Andrographis paniculata methanol extract suppresses the phosphorylation of ETV6­NTRK3.

ETS variant transcription factor 6 (ETV6)-neurotrophic receptor tyrosine kinase 3 (NTRK3) (EN) fusions are typically found in rare diseases, such as primary renal fibrosarcoma (only six cases have been reported), secretory carcinoma of the breast and salivary gland (1 case), and AML (4 cases). Few cases have been reported, and expression of the EN gene fusion requires additional clinical data and fundamental research to be supported. The aim of the present study was to determine the inhibitory effect of Andrographis paniculata methanol extract (MeAP) on EN-related cell lines, IMS-M2 and BaF3/EN, as well as evaluate the mechanism of action. Vero cells were used as control cells. Trypan blue staining and MTT were used to evaluate the inhibitory effect of MeAP on tested cells. Western blotting and immunoprecipitation were used to detect the activation of EN after MeAP treatment. The IC50 values of MeAP were found to be 12.38±0.57 µg/ml (IMS-M2) and 13.06±0.49 µg/ml (BaF3/EN). MeAP was observed to inhibit cell proliferation in a time, dose, and cell density-dependent manner. The IC50 value for MeAP in Vero cells was markedly higher, at 109.97±4.24 (µg/ml), indicating a much less sensitive effect. Furthermore, MeAP treatment inhibited EN phosphorylation and induced apoptosis in these cells. Collectively, the present study demonstrated that MeAP has an oncogenic effect on EN fusion-positive cell lines, in particular.

ETV6-NTRK3 as a therapeutic target of small molecule inhibitor PKC412.

The ETV6-NTRK3 (EN) fusion gene which encodes a chimeric tyrosine kinase was first identified by cloning of the t(12;15)(p13;q25) translocation in congenital fibrosarcoma (CFS). Since then, EN has been also found in congenital mesoblastic nephroma (CMN), secretory breast carcinoma (SBC) and acute myelogenous leukemia (AML). Using IMS-M2 and M0-91 cell lines harboring the EN fusion gene, and Ba/F3 cells stably transfected with EN, we demonstrated that PKC412, also known as midostaurin, is an inhibitor of EN. Inhibition of EN activity by PKC412 suppressed the activity of it downstream molecules leading to inhibition of cell proliferation and induction of apoptosis. Our data for the first time suggested that PKC412 could serve as therapeutic drug for treatment of patients with this fusion.

Artemisia vulgaris inhibits BCR/ABL and promotes apoptosis in chronic myeloid leukemia cells.

In previous research, the authors demonstrated that the methanol extract of Artemisia vulgaris (AVM) has the ability to inhibit chronic myeloid leukemia (CML) cell proliferation. The aim of the present study was to determine and clarify the mechanism of action of AVM. BCR/ABL activation is present in >90% of CML cases. As a result, cells expressing different forms of BCR/ABL were recruited for the present study, including K562 (human wild-type) or TCCY-T315I (human imatinib-resistant) and the Ba/F3-(T315I/E279K/Y253H) (mouse BCR/ABL point mutation-transfected cells). The results revealed that AVM inhibited the phosphorylation of BCR/ABL and their subsequent molecular signals including AKT and MAPK activation. AVM induced the release of cleaved PARP and cleaved caspase-3 caused apoptosis and inhibited the viability of these cells. Interestingly, AVM appeared to be more sensitive to imatinib-resistant (T315I, Y253H, and E279K) than wild-type BCR/ABL cells, indicating its potential to overcome imatinib-resistant severe issues in CML. Moreover, the effects of various sub-fractions of AVM were then investigated in order to determine the optimal solvent for the identification of anticancer bioactive compounds. The results demonstrated that the ethyl acetate and chloroform fractions were more effective than the n-hexane and water fractions. It is thus concluded that AVM inhibits the activity of BCR/ABL and their subsequent molecular signals, including AKT and MAPK, resulting in cytotoxicity via apoptosis.

Sphagneticola Trilobata (L.) Pruski (Asteraceae) Methanol Extract Induces Apoptosis in Leukemia Cells through Suppression of BCR/ABL.

We will study the effects of the methanol extract of Sphagneticola trilobata (L.) Pruski (Asteraceae) (MeST) on the growth of leukemia cells that may contain the BCR/ABL gene. This study also clarifies the mechanism of this effect on these cells. For this purpose, the cells harboring wild-type BCR/ABL, imatinib-resistant BCR/ABL (K562 and TCCYT315I), or Ba/F3 cells transfected with wild-type or mutant BCR/ABL genes were used. The results showed that MeST effectively inhibited the viability of leukemia cells in both a dose- and time-dependent manner. The effect of MeST seems to be more sensitive in the cells that carry imatinib-resistant BCR/ABL (especially the T315I BCR/ABL mutation) than those with wild-type BCR/ABL. Furthermore, we have demonstrated that the death caused by MeST is apoptosis and the treatment with MeST could suppress the expression of BCR/ABL, subsequently altering the downstream cascade of BCR/ABL such as AKT and MAPK signaling. In conclusion, MeST has been able to suppress the growth of leukemia cells harboring BCR/ABL. The mechanism of the anti-leukemic effect of MeST on cells harboring imatinib-resistant BCR/ABL mutations could be due to the disruption of the BCR/ABL oncoprotein signaling cascade.

Green tea epigallocatechin gallate exhibits anticancer effect in human pancreatic carcinoma cells via the inhibition of both focal adhesion kinase and insulin-like growth factor-I receptor.

The exact molecular mechanism by which epigallocatechin gallate (EGCG) suppresses human pancreatic cancer cell proliferation is unclear. We show here that EGCG-treated pancreatic cancer cells AsPC-1 and BxPC-3 decrease cell adhesion ability on micro-pattern dots, accompanied by dephosphorylations of both focal adhesion kinase (FAK) and insulin-like growth factor-1 receptor (IGF-1R) whereas retained the activations of mitogen-activated protein kinase and mammalian target of rapamycin. The growth of AsPC-1 and BxPC-3 cells can be significantly suppressed by EGCG treatment alone in a dose-dependent manner. At a dose of 100 µM which completely abolishes activations of FAK and IGF-1R, EGCG suppresses more than 50% of cell proliferation without evidence of apoptosis analyzed by PARP cleavage. Finally, the MEK1/2 inhibitor U0126 enhances growth-suppressive effect of EGCG. Our data suggests that blocking FAK and IGF-1R by EGCG could prove valuable for targeted therapy, which can be used in combination with other therapies, for pancreatic cancer.

Combined effect of (-)-epigallocatechin-3-gallate and all-trans retinoic acid in FLT3-mutated cell lines.

Patents diagnosed with acute promyelocytic leukemia were treated with Vesanoid® [all-trans retinoic acid (ATRA)]. ATRA promotes the maturation and differentiation of leukemia cells and is therefore capable of reducing the symptoms of leukemia by preventing aggregation of myeloid cells. However, the clinical applications of ATRA are limited by its side effects, including acute retinoid resistance, hypertriglyceridemia, mucocutaneous dryness, nausea, brief recovery time relapse and drug resistance. Therefore, combinations of ATRA and other anticancer drugs are being investigated to overcome these limitations. In our previous study it was shown that in leukemia cells, (-)-epigallocatechin-3-gallate (EGCG) reduced cell proliferation and induced apoptotic cell death. In the present study, an in vitro evaluation of the effects of the combination of EGCG and ATRA on FLT3-mutated cell lines was performed using the isobologram method. The results showed that there was an additive effect in leukemic cells when treated with a combination of ATRA and EGCG. Thus, it was concluded that the cytotoxic effects of EGCG were improved by ATRA.

Effects of green tea epigallocatechin-3-gallate on transcription factors regulating expression of FLT3.

PURPOSE: In our previous paper we previously reported that epigallocatechin-3-gallate (EGCG) inhibits FLT3 expression in cell lines harboring FLT3 mutations. In this research, we carried on to investigate the influence of EGCG on FLT3 promoter activity and FLT3 transcription. Methods The effect of EGCG on the mRNA expression of flt3 and flt3-promoter activity was evaluated using semiquantitative reverse transcription-PCR and luciferase reporter assay. The gene expression profiling analysis was done for detecting the effect of EGCG on flt3-transcription factors. Then, the protein level of C-MyB was obsvered using western blot analysis. RESULTS: The results showed that EGCG reduced the transcription level of FLT3 by suppressing its promoter activity. By doing gene expression profile analysis in MOLM-13 cells established from acute monocytic leukemia patient with two mutations within FLT3 EXON 14 in a time-dependent manner, we found that the expression of mRNA of FLT3 was first observed to downregulate at 6 h together with the decreasing of Homeobox A9 (HOXA9) transcription factor after EGCG treatment. The changing of C/EBPα expression was found at 8 h. Interestingly, the reducing mRNA of c-Myb by EGCG was observed at 4 h, earlier than FLT3 was downregulated. There was no change in Meis Homeobox 1 (Meis1) by EGCG. We also found the protein level c-Myb was inhibited by EGCG in MOLM-13 and MOLM-14 cells after treating these cells with 60µM of EGCG for 8 h. CONCLUSION: This data indicated the involvement of transcription factors in controlling the expression of FLT3 by EGCG.

Recurrent BRCA1 Mutation, but no BRCA2 Mutation, in Vietnamese Patients with Ovarian Carcinoma Detected with Next Generation Sequencing.

BACKGROUND: Identification of germline and somatic BRCA1/2 mutations in ovarian cancer is important for genetic counseling and treatment decision making with poly ADP ribose polymerase inhibitors. Unfortunately, data on the frequency of BRCA1/2 mutations in Vietnamese patients are scare. METHODS: We aim to explore the occurrence of BRCA1/2 mutations in 101 Vietnamese patients with ovarian cancer including serous (n = 58), endometrioid (n = 14), mucinous (n = 24), and clear cell (n = 5) carcinomas. BRCA1/2 mutations were detected from formalin-fixed parafin-embedded tumor samples using the OncomineTM BRCA Research Assay on Personal Genome Machine Platform with Ion Reporter Software for sequencing data analysis. The presence of pathogenic mutations was confirmed by Sanger sequencing. RESULTS: We found no BRCA2 mutation in the entire cohort. Four types of pathogenic mutations in BRCA1 (Ser454Ter, Gln541Ter, Arg1751Ter, and Gln1779AsnfsTer14) were detected in 8 unrelated patients (7.9%) belonging to serous and endometrioid carcinoma groups. Except for the c.1360_1361delAG (Ser454Ter) mutation in BRCA1 exon 11 that was somatic, the other mutations in exons 11, 20, and 22 were germline.  Interestingly, the recurrent Arg1751Ter mutation in BRCA1 exon 20 appeared in 4 patients, suggesting that this is a founder mutation in Vietnamese patients. CONCLUSION: Mutational analysis of tumor tissue using next generation sequencing allowed the detection of both germline and somatic BRCA1/2 mutations.
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ETV6/FLT3 Fusion Is a Novel Client Protein of Hsp90.

FMS-like tyrosine kinase-3 fragments from exon 14 to the end without any mutations or deletions have been reported to fuse to ETV6 (TEL) in a few cases of myeloid/lymphoid neoplasms with eosinophilia carrying a translocation t(12;13)(p13;q12). This fusion protein confers constitutive activation on the FLT3 fragment and induces factor-independent growth in transfected Ba/F3 cells, indicating that it is an oncoprotein. However, the mechanism controlling the stability of this oncoprotein is unknown. In this study, we focus on finding factors controlling the stability of ETV6/FLT3. We have shown that the stability of ETV6/FLT3 is regulated by the Hsp90 chaperone. ETV6/FLT3 fusion protein forms a complex with Hsp90 by coimmunoprecipitation analyses using an Hsp90 antibody. The association between ETV6/FLT3 fusion protein and Hsp90 was impaired after treating ETV6/FLT3 transient transfection cos7 cells with 17-allylamino-17-demethoxygeldanamycin (17-AAG). 17-AAG induced a time- and dose-dependent downregulation of ectopically expressed ETV6/FLT3 protein in cos7 and HeLa-transfected cells. By using cycloheximide to block new protein translation, we found that 17-AAG accelerated the decay of ETV6/FLT3. Our findings could contribute to more understanding of the ETV6/FLT3 regulation through Hsp90 chaperone and open the way to finding effective treatment strategies for this rare disease.

Synergistic effect of all­trans retinoic acid in combination with protein kinase C 412 in FMS-like tyrosine kinase 3-mutated acute myeloid leukemia cells.

Acute myeloid leukemia (AML) is a heterogeneous disease. Numerous molecular abnormalities have been identified in AML and, amongst these, FMS­like tyrosine kinase 3 (FLT3) mutations are one of the most common somatic alterations detected. In the present study, an in vitro investigation was performed to evaluate the effects of all­trans retinoic acid (ATRA) and PKC412, alone and in combination, in FLT3­mutated AML cell lines. Trypan blue exclusion test, as well as morphological, western blot and isobologram analyses were conducted. The results indicated that the combined ATRA and PKC412 treatment exhibited additive or synergistic effects in FLT3­mutated AML cell lines. These results provided in vitro evidence for the future clinical trials evaluating the effects of a combination treatment using PKC412 and ATRA on AML patients with FLT3­mutations.

Down-regulated expression of NPM1 in IMS-M2 cell line by (-)-epigallocatechin-3-gallate.

OBJECTIVE: To investigate the inhibited effect of epigallocatechin-3-gallate (EGCG) on the expression of NPM1 in IMS-M2 cells harboring the NPM1 mutations. METHODS: Cell proliferation assay was performed to test the effects of EGCG on cell growth of IMS-M2 cells harboring the NPM1 mutations. Western blot analysis were performed to test the protein expression of NPM1, AKT, those associated with apoptosis. RESULTS: EGCG can down-regulate the expression of NPM1 in IMS-M2 cells harboring the NPM1 mutations. Moreover, EGCG also suppressed the cell proliferation and induced apoptosis in IMS-M2 cells. CONCLUSIONS: The results suggested that EGCG could be considered as a reagent for treatment of AML patients with NPM1 mutations.

Inhibition of FLT3 expression by green tea catechins in FLT3 mutated-AML cells.

Acute myeloid leukemia (AML) is a heterogeneous disease characterized by a block in differentiation and uncontrolled proliferation. FLT3 is a commonly mutated gene found in AML patients. In clinical trials, the presence of a FLT3-ITD mutation significantly correlates with an increased risk of relapse and dismal overall survival. Therefore, activated FLT3 is a promising molecular target for AML therapies. In this study, we have shown that green tea polyphenols including (-)-epigallocatechin-3-gallate (EGCG), (-)-epigallocatechin (EGC), and (-)-epicatechin-3-gallate (ECG) suppress the proliferation of AML cells. Interestingly, EGCG, EGC and ECG showed the inhibition of FLT3 expression in cell lines harboring FLT3 mutations. In the THP-1 cells harboring FLT3 wild-type, EGCG showed the suppression of cell proliferation but did not suppress the expression of FLT3 even at the concentration that suppress 100% cell proliferation. Moreover, EGCG-, EGC-and ECG-treated cells showed the suppression of MAPK, AKT and STAT5 phosphorylation. Altogether, we suggest that green tea polyphenols could serve as reagents for treatment or prevention of leukemia harboring FLT3 mutations.

Detection of exon 12 type A mutation of NPM1 gene in IMS-M2 cell line.

Nucleophosmin 1 (NPM1), a protein that shuttles between the nucleus and cytoplasm, is mostly located in nucleoli. This is a multifunctional phosphoprotein to which both tumor-suppressor and oncogenic functions have been attributed. Here, we have found the cell line with the type A NPM1 mutation and with the other genetic alterations including ETV6-NTRC fusion. It will provide a good in vitro model for bio-molecular studies of interaction of mutated NPM1 gene and other genetic abnormalities as well as a useful tool for developing new molecularly targeted drugs.

Green tea (-)-epigalocatechin-3-gallate inhibits KIT activity and causes caspase-dependent cell death in gastrointestinal stromal tumor including imatinib-resistant cells.

Imatinib, a selective tyrosine kinase inhibitor, has been used as a standard first-line therapy for gastrointestinal stromal tumor (GIST) patients. Unfortunately, most patients responding to imatinib will eventually exhibit the resistance, the cause of which is not fully understood. The serious clinical problems of imatinib-resistance demand alternative treatment strategy. (-)-Epigallocatechin-3-gallate (EGCG), a main component of green tea catechin, has been demonstrated potential anti-tumor effects on various types of cancer cells. Here, we report for the first time that EGCG has shown anti-tumor effects on gastrointestinal stromal tumor cell line GIST-T1 by suppressing cell proliferation and eventually inducing cell death via caspase-dependent pathways. GIST-T1 and imatinib resistant GIST-T1 (GIST-T1 IR) cells were used to assess the effects of EGCG. In both cell types, KIT activity was completely inhibited after 4 h treatment with 60 muM EGCG. EGCG specifically inhibited activated KIT, which was demonstrated by using Ba/F3 cells transfected with human wild-type KIT construct. At a dose of 30 muM EGCG, the KIT activity remains but at more than 40 muM EGCG, the KIT activity was abolished in these transfected-Ba/F3 cells. Our results suggest that EGCG has a promising potential as a natural KIT inhibitor and therefore it could be used as a novel therapeutic or preventive reagent for GISTs including the imatinib-resistant cases.