Leflunomide increased the renal exposure of acyclovir by inhibiting OAT1/3 and MRP2.

Rheumatoid arthritis patients can be prescribed a combination of immunosuppressive drug leflunomide (LEF) and the antiviral drug acyclovir to reduce the high risk of infection. Acyclovir is a substrate of organic anion transporter (OAT) 1/3 and multidrug resistance-associated protein (MRP) 2. Considering the extraordinarily long half-life of LEF's active metabolite teriflunomide (TER) and the kidney injury risk of acyclovir, it is necessary to elucidate the potential impact of LEF on the disposition of acyclovir. Here we used a specific MRP inhibitor MK571 and probenecid (OAT1/3 and MRP2 inhibitor) to assess the effects of MRP2 and OAT1/3 on the pharmacokinetics and tissue distribution of acyclovir in rats. We showed that LEF and probenecid, but not MK571 significantly increased the plasma concentration of acyclovir. However, kidney and liver exposures of acyclovir were increased when coadministered with LEF, probenecid or MK571. The kidney/plasma ratio of acyclovir was increased to approximately 2-fold by LEF or probenecid, whereas it was increased to as much as 14.5-fold by MK571. Consistently, these drugs markedly decreased the urinary excretion of acyclovir. TER (0.5-100 µmol/L) dose-dependently increased the accumulation of acyclovir in MRP2-MDCK cells with an IC50 value of 4.91 µmol/L. TER (5 µmol/L) significantly inhibited the uptake of acyclovir in hOAT1/3-HEK293 cells. These results suggest that LEF/TER increased the kidney accumulation of acyclovir by inhibiting the efflux transporter MRP2, which increased its kidney/plasma ratio and renal injury risk. However, the inhibitory effects of LEF/TER on OAT1/3 reduced the tubular cells' uptake of acyclovir and increased the plasma concentration.

UDP-glucuronosyltransferases (UGTs) and their related metabolic cross-talk with internal homeostasis: A systematic review of UGT isoforms for precision medicine.

UDP-glucuronosyltransferases (UGTs) are the primary phase II enzymes catalyzing the conjugation of glucuronic acid to the xenobiotics with polar groups for facilitating their clearance. The UGTs belong to a superfamily that consists of diverse isoforms possessing distinct but overlapping metabolic activity. The abnormality or deficiency of UGTs in vivo is highly associated with some diseases, efficacy and toxicity of drugs, and precisely therapeutic personality. Despite the great effects and fruitful results achieved, to date, the expression and functions of individual UGTs have not been well clarified, the inconsistency of UGTs is often observed in human and experimental animals, and the complex regulation factors affecting UGTs have not been systematically summarized. This article gives an overview of updated reports on UGTs involving the various regulatory factors in terms of the genetic, environmental, pathological, and physiological effects on the functioning of individual UGTs, in turn, the dysfunction of UGTs induced disease risk and endo- or xenobiotic metabolism-related toxicity. The complex cross-talk effect of UGTs with internal homeostasis is systematically summarized and discussed in detail, which would be of great importance for personalized precision medicine.

The expression of MACC1 and its role in the proliferation and apoptosis of salivary adenoid cystic carcinoma.

BACKGROUND: The objective of this study was to investigate the relationship between metastasis-associated in colon cancer-1 and patient clinical characteristics. We also examined the role of metastasis-associated in colon cancer-1 in the proliferation and apoptosis in adenoid cystic carcinoma. MATERIAL AND METHODS: Metastasis-associated in colon cancer-1 expression was analysed in 65 paraffin-embedded tissue specimens of salivary adenoid cystic carcinoma and 25 adjacent non-cancerous tissues by immunohistochemistry (IHC). We used RNA interference technology to silence metastasis-associated in colon cancer-1 expression in ACCM cells. Cell Counting Kit-8 tests, transwell experiments and flow cytometry were used to test the proliferation, cisplatin resistance, migration, invasion and apoptosis of ACCM cells. RESULTS: Metastasis-associated in colon cancer-1 nuclear and cytoplasmic expression in salivary adenoid cystic carcinoma tissue was higher than in the adjacent normal salivary tissue. The expression level was closely associated with tumour histological grading, perineural invasion and surrounding tumour invasion. The downregulation of metastasis-associated in colon cancer-1 expression inhibited proliferation and induced apoptosis in ACCM cells. The knock-down of metastasis-associated in colon cancer-1 expression had no effect on migration, invasion and chemoresistance. CONCLUSIONS: Metastasis-associated in colon cancer-1 may have an important role in tumour development in adenoid cystic carcinoma. Metastasis-associated in colon cancer-1 is a potential biomarker for adenoid cystic carcinoma.

The biological characteristics of DAstV molecular epidemiology and pathogenicity of duck astrovirus causing hepatitis in ducks and chickens in Southeast China.

A suspected outbreak of duck astrovirus (DAstV) disease occurred in a large Muscovy duck farm in Guangdong Province, China, in June 2022, which severely affected the production performance and health of Muscovy ducks. This study aimed to investigate the prevalence of DAstV disease in Southeast China. Herein, we employed semi-nested PCR ethodto screen 5203 swab and liver samples from 11 Muscovy duck farms in 5 provinces of China for the presence of DAstV. Among them, 1356 samples (26.06%, 1356/5203) tested positive for DAstV, out of which 11 DAstV strains were isolated after 10 generations of blind transmission through Leghorn male hepatoma (LMH) cells and performed their whole-genome sequencing. The alignment results showed that the 11 DAstV isolates exhibited relatively low homology (15.4%-75%) with the astrovirus isolates from other species published in GenBank, whereas their homology (nucleotide: 90.4%-99.99%; amino acid: 94%-99.8%) with the DAstV type 1 (DAstV-1) reference strain was higher, indicating considerable homology. The results indicated that DAstV-1 was the main pathogenic factor. Herein, we successfully recreated the clinical symptoms of natural infection in 28-day-old specific-pathogen-free (SPF) ducks using the DAstV-1-GDB-2022 strain. The primary clinical manifestations included liver enlargement, hemorrhaging, and disruptions in liver function. Additionally, we confirmed the cross-species transmission potential of DAstV-1, marking the first occurrence of clinical symptoms of DAstV in 28-day-old SPF chickens. Our findings provide new perspectives on the epidemiology and pathogenicity of DAstV-1 and may help in advancing the development of DAstV vaccines.

High expression of long noncoding RNA plasmacytoma variant translocation 1 is an independent risk factor for recurrence after radiofrequency ablation in atrial fibrillation patients.

Atrial fibrillation (AF) is a common arrhythmia. Radiofrequency ablation (RFA) is the major AF treatment. Long noncoding RNA (lncRNA) plasmacytoma variant translocation 1 (PVT1) is related to AF diagnosis. This study explored the clinical roles of PVT1 in AF. Totally, 168 AF patients and 100 healthy controls were selected. Plasma lncRNA PVT1 in AF patients before/after RFA was detected and the diagnostic efficacy and postoperative recurrence prediction value in AF were analyzed. Effects of plasma PVT1 expression on AF recurrence and its correlation with transforming growth factor beta 1 (TGF-ß1) in the recurrence and non-recurrence groups were analyzed by Pearson coefficient. The risk factors of AF recurrence were evaluated. Plasma PVT1 was highly expressed in AF patients and diminished after RFA. PVT1 level >1.255 assisted AF diagnosis. The plasma PVT1 level in the recurrence group was higher than that of the non-recurrence group. PVT1 level >1.525 assisted the prediction for postoperative recurrence. AF postoperative recurrence incidence in high PVT1 expression group was clearly higher than that in low PVT1 expression group, and plasma PVT1 expression in patients of the recurrence and non-recurrence groups was positively correlated with TGF-ß1 content. High PVT1 expression was an independent risk factor for postoperative recurrence. Briefly, high PVT1 level assisted AF diagnosis and recurrence evaluation after RFA and was an independent risk factor for AF postoperative recurrence.

Engineering and Structural Insights of a Novel BBI-like Protease Inhibitor Livisin from the Frog Skin Secretion.

The Bowman-Birk protease inhibitor (BBI) family is a prototype group found mainly in plants, particularly grasses and legumes, which have been subjected to decades of study. Recently, the discovery of attenuated peptides containing the canonical Bowman-Birk protease inhibitory motif has been detected in the skin secretions of amphibians, mainly from Ranidae family members. The roles of these peptides in amphibian defense have been proposed to work cooperatively with antimicrobial peptides and reduce peptide degradation. A novel trypsin inhibitory peptide, named livisin, was found in the skin secretion of the green cascade frog, Odorrana livida. The cDNA encoding the precursor of livisin was cloned, and the predicted mature peptide was characterized. The mature peptide was found to act as a potent inhibitor against several serine proteases. A comparative activity study among the native peptide and its engineered analogs was performed, and the influence of the P1 and P2' positions, as well as the C-terminal amidation on the structure-activity relationship for livisin, was illustrated. The findings demonstrated that livisin might serve as a potential drug discovery/development tool.

Identification of new dermaseptins with self-assembly tendency: membrane disruption, biofilm eradication, and infected wound healing efficacy.

Severe infections associated with antibiotic-resistant bacteria and biofilms have attracted increasing interest as these diseases are difficult to treat with current antibiotics. Typical cationic antimicrobial peptides dermaseptins are considered to be the most promising next-generation antibiotics because of their broad-spectrum antimicrobial activities and minor side effects. Two new dermaseptin peptides, DMS-PS1 and DMS-PS2, have been identified by "shotgun" molecular cloning of encoding cDNAs in the crude skin secretions of the waxy monkey tree frog, Phyllomedusa sauvagei. The mature peptide sequences predicted from the cloned cDNAs were separated from crude skin secretions and confirmed by mass spectrometry. Chemically synthetic replicates were assessed for various biological activities. Both dermaseptins were potently effective against a broad spectrum of microorganisms including antibiotic-resistant bacteria and displayed significant potency against gram-positive and gram-negative bacterial biofilms with low toxicity towards mammalian red blood cells. Remarkably, DMS-PS2 was effective against infections in murine skin caused by methicillin-resistant Staphylococcus aureus as a result of an induced wound. The actions of DMS-PS2 were with a membrane permeabilization mode. Overall, the data provided convincing evidence for the development of anti-infectious agents and/or biomaterials as a new therapeutic approach against bacterial infections. STATEMENT OF SIGNIFICANCE: Bacterial adhesion to biomaterials remains a major problem. Antimicrobial peptides (AMPs) are well-known components of the innate immune system that can be applied to overcome biofilm-associated infections. Cationic dermaseptin peptides showed significant broad-spectrum antimicrobial activities and activities against bacterial biofilms of persistent infections in association with weak toxicity for mammalian red blood cells. The membrane permeabilizing ability of DMS-PS2 was confirmed, and importantly, it demonstrated potent efficiency of the treatment of MRSA infected murine skin model. Furthermore, beyond our expectation, DMS-PS2 showed a self-aggregating parameter, indicating a promising potential for the use of immobilized AMPs in clinical applications., which makes it also a promising suggestion for infection-proof biomaterial development.

Logistic regression analysis of clinical and computed tomography features of pulmonary abscesses and risk factors for pulmonary abscess-related empyema.

OBJECTIVES: This study was conducted to investigate the risk factors for pulmonary abscess-related empyema by investigating the clinical characteristics and chest computed tomography imaging features of patients with pulmonary abscesses. METHODS: We retrospectively analyzed the chest computed tomography findings and clinical features of 101 cases of pulmonary abscess, including 25 cases with empyema (the experimental group) and 76 cases with no empyema (the control group). The potential risk factors for pulmonary abscess-related empyema were compared between the groups by using univariate and multivariate logistic regression analyses. RESULTS: The incidence of pulmonary abscess-related empyema was 24.8% (25/101). Univariate analysis showed that male gender, diabetes, pleuritic symptoms, white blood cells >10×109/L, albumin level <25 g/L, and positive sputum cultures were potential clinical-related risk factors and that an abscess >5 cm in diameter and transpulmonary fissure abscesses were potential computed tomography imaging-related risk factors for pulmonary abscess-related empyema. Multivariate logistic regression analysis showed that transpulmonary fissure abscesses (odds ratio=9.102, p=0.003), diabetes (odds ratio=9.066, p=0.003), an abscess >5 cm in diameter (odds ratio=8.998, p=0.002), and pleuritic symptoms (odds ratio=5.395, p=0.015) were independent risk factors for pulmonary abscess-related empyema. CONCLUSIONS: Transpulmonary fissure abscesses, diabetes, giant pulmonary abscesses, and pleuritic symptoms increased the risk of empyema among patients with pulmonary abscesses.

Ectopic expression of GA 2-oxidase 6 from rapeseed (Brassica napus L.) causes dwarfism, late flowering and enhanced chlorophyll accumulation in Arabidopsis thaliana.

Gibberellins (GAs) are endogenous hormones that play an important role in higher plant growth and development. GA2-oxidase (GA2ox) promotes catabolism and inactivation of bioactive GAs or their precursors. In this study, we identified the GA2-oxidase gene, BnGA2ox6, and found it to be highly expressed in the silique and flower. Overexpression of BnGA2ox6 in Arabidopsis resulted in GA-deficiency symptoms, including inhibited elongation of the hypocotyl and stem, delayed seed germination, and late flowering. BnGA2ox6 overexpression reduced silique growth, but had no effect on seed development. Additionally, BnGA2ox6 overexpression enhanced chlorophyll b and total chlorophyll accumulation, and downregulated mRNA expression levels of the CHL1 and RCCR genes, which are involved in the chlorophyll degradation. These findings suggest that BnGA2ox6 regulates plant hight, silique development, flowering and chlorophyll accumulation in transgenic Arabidopsis.

Distinct Gene Expression and Epigenetic Signatures in Hepatocyte-like Cells Produced by Different Strategies from the Same Donor.

Hepatocyte-like cells (HLCs) can be generated through directed differentiation or transdifferentiation. Employing two strategies, we generated induced pluripotent stem cell (iPSC)-HLCs and hiHeps from the same donor cell line. Both types of HLCs clustered distinctly from each other during gene expression profiling. In particular, differences existed in gene expression for phase II drug metabolism and lipid accumulation, underpinned by H3K27 acetylation status in iPSC-HLCs and hiHeps. While distinct phenotypes were achieved in vitro, both types of HLCs demonstrated similar phenotypes following transplantation into Fah-deficient mice. In conclusion, functional HLCs can be obtained from the same donor using two strategies. Global gene expression defined the differences between those populations in vitro. Importantly, both HLCs displayed partial but markedly improved hepatic function following transplantation in vivo, demonstrating plasticity and the potential for cell-based modeling in the dish and cell-based therapy in the future.

High fat diet aggravates the nephrotoxicity of berberrubine by influencing on its pharmacokinetic profile.

Berberrubine (BRB), the active metabolite of berberine (BBR), possesses various pharmacological activities. In this study, we found BRB showed not only a stronger lipid-lowering effect than berberine but also a specific nephrotoxicity in mice fed with high fat diet (HFD). To explore the underlying mechanism, the pharmacokinetics of BRB were evaluated. There was a greater in vivo exposure of BRB in C57BL/6J mice fed with HFD than with routine chows, in terms of Cmax, AUC0-t, levels of BRB in kidney and urinary excretion. Moreover, in vitro assessment clearly showed BRB had a toxic effect on renal cell lines, while the primary metabolite, berberrubine-9-O-ß-d-glucuronide (BRBG), did not show any obvious toxicity. These results suggested HFD aggravated BRB-induced nephrotoxicity by promoting the in vivo exposure of BRB especially in urine and kidney. Although our previous study indicated BRB could be metabolized into BRBG, BRBG did not show any obvious toxicity in vitro.

Logistic regression analysis of clinical and computed tomography features of pulmonary abscesses and risk factors for pulmonary abscess-related empyema

OBJECTIVES: This study was conducted to investigate the risk factors for pulmonary abscess-related empyema by investigating the clinical characteristics and chest computed tomography imaging features of patients with pulmonary abscesses. METHODS: We retrospectively analyzed the chest computed tomography findings and clinical features of 101 cases of pulmonary abscess, including 25 cases with empyema (the experimental group) and 76 cases with no empyema (the control group). The potential risk factors for pulmonary abscess-related empyema were compared between the groups by using univariate and multivariate logistic regression analyses. RESULTS: The incidence of pulmonary abscess-related empyema was 24.8% (25/101). Univariate analysis showed that male gender, diabetes, pleuritic symptoms, white blood cells >10×109/L, albumin level <25 g/L, and positive sputum cultures were potential clinical-related risk factors and that an abscess >5 cm in diameter and transpulmonary fissure abscesses were potential computed tomography imaging-related risk factors for pulmonary abscess-related empyema. Multivariate logistic regression analysis showed that transpulmonary fissure abscesses (odds ratio=9.102, p=0.003), diabetes (odds ratio=9.066, p=0.003), an abscess >5 cm in diameter (odds ratio=8.998, p=0.002), and pleuritic symptoms (odds ratio=5.395, p=0.015) were independent risk factors for pulmonary abscess-related empyema. CONCLUSIONS: Transpulmonary fissure abscesses, diabetes, giant pulmonary abscesses, and pleuritic symptoms increased the risk of empyema among patients with pulmonary abscesses.

[microRNAs expression profile in acute promyelocytic leukemia cell differentiation induced by all-trans retinoic acid and arsenic trioxide].

OBJECTIVE: To study the expression profile of microRNAs in acute promyelocytic leukemia (APL) cells during differentiation. METHODS: Differentiation of APL cell line NB4 cells was induced by all-trans retinoic acid (ATRA) and arsenic trioxide (As2O3). Morphological and immunological assay was performed by Wright-Giemsa staining and flow-cytometric analysis of CD11b surface expression. During in vitro NB4 differentiation induced by ATRA and As2O3, microRNA expression profiles (miR-15b, miR-16, miR-34a, miR-107, miR-124a, miR-146, miR-155, miR-181a, miR-223, miR-342, let7c) were detected by real time RT-PCR, and the relative expression level of microRNAs were quantitatively analyzed by using 2(-ΔΔCt), and compared with that of control group. Meanwhile, the microRNA expression profiles were also detected in 15 newly diagnosed APL patients and 15 complete remission (CR) APL cases by real time RT-PCR, and the relative expression level of microRNA was quantitated by using 2(-ΔCt), and compared with that of control group (newly diagnosed APL as control group). These data were expressed as x(-) ± s, and differences between groups were examined using t test. P < 0.05 was considered statistically significant. RESULTS: The expression levels of miR-15b, miR-16, miR-107, miR-223 and miR-342 in NB4 differentiation group were obviously up-regulated (3.40, 4.22, 5.41, 20.03 and 5.29 folds higher in ATRA treated NB4 cells than that of control group respectively, and 3.62, 2.49, 2.58, 4.27 and 1.94 folds higher in AS2O3 treated NB4 cells than that of control group respectively), except for miR-15b, the expression levels of miR-16, miR-107, miR-223 and miR-342 in ATRA treated group was significantly higher than that in As2O3 treated group. The relative expression levels of miR-15b, miR-16, miR-107, miR-181a, miR-223 and miR-342 were 0.4137, 0.6367, 0.1260, 0.0522, 0.6611, 0.0280 in APL CR group, and 0.0751, 0.2022, 0.0425, 0.3064, 0.1733, 0.0090 in newly diagnosed APL group, respectively. The expression level of miR-15b, miR-16, miR-107, miR-223 and miR-342 in APL CR group were significantly upregulated compared with that of newly diagnosed APL groups (P < 0.05), while the expression level of miR-181a was significantly downregulated (P < 0.05). CONCLUSION: Specific expression of microRNA profiles is a key contributing factor in the differentiation of APL.

[Packaging of lentivirus carrying gene hßc and overexpression of gene hßc in NB4 cells].

This study was aimed to overexpress gene hßc in NB4 cells via the method of lentivirus-mediated gene transfer, to observe the differentiation behaviour change of hßc over-expressing NB4 cells treated with IL-3 or GM-CSF, to explore the relationship between hßc gene and the differentiation behaviour of NB4 cells. The targeted hßc gene was amplified by PCR from the cloned vector carrying ORF of hßc. The PCR product containing PmeI and BstBI site introduced by primer was digested, and then cloned into lentivirus vector pRRLSIN.cPPT.PGK/IRES/GFP.WPRE to construct a lentiviral vector carrying hßc, named pLV-hßc. And the pLV-hßc plasmid was confirmed by restriction and sequencing. The recombinant lentivirus was produced by co-transfecting three plasmids into 293T packing cells. After transfection, the lentiviral supernatant was collected to transfect NB4 cells. GFP expression was examined by fluorescent microscope and the expression of hßc gene was detected by Western blot. Then, the NB4 cells over-expressing hßc were treated with IL-3 (10 ng/ml), GM-CSF (10 ng/ml), ATRA (1 µmol/L) respectively, and the CD11b expression, morphology and differentiation behaviour changes of every groups were observed by flow cytometry and microscopy, while NB4 cells transfected with blank lentivirus (NB4-blank cells) were used as controls. The results showed that the recombinant lentivirus vector carrying hßc gene could efficiently transfect NB4 cells and made NB4 cells to stably over-express hßc gene. The expression of CD11b was up-regulated in NB4-hßc cells treated with of IL-3 or GM-CSF, but it was not as obvious as the effect of ATRA, and no morphological change was observed in NB4 hßc cells treated with the IL-3 or GM-CSF. It is concluded that IL-3 or GM-CSF can induce NB4 cells over-expressing hßc to differentiate to neutrophils, but can not make them fully matured.

[Expression pattern of myeloid differentiation-related transcription factor mRNA in differentiation of NB4 and HL-60 cells induced by all-trans retinoic acid].

Hematopoiesis is coordinated by a complex regulatory network of transcription factors that involves proliferation, differentiation and maturation of a very small population of pluripotent hematopoietic stem cells with self-renewing and differentiating into various specialized and distinct blood cell types. Malfunction of transcription factors may lead to diseases such as acute myeloid leukemia (AML). The purpose of this study was to investigate the expression pattern of transcription factor mRNA in acute myeloid leukemia (AML) cells during in vitro differentiation. The 2 human leukemic cell lines HL-60 and NB4 had been used as model cell lines. Differentiation of HL-60 and NB4 cells was induced by all-trans retinoic acid (ATRA) for 4 days. Morphological changes were observed by May-Grunwald Giemsa stainings, the CD11b expression level was detected by flow cytometry. Transcription factor mRNA profiles (PU.1, C/EBPα, ε, γ, GATA-1, GATA-2) were determined by real time RT-PCR during in vitro HL-60 and NB4 differentiation; The expression level of transcription factor mRNA was relatively quantitatively analyzed by using 2(-ΔΔCT) and compared with control group. The results showed that the expression levels of PU.1 and C/EBP ε mRNA in NB4 differentiation group were 5.75 and 6.16, respectively, which were significantly higher than those in untreated group; while the expression level of C/EBPα, γ, GATA-1, GATA-2 mRNA in NB4 differentiation group were 62%, 31%, 63% and 8.7% respectively, which were significantly lower than those in untreated group; In HL-60 differentiation group, the expression levels of PU.1, C/EBPα, ε were 1.97, 1.95 and 2.35 respectively, which were significantly higher than those in untreated group; while the expression levels of C/EBPγ, GATA-1, GATA-2 in HL-60 differentiation group were 20%, 21% and 18% respectively, which were significantly lower than those in untreated group. It is concluded that dysregulation of transcription factors is a key contributing factor in the pathogenesis of acute myeloid leukemia.

[Expression change of IL-3 receptor system in all-trans retinoic acid induced differentiation of NB4 cells].

Interleukin-3 receptor (IL-3R) is a heterodimeric membrane receptor. The α subunit is essential for ligand binding and confers ligand specificity to the receptor. The common beta chain (ßc) subunit, which is shared by the granulocyte macrophage-colony stimulating factor (GM-CSF), IL-3 and IL-5 receptors, is required for high-affinity ligand binding and signal transduction, mediating growth and survival of hematopoietic progenitor cells and the production and activation of mature hematopoietic cells. In order to investigate the role of IL-3 receptor system (IL-3Rα, GM-CSFRα and hßc) in myeloid differentiation, the expression level of IL-3 receptor system gene in all-trans retinoic acid (ATRA)-induced NB4 cell differentiation was detected by quantitative real time RT-PCR. At the same time, DNA sequence change was analyzed by cDNA sequencing. The results showed that the expression level of IL-3Rα mRNA was obviously down-regulated in NB4 cells treated with ATRA for 24 hours, but during differentiation of ATRA induced NB4 cells, the expression level of IL-3Rα mRNA was gradually restored, while the expression levels of GM-CSFRα mRNA and hßc mRNA were gradually up-regulated. The sequence of IL-3Rα and GM-CSFRα gene did not change before and after NB4 cells differentiation, but the sequence of hßc gene changed when NB4 cells were treated with ATRA, the expression of hßc mRNA sequence before NB4 cell differentiation taken truncated mutation as dominant, as regards expression of hßc mRNA sequence after NB4 cell differentiation, the truncated mutation of hßc mRNA had restored to wild type. It is concluded that the IL-3 receptor abnormality exists in NB4 cells, over expression of IL-3Rα and truncated mutation of hßc may be involved in proliferation and differentiation block in NB4 cells.