Gram-Scale Laboratory Synthesis of UM171, a Potent Agonist of Human Hematopoietic Stem Cell Self-Renewal

Enhancement of proliferation of human umbilical cord blood–derived CD34+ hematopoietic stem cells by a combination of hyper-interleukin-6 and small molecules

Umbilical cord blood (UCB) is an alternative source of allogeneic hematopoietic stem cells (HSCs) for transplantation to treat various hematological disorders. The major limitation to the use of UCB-derived HSCs (UCB–HSCs) in transplantation, however, is the low numbers of HSCs in a unit of cord blood. To overcome this limitation, various cytokines or small molecules have been used to expand UCB-HSCs ex vivo. In this study, we investigated a synergistic effect of the combination of HIL-6, SR1, and UM171 on UCB-HSC culture and found that this combination resulted in the highest number of CD34⁺ cells. These results suggest that the combination of SR1, UM171 and HIL-6 exerts a synergistic effect in the proliferation of HSCs from UCB and thus, SR1, UM171 and HIL-6 is the most suitable combination for obtaining HSCs from UCB for clinical transplantation.

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Hyper IL-6 enhances the proliferation of both total nucleated cells and CD34⁺ cells.

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The combination of SR1 and UM171 with Hyper IL-6 led to increases in TNC and CD34⁺ cells number exvivo human cord blood HSCs.

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It potentially provides an optimization to achieving a successful strategy through exvivo expansion of HSCs for application.

Synthesis and evaluation of pyrimidoindole analogs in umbilical cord blood ex vivo expansion

The scarcity of hematopoietic stem cells (HSCs) significantly hindered their clinical potentials. Umbilical cord blood (UCB) has become the leading source of HSCs for both research and clinical applications. But the low content of HSCs in a single UCB unit limited its use only to pediatric patients. Various cytokines and small molecules have demonstrated strong abilities in promoting HSC ex vivo expansion, of which UM171 is the newest and by far the most potent HSC ex vivo expansion agent. In this study, we synthesized 37 pyrimidoindole analogs and identified 6 compounds to be potent in promoting HSC ex vivo expansion. In particular, analog 11 was found to be the most effective in stimulating ex vivo expansion of UCB CD34⁺ cells and CD34⁺CD38^- cells. Initial data indicated that compound 11 promoted the absolute number of long term HSCs and inhibited their differentiation. UCB HSCs expanded with 11 retained adequate multi-lineage differentiation capacity. In addition, compound 11 is not cytotoxic at its test concentrations, suggesting that it merits further investigation for potential clinical applications.

Pyrimido[4,5-b]indole derivatives and use thereof in the expansion of hematopoietic stem cells US2015011543 (a1): a patent evaluation

INTRODUCTION

There is an unmet need of strategies for ex-vivo expansion of hematopoetic stem cells (HSCs) without loss of their primitive nature or stemness. We evaluate here a patent that attempts to address this need via key small molecules 1 and 40 that possess a pyrimido[4,5-b]indole core. Areas covered: (i) Discussion on literature reports of diverse strategies for ex-vivo expansion of stem cells. (ii) Synthetic scheme to 1, and general synthetic schemes for compounds 1-55 reported in the patent application. (iii) Analysis of the in vitro biological data for 1 and 40. Highlight here is: 1 and 40 when used in combination with StemReginin1 (SR1), an established aryl hydrocarbon receptor antagonist known for ex-vivo HSC expansion, demonstrate better HSC expansion relative to SR1 alone. (iv) Analysis of the in vivo biological data for 1 and 40. Expert opinion: Compelling evidence on the molecular mechanism of action of 1 and 40 is not provided making it difficult to optimize this series. It is suggested here that combining these molecules with homing molecules will possibly improve overall engraftment time and hematopoietic recovery. The numerous literature reports and biological data indicates that these pyrimido[4,5-b]indole derivatives are promising candidates for the development of potential therapies for hematopoietic ailments.