BCR-ABL^T315I mutation is the main mechanism of resistance to the first and second generation tyrosine kinase inhibitor (TKI) for patients with chronic myeloid leukemia (CML). Ponatinib as the third generation TKI has been found that can significantly improve the prognosis of CML patients with T315I mutation. However, the latest report has discovered that the T315I compound mutant is even resistant to ponatinib, which aroused the enthusiasm of research on the mechanism of CML resistance and targeted therapy once again. Previous studies have shown that TKI combined with other targeted drugs is effective to CML patients with drug resistance or relapse due to T315I mutation. The latest research has found that the allosteric inhibitor asciminib combined with TKI therapy is equally effective to CML patients with T315I compound mutant, but the specific mechanism is not yet clarified. This review will focus on the latest research progress of therapy for CML with BCR-ABL^T315I mutation, hoping to provide reference for researching new drugs and improve therapy for treating CML with T315I mutation.
Humans ; Drug Resistance, Neoplasm/genetics* ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics* ; Fusion Proteins, bcr-abl/genetics* ; Protein Kinase Inhibitors/therapeutic use* ; Mutation ; Antineoplastic Agents/pharmacology*

The treatment of chronic myeloid leukemia (CML) was revolutionized with the advent of the first-generation tyrosine kinase inhibitors (TKIs), but drug resistance developed during treatment, leading to the development of the second-generation (dasatinib, nilotinib, and bosutinib) and third-generation (ponatinib) TKI. Compared with previous treatment regimens, specific TKI can significantly improve the response rate, overall survival rate and prognosis of CML. Only a few patients with BCR-ABL mutation are insensitive to the second-generation TKIs, so it is suggested to select the second-generation TKIs for patients with specific mutations. For patients with other mutations and without mutations, the second-generation TKI should be selected according to the patient's medical history, while the third-generation TKIs should be selected for mutations that are insensitive to the second-generation TKIs, such as T315I mutation that is sensitive to ponatinib. Due to different BCR-ABL mutations in patients with different sensitivity to the second and third-generation TKIs, this paper will review the latest research progress of the efficacy of the second and third-generation TKIs in CML patients with BCR-ABL mutations.
Humans ; Antineoplastic Agents/pharmacology* ; Dasatinib/pharmacology* ; Drug Resistance, Neoplasm/genetics* ; Fusion Proteins, bcr-abl/genetics* ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy* ; Mutation ; Protein Kinase Inhibitors/therapeutic use*

OBJECTIVE: To explore the combined pro-apoptosis effect of HSP90 inhibitor BIIB021 and chloroquine (CQ) in chronic myeloid leukemia (CML) cells bearing T315I mutation and its mechanism. METHODS: The p210-T315I cells were divided into 4 groups by different treatment: control, BIIB021, CQ, and BIIB021 + CQ. After treated with BIIB021 or/and CQ for 24 hours, Annexin V/PI binding assay was used to detect apoptosis rates of CML cells. DAPI staining was used to observe nuclear fragmentation, and Western blot was used to detect the expression of caspase 3, PARP (apoptosis related proteins) and p62, LC3-I/II (autophagy related proteins). P210-T315I cells were inoculated subcutaneously into mice and CML mouse models were established. The mice in treatment groups were injected with BIIB021 and/or CQ while mice in control group were treated with PBS and normal saline. The tumor volume of mice was measured every 4 days, and protein level of cleaved-caspase 3 and LC3-II in tumor tissue were detected by immunohistochemistry. RESULTS: The results showed that BIIB021 induced apoptosis of CML cells in a dose-dependent manner ( r=0.91). CQ could enhance the apoptosis-inducing effect of BIIB021. Flow cytometry analysis results showed that the apoptosis rate of p210-T315I cells in combination group was higher than that in BIIB021 or CQ only group (P<0.05). DAPI staining showed nuclear fragmentation in combination group could be observed more obviously. Western blot analysis showed that BIIB021 could induce LC3-I to convert to LC3-II and decrease p62 protein levels (P<0.05). Moreover, the combination group had higher expression of LC3-II, p62 (P<0.05), activated PARP and activated caspase 3 than BIIB021 only group (P<0.05). Besides, experiment in vivo showed the mean tumor volume in co-treatment group was lower than that in single drug group (P<0.01). Immunohistochemistry of tumor tissue also showed the protein level of cleaved-caspase 3 and LC3-II in combined group was higher than that in BIIB021 only group. CONCLUSION HSP90 inhibitor BIIB021 induced significant apoptosis of CML cells bearing T315I both in vivo and in vitro. CQ can enhance this effect probably by autophagy inhibition.
Adenine/analogs & derivatives* ; Animals ; Apoptosis ; Autophagy ; Caspase 3/metabolism* ; Cell Line, Tumor ; Chloroquine/therapeutic use* ; Fusion Proteins, bcr-abl/pharmacology* ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive/drug therapy* ; Mice ; Mutation ; Poly(ADP-ribose) Polymerase Inhibitors/therapeutic use* ; Pyridines

Tyrosine kinase inhibitor (TKI) has significantly improved the treatment of chronic myeloid leukemia (CML), however the resistance often resulted in treatment failure. Currently, it is known that the survival of CML cells can be affected by regulating autophagy, oxidative stress and mitochondrial metabolism, among which autophagy is an evolution-conserved catabolism process, and closely related to the pathogenesis of CML, thus playing a dual role in regulating the biological characteristics of cells. On the one hand, autophagy can promote the apoptosis of CML cells, and also can induce the drug resistance of CML cells on the other hand. In this review, the effect of autophagy on CML cells was summarzed briefly, so as to provide a useful idea to explore the combination of TKI with the autophagy inhibitor or inducer to overcome the resistance of CML to TKI.
Apoptosis ; Autophagy ; Drug Resistance, Neoplasm ; Fusion Proteins, bcr-abl ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; Protein Kinase Inhibitors/pharmacology* ; Research

OBJECTIVETo explore the effect of a novel emodin derivative E19 on proliferation inhibition and apoptosis induction of human chronic myelogenous leukemia (CML) cell line K562 and imatinib-resistant CML cell line (K562/G01), and to clarify the involved mechanisms.

METHODSMTT and colony formation test were used to detect the cell proliferation. Apoptotic induction effects were examined by DAPI staining method and DNA ladder assay. Western blot was performed to detect the changes of P210(Bcr-Abl) protein.

RESULTSThe emodin derivative E19 could efficiently inhibit proliferation and induce apoptosis in K562 and K562/G01 cells. IC50 of K562 cells and IC50 of K562/G01 cells were (1.20 ± 0.19) µmol/L and (1.22 ± 0.16) µmol/L, respectively. DNA fragmentation in K562 cells and K562/G01 cells confirmed that the E19 induced apoptosis in dose-dependent manner. Western blot showed that emodin derivative inhibited phosphorylation of P210 protein in K562 cells and K562/G01 cells and down-regulated the expression level of P210 in dose- and time-dependent manners.

CONCLUSIONThe emodin derivative E19 can efficiently inhibit growth and induce apoptosis of K562 cells and K562/G01 cells, while the inhibition of phosphorylation of P210 protein and down-regulation of P210 protein expression may be involved in these processes.

Apoptosis ; drug effects ; Cell Proliferation ; Down-Regulation ; Drug Resistance, Neoplasm ; Emodin ; analogs & derivatives ; pharmacology ; Fusion Proteins, bcr-abl ; metabolism ; Humans ; Imatinib Mesylate ; pharmacology ; K562 Cells ; drug effects ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; pathology ; Phosphorylation

OBJECTIVETo investigate the effects of Sinopodophyllum hexundrum on apoptosis in K562 cells.

METHODSK562 cells were treated with Sinopodophyllum hexundrum at different concentrations and for different lengths of time to determine the optimal conditions of SinoPodophyllum hexandrum treatment for K562 cells using CCK8 assay. The cell apoptotic rate was detected by flow cytometry, and the cell morphology and nuclear morphology of K562 cells were observed with Wright staining and DPAI staining, respectively. The protein expressions of BCR/ABL, p-BCR/ABL, STAT5, p-STAT5 and the apoptosis-related proteins PARP, caspase-3 and cleaved-caspase-3 were determined with Western blotting.

RESULTSThe cell proliferation was inhibited in a concentration-and time-dependent manner by 1, 2, and 3 µg/mL Sinopodophyllum hexundrum. The treatment was optimal with a Sinopodophyllum hexundrum concentration of 2 µg/mL a treatment time of 48 h, and the cell apoptotic rate increased in a time-dependent manner and significantly increased at 48 h (P<0.001). The expression of apoptosis-related proteins PARP, caspase-3 and cleaved-caspase-3 were also activated in a time-dependent manner. The cells showed typical apoptotic changes after treatment with 2 µg/mL Sinopodophyllum hexundrum for 48 h with significantly reduced expressions of BCR/ABL, p-BCR/ABL, STAT5, AND p-STAT5.

CONCLUSIONSinopodophyllum hexundrum promotes K562 cell apoptosis possibly by inhibiting BCR/ABL-STAT5 survival signal pathways and activating the mitochondrion-associated apoptotic pathways.

Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Cell Proliferation ; Drugs, Chinese Herbal ; pharmacology ; Fusion Proteins, bcr-abl ; metabolism ; Humans ; K562 Cells ; Mitochondria ; metabolism ; STAT5 Transcription Factor ; metabolism ; Signal Transduction

OBJECTIVETo investigate the effect of indomethacin on the proliferation and Wnt/β-catenin pathway in K562 cells.

METHODSThe cell growth of K562 cells treated with different concentrations of indomethacin was assessed with MTT assay, and the colony-forming ability of the cells was evaluated by colony-forming assay. The mRNA expressions of BCR/ABL and β-catenin were detected by RT-PCR, and the protein expressions of pBCR/ABL, total BCR/ABL, β-catenin, pGSK-3β and c-myc were analyzed by Western blotting.

RESULTSIndomethacin significantly suppressed the growth and colony-forming ability of K562 cells in a dose-dependent manner. Indomethacin treatment dose-dependently decreased the protein level of pBCR/ABL and total BCR/ABL without affecting bcr-abl mRNA expressions. Compared with the control groups, indomethacin-treated cells showed obviously decreased mRNA and protein expressions of β-catenin and decreased protein expressions of pGSK-3β and c-myc.

CONCLUSIONIndomethacin inhibits the proliferation of K562 cells by suppressing the activity of bcr-abl-Wnt/β-catenin pathway.

Cell Cycle ; Cell Proliferation ; Fusion Proteins, bcr-abl ; metabolism ; Humans ; Indomethacin ; pharmacology ; K562 Cells ; drug effects ; RNA, Messenger ; Wnt Signaling Pathway ; drug effects ; beta Catenin ; metabolism

OBJECTIVETo investigate the antitumor efficacy and mechanism of HSP90 inhibitor FW-04-806 against Bcr/Abl(+) leukemia K562 and HL60 cells and their mechanisms of action.

METHODSMTT assay was used to assess the proliferation-inhibiting effect of FW-04-806. Cell cycle was analyzed with propidium iodide by flow cytometry. Cell apoptosis was determined using the FITC mV apoptosis detection kit. Western blot was applied to reveal the protein expression of related proliferative and apoptotic signaling pathways. The changes of mitochondrial membrane potential were detected by flow cytometry. Protein-protein interactions was shown by co-immunoprecipitation. The level of mRNA was assessed by real-time RT-PCR.

RESULTSFW-04-806 obviously inhibited cell proliferation in the HL60, K562 and HL60/Bcr-Abl cell lines, with an IC50 of (30.89 ± 0.12) µmol/L, (9.76 ± 0.19) µmol/L and (8.03 ± 0.26) µmol/L, respectively (P<0.001). Compared with the vehicle group, the two increasing doses of FW-04-806 showed inhibition of tumor growth at a rate of (17.40 ± 0.34)% and (34.33 ± 5.00)%, respectively, in the K562 cell line groups (P=0.003), and (18.90 ± 1.45)% and (35.60 ± 3.55)% (P=0.001) in the HL60/Bcr-Abl cell line groups. FW-04-806 dissociated Hsp90/Cdc37 chaperon/co-chaperon complex, followed by degradation of the Hsp90 proteins through proteasome pathway without affecting mRNA expression. FW-04-806 induced apoptosis and led to G2/M arrest.

CONCLUSIONOur findings indicate that FW-04-806 displays potential antitumor effect by suppressing the proliferation and apoptosis in Bcr/Abl(+) leukemia cells in vivo.

Apoptosis ; drug effects ; Cell Cycle ; Cell Proliferation ; drug effects ; Fusion Proteins, bcr-abl ; HL-60 Cells ; HSP90 Heat-Shock Proteins ; antagonists & inhibitors ; Humans ; K562 Cells ; Leukemia ; drug therapy ; metabolism ; pathology ; Membrane Potential, Mitochondrial ; Oxazoles ; pharmacology ; RNA, Messenger ; metabolism ; Signal Transduction

OBJECTIVETo explore the inhibitory effect of alantolactone on the proliferation of adriamycin-resistant human chronic myelogenous leukemia cell line K562/ADR cells and its mechanism.

METHODSK562/ADR cells were treated with various concentrations of alantolactone (0, 1, 2, 4, 6, 8, and 10 μmol/L) for different time points. Cell viability was analyzed with MTT assay. The effect of alantolactone on the apoptosis of K562/ADR cells was measured by flow cytometry. The expression of apoptosis-related proteins after treatment with alantolactone was analyzed using Western blot.

RESULTSAlantolactone could effectively inhibit the proliferation of K562/ADR cells in dose- and time- dependent manner, the IC50 value of alantolactone treatment of K562/ADR cells for 24 h was 4.7 μmol/L (P<0.05). Flow cytometric analysis displayed that the apoptotic rates were 1.35%, 16.91%, 29.61% and 46.26%, respectively, after treatment with alantolactone at 0, 2.5, 5 and 7.5 μmol/L. Meanwhile, the expression of Bcl-2 and BCR-ABL proteins were significantly decreased and that of Bax, cytochrome C, cleaved-caspase-9, cleaved-caspase-3 and cleaved-PARP increased by alantolactone treatment.

CONCLUSIONAlantolactone had obvious inhibitory effect on the proliferation of K562/ADR cells through the caspase dependent mitochondrial(or intrinsic)apoptotic pathway.

Apoptosis ; Caspase 3 ; metabolism ; Caspase 9 ; metabolism ; Cell Proliferation ; drug effects ; Fusion Proteins, bcr-abl ; metabolism ; Humans ; K562 Cells ; Lactones ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Sesquiterpenes, Eudesmane ; pharmacology ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo investigate the effects of quercetin on Hedgehog (Hh) signaling in chronic myeloid leukemia KBM7 cells.

METHODSThe KBM7 cells were treated with 50, 100 and 200 μmol/L quercetin for 48 h respectively. And then the trypan blue assay was used to examine the proliferative inhibition of quercetin. Apoptotic cells and cell cycle were measured by flow cytometry. The mRNA and protein expression were detected by quantitative real-time polymerase chain reaction (PCR) and Western blot, respectively.

RESULTSQuercetin significantly inhibited KBM7 cell proliferation, induced cell apoptosis, and blocked cell cycle at G1 phase, which were in dose-dependent manners. The mRNA and protein expression of Smoothened and Glioma1 (Gli1), the members of Hh pathway decreased after treatment with quercetin. The Bcl-2 and Cyclin D1, targets of Hh signaling, also decreased after treatment with quercetin, respectively. Quercetin also could increase p53 and Caspase-3 expression. Bcr-abl mRNA copies decreased, but no changes of phosphorylated Bcr-abl and Bcr-abl proteins were observed, after treatment with quercetin.

CONCLUSIONQuercetin could inhibit Hh signaling and its downstream targets in the KBM7 cells. And it might be one of mechanisms of inducing apoptosis and inhibiting cell cycle by quercetin.

Apoptosis ; drug effects ; Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Fusion Proteins, bcr-abl ; genetics ; metabolism ; Gene Expression Regulation, Leukemic ; drug effects ; Hedgehog Proteins ; metabolism ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; genetics ; pathology ; Quercetin ; pharmacology ; RNA, Messenger ; genetics ; metabolism ; Signal Transduction ; drug effects