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M Guigon

Publications and source records attributed to M Guigon.

At least 37 records · Page 2Linked to original sources
PubMed1995

Comparison of the inhibitory effect of AcSDKP, TNF-alpha, TGF-beta, and MIP-1 alpha on marrow-purified CD34+ progenitors.

The aim of this study was to compare the inhibitory effect of the tetrapeptide AcSDKP, tumor necrosis factor-alpha (TNF-alpha), which contains the sequence of the peptide, transforming growth factor-beta (TGF-beta), and macrophage inflammatory protein-1 alpha (MIP-1 alpha) on sorted CD34+ cells using both proliferation and clonogenic assays. Although a short treatment with any of the molecules decreased the growth of colony-forming unit granulocyte/macrophage (CFU-GM) and burst-forming unit-erythroid (BFU-E) progenitors (except for TNF-alpha as it is a greater inhibitor for CFU-GM), further experiments using a 6-day liquid culture in the presence of a combination of growth factors (recombinant human interleukin-3 [rhIL-3], IL-6, IL-1 beta, GM colony-stimulating factor [GM-CSF], G-CSF, erythropoeitin [Epo], and stem cell factor [SCF]) allowed us to determine a number of differences between their effects: 1) TGF-beta and TNF-alpha induced a stronger decrease in the proliferation and clonogenicity of CD34+ subsets than MIP-1 alpha and AcSDKP, 2) the dose-response curves appeared different, and 3) contrary to TGF-beta and TNF-alpha, AcSDKP and MIP-1 alpha required repeated addition to induce inhibition. Therefore, our data clearly show that while the inhibitory effect of TNF-alpha and AcSDKP appeared to be different, there is a close similarity in the effect of AcSDKP and MIP-1 alpha on normal human progenitor response to the combination of growth factors used.

Antigens, CD↗
PubMed1995

Inhibitory peptides in hematopoiesis.

This paper will review the present knowledge on two small chemically unrelated peptides, the pentapeptide pGlu-Glu-Asp-Cys-Lys (pEEDCK) and the tetrapeptide acetyl-N-Ser-Asp-Lys-Pro (AcSDKP, Seraspenide) focusing on 1) their inhibitory effects on normal hematopoiesis, 2) their effect on malignant cells, especially leukemic cells, and 3) their potential clinical use as marrow protectors during cancer therapy.

Animals↗
PubMed1994

Tumor necrosis factor alpha (TNF alpha) downregulates c-kit proto-oncogene product expression in normal and acute myeloid leukemia CD34+ cells via p55 TNF alpha receptors.

Tumor necrosis factor alpha (TNF alpha), as a modulator of hematopoiesis, interacts with many growth factor receptors, such as interleukin-3, granulocyte-macrophage colony-stimulating factor (CSF), and granulocyte-CSF receptors. Here, we studied the interactions between TNF alpha and the stem cell factor (SCF) receptor, c-kit, in normal CD34+ hematopoietic progenitors and their leukemic counterpart, ie, acute myeloid leukemic (AML) CD34+ cells coexpressing c-kit antigen. The results showed that (1) incubation of normal bone marrow mononuclear cells with 200 U/mL rhTNF alpha for 20 hours induced a diminution of 31.2% +/- 5.2% of CD34+ cells coexpressing c-kit; (2) the same decrease was observed using purified CD34+ cells and, furthermore, their proliferative response to SCF was inhibited by 31.5% +/- 7.3% after exposure to TNF alpha; (3) similar experiments performed on CD34+ c-kit+ AML cells from 11 patients gave comparable results. Further analysis at the mRNA level indicated that TNF alpha decreased c-kit mRNA transcripts. Moreover, using monoclonal antibodies against the two types of TNF alpha receptors, p75 and p55, we showed that the downregulation of c-kit proto-oncogene product by TNF alpha, on normal and leukemic CD34+ cells, was exclusively mediated by the TNF alpha p55 receptor. Therefore, we conclude that TNF alpha acts as a downregulator of the SCF receptor expression.

Adult↗
PubMed1994

Bone marrow protection.

During the Third International Conference on Negative Control of Hematopoiesis (Paris, April 1993), a special session was devoted to bone marrow protection. Myelotoxicity is often a limiting factor in the use of efficient doses of chemo- or radiotherapy. It appeared therefore of great importance to protect hematopoietic stem cells in order to allow the restoration of hematopoiesis and to prevent the occurrence of lethal aplasia. Several approaches to decrease the myelotoxicity of chemo- and/or radiotherapy were discussed: MDR gene therapy, use of chemical compounds (AS101, WR 2721), cytokines such as TNF alpha and IL-1 and small peptides, pEEDCK and AcSKDP. Interestingly, several of these molecules appear of interest to protect normal stem cells during marrow purging for autograft.

Amino Acid Sequence↗
PubMed1994

Photoprotection of normal human hematopoietic progenitors by the tetrapeptide N-AcSDKP.

The tetrapeptide AcSDKP (Ser-Asp-Lys-Pro) is a reversible inhibitor of normal human hematopoietic progenitor growth. In this paper, we report that preincubation of bone-marrow mononuclear cells (MNC) with AcSDKP at 10(-10) M for 20 hours protects the granulocyte-macrophage colony-forming unit (CFU-GM) progenitors against photofrin II-mediated phototherapy. This protective effect was observed after short-term exposure to photofrin (2.5 micrograms/mL) and irradiation by high-energy doses at 514 nm. Nevertheless, AcSD-KP, which has no effect on leukemic cell proliferation, does not protect the HL-60 and K-562 leukemic cell lines against photosensitization.

Amino Acid Sequence↗
PubMed1993

Direct and reversible inhibitory effect of the tetrapeptide acetyl-N-Ser-Asp-Lys-Pro (Seraspenide) on the growth of human CD34+ subpopulations in response to growth factors.

The tetrapeptide Acetyl-N-Ser-Asp-Lys-Pro (AcSDKP, Seraspenide; Ipsen-Biotech, Paris, France), an inhibitor of murine spleen colony-forming units reduces the number and the percentage in DNA synthesis of progenitors from human unfractionated bone marrow. To determine whether AcSDKP may directly affect the growth potential of purified progenitors even at the most primitive level, CD34+HLA-DRhigh and CD34++HLA-DRlow cells were highly purified by cell sorting. Then, CD34+ subsets were stimulated in liquid culture with combinations of growth factors (GFs) and AcSDKP was added for 20 hours or 6 days and cells plated in methylcellulose. After a 20-hour incubation, we show that AcSDKP (at 10(-10) mol/L) significantly inhibits the colony formation of both CD34+ subsets. Moreover, when added daily for 6 days, AcSDKP: (1) reduces the proliferation of both CD34+ cell fractions stimulated by 3 or 7 GFs, and (2) decreases the number of progenitors generated from the CD34+HLA-DRhigh and CD34++HLA-DRlow cell fractions. Furthermore, we show for the first time, using both high proliferative potential cell and long-term culture initiating cell assays, that AcSDKP inhibits the most primitive cells contained in the CD34++HLA-DRlow subpopulation. Finally, by using limiting dilution assays we demonstrated that AcSDKP acts directly at a single cell level and that its inhibitory effect is reversible and dose dependent.

Amino Acid Sequence↗
PubMed1993

The tetrapeptide AcSerAspLysPro (Seraspenide), a hematopoietic inhibitor, may reduce the in vitro toxicity of 3'-azido-3'-deoxythymidine to human hematopoietic progenitors.

3'-azido-3'-deoxythymidine (AZT), the main antiviral drug used in AIDS treatment, is known to induce anemia and neutropenia. These effects have been attributed to its toxicity to hematopoietic progenitors. In this report, we present a new approach to reduce AZT hematotoxicity by using an inhibitory factor of the hematopoietic stem cells, the tetrapeptide AcSerAspLysPro (AcSDKP, Seraspenide), which has been shown to increase the survival of mice subjected to high doses of chemotherapy and to block reversibly the cycling of human granulocyte-macrophage colony forming unit (CFU-GM) and burst forming unit erythroid (BFU-E) progenitors. Normal bone marrow mononuclear cells (BMMNC) from 14 subjects were incubated with or without AcSDKP (10(-10) M) for 20 h and with or without AZT (100 microM) for another 2 h. After washing, cells were plated in methylcellulose in the presence of interleukin 3 (IL-3), granulocyte-macrophage colony stimulating factor (GM-CSF) and erythropoietin (EPO). Under these conditions, the preincubation of cells with AcSDKP reduced significantly the toxicity of AZT to both BFU-E and CFU-GM at least in 3 out of 8 and 4 out of 10 cases, respectively. A careful statistical analysis of these observations indicates that AcSDKP may be an efficient factor in preserving progenitors against AZT-induced hematopoietic toxicity.

Amino Acid Sequence↗
PubMed1992

Tumor necrosis factor alpha in human long-term bone marrow cultures: distinct effects on nonadherent and adherent progenitors.

Although tumor necrosis factor alpha (TNF alpha) exerts a variety of activities on hematopoietic cells, suggesting it may have some potential therapeutic applications, its long-term effects on hematopoiesis are not well defined. Therefore, we took the advantage of long-term bone marrow cultures (LTBMCs) to evaluate the long-term role of TNF alpha on both the microenvironment and the hematopoietic progenitors. LTBMCs were inoculated with 100 U/ml of recombinant human TNF alpha (rhTNF alpha) either at the onset of the cultures (d0) or at day 21 (d21) when the adherent layer (AL) was already established. Then TNF alpha was added at each weekly medium change. The cellularity and the content of progenitors in both the nonadherent layer (NAL) and AL, the formation of the AL, and the presence of various cytokines in the supernatants were examined weekly. The data showed 1) a strong and durable inhibitory effect on total nonadherent cells; 2) a rapid and transient inhibition of NA progenitors, whereas adherent progenitors were lately affected; and 3) microenvironmental changes consisting of the disappearance of adipocytes and the secretion of high levels of interleukin 6. The results suggest that the inhibitory effects of TNF alpha on the NAL are in part counterbalanced by stromal modifications that in turn lead to a faster exhaustion of hematopoiesis.

Bone Marrow↗
PubMed1992

Reversible inhibitory effects and absence of toxicity of the tetrapeptide acetyl-N-Ser-Asp-Lys-Pro (AcSDKP) in human long-term bone marrow culture.

The effects of acetyl-N-Ser-Asp-Lys-Pro (Ac-SDKP) in human long-term bone marrow cultures (LTBMCs) were assessed by measuring the number of progenitors and the development of stromal cells over a 6-week course. In a first set of experiments, AcSDKP was added weekly at each medium change. Under these conditions, no significant effect of the peptide was observed. In contrast, by adding AcSDKP daily at 10(-10) M, the growth of the progenitors of the non-adherent (NA) compartment was inhibited by about 35%. This inhibition was entirely reversible; after stopping the addition of the peptide at the fourth week, the number of progenitors returned to control level within 2 weeks. Conversely, AcSDKP did not significantly change the number of the progenitors present in the adherent layer. In addition, AcSDKP did not affect the formation of the stromal layer nor induce the secretion of cytokines, such as tumor necrosis factor alpha (TNF-alpha), interleukin 1 beta (IL-1 beta), granulocyte colony-stimulating factor (G-CSF), interleukin 3 (IL-3), or interleukin 6 (IL-6). Our results indicate that AcSDKP has inhibitory but reversible effects on NA progenitors and does not induce long-term modifications of the microenvironment, both of particular interest for its clinical application.

Amino Acid Sequence↗
PubMed1992

The tetrapeptide AcSDKP, an inhibitor of the cell-cycle status for normal human hematopoietic progenitors, has no effect on leukemic cells.

The tetrapeptide acetyl-N-Ser-Asp-Lys-Pro (AcSDKP) inhibits the entry into DNA synthesis of murine spleen colony-forming units (CFU-S) and protects these cells during chemotherapy. This synthetic peptide also inhibits the growth of normal human marrow progenitors granulocyte-macrophage colony-forming units (CFU-GM) and erythroid burst-forming units (BFU-E) and decreases their percentage in DNA synthesis at nanomolar concentration. In view of its clinical application as a marrow protector, we have investigated its effects on malignant cells. Studies were carried out on HL-60 cells and on fresh leukemic cells from patients with either chronic myeloid leukemia (CML) or acute myeloid leukemia (AML). Results showed that AcSDKP, whatever the doses used, did not modify the proliferation of both HL-60 cells and AML cells even when enhanced by stimulating factors such as interleukin 3 or granulocyte-macrophage colony-stimulating factor (GM-CSF). In addition, no change in the number and the percentage in S-phase of both HL-60 clonogenic cells and CML progenitors was observed. Our data clearly demonstrate that the tetrapeptide AcSDKP was ineffective on leukemic cells and therefore by acting selectively on normal progenitors represents a potent therapeutical agent for the protection of normal bone marrow progenitors during chemotherapy.

Adult↗
PubMed1990

Prevention of hematotoxic side effects of cytostatic drugs in mice by a synthetic hemoregulatory peptide.

The application of certain cytostatic drugs causes the recruitment of pluripotent hemopoietic stem cells (CFU-S) into active proliferation. Further application of the drug(s) may then lead to severe and long lasting disturbances of hemopoiesis. We investigated if the hemoregulatory peptide pGlu-Glu-Asp-Cys-Lys (HP5b) could be used to inhibit stem cell recruitment and consequently to protect mice against the toxicity of repeated high doses of 1-beta-D-arabinofuranosylcytosine (ara-C). CFU-S recruitment (induced by injecting a single dose of 900 mg/kg ara-C) was prevented by either treating the bone marrow of these mice in vitro with 1 x 10(-7) M/liter HP5b, or by injecting 0.6 microgram HP5b (10(-9) mol, 30 micrograms/kg) at -2, +2, and +6 h relative to the ara-C injection. Multiple high dose ara-C applications (4 x 900 mg/kg at 0, 7, 24, and 30 h) lead to proliferative activation of CFU-S and resulted in the death of 90% of the mice within 7-9 days. Reconstitution of the hemopoietic system by a bone marrow transplant given after ara-C application decreased the mortality to about 45%, indicating the nonhematological component of ara-C toxicity. A single injection of HP5b (30 micrograms/kg at 26 h, when few CFU-S were found in S phase) decreased the mortality to 59%, not significantly different from the transplanted group. Inactive peptides given instead of HP5b had no protective effect. HP5b did not change the ara-C sensitivity of transformed cell lines (HL-60, Raji, Friend), even not in such cases (myeloid cell lines) where it had a direct inhibitory effect on the cells (e.g., HL-60). These results suggest that HP5b may be used as a myeloprotector in cancer chemotherapy by keeping hemopoietic stem cells out of cycle during the most hazardous treatment phase. Its lack of species specificity, its low toxicity, its high selectivity for hemopoiesis, the small size, as well as the availability through standard synthetic techniques may be of advantage for its clinical use.

Animals↗
PubMed1990

Secretion of tumor necrosis factor-alpha by fresh human acute nonlymphoblastic leukemic cells: role in the disappearance of normal CFU-GM progenitors.

The disappearance of normal hematopoiesis during acute nonlymphoblastic leukemia (ANLL) is poorly understood. Several reports indicate that conditioned medium obtained from leukemic cells might inhibit the formation of normal hematopoietic progenitors. However, these blast-conditioned medium (BCM) inhibitory activities are not well characterized. In order to evaluate whether BCM might contain an activity inhibiting the growth of normal marrow progenitors, BCM from 13 consecutive patients with ANLL were tested on normal bone marrow in methylcellulose assays. In all the cases, a significant inhibition of the growth of granulocyte-macrophage colony-forming unit (CFU-GM) progenitors was observed, whereas erythroid burst-forming unit (BFU-E) progenitors were not affected. Further characterization of the BCM inhibitory activity showed using both a biological assay and RIA, the presence of tumor necrosis factor-alpha (TNF-alpha) in 10 out of 13 BCM. Northern blot analysis performed in six patients showed a correlation between the expression of TNF-alpha mRNA by leukemic cells and the presence of TNF-alpha in BCM. Moreover, the BCM inhibitory activity could be neutralized with an anti-TNF-alpha antiserum. These data indicate that leukemic cells express and release frequently TNF-alpha, which may therefore play an important role in the inhibition of granulopoiesis during leukemia.

Adult↗