Ginsenoside Rg1 induces senescence of leukemic stem cells by upregulating p16INK4a and downregulating hTERT expression

Abstract

Background. Leukemic stem cells (LSCs) play an important role in the pathogenesis of leukemia. This research attempted to clarify effects of the telomere system on ginsenoside Rg1-induced senescence of LSCs.Objectives. This research attempted to clarify effects of the telomere system on ginsenoside Rg1-induced senescence of LSCs.Materials and methods. CD34 + CD38 − LSCs were isolated, sorted, and divided into a control group and a Rg1 group (treated with 40 μmol/L Rg1). Cell Counting Kit-8 (CCK-8) was used to evaluate cell proliferation, and flow cytometry was used to assess the cell cycle of CD34 + CD38 − LSCs. The senescenceassociated β-galactosidase (SA-β-Gal) staining and CFU-Mix assay were conducted to measure senescence of CD34 + CD38 − LSCs. The mRNA transcription and protein expression of p16 INK4a and human telomerase reverse transcriptase (hTERT) were determined using a real-time polymerase chain reaction (RT-PCR) and western blot assay, respectively.Results. The Rg1 treatment significantly attenuated proliferative activity and decreased the proliferative index (PI) of CD34 + CD38 − LSCs compared to those of the control group (p < 0.05). It remarkably increased positive SA-β-Gal staining rate, and suppressed formation of the CFU-Mix of CD34 + CD38 − LSCs compared with those of the control group (p < 0.05). The Rg1 treatment markedly boosted telomere effector, p16 INK4a , in CD34 + CD38 − LSCs compared with that of control group (p < 0.05). Such treatment obviously reduced telomere regulator, hTERT, in CD34 + CD38 − LSCs compared with the control group (p < 0.05).Conclusions. Ginsenoside Rg1-induced senescence of CD34 + CD38 − LSCs through upregulating p16 INK4a and downregulating hTERT expression, both of which are associated with telomere systems. The present study would be beneficial for the treatment of leukemia by providing a promising strategy to induce senescence of CD34 + CD38 − LSCs.

Telomerase Inhibition in the Treatment of Leukemia: A Comprehensive Review

“…Ginsenoside Rg1 (Rg1) is a bioactive substance that can be found in the roots of ginseng (Panax ginseng) and turned white or red ginseng [124,125]. Rg1 has a hepatoprotective effect, promotes cerebral angiogenesis and lymphatic drainage, improves chronic inflammatory arthritis, and prevents PTSD-like behaviors [126][127][128][129].…”

“…Rg1 has a hepatoprotective effect, promotes cerebral angiogenesis and lymphatic drainage, improves chronic inflammatory arthritis, and prevents PTSD-like behaviors [126][127][128][129]. A study on CD34+CD38− leukemic stem cells (LSC) showed that Rg1 down-regulates the expression of hTERT and up-regulates p16 INK4a (a protein that slows down the cell cycle) expression, which causes senescence of LSC [124]. Another study, using Korean red ginseng (KRG) on U937 cells, showed its anti-cancer properties.…”

Telomerase Inhibition Potential of Natural Compounds in Leukemia Treatment

“…Rg1 has a hepatoprotective effect, promotes cerebral angiogenesis and lymphatic drainage, improves chronic inflammatory arthritis, and prevents PTSD-like behaviors [92,93,94,95]. A study on CD34+CD38− leukemic stem cells (LSC) showed, that Rg1 downregulates the expression of hTERT and upregulates p16 INK4a (protein, that slows down the cell cycle) expression, which causes senescence of LSC [104]. Another study, using Korean red ginseng (KRG) on U937 cells showed its anti-cancer properties.…”

Ginsenosides on stem cells fate specification—a novel perspective

“…This enhanced telomerase activity may be an adaptive mechanism aimed at maintaining the continuous replication of LSCs and promoting leukemia development ( Kuo and Bhatia, 2014 ). A recent study found that ginsenoside Rg1 inhibited CD34 + CD38-LSCs proliferative activity, increased expression of telomere damage effector p16 INK4a , and decreased human telomerase reverse transcriptase (hTERT, catalytic subunit of telomerase) to induce its replicative senescence for the treatment of leukemia ( Tang et al, 2021 ). The above findings suggest that ginsenoside Rg1 inhibits the ability of LSCs to self-renewal and proliferation, and its targeted therapy based on the intervention of LSCs senescence is a valuable direction for healing leukemia in the future.…”