomib and ketoconazole or other OGA inhibitors may present a promising strategy for the treatment of drug-resistant MCL. Mol Cancer Ther; 17(2); 484-96. ©2017 AACR.

Serum adhesion molecule-1 (ICAM-1) as a potential prognostic marker for cholangiocarcinoma patients

Cholangiocarcinoma (CCA) is a malignancy of bile ducts with a high incidence of invasion and metastasis. This disease is often detected in advanced stages because of the difficulties of early diagnosis, leading to a high mortality rate. However, biomarkers for early CCA detection are still lacking. In this study, to identify potential biomarker proteins, differential secretome analysis by the GeLC-MS/MS approach was applied with four CCA cell lines and a control immortalized cholangiocyte cell line. Among 78 up-regulated proteins, 53 including ICAM- 1 were exclusively expressed in four CCA secretomes but not in MMNK1. Based on this result, we measured ICAM-1 levels in serum samples of CCA patients and healthy controls and found significantly higher values in CCA patients' sera. Receiver operating characteristic curve analysis suggested that serum ICAM-1 level could be a discriminatory diagnostic marker for CCA and healthy controls (area under curve=0.829) with a sensitivity of 77% and a specificity of 70% at a cut off value of 167 ng/ml. Moreover, the serum ICAM-1 showed positive correlations with alkaline phosphatase and carcinoembryonic antigen levels. Comparison of ICAM-1 levels of paired pre- and post-operative sera of 12 cases revealed significant decrease after tumor resection. However, serum ICAM-1 levels were not significantly different between CCA and benign biliary diseases with mainly inflammatory features.