Rubin Cheng

Cryptotanshinone induces cell cycle arrest and apoptosis of multidrug resistant human chronic myeloid leukemia cells by inhibiting the activity of eukaryotic initiation factor 4E

Cryptotanshinone (CPT), a diterpene quinone isolated from Salvia miltiorrhiza, is recently reported to have obvious anticancer activities against diverse cancer cells. However, the effect and regulatory mechanism of CPT remain unclear in human chronic myeloid leukemia (CML) cells. In this study, we investigated the antiproliferative activity of CPT on the multidrug resistant CML cells K562/ADM. Our results demonstrated that CPT decreased the cell viability of K562/ADM cells by inducing cell cycle arrest and apoptosis through suppressing the expression of cyclin D1 and Bcl-2. Further studies indicated that CPT mainly functions at post-transcriptional levels, suggesting the involvement of eukaryotic initiation factor 4E (eIF4E). CPT significantly reduced the expression and activity of eIF4E in K562/ADM cells. Overexpression of eIF4E obvious conferred resistance to the CPT antiproliferation and proapoptotic activity as well as the cyclin D1 and Bcl-2 expressions. Knockdown of eIF4E significantly reduced the inhibitory effect of CPT in K562/ADM, confirming the participation of eIF4E during CPT function process. More importantly, the relative inhibitory efficiency of CPT positively correlated with the reductions on eIF4E in primary CML specimens. These results demonstrated that CPT played antitumor roles in K562/ADM cells by inhibiting the eIF4E regulatory system. Our results provide a novel anticancer mechanism of CPT in human CML cells.

Cryptotanshinone suppresses the proliferation and induces the apoptosis of pancreatic cancer cells via the STAT3 signaling pathway.

Pancreatic cancer remains a challenging disease worldwide. Cryptotanshinone (CPT) is one of the active constituents of Salvia miltiorrhiza Bunge and exhibits significant antitumor activities in several human cancer cells. However, the efficacy and molecular mechanism of CPT in pancreatic cancer remains to be elucidated. In the present study, the effect of CPT on the proliferation, apoptosis and cell cycle of human pancreatic cancer cell BxPC‑3 cells was evaluated. The results demonstrated that CPT inhibited proliferation of the BxPC‑3 cells in a concentration‑dependent manner, and significantly induced cell apoptosis and cell cycle arrest. The protein levels of cleaved caspase‑3, caspase‑9 and poly ADP ribose polymerase were upregulated, while the levels of c‑myc, survivin and cyclin D1 were downregulated following treatment with CPT. In addition, CPT decreased the activities of signal transducer and activator of transcription 3 (STAT3) and several upstream regulatory signaling pathways after 24 h. However, CPT only inhibited the phosphorylation of STAT3 Tyr705 within 30 min, without marked effects on the phosphorylation of the other proteins. These results suggested that the inhibition of STAT3 activity by CPT was directly and independent of the upstream regulators in human pancreatic cancer. The present study demonstrated that CPT exerts anticancer effects by inducing apoptosis and cell cycle arrest via inhibition of the STAT3 signaling pathway in human BxPC-3 cells.

Saponins from Rubus parvifolius L. induce apoptosis in human chronic myeloid leukemia cells through AMPK activation and STAT3 inhibition.

BACKGROUND Saponins are a major active component for the traditional Chinese medicine, Rubus parvifolius L., which has shown clear antitumor activities. However, the specific effects and mechanisms of saponins of Rubus parvifolius L. (SRP) remain unclear with regard to human chronic myeloid leukemia cells. The aim of this study was to investigate inhibition of proliferation and apoptosis induction effects of SRP in K562 cells and further elucidate its regulatory mechanisms. MATERIALS AND METHODS K562 cells were treated with different concentrations of SRP and MTT assays were performed to determine cell viability. Apoptosis induction by SRP was determined with FACS and DAPI staining analysis. Western blotting was used to detect expression of apoptosis and survival related genes. Specific inhibitors were added to confirm roles of STAT3 and AMPK pathways in SRP induction of apoptosis. RESULTS Our results indicated that SRP exhibited obvious inhibitory effects on the growth of K562 cells, and significantly induced apoptosis. Cleavage of pro-apoptotic proteins was dramatically increased after SRP exposure. SRP treatment also increased the activities of AMPK and JNK pathways, and inhibited the phosphorylation expression level of STAT3 in K562 cells. Inhibition of the AMPK pathway blocked the activation of JNK by SRP, indicating that SRP regulated the expression of JNK dependent on the AMPK pathway. Furthermore, inhibition of the latter significantly conferred resistance to SRP pro- apoptotic activity, suggesting involvement of the AMPK pathway in induction of apoptosis. Pretreatment with a STAT3 inhibitor also augmented SRP induced growth inhibition and cell apoptosis, further confirming roles of the STAT3 pathway after SRP treatment. CONCLUSIONS Our results demonstrated that SRP induce cell apoptosis through AMPK activation and STAT3 inhibition in K562 cells. This suggests the possibility of further developing SRP as an alternative treatment option, or perhaps using it as adjuvant chemotherapeutic agent for chronic myeloid leukemia therapy.

Cryptotanshinone acts synergistically with imatinib to induce apoptosis of human chronic myeloid leukemia cells

Abstract Imatinib resistance has emerged as a significant clinical problem in chronic myeloid leukemia (CML) treatment. In this study, we investigated the effect and mechanism of combination treatment with imatinib and cryptotanshinone (CPT) in CML cells. Cotreatment with imatinib and CPT showed a significant synergistic killing effect in both imatinib sensitive and resistant CML cell lines, as well as primary CML cells. Furthermore, combination treatment induced apoptosis significantly, as indicated by increases in apoptotic cell fraction and activities of proapoptotic proteins. Subsequent studies revealed that CPT significantly inhibited Bcr/Abl protein expression, as well as phosphorylation expression levels of signal transducer and activator of transcription 3 (STAT3), mammalian target of rapamycin (mTOR) and eukaryotic translation initiation factor 4E (eIF4E), which are critical mediators of Bcr/Abl transformation. Furthermore, CPT in combination with imatinib dramatically decreased the activity of the Bcr/Abl pathway in both K562 and K562-R cells. Our results demonstrated that CPT increased imatinib-induced apoptosis in a Bcr/Abl dependent manner, suggesting a novel strategy for the treatment of CML.

Complete mitochondrial genome sequence of the Jayakar’s seahorse Hippocampus jayakari Boulenger, 1900 (Gasterosteiformes: Syngnathidae)

Abstract In the present study, we report the complete mitochondrial genome of Jayakar’s seahorse, Hippocampus jayakari Boulenger, 1900. The genome of H. jayakari is found to be 16,520 bp in length and has a base composition of A (32.82%), C (23.28%), G (14.13%), and T (29.67%). Similar to other Hippocampus species, it contains a typically conserved structure including 13 protein-coding genes, 2 rRNA genes, 1 control region (D-loop), and 22 tRNA genes. The protein-coding genes had ATG or GTG as the initiation codon and only 6 genes (COX1, ATP8, ATP6, ND4L, ND5 and ND6) terminated by the complete typical stop codon TAA. The lengths of 12S rRNA and 16S rRNA are 939 bp and 1686 bp, respectively. All tRNA genes typically formed a cloverleaf secondary structure, except for tRNA-Ser containing a dihydrouridine arm replacement loop. Hippocampus jayakari exhibited a relatively distant genetic relationship with other 13 Hippocamupus species according to the phylogenetic analysis. The complete mitochondrial genome sequence provided here would be useful for further understanding the evolution of Hippocamupus and conservation genetics of H. jayakari.

Characterization of the complete mitochondrial genome of the medical pipefish Doryichthys boaja Bleeker 1850

Abstract In the present study, we reported the complete mitochondrial genome of medical pipefish Doryichthys boaja Bleeker 1850. The complete mitochondrial genome of D. boaja was 16,562 bp in length and had a base composition of A (31.10%), C (24.14%), G (14.36%), and T (30.40%). Similar to other Syngnathidae species, it contained a typically conserved structure, including 13 protein-coding genes, 2 rRNA genes, 1 control region (D-loop), and 22 tRNA genes. The 13 protein-coding genes encoded 3800 amino acids in total, most of which used the initiation codon ATG except CO1 gene started with GTG. For the stop codon, 6 genes applied TAA as the stop codon, while the other 7 genes used an incomplete stop codon T or TA. The lengths of 12S rRNA and 16S rRNA were 941 bp and 1671 bp, respectively. The control region of D. boaja ranged from 15,615 bp to 16,562 bp, which was 948 bp in length. The complete mitochondrial genome of D. boaja provided essential and important molecular data for phylogeography and evolutionary analysis of Syngnathidae Family.

The complete mitochondrial genome of Amphioctopus marginatus (Cephalopoda: Octopodidae) and the exploration for the optimal DNA barcoding in Octopodidae

In this study, the complete mitochondrial genome of Amphioctopus marginatus (Cephalopoda: Octopodidae) was sequenced. The length of A. marginatus was 15,719 base pairs (bp) and the composition of genome is A (41.74%), T (33.53%), C (16.77%), and G (7.96%). The whole mitogenome was composed of 13 protein-coding genes (PCGs), 2 ribosomal RNA genes, 22 transfer RNA genes, and a major non-coding region. The overall A+T content of A. marginatus showed remarkable similarity to other Octopodidae species reported before, with the characteristic of extremely richer than G+C. The gene order of the protein-coding genes was identical to other octopodids, but the tRNA genes were rearranged, making the gene order unique. The phylogenetic analysis showed relationships between A. marginatus and Amphioctopus aegina is close. The new mtDNA data enriched the database, which was beneficial to refine the phylogenetic relationships within Octopodidae further. ND5 gene could become an optimal DNA barcoding in taxon identification of the family.

Sequencing and analysis of the complete mitochondrial genome of Hippocampus spinosissimus Weber, 1913 (Gasterosteiformes: Syngnathidae)

abtract The complete mitochondrial genome of the Hedgehog Seahorse (Hippocampus spinosissimus) is 16 530 bp in length, containing 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a control region. The gene organization of H. spinosissimus was similar to that observed in most vertebrate creatures. All protein-coding genes use the typical initiation codon ATG, except for COX1 that uses GTG. The overall base composition of H. spinosissimus is 32.2% for A, 22.72% for C, 30.19% for T, and 14.89% for G, with a slight AT bias of 62.39%. Hippocampus spinosissimus showed a closer genetic relationship with H. kelloggi according to the phylogenetic analysis.

Dihydrotanshinone induces apoptosis of SGC7901 and MGC803 cells via activation of JNK and p38 signalling pathways

Abstract Context: Dihydrotanshinone (DHT), a natural compound from Salvia miltiorrhiza Bunge (Lamiaceae), showed higher cytotoxic potential compared with other tanshinones. Its effect and mechanism on gastric cancer have not been investigated. Objective: This study evaluates the effects of DHT on cell proliferation and apoptosis on gastric cancer cells, and elucidates its molecular mechanisms. Materials and methods: Human gastric cancer MGC803 and SGC7901 cells were treated with various concentrations of DHT (0–15 μM) for 24 and 48 h, and cell growth was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Cell apoptosis was analysed by flow cytometry and DAPI staining. Western blots were performed to investigate changes in the level of apoptosis related genes in gastric cancer cell. Results: DHT exhibited obvious inhibition of the survival of gastric cancer cells. The IC50 values in SGC7901 and MGC803 cells were 9.14 and 5.39 μM for 24 h, respectively. Cells treated with 6 μM DHT resulted in 41.3% and 35.4% apoptotic cell fractions in SGC7901 and MGC803 cells, respectively, significantly higher than that of the control. Hallmarks of apoptosis were observed in gastric cancer cells after DHT exposure. DHT enhanced the expression levels of cleaved caspase-3, caspase-9 and poly-ADP-ribose polymerases. Furthermore, DHT increased the phosphorylation of JNK and p38 in SGC7901 and MGC803 cells. Conclusion: DHT induced growth inhibition and apoptosis of gastric cancer cells, involving activation of caspase proteins and the JNK/p38 signaling pathway. The results indicated that DHT has a promising chemotherapeutic potential for human gastric cancer.