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. Author manuscript; available in PMC: 2014 Sep 1.
Published in final edited form as: Mol Cancer Res. 2013 Jun 10;11(9):1004–1016. doi: 10.1158/1541-7786.MCR-13-0114

Figure 2. Surface CXCR4 levels change consistently in response to chemotherapy and cell lines that upregulate CXCR4 are protected by stroma from chemotherapy-induced apoptosis.

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Cell lines were treated for 48 hours with dose ranges of 5 chemotherapeutic agents: daunorubicin (Dauno), vincristine (VCR), cytarabine (AraC), etoposide (Etop), and methotrexate (MTX). Surface CXCR4 expression was measured in the live populations by flow cytometry. Live gates were drawn using forward and side scatter characteristics. (a) Histograms of surface CXCR4 expression for MOLM-14 after treatment for 48 hours with daunorubicin are shown as representative examples of primary analysis. (b) Maximal changes in surface CXCR4 expression from baseline after treatment with all 5 agents are represented in the 6 cell lines. (c-h) Cells were treated with daunorubicin, cytarabine, or etoposide for 48 hours in the presence or absence of normal human bone marrow stroma feeder layers. Apoptosis was measured by Annexin V and 7-AAD staining. Examples of primary analysis after daunorubicin treatment of (c) 697 and (d) MOLM-14 are shown. To quantify the protective effect of stroma, the protective index (PI) after treatment with (e) daunorubicin, (f) cytarabine, and (g) etoposide was calculated for each cell line. (h) Collectively, CXCR4-upregulating cell lines (697, MOLM-14, and MV4-11) were preferentially protected by stroma from chemotherapy-induced apoptosis compared to CXCR4-downregulating cell lines (HB-1119, Nalm-6, and SEM-K2). *p<0.05, **p<0.01 for upregulators vs. downregulators.