OBJECTIVETo investigate the effect of human umbilical cord-derived mesenchymal stem cells (UC-MSC) on the differentiation of leukemic cells.

METHODSThe co-culture system of UC-MSC with acute promyelocytic leukemic cell line NB4 cells was constructed in vitro,and the differentiation status of the leukemic cells was assessed by cell morphology,nitroblue tetrazolium reduction test,and cell surface differentiation marker CD11b.

RESULTSUC-MSC induced the granulocytic differentiation of NB4 cells. When UC-MSC and a small dose of all-trans retinoic acid were applied together,the differentiation-inducing effect was enhanced in an additive manner. Interleukin (IL)-6Ra neutralization attenuated differentiation and exogenous IL-6-induced differentiation of leukemic cells.

CONCLUSIONUC-MSC can promotd granulocytic differentiation of acute promyelocytic leukemia cells by way of IL-6 and presented additive effect when combined with a small dose of all-trans retinoic acid.

Cell Differentiation ; Cell Line, Tumor ; Humans ; Interleukin-6 ; metabolism ; Leukemia, Promyelocytic, Acute ; pathology ; Mesenchymal Stromal Cells ; metabolism ; Tretinoin ; pharmacology ; Umbilical Cord ; cytology

OBJECTIVETo investigate the effect of silencing SET gene on the biological characteristics of acute promyelocytic leukemia NB4-R1 cells.

METHODSThe expression vector of pGCSIL containing SET-shRNA were transfected into 293T cells by using other packaging plasmids. The supernatant of the 293T cells was harvested for lentivirus. The SET-shRNA lentiviral vector was transfected into acute promyelocytic leukemia NB4-R1 cells and a stably transfected cell line was established. Real-time quantitative PCR and Western blot were used to assay the silencing efficiency on SET gene and the expression of PP2A. The cell cycle distribution was tested by flow cytometry.

RESULTSThe expression of SET in experimental group statistically decreased as compared with that of the control group. The expression of PP2A was obviously raised at the level of mRNA and protein. The percentage of NB4-R1 cells in G0/G1 phase significantly increased, while the percentage of cells in S phase significantly decreased.

CONCLUSIONThe silencing gene in acute promyelocytic leukemia NB4-R1 cells using SET-shRNA lentiviral vector can increase the expression of PP2A and interfere of the cell cycle in NB4-R1 cells. This study has laid a experimental base for targed therapy of patients with acute promyelocytic leukemia.

Cell Cycle ; Cell Line, Tumor ; Gene Silencing ; Genetic Vectors ; HEK293 Cells ; Histone Chaperones ; genetics ; Humans ; Lentivirus ; Leukemia, Promyelocytic, Acute ; genetics ; pathology ; Protein Phosphatase 2 ; metabolism ; RNA, Messenger ; RNA, Small Interfering ; Transcription Factors ; genetics ; Transfection

OBJECTIVETo investigate the effect of everolimus(RAD001)combined with all-trans retinoid acid(ATRA) on drug resistance of ATRA-resistance acute promyelocytic leukemia(APL) cell line NB4-R1 and its molecular mechanism.

METHODSAPL NB4-R1 cells were treated with different concentrations of RAD001(1 nmol/L, 10 nmol/L and 100 nmol/L) with ATRA(1μmol/L) for 24, 48 and 72 h, respectively. The differentiation of NB4-R1 cells was analyzed by flow cytometry with CD11b staining and nitro blue tetrozolium(NBT) reduction test. Cell cycle was detected by cell cycle staining kit and apoptosis was detected by flow cytometry with Annexin V/PI staining. Protein expressions of LC-3II, PML-RARα, P-P70S6K and P-4E-BP1 were determined by Western blotting.

RESULTSRAD001 combined with ATRA significantly induced NB4-R1 cells differentiation, but RAD001 or ATRA alone did not enhance NB4-R1 differentiation. The co-treatment induced accumulation of cells in G1 phase and decreased the proportion of cells in S phase. The combined treatment had no effect on cell apoptosis. The differentiation rate of NB4-R1 cells in 100 nmol/L RAD001, 1μmol/L ATRA, RAD001 combined with ATRA and control groups was(2.29±0.57)%,(17.06±2.65)%,(54.47±4.91)% and(2.54±0.53)%, respectively; the proportion of cells in G1 phase was(35.20±11.97)%,(33.54±6.25)%,(53.70±8.73)% and(27.40±6.01)%, respectively; cells apoptosis rate was(2.30±0.14)%,(2.25±0.21)%,(2.40±0.28)% and(1.95±0.07)%, respectively. The combination of RAD001 with ATRA significantly inhibited mTOR signaling downstream proteins P-P70S6K, P-4E-BP1 and enhanced autophagy-related protein LC3-II and Beclin 1. The co-treatment also induced degradation of fusion protein PML-RARα.

CONCLUSIONRAD001 combined with ATRA can induce cell differentiation, inhibit cell cycle, resulting the reverse of drug resistance in NB4-R1 cells, which is associated with increase of autophagy level and degradation of PML-RARα.

Adaptor Proteins, Signal Transducing ; metabolism ; Antineoplastic Agents ; pharmacology ; Apoptosis ; Cell Cycle ; Cell Differentiation ; Cell Line, Tumor ; drug effects ; Drug Resistance, Neoplasm ; Everolimus ; pharmacology ; Humans ; Leukemia, Promyelocytic, Acute ; pathology ; Oncogene Proteins, Fusion ; metabolism ; Phosphoproteins ; metabolism ; Ribosomal Protein S6 Kinases, 70-kDa ; metabolism ; Signal Transduction ; Tretinoin ; metabolism

We describe a 44-year old man who suffered an isolated external auditory canal granulocytic sarcoma in remission of acute myeloid leukemia. The patient confirmed acute promyelocytic leukemia three years ago and the disease was in remission after treatment. Two months ago he presented pain and hearing loss in the left ear and the symptom developed gradually. At otoscopic examination a tumoral lesion was noted in the external auditory canal and computerized tomography scan showed a mass in the left external acoustic meatus without bone erosion.
Adult ; Ear Canal ; diagnostic imaging ; pathology ; Hearing Loss ; Humans ; Leukemia, Promyelocytic, Acute ; Male ; Sarcoma, Myeloid ; diagnostic imaging ; pathology ; Tomography, X-Ray Computed

OBJECTIVETo explore the effect of RNA interference of human I2PP2A gene on the proliferation and apoptosis of retinoic acid-resistant human acute promyelocytic leukemia (APL) cell line NB4-R1.

METHODSDesigned and constructed a RNA interference lentiviral vector I2PP2A-shRNA which targeted against I2PP2A gene, then transfected it into NB4-R1 via polybrene mediation. The I2PP2A expression levels before and after transfection were detected by qRT-PCR and Western blot, respectively. Meanwhile, the proliferation and apoptosis rates of each group were determined by CCK-8 and flow cytometry assay. The protein expressions of caspase-8 and PARP were detected by Western blot.

RESULTSBoth qRT-PCR and Western blot data showed the I2PP2A expression level was significantly downregulated in the transfection group. The I2PP2A mRNA expression level decreased by (70.0 ± 9.6)% and (64.0 ± 6.2)% respectively, compared with blank control and negative control group, and the I2PP2A protein expression level showed a consistent trend. CCK-8 proliferation assay indicated the NB4-R1 cell proliferation rate in I2PP2A-shRNA transfection group significantly reduced compared to blank control group (P<0.05). Flow cytometry results showed that NB4-R1 apoptosis rate in I2PP2A-shRNA transfection group increased by (6.30 ± 0.67) times and (6.04 ± 0.56) times, respectively (P<0.01). After inhibition of I2PP2A, the total caspase-8 and total PARP expressions decreased by (44.0 ± 3.1)% and (57.0 ± 4.0)%, respectively; Meanwhile, the cleaved caspase-8 (p43) and cleaved PARP (p89) increased by (36.0 ± 2.5)% and (45.0 ± 4.8)%, respectively compared with blank control group (P<0.05).

CONCLUSIONI2PP2A gene silenced by RNA interference could inhibit the proliferation and promote the apoptosis of NB4-R1, which may be regulated through caspase-8-induced exogenous apoptosis pathway.

Apoptosis ; genetics ; Caspase 8 ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; genetics ; Drug Resistance, Neoplasm ; Histone Chaperones ; genetics ; metabolism ; Humans ; Leukemia, Promyelocytic, Acute ; metabolism ; pathology ; RNA Interference ; Transcription Factors ; genetics ; metabolism ; Tretinoin ; pharmacology

No abstract available.
Blood Cell Count ; Bone Marrow Cells/metabolism/pathology ; Humans ; Leukemia, Promyelocytic, Acute/complications/*diagnosis/pathology ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Multiple Myeloma/complications/*diagnosis/pathology ; Paraproteinemias/diagnosis ; Syndecan-1/metabolism

Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Flavonoids ; pharmacology ; Humans ; Isoflavones ; chemistry ; Leukemia, Promyelocytic, Acute ; pathology ; Tretinoin ; pharmacology

OBJECTIVETo investigate the growth inhibition effect, cytotoxicity and apoptotic induction of harringtonine (HT) in human acute promyelocytic leukemia (APL) NB4 cells,and the related mechanism.

METHODSNB4 cells were treated with HT. Total cell numbers were counted by hemocytometer, and cell viabilities were determined by trypan blue exclusion. Apoptotic cells were determined by fluorescence microscopy and FACS after staining with AO and EB or PI, respectively. The cleavage of PARP and the activation of Bax and the expression of anti-apoptotic proteins were determined by Western Blot. siRNA was used to silence the expression of target genes. Primary cells were isolated following Ficoll-Hypaque density gradient centrifugation method.

RESULTSHT inhibited cell growth and induced apoptosis of NB4 cells in a dose- and time-dependent manner. Apoptosis induced by HT was correlated with the down-regulation of Mcl-1 and the cleavage of PARP, while HT did not affect the protein level of Bax and Bak or change the protein level of Bcl-2. The silence of Bcl-XL sensitized HT-induced apoptosis in NB4 cells.Apoptosis induced by HT in primarily cultured APL cells was also correlated with the down-regulation of Mcl-1.

CONCLUSIONHT inhibits cell growth and induces apoptosis in NB4 cells and primarily cultured APL cells, which may be associated with down-regulation of Mcl-1.

Apoptosis ; drug effects ; Cell Line, Tumor ; Harringtonines ; pharmacology ; Humans ; Leukemia, Promyelocytic, Acute ; metabolism ; pathology ; Proteins ; metabolism ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; bcl-2 Homologous Antagonist-Killer Protein ; metabolism ; bcl-2-Associated X Protein ; metabolism

In order to investigate the effect of curcumin combined with all-trans retinoid acid (ATRA) on differentiation of ATRA-resistant acute promyelocytic leukemia (APL) cells and its molecular mechanism, the NB4-R1, an ATRA-resistant APL cells, was used as a model, counting of NB4-R1 and cell morphologic observation were performed, the effect of curcumin alone or combined with ATRA on proliferation, differentiation of NB4-R1 cells was detected by flow cytometry (FCM), the change of AKT phosphorylation in cell differentiation was detected by Western blot. The results showed that ATRA had no influence on NB4-R1 cell proliferation, but enhanced the inhibitory effect of curcumin on NB4-R1 cell growth; the curcumin or ATRA alone did not affect NB4-R1 differentiation; curcumin combined with ATRA could obviously induce CD11b expression; the cell morphology showed obvious differentiation characteristics. ATRA could promote phosphorylation of AKT in NB4 cells at short time, but not had effect on phosphorylation of AKT in NB4-R1 cells; the curcumin could enhance the phosphorylation of AKT in NB4-1R cells, the curcumin combined with ATRA could further enhance the phosphorylation of AKT. It is concluded that PI3K/AKT pathway inactivation may be one of the factors of drug resistance in APL and curcumin promotes differentiation of NB4-R1 through activating PI3K/AKT pathway.
Cell Differentiation ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Curcumin ; pharmacology ; Drug Resistance, Neoplasm ; drug effects ; Humans ; Leukemia, Promyelocytic, Acute ; pathology ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; Signal Transduction ; Tretinoin ; pharmacology

Despite its dual role in determining cell fate in a wide array of solid cancer cell lines, autophagy has been robustly shown to suppress or kill acute myeloid leukemia cells via degradation of the oncogenic fusion protein that drives leukemogenesis. However, autophagy also induces the demise of acute leukemia cells that do not express the known fusion protein, though the molecular mechanism remains elusive. Nevertheless, since it can induce cooperation with apoptosis and differentiation in response to autophagic signals, autophagy can be manipulated for a better therapy on acute myeloid leukemia.
Antineoplastic Agents ; therapeutic use ; Apoptosis ; Apoptosis Regulatory Proteins ; metabolism ; Autophagy ; drug effects ; Humans ; Leukemia, Myeloid, Acute ; drug therapy ; metabolism ; pathology ; Leukemia, Promyelocytic, Acute ; drug therapy ; metabolism ; pathology ; Molecular Targeted Therapy ; Oncogene Proteins, Fusion ; metabolism ; Tretinoin ; therapeutic use