Delineating the effects of 5-fluorouracil and follicle-stimulating hormone on mouse bone marrow stem/progenitor cells

Abstract

BackgroundPluripotent, Lin–/CD45–/Sca-1+ very small embryonic-like stem cells (VSELs) in mouse bone marrow (BM) are resistant to total body radiation because of their quiescent nature, whereas Lin–/CD45+/Sca-1+ hematopoietic stem cells (HSCs) get eliminated. In the present study, we provide further evidence for the existence of VSELs in mouse BM and have also examined the effects of a chemotherapeutic agent (5-fluorouracil (5-FU)) and gonadotropin hormone (follicle-stimulating hormone (FSH)) on BM stem/progenitor cells.MethodsVSELs and HSCs were characterized in intact BM. Swiss mice were injected with 5-FU (150 mg/kg) and sacrificed on 2, 4, and 10 days (D2, D4, and D10) post treatment to examine changes in BM histology and effects on VSELs and HSCs by a multiparametric approach. The effect of FSH (5 IU) administered 48 h after 5-FU treatment was also studied. Bromodeoxyuridine (BrdU) incorporation, cell cycle analysis, and colony-forming unit (CFU) assay were carried out to understand the functional potential of stem/progenitor cells towards regeneration of chemoablated marrow.ResultsNuclear OCT-4, SCA-1, and SSEA-1 coexpressing LIN–/CD45– VSELs and slightly larger LIN–/CD45+ HSCs expressing cytoplasmic OCT-4 were identified and comprised 0.022 ± 0.002 % and 0.081 ± 0.004 % respectively of the total cells in BM. 5-FU treatment resulted in depletion of cells with a 7-fold reduction by D4 and normal hematopoiesis was re-established by D10. Nuclear OCT-4 and PCNA-positive VSELs were detected in chemoablated bone sections near the endosteal region. VSELs remained unaffected by 5-FU on D2 and increased on D4, whereas HSCs showed a marked reduction in numbers on D2 and later increased along with the corresponding increase in BrdU uptake and upregulation of specific transcripts (Oct-4A, Oct-4, Sca-1, Nanog, Stella, Fragilis, Pcna). Cells that survived 5-FU formed colonies in vitro. Both VSELs and HSCs expressed FSH receptors and FSH treatment enhanced hematopoietic recovery by 72 h.ConclusionBoth VSELs and HSCs were activated in response to the stress created by 5-FU and FSH enhanced hematopoietic recovery by at least 72 h in 5-FU-treated mice. VSELs are the most primitive pluripotent stem cells in BM that self-renew and give rise to HSCs under stress, and HSCs further divide rapidly and differentiate to maintain homeostasis. The study provides a novel insight into basic hematopoiesis and has clinical relevance.Electronic supplementary materialThe online version of this article (doi:10.1186/s13287-016-0311-6) contains supplementary material, which is available to authorized users.

Mechanoresponsive stem cells to target cancer metastases through biophysical cues

“…There was also no significant change in the bone marrow cell population after treatment (fig. S14B), showing that the bone marrow was not depleted by the MRCS-CD treatment, unlike in conventional chemotherapy (44). There was also no observable damage in bone marrow (fig.…”

Do Somatic Cells De-differentiate/Trans-differentiate or VSELs Initiate Cancer and Explain Plasticity in Adult Tissues?

“…VSELs truly explain the pluripotent nature or 'plasticity' of bone marrow and their ability to differentiate into HSCs [47] and all 3 lineages [48,49] has been reported in vitro. They also participate in regeneration of mouse bone marrow after treating mice with 5-fluorouracil [50]. The existing controversy that LSCs do not express Thy-1 and cKit which are specific markers for HSCs (discussed above) is easily explained because LSCs are indeed Thy-1 and cKit negative VSELs which exists as a sub-population among HSCs.…”

“…It is even expressed in several different kinds of cancers however, various studies failed to discriminate between Oct-4A and Oct-4B which are alternatively spliced isoforms and only nuclear Oct-4A is responsible for pluripotent state. We have earlier shown that Oct-4A is expressed by VSELs and Oct-4B by the HSCs and is gradually lost as cells further differentiate in mouse BM and human cord blood [50,51]. Besides the presence of alternatively spliced isoforms of OCT-4 that has confused scientific community, VSELs are invariably discarded while processing samples for various experiments [23,52].…”

The endocrine influence on the bone microenvironment in early breast cancer

“…Thus, the specific effects of FSH on bone turnover still need to be defined. FSH has effects on HSC in bone, with evidence from in vivo models that bone-derived HSC express FSH receptor and that treatment with FSH enhances haematopoetic recovery after chemotherapy (Shaikh et al 2016). FSH also influences the vasculature; the FSH receptor (not normally expressed on vascular endothelium) is upregulated in the vasculature of bone metastases (Siraj et al 2013).…”