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Sine oculis homeobox homolog 1 (Six1) is crucial in normal organ development. Recently, Six1 is reported to display aberrant expression in various cancers and plays important roles in cancer development. However, the regulatory mechanism of Six1 in gastric cancer is largely unknown. In the current study, we found that Six1 was increased in gastric cancer tissues, and its upregulation significantly associated with lymph node metastasis (p=0.042) and poor differentiation (p=0.039). Next, we took advantage of public available microarray data to assess Six1 prognostic value with online K-M Plotter software in gastric cancer, which demonstrated that patients with higher Six1 expression had shorter survival time (p=0.02). To explore the underlying mechanism of Six1, we silenced its upregulation in gastric cells to detect cellular functions. Our results indicated that knock-down Six1 could decrease colony formation number and rendered cells sensitive to 5- Fluorouracil drug treatment. The flow cytometry analyses showed that Six1 silence could promote apoptosis but had little effect on cell cycle transition. Along this clue, we tested mitochondrial membrane potential with JC-1 assay, which suggested that Six1 inhibition could trigger mitochondrial apoptosis. Our subsequent results revealed that Six1 knock-down could reduce the level of anti-apoptotic protein Bcl-2, and caspase-7 but not caspase-3 was involved to execute the mitochondrial apoptosis pathway. Taken together, we find Six1 has oncogenic role in gastric cancer development, and silenced Six1 expression can promote mitochondrial apoptosis by repressing Bcl-2 and activating executor caspase-7. These findings suggest that Six1 may become a valuable prognostic and therapeutic target in gastric cancer., Competing Interests: Competing Interests: The authors have declared that no competing interest exists.

Background: Aberrant modulation of store-operated calcium ions (Ca(2+)) entry promotes the progression of human malignancies. Previously, we reported that the blockage of store-operated Ca(2+) entry inhibited epidermal growth factor (EGF)-stimulated migration and distant metastasis in nasopharyngeal carcinoma (NPC) cells. However, the effects of pharmacological blocker on other Ca(2+) signaling-regulated malignant characteristics in NPC cells remained poorly understood., Methods: We examined the effects of SKF96365, an inhibitor of store-operated Ca(2+) channel, on EGF-launched Ca(2+) signaling in two NPC cell lines. We determined the effects of SKF96365 on cell proliferation, colony formation, apoptosis, and cell-cycle status in vitro. We further elucidated the antitumor activity of SKF96365 in xenograft-bearing mice., Results: It was found that SKF96365 disturbed the thapsigargin (TG)-stimulated Ca(2+) release from endoplasmic reticulum and the subsequent Ca(2+) influx. SKF96365 alone stimulated Ca(2+) responses merely due to endoplasmic reticulum-released Ca(2+). SKF96365 promoted cell mortality, inhibited colony formation, and induced apoptosis and cell-cycle arrest, while blunting the EGF-evoked Ca(2+) signaling. Furthermore, we confirmed that SKF96365 reduced NPC xenograft growth while activating caspase-7-related apoptotic pathway., Conclusion: SKF96365 exerts multiple antitumor activities through the distraction on the oncogenic Ca(2+) signaling transduction in NPC cells.

We recently reported that miR-224 was significantly up-regulated in non-small cell lung cancer (NSCLC) tissues, in particular in resected NSCLC metastasis. We further demonstrated that miR-224 functions as an oncogene in NSCLC by directly targeting TNFAIP1 and SMAD4. However, the biological functions of miR-224 in NSCLC are controversial and underlying mechanisms of miR-224 in the progression and metastasis of lung cancer remain to be further explored. Here we report that caspase3 (CASP3) and caspase7 (CASP7) are previously unidentified targets of miR-224 in NSCLC, and that miR-224 promotes lung cancer cells proliferation and migration in part by directly targeting CASP7 and down-regulating its expression. In addition, miR-224 attenuated TNF-α induced apoptosis by direct targeting of CASP3 resulting in reduction of cleaved PARP1 expression in lung cancer cells. Furthermore, the expression of miR-224 negatively correlates with the expression of CASP7 and CASP3 in tissue samples from patients with lung cancer. Finally, we found that activated NF-κB signaling is involved in the regulation of miR-224 expression in lung cancer. Our study provides new insight in understanding of oncogenic role of miR-224 in the lung cancer pathogenesis and suggests that NF-κB/miR-224/CASP3, 7 pathway could be a putative therapeutic target in lung cancer.

Cisplatin-based therapy is common in the treatment of several types of cancers, including lung cancers. In our previous study, GMI, an immunomodulatory protein cloned from Ganoderma microsporum, induced a cytotoxic effect in lung cancer cells via autophagy. The aim of this study is to examine the role of GMI in enhancing cisplatin-mediated cell death. On the basis of MTT assay and Combination Index, GMI and cisplatin cotreatment induced a synergistic cytotoxic effect. GMI and cisplatin-induced apoptosis was determined by sub-G1, nuclear condensation, and annexin-V/propidium iodide analyses. On Western blot, expressions of γH2AX and cleaved forms of PARP, caspase-3, and caspase-7 were induced by combined treatment. Akt/mTOR pathway activity, LC3-II expression, and acidic vesicular organelle development demonstrated that cisplatin does not abolish GMI-mediated autophagy. Cyto-ID Green/hoechst 33342 double staining and time-dependent experiment indicated that GMI and cisplatin-treated A549 cells simultaneously express autophagosomes and apoptotic nuclei. To elucidate the role of autophagy in inducing apoptosis by GMI and cisplatin, chemical inhibitors and LC3 shRNA were used to inhibit autophagy. The results showed that 3-methyladenine decreases, while chloroquine increases GMI and cisplatin cotreatment-induced cleavage of caspase-7 and PARP. LC3 silencing abolished activation of apoptosis in A549 cells. Caspase inhibitors and caspase-7 silencing mitigated GMI and cisplatin-elicited cell viability inhibition and apoptosis. This is the first study to reveal the novel function of GMI in potentiating cisplatin-mediated apoptosis. GMI and cisplatin induce apoptosis via autophagy/caspase-7-dependent and survivin- and ERCC1-independent pathway. GMI may be a potential cisplatin adjuvant against lung cancer.

The bis(3,5-dimethyl-1H- pyrazol-1yl)acetic acid (bdmpza) ligand was conjugated with tert-butyl-N-(2-aminoethyl) carbonate, methyl-2-amino-4-(methylthio)butanoate and 1,3,4,6-tetra-O-acetyl-β-d-glucosamine hydrochloride via amide coupling method to form three ligands L1-L3 which were then reacted with Zn(II) salts to form four zinc complexes (1-4). The complexes were characterized by (1)H NMR, (13)C NMR, electrospray ionization mass spectrometry (ESI-MS), FT-IR, CHN analyses. Complexes 1, 2 and 4 were also characterized by single crystal X-ray diffraction. It was found that Zn(II) salts could selectively remove the acetyl group from anomeric position leaving everything else intact. The cytotoxicity studies of the ligand and the complexes showed that the conjugation to acetylated glucosamine enhances cytotoxic ability although the complexes become more hydrophilic. Cytotoxicity studies in human breast adenocarcinoma (MCF-7), human cervical cancer (HeLa WT) and human lung adenocarcinoma (A549) showed that the acetylated glucosamine conjugation to the bis-pyrazole ligated Zn(II) complex led to 2-4 fold increase in cytotoxicity (IC50 values ca. 57-80μM) against HeLa WT and MCF-7 cell lines. The Zn(II) complex bearing the acetylated glucosamine inhibits the cell cycle in the G2/M phase of MCF-7 cell line. ICP-MS data shows more accumulation of Zn(II) inside the cell upon use of complex 4 as compared to Zn(II) salts or the other presented complexes. Further studies suggest that the mitochondrial transmembrane potential changes in the presence of complex 4 and caspase-7 is activated by Zn(II) salts but the activation is much more by complex 4 and hence there is apoptosis and dose dependent chromatin condensation/nuclear fragmentation as observed by microscopy., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Glioblastoma (GBM) is an astrocytic brain tumor characterized by an aggressive clinical course and intense resistance to all therapeutic modalities. Here, we report the identification and functional characterization of Bcl2L12 (Bcl2-like-12) that is robustly expressed in nearly all human primary GBMs examined. Enforced Bcl2L12 expression confers marked apoptosis resistance in primary cortical astrocytes, and, conversely, its RNA interference (RNAi)-mediated knockdown sensitizes human glioma cell lines toward apoptosis in vitro and impairs tumor growth with increased intratumoral apoptosis in vivo. Mechanistically, Bcl2L12 expression does not affect cytochrome c release or apoptosome-driven caspase-9 activation, but instead inhibits post-mitochondrial apoptosis signaling at the level of effector caspase activation. One of Bcl2L12's mechanisms of action stems from its ability to interact with and neutralize caspase-7. Notably, while enforced Bcl2L12 expression inhibits apoptosis, it also engenders a pronecrotic state, which mirrors the cellular phenotype elicited by genetic or pharmacologic inhibition of post-mitochondrial apoptosis molecules. Thus, Bcl2L12 contributes to the classical tumor biological features of GBM such as intense apoptosis resistance and florid necrosis, and may provide a target for enhanced therapeutic responsiveness of this lethal cancer. [ABSTRACT FROM AUTHOR]

Proteolytic enzymes of the caspase family, which reside as latent precursors in most nucleated metazoan cells, are core effectors of apoptosis. Of them, the executioner caspases- 3 and -7 exist within the cytosol as inactive dimers and are activated by a process called dimerization. Caspase inhibition is looked upon as a promising approach for treating multiple diseases. Though caspases have been extensively studied in the human system, their role in eukaryotic pathogens and parasites of human hosts has not drawn enough attention. In protein sequence analysis, caspases of blood flukes (Schistosoma spp) were revealed to have a low sequence identity with their counterparts in human and other mammalian hosts, which encouraged us to analyse interacting domains that participate in dimerization of caspases in the parasite and to reveal differences, if any, between the host-parasite systems. Significant differences in the molecular surface arrangement of the dimer interfaces reveal that in schistosomal caspases only eight out of forty dimer conformations are similar to human caspase structures. Thus, the parasite-specific dimer conformations (that are different from caspases of the host) may emerge as potential drug targets of therapeutic value against schistosomal infections. Three important factors namely, the size of amino acids, secondary structures and geometrical arrangement of interacting domains influence the pattern of caspase dimer formation, which, in turn, is manifested in varied structural conformations of caspases in the parasite and its human hosts.