Specific stimulation of T lymphocytes with erythropoietin for adoptive immunotherapy

Abstract

In adoptive T-cell immunotherapy of cancer, expansion and persistence of effector cells is a key determinant of response. We tested whether T lymphocytes could be rendered sensitive to erythropoietin (Epo) through ectopic expression of its wild-type receptor or a truncated form (EpoRm), which augments Epo signaling in erythrocyte progenitors. Both receptors could be expressed in human T lymphocytes; Epo ligation induced STAT5 phosphorylation, which was abrogated by nontoxic concentrations of the JAK1/2 inhibitor ruxolitinib. EpoRm had higher expression and triggered more potent stimulation than its wild-type counterpart, including superior T-cell survival and proliferation. Using a bicistronic vector, we expressed EpoRm together with an anti–CD19-41BB-CD3ζ chimeric antigen receptor (CAR), while maintaining the functions of each receptor. In the presence of Epo, EpoRm-CAR T cells had greater ex vivo expansion than CAR T cells and killed CD19+ leukemic cells more effectively in long-term cultures. In immunodeficient mice, physiologic levels of murine Epo were sufficient to preferentially expand EpoRm-CAR T cells, yielding a significantly higher antileukemic activity. Thus, outfitting adoptive T cells with EpoRm should yield greater effector-to-target ratios with a smaller number of infused cells; Epo or ruxolitinib administration could be used to adjust their levels postinfusion, maximizing antitumor activity and minimizing toxicity.

Recent Advances in Solid Tumor CAR-T Cell Therapy: Driving Tumor Cells From Hero to Zero?

“…Recently, one study has discovered that engineered expression of the native form erythropoietin receptor (EpoR) or its truncated form (tEpoR) on the surface of CAR-Ts endows them with the ability to tune up their expansion, survival, and proliferation rate in response to erythropoietin ( 133 ). It has been evident that tEpoR exhibits supervisor characteristics, in comparison to EpoR, in terms of T-cell expansion, proliferation, and survival stimulation ( 133 ). Vinanica et al.…”

“…Vinanica et al. generated tEpoR-expressing CD19-redirected CAR-Ts (tEpoR-CAR-Ts) and reported that these cells demonstrated pronounced ex vivo expansion and in vitro tumoricidal capacity against leukemic cells in the presence of erythropoietin ( 133 ). These results confirmed that the expression of either receptor does not negatively impact the functionality of the other ( 133 ).…”

“…generated tEpoR-expressing CD19-redirected CAR-Ts (tEpoR-CAR-Ts) and reported that these cells demonstrated pronounced ex vivo expansion and in vitro tumoricidal capacity against leukemic cells in the presence of erythropoietin ( 133 ). These results confirmed that the expression of either receptor does not negatively impact the functionality of the other ( 133 ). Furthermore, tEpoR-CAR-Ts have been known to require lower cell dosing, in comparison with their conventional counterparts, since physiologic levels of erythropoietin would simply suffice to expand tEpoR-CAR-Ts, thus eliciting an accentuated tumoricidal response in mouse models ( 133 ).…”

“…Furthermore, tEpoR-CAR-Ts have been known to require lower cell dosing, in comparison with their conventional counterparts, since physiologic levels of erythropoietin would simply suffice to expand tEpoR-CAR-Ts, thus eliciting an accentuated tumoricidal response in mouse models ( 133 ). Of note, erythropoietin and ruxolitinib can be utilized to amplify the effector function of tEpoR-CAR-Ts or to diminish unwanted complications, respectively ( 133 ).…”

Using erythrocyte tools to enhance CAR T cells

“…In this issue of Blood, Vinanica et al explore a novel strategy to enhance the efficacy of adoptive T-cell therapy through the expression of an erythropoietin (Epo) receptor capable of delivering a signal that boosts the survival and function of chimeric antigen receptor (CAR) T cells. 1 Over the last 10 years, great strides have been made in the application of adoptive cellular therapy to treat malignant diseases. Through technological advances that enable the robust ex vivo expansion of T cells collected from peripheral blood as well as efficient redirection of T-cell specificity through CARs or engineered T-cell receptors (TCRs), it is now possible to manufacture and deliver sufficient numbers of leukemia-reactive T cells to treat, and even eradicate, chemotherapy refractory cancers.…”