Bryostatin 5 induces apoptosis in acute monocytic leukemia cells by activating PUMA and caspases

WTIP upregulates FOXO3a and induces apoptosis through PUMA in acute myeloid leukemia

Acute myeloid leukemia (AML) is an aggressive and heterogeneous clonal hematologic malignancy for which novel therapeutic targets and strategies are required. Emerging evidence suggests that WTIP is a candidate tumor suppressor. However, the molecular mechanisms of WTIP in leukemogenesis have not been explored. Here, we report that WTIP expression is significantly reduced both in AML cell lines and clinical specimens compared with normal controls, and low levels of WTIP correlate with decreased overall survival in AML patients. Overexpression of WTIP inhibits cell proliferation and induces apoptosis both in vitro and in vivo. Mechanistic studies reveal that the apoptotic function of WTIP is mediated by upregulation and nuclear translocation of FOXO3a, a member of Forkhead box O (FOXO) transcription factors involved in tumor suppression. We further demonstrate that WTIP interacts with FOXO3a and transcriptionally activates FOXO3a. Upon transcriptional activation of FOXO3a, its downstream target PUMA is increased, leading to activation of the intrinsic apoptotic pathway. Collectively, our results suggest that WTIP is a tumor suppressor and a potential target for therapeutic intervention in AML.

Integrated analysis of microRNA and transcription factors in the bone marrow of patients with acute monocytic leukemia

Acutemonocytic leukemia (AMoL) is a distinct subtype of acute myeloid leukemia (AML) with poor prognosis. However, the molecular mechanisms and key regulators involved in the global regulation of gene expression levels in AMoL are poorly understood. In order to elucidate the role of microRNAs (miRNAs/miRs) and transcription factors (TFs) in AMoL pathogenesis at the network level, miRNA and TF expression level profiles were systematically analyzed by miRNA sequencing and TF array, respectively; this identified 285 differentially expressed miRNAs and 139 differentially expressed TFs in AMoL samples compared with controls. By combining expression level profile data and bioinformatics tools available for predicting TF and miRNA targets, a comprehensive AMoL-specific miRNA-TF-mediated regulatory network was constructed. A total of 26 miRNAs and 23 TFs were identified as hub nodes in the network. Among these hubs, miR-29b-3p, MYC, TP53 and NFKB1 were determined to be potential AMoL regulators, and were subsequently extracted to construct sub-networks. A hypothetical pathway model was also proposed for miR-29b-3p to reveal the potential co-regulatory mechanisms of miR-29b-3p, MYC, TP53 and NFKB1 in AMoL. The present study provided an effective approach to discover critical regulators via a comprehensive regulatory network in AMoL, in addition to enhancing understanding of the pathogenesis of this disease at the molecular level.

Starvation tactics using natural compounds for advanced cancers: pharmacodynamics, clinical efficacy, and predictive biomarkers

The high mortality associated with oncological diseases is mostly due to tumors in advanced stages, and their management is a major challenge in modern oncology. Angiogenesis is a defined hallmark of cancer and predisposes to metastatic invasion and dissemination and is therefore an important druggable target for cancer drug discovery. Recently, because of drug resistance and poor prognosis, new anticancer drugs from natural sources targeting tumor vessels have attracted more attention and have been used in several randomized and controlled clinical trials as therapeutic options. Here, we outline and discuss potential natural compounds as salvage treatment for advanced cancers from recent and ongoing clinical trials and real-world studies. We also discuss predictive biomarkers for patients' selection to optimize the use of these potential anticancer drugs.

Cytotoxic Bryostatin Derivatives from the South China Sea Bryozoan Bugula neritina

Four new macrocyclic lactones, bryostatin 21 (1) and 9-O-methylbryostatins 4, 16, and 17 (2-4), together with three known related compounds, bryostatins 4, 16, and 17 (5-7), have been isolated from an extract of the South China Sea bryozoan Bugula neritina. The structures of all compounds were unambiguously elucidated using detailed spectroscopic analysis. Structurally, the presence of a single methyl group at C-18 in compound 1 has not been observed before for known bryostatins. The isolated macrolides exhibited inhibitory effects against a small panel of human cancer cell lines.

BCR/ABL mRNA targeting small interfering RNA effects on proliferation and apoptosis in chronic myeloid leukemia

BACKGROUND

To investigate the effects of small interference RNA (siRNA) targeting BCR/ABL mRNA on proliferation and apoptosis in the K562 human chronic myeloid leukemia (CML) cell line and to provide a theoretical rationale and experimental evidence for its potential clinical application for anti-CML treatment.

MATERIALS AND METHODS

The gene sequence for BCR/ABL mRNA was found from the GeneBank. The target gene site on the BCR/ABL mRNA were selected according to Max-Planck-Institute (MPI) and rational siRNA design rules, the secondary structure of the candidate targeted mRNA was predicted, the relevant thermodynamic parameters were analyzed, and the targeted gene sequences were compared with BLAST to eliminate any sequences with significant homology. Inhibition of proliferation was evaluated by MTT assay and colony-formation inhibiting test. Apoptosis was determined by flow cytometry (FCM) and the morphology of apoptotic cells was identified by Giemsa-Wright staining. Western blotting was used to analyze the expression of BCR/ABL fusion protein in K562 cells after siRNA treatment.

RESULTS

The mRNA local secondary structure calculated by RNA structure software, and the optimal design of specific siRNA were contributed by bioinformatics rules. Five sequences of BCR/ABL siRNAs were designed and synthesized in vitro. Three sequences, siRNA1384, siRNA1276 and siRNA1786, which showed the most effective inhibition of K562 cell growth, were identified among the five candidate siRNAs, with a cell proliferative inhibitory rate nearly 50% after exposure to 12.5 nmol/L~50 nmol/L siRNA1384 for 24,48 and 72 hours. The 50% inhibitory concentrations (IC50) of siRNA1384, siRNA1276 and siRNA1786 for 24 hours were 46.6 nmol/L, 59.3 nmol/L and 62.6 nmol/L, respectively, and 65.668 nmol/L, 76.6 nmol/L, 74.4 nmol/L for 72 hours. The colony-formation inhibiting test also indicated that, compared with control, cell growth of siRNA treated group was inhibited. FCM results showed that the rate of cell apoptosis increased 24 hours after transfecting siRNA. The results of annexinV/PI staining indicated that the rate of apoptosis imcreased (1.53%, 15.3%, 64.5%, 57.5% and 21.5%) following treamtne with siRNAs (siRNA34, siRNA372, siRNA1384, siRNA1276 and siRNA1786). Morphological analysis showed td typical morphologic changes of apoptosis such as shrunken, fragmentation nucleus as well as "apoptotic bodies" after K562 cell exposure to siRNA. Western blot analysis showed that BCR/ABL protein was reduced sharply after a single dose of 50 nmol/L siRNA transfection.

CONCLUSIONS

Proliferation of K562 cells was remarkbly inhibited by siRNAs (siRNA1384, siRNA1276 and siRNA1786) in a concentration-dependent manner in vitro, with effective induction of apoptosis at a concentration of 50 nmol/L. One anti-leukemia mechanism in K562 cells appeared that BCR/ABL targeted protein was highly down-regulated. The siRNAs (siRNA1384, siRNA1276 and siRNA1786) may prove valuable in the treatment of CML.

Taurine induces the apoptosis of breast cancer cells by regulating apoptosis-related proteins of mitochondria

Taurine (Tau), the most abundant free amino acid in humans has numerous potential health benefits through its antioxidant and anti-inflammatory properties. However, limited studies have assessed its effect on tumors and the antitumor mechanism remains unknown. The present study investigated the cellular and molecular changes induced by Tau, leading to the induction of apoptosis in human breast cancer cell lines MCF-7 and MDA-MB-231. MCF-7 is p53 proficient (p53+/+) and MDA-MB-231 is a p53 null mutant (p53-/-). Cell proliferation and viability were assessed by MTT. Flow cytometry and hoechst33342 fluorescent staining were employed to detect apoptosis. Spectrophotometry was used to detect caspase-3 activity. Reverse transcription-polymerase chain reaction and western blot analysis were used to detect the levels of mRNA and proteins of p53-upregulated modulator of apoptosis (PUMA), Bax and Bcl-2. Finally, the affect of Tau on the growth of MDA-MB-231-cell-nude mice xenografts was examined. In the study, Tau inhibited growth and induced apoptosis of the two cell lines in a concentration- and time-dependent manner. Notably, the inhibitory effect of Tau on p53-/- cancer cells was clearly significant compared to the p53+/+ cancer cells. Further studies showed that Tau promoted apoptosis in human breast cancer cells and inhibited the growth of tumor in nude mice by inducing the expression of PUMA, which further up- and downregulated the expression of Bax and Bcl-2 protein, giving rise to increased activation of caspase-3. Collectively, these results indicate that Tau is a potent candidate for the chemotherapy of breast cancer through increasing the PUMA expression independent of p53 status.