Search

This study compares the immune properties of peripheral blood stem cell (PSC) products mobilized with different hematopoietic growth factors (HGFs) as well as apheresis products and peripheral blood leukocytes (PBL) from normal individuals. We found that monocytes in mobilized PSC products appear to inhibit T cell function independent of whether granulocyte colony- stimulating factor (G-CSF) or granulocyte–macrophage colony-stimulating factor (GM-CSF) was used for mobilization. In addition, the GF used to mobilize the stem cell product may be less important to the CD4:CD8 ratio than the extent of prior chemotherapy, as we found an inverse correlation between chemotherapy and the CD4:CD8 ratio. In other observations, all apheresis products, whether mobilized or unmobilized, contained significantly more monocytes compared to normal PBL. The mononuclear cells (MNC) from G-CSF or GM-CSF mobilized PSC products had a similar T cell phytohemagglutinin (PHA) mitogenic response that was significantly lower (P = 0.001 and P = 0.005, respectively) than non-mobilized apheresis products. We also examined the T cell inhibitor (TI) activity of the MNC from the PSC products for allogeneic lymphocyte proliferation and found that PSC products significantly reduced the proliferation of allogeneic PBL to PHA. A significant correlation (P = 0.001, r = 0.517) between the frequency of monocytes and TI activity also was observed. [ABSTRACT FROM AUTHOR]

In these studies, we compared the phenotype, function, and expression of type 1, type 2, and monocyte-associated cytokine mRNA transcripts in autologous bone marrow (BM) and growth factor-mobilized peripheral blood stem cell (PSC) products. These studies demonstrate that lymphocytes and monocytes in stem cell products are abnormally activated, expressing significantly higher levels of interleukin (IL)-2, 4 and 10, interferon gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α), but not IL-8, as compared to normal peripheral blood mononuclear cells (PBMC). In addition, the levels of IL-2, IL-10 and TNF-α are significantly higher in mobilized PSC as compared to BM products. The high cytokine levels are unexpected as T cell function in stem cell products is depressed. PSC products have high levels of T cell inhibitory activity, which directly correlates with IL-10 expression, both of which are mechanisms that might be involved in the immune dysfunction within stem cell products used for autologous stem cell transplantation. These data demonstrate that: (1) immune cells in autologous BM and PSC products are activated with the expression of high levels of type 1 and type 2 cytokines as well as monokines; (2) PSC products contain a high frequency of monocytes which mediate T cell inhibitory activity; and (3) despite the high levels of cytokine expression, T cell function in stem cell products is depressed. The significance of these immune abnormalities within stem cell products for myeloid and lymphoid recovery following autologous stem cell transplantation remains to be determined. [ABSTRACT FROM AUTHOR]

Background: Cancer-related inflammation is recognized as a driver for tumor progression and chemokines are important players in both inflammation and the progression of many cancer types. CXC chemokines, especially CXCL8, have been implicated in melanoma growth and metastasis, while less is known for their roles in drug resistance., Methods: We generated drug-resistant cells by continuous exposure to chemotherapeutic drugs and analyzed the mechanism(s) of therapy resistance in malignant melanoma., Results: We report chemotherapies induced upregulation of a variety of chemokines in the CXCR1/CXCR2 network by an NF-κB-dependent mechanism. Notably, analysis of the drug-resistant melanoma cell line selected after prolonged exposure to chemotherapeutic drug dacarbazine revealed higher levels of CXCL8 and CXCR2 compared with parent cells as a signature of drug resistance. CXCR2 neutralization markedly improved sensitivity to dacarbazine in melanoma cells., Conclusion: These data provide insights into what drives melanoma cells to survive after chemotherapy treatment, thus pointing to strategies for developing combined drug therapies for combating the problem of chemotherapy resistance in melanoma., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Purpose: In the present study, we examined the expression of a multifunctional cytokine, interleukin 8 (IL-8), and its receptors, CXCR1 and CXCR2, in human colon carcinoma cells with different metastatic potentials and determined their role in modulating phenotypes associated with metastasis., Experimental Design: IL-8, CXCR1, and CXCR2 protein and mRNA expression were examined using ELISA, immunocytochemistry, and reverse transcription-PCR in human colon carcinoma cells with different metastatic potentials. IL-8-mediated proliferation, migration, and tumor-endothelial cell interaction were analyzed., Results: IL-8 mRNA and protein expression was very low in Caco2 cells but elevated in KM12C cells and very high in KM12L4 cells, suggesting an association between the IL-8 production and metastatic potential. Similarly, CXCR1 and CXCR2 expression was lower in Caco2 cells than in low and high metastatic KM12C and KM12L4 cells. The recombinant human IL-8 enhanced the proliferation of colon carcinoma cells. Furthermore, proliferation of low and high metastatic cells expressing different levels of IL-8 was inhibited by neutralizing antibodies to IL-8, CXCR1, and CXCR2. We observed significant differences in the invasive potential of colon carcinoma cells expressing different levels of IL-8. In addition, we observed that IL-8 modulates adhesion of tumor cells to endothelial cells in an autocrine and paracrine manner., Conclusion: Our present data suggest an association between constitutive expression of IL-8 and aggressiveness in human colon carcinoma cells and the possible role of IL-8 in modulating different metastatic phenotypes associated with progression and metastasis.

This review article has described briefly studies supporting the concept that IL-8 expression and its regulation by inflammatory cytokines like IL-1 may play an important role in controlling the phenotypes associated with melanoma progression and metastasis. It is clear from the experiments presented here that IL-8 is an important autocrine multifunctional cytokine that modulates melanoma/cell proliferation, migration by induction of extracellular matrix degradation enzymes and induces neovascularization, all of which are critical for melanoma growth and metastasis. In addition, their expression in melanoma tumor specimens suggests an association between IL-8 expression and tumor aggressiveness. Further, inflammatory cytokines produced by either tumor cells or stromal cells may regulate IL-8 expression, which can control melanoma growth and enhance our current knowledge regarding melanoma progression and metastasis. Understanding these events and their significance will allow us to design novel therapeutic approaches for treatment of melanoma.

We report the preferential expression of Fas on CD4+ T cells and Fas ligand (FasL) on monocytes and their potential role in the selective loss of CD4+ T cells in breast cancer patients undergoing high-dose chemotherapy and peripheral blood stem cell transplantation (PSCT). A high frequency of apoptotic CD4+ T cells (28-51%) is observed during the first 100 days after PSCT concomitant with a significant increase in monocyte frequency and FasL expression (11.6-23%) on monocytes. The preferential expression of Fas on CD4+ T cells (73-92%) in the peripheral blood (PB) of these patients is associated with a significantly higher frequency of CD4+ T-cell apoptosis compared with CD8+ T cells (28-47%) and CD4+ T cells (46 +/- 5.7%) in normal PB. These data suggest that "primed" Fas+ CD4+ lymphocytes interact with activated monocytes that express FasL, resulting in apoptosis, leading to deletion of CD4+ T cells, an inversion in the CD4:CD8 T-cell ratio, and immune dysfunction. The prevention of CD4+ T-cell apoptosis and improved immune reconstitution by the manipulation of PB stem cell products, blockade of Fas-FasL interactions, or cytokine support after transplantation may be important adjuvant immunotherapeutic strategies in patients undergoing high-dose chemotherapy and PSCT.

Here, we report the molecular regulation of interleukin (IL)-8 expression in human melanoma cells. The inflammatory cytokines IL-1beta and tumor necrosis factor-alpha (TNF-alpha) up-regulated IL-8 expression, in a time- and concentration-dependent manner, in three metastatic melanoma variants, SBC-2 (nonmetastatic), A375P (low metastatic), and A375SM (high metastatic), by increased transcription of the IL-8 gene, leading to increased levels of IL-8 mRNA and protein production. Furthermore, we report that IFN-alpha and IFN-beta did not inhibit steady-state IL-8 production. However, IFN-alpha and IFN-beta inhibited IL-1beta or TNF-alpha-mediated up-regulation of IL-8 mRNA. In addition, IFN-beta demonstrated a more potent inhibitory effect at a lower concentration than did IFN-alpha. Both pretreatment and simultaneous treatment of melanoma cells with IFN-alpha or IFN-beta inhibited the IL-1beta and TNF-alpha up-regulation of IL-8 mRNA levels. This inhibition was at the transcriptional levels and was unaffected by a protein synthesis inhibitor, suggesting that this did not require de novo protein synthesis. Further, modulation of IL-8 levels by IL-1beta, alone or in combination with IFN-beta, affected the proliferation of melanoma cells. In summary, our data suggest that the up-regulation of IL-8 expression in melanoma cells is regulated at the transcriptional level and is rapidly and specifically inhibited by IFN-alpha or IFN-beta, independent of de novo protein synthesis, perhaps due to a transient modification of a preexisting factor(s).

Bestatin (ubenimex), an inhibitor of aminopeptidase, is an oral immunomodulator that binds to CD13 (aminopeptidase N) on macrophages/monocytes. To examine its immunomodulatory effect after high-dose therapy and autologous bone marrow transplantation (BMT), a dose-finding phase Ib trial was conducted with 30 Hodgkin's disease and non-Hodgkin's lymphoma patients who received no drug (control), 10 and 30 mg (low dose), or 90 and 180 mg (high dose) of bestatin daily for 60 days following autologous BMT. Bestatin administration was initiated when the absolute neutrophil count was greater than 250/mm3 on 2 consecutive days. The serum neopterin levels, an indicator of monocyte/macrophage activation, increased in the high-dose group compared to the control group (not significantly) and the low-dose group (significantly). Similarly, the colony-stimulating activity in the sera was significantly increased in the high-dose group compared to the control and low-dose groups. We also examined the expression of cell-surface markers on monocytes in these patients by fluorescent cytometry analysis. There was no significant difference either in the frequency or absolute number of monocytes (CD14+) among the three groups at any time. However, a significant increase in the frequency of CD16(FcgRIII)-positive monocytes (a marker of activation) was observed in the high-dose group compared to controls from day 14 to day 60 after the start of bestatin administration. Further, the frequency of HLA-DR+ monocytes (another marker of activation) was significantly increased in the high-dose group. These results indicate that bestatin at higher doses (90 and 180 mg daily), but not lower doses, activates macrophages/monocytes, as demonstrated by phenotypic marker (HLA-DR and CD16) up-regulation, and this provides augmentation of neopterin and colony-stimulating activity in the serum of patients following autologous BMT.

The T cell-mediated antineoplastic activity observed following allogeneic transplantation and the suggestion of improved therapeutic efficacy by autologous peripheral stem cell transplantation (PSCT) as compared to autologous bone marrow transplantation (ABMT) for non-Hodgkin's lymphoma (NHL) stimulated our interest in the immunologic competence of stem cell products. We report the immune phenotype and function of normal peripheral blood (PB) cells, bone marrow (BM) cells from normal donors and cancer bearing patients, GM-CSF-mobilized and apheresed blood mononuclear cells from NHL patients, unmobilized apheresed mononuclear cells from normal volunteers and umbilical cord blood (CB). The analyses include three-color fluorescent cytometry of the major hematologic and immunologic phenotypes as well as natural killer (NK) activity, natural suppressor (NS) activity, and phytohemagglutinin (PHA) and pokeweed (PWM) mitogenesis. These studies demonstrated an increased frequency of T cells in apheresis products as compared to BM and CB products. Specifically, the mobilized PSC had significant increases in CD3+, CD4+, CD45RO+ and CD56+ cells relative to BM cells. In addition, the frequency of TCR gamma/delta + cells in all the stem cell products, with the exception of CB, were also increased compared to normal peripheral blood leukocytes (PBL). However, all the stem cell products had a significant depression in T (PHA mitogenesis) and B (PWM mitogenesis) cell function. The depression in immune cell functionality, in the PSC products was perhaps due to the high frequency of monocytes which appeared to be increased due to both mobilization and apheresis. The frequency of the NK cell phenotype (CD56) but not function was increased in the mobilized PSC products, while the NK cell function in the BM products from cancer patients but not normal donors was depressed as compared to normal PBL. In summary, there are significant differences in the cellular phenotypes and immunologic competence among the various stem cell products with potential therapeutic implications.