-
[show abstract]
[hide abstract]
ABSTRACT: Bim, a proapoptotic BH3-only member of Bcl-2 family, has been considered to play an important role in initiating mitochondrial apoptotic pathway. Our previous studies have shown the ability of dihydroarteminsin (DHA) to induce apoptosis in human lung adenocarcinoma (ASTC-a-1) cells. In this study, we investigated the function of Bim during DHA-induced apoptosis in ASTC-a-1 and another human lung adenocarcinoma (A549) cell lines. Confocal imaging of single living cell expressing GFP-BimL showed the translocation of Bim to endoplasmic reticulum (ER) rather than mitochondria during DHA-induced apoptosis. Moreover, we also found that DHA induced ER stress and an increase of Bim protein levels. However, silencing Bim by short hairpin RNA did not inhibit DHA-induced caspase-9 activation and cell apoptosis. Taken together, our results demonstrate for the first time that DHA induces Bim translocation to ER, but DHA-induced apoptosis is not dependent on Bim in ASTC-a-1 and A549 cell lines.
Pathology & Oncology Research 03/2012; 18(4):809-16. · 1.37 Impact Factor
-
Li-hui Wang,
Jin Xiang,
Min Yan,
Yan Zhang,
Yan Zhao,
Cai-feng Yue,
Jie Xu,
Fei-meng Zheng,
Jin-na Chen,
Zhuang Kang, Tong-sheng Chen,
Da Xing,
Quentin Liu
[show abstract]
[hide abstract]
ABSTRACT: The mitotic kinase Aurora-A (Aur-A) is required to form the bipolar spindle and ensure accurate chromosome segregation before cell division. Aur-A dysregulation represents an oncogenic event that promotes tumor formation. Here, we report that Aur-A promotes breast cancer metastasis. Aur-A overexpression enhanced mammary cell migration by dephosphorylation and activation of cofilin, which facilitates actin reorganization and polymerization. Cofilin knockdown impaired Aur-A-driven cell migration and protrusion of the cell membrane. Conversely, overexpression of activated cofilin abrogated the effects of Aur-A knockdown on cell migration. Moreover, Aur-A overexpession increased the expression of the cofilin phosphatase Slingshot-1 (SSH1), contributing to cofilin activation and cell migration. We found that phosphatidylinositol 3-kinase (PI3K) inhibition blocked Aur-A-induced cofilin dephosphorylation, actin reorganization, and cell migration, suggesting crosstalk with PI3K signaling and a potential benefit of PI3K inhibition in tumors with deregulated Aur-A. Additionally, we found an association between Aur-A overexpression and cofilin activity in breast cancer tissues. Our findings indicate that activation of the cofilin-F-actin pathway contributes to tumor cell migration and metastasis enhanced by Aur-A, revealing a novel function for mitotic Aur-A kinase in tumor progression.
Cancer Research 11/2010; 70(22):9118-28. · 7.86 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The C-Jun N-terminal Kinase (JNK) inhibitor SP600125 is widely used to inhibit the JNK-mediated Bax activation and cell apoptosis. However, this report demonstrates that SP600125 synergistically enhances the dihydroartemisinin (DHA)-induced human lung adenocarcinoma cell apoptosis by accelerating Bax translocation and subsequent intrinsic apoptotic pathway involving mitochondrial membrane depolarization, cytochrome c release, caspase-9 and caspase-3 activation. The dynamical analysis of GFP-Bax mobility inside single living cells using fluorescence recovery after photobleaching revealed that SP600125 aggravated the DHA-induced decrease of Bax mobility and Bax translocation. These results for the first time present a novel pro-apoptotic action of SP600125 in DHA-induced apoptosis.
FEBS letters 09/2010; 584(18):4019-26. · 3.54 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Taxol (Paclitaxel) is an important natural product for the treatment of solid tumors such as ovarian, breast, non-small-cell lung tumors, and some head and neck carcinomas. Different concentrations of taxol trigger distinct effects on cell death forms. In present study, cell counting kit (CCK-8) assay, confocal fluorescence microscopy imaging, flow cytometry (FCM) and western blotting (WB) analysis were used to analyze the characteristics of cell death induced by low (35 nM) and high (70 microM) concentration of taxol respectively in human lung adenocarcinoma (ASTC-a-1) cells. Our results showed that low concentration of taxol induced cell death dominantly in apoptotic fashion associated with nuclear fragmentation, protein synthesis, phosphatidylserine (PS) externalization, G2/M cell cycle arrest, Bax translocation into mitochondria and caspase-3 activation, whereas high concentration of this drug induced significant cytoplasm vacuolization, mitochondria swelling and paraptosis-like cell death form without protein synthesis that is necessary for paraptosis. Although the mechanism of high concentration of taxol-induced paraptosis-like cell death has not been clear, this finding might have a potential implication for cancer therapy, especially for apoptosis-resistant cancer.
Journal of X-Ray Science and Technology 01/2010; 18(3):293-308. · 1.11 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In order to non-invasively investigate nucleoplasmic viscosity in real time with good temporal resolution, the present study firstly introduced a new method based on fluorescence correlation spectroscopy (FCS). FCS is a kind of single-molecule technique with high temporal and spatial resolution to analyze the dynamics of fluorescent molecules in nanomolar concentration. Through a time correlation analysis of spontaneous intensity fluctuations, this technique in conjunction with EGFP as a probe is capable of determining nucleoplasmic viscosity in terms of Stokes-Einstein equation as well as its corresponding analysis of the diffusion coefficient for EGFP in the nucleus. The results showed that nucleoplasmic viscosity of ASTC-a-1 cells and HeLa cells were respectively (2.55 +/- 0.61) cP and (2.04 +/- 0.49) cP at pH 7.4 and 37 degrees C, consistent with the results by traditional methods, and nucleoplasmic viscosity was found to be larger than cytoplasmic viscosity. Meanwhile, the real-time analysis of nucleoplasmic viscosity in living cells exposed to hypotonic media proved that FCS could be used to track the changing rheological characteristics of the nucleoplasm in living cells. Taken together, this study suggests that FCS provides an accurate and non-invasive method to investigate the microenvironment in living cells on the femtoliter scale and it can be used as a powerful tool in researches on the dynamical processes of intracellular molecules.
Guang pu xue yu guang pu fen xi = Guang pu 03/2009; 29(2):459-62. · 0.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Dihydroartemisinin (DHA), a semi-synthetic derivative of artemisinin, isolated from the traditional Chinese herb Artemisia annua, is recommended as the first-line anti-malarial drug with low toxicity. DHA has been shown to possess promising anticancer activities and induce cancer cell death through apoptotic pathways, although the molecular mechanisms are not well understood.
In this study, cell counting kit (CCK-8) assay was employed to evaluate the survival of DHA-treated ASTC-a-1 cells. The induction of apoptosis was detected by Hoechst 33258 and PI staining as well as flow cytometry analysis. Collapse of mitochondrial transmembrane potential (DeltaPsim) was measured by dynamic detection under a laser scanning confocal microscope and flow cytometry analysis using Rhodamine123. Caspase-3 activities measured with or without Z-VAD-fmk (a broad spectrum caspase inhibitor) pretreatment by FRET techniques, caspase-3 activity measurement, and western blotting analysis.
Our results indicated that DHA induced apoptotic cell death in a dose- and time-dependent manner, which was accompanied by mitochondrial morphology changes, the loss of DeltaPsim and the activation of caspase-3.
These results show for the first time that DHA can inhibit proliferation and induce apoptosis via caspase-3-dependent mitochondrial death pathway in ASTC-a-1 cells. Our work may provide evidence for further studies of DHA as a possible anticancer drug in the clinical treatment of lung adenocarcinoma.
Journal of Biomedical Science 02/2009; 16:16. · 2.01 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In the present report, the authors for the first time described the characteristics of taxol-induced paraptosis-like for the human lung adenocarcinoma cells (ASTC-a-1). CCK-8 was used to assay the inhibition of taxol on the cells viability. Cell viability was inhibited obviously 24 h after taxol treatment. Confocal fluorescence scanning microscope was used to monitor the morphology changes in cells with taxol treatment. Fluorescence resonance energy transfer (FRET) and acceptor photobleaching techniques were used to analyze the caspase-3 activation in the taxol-induced cell swelling and cell dearth. Taxol induced cell swelling, cytoplasmatic vacuolization and cell death without cell shrinkage, an apoptotic feature, and membrane rupture, a necrotic feature. The emission spectra of scat3 inside living cells expressed stably with scat3 were the same for control (without taxol). Further analysis with FRET and acceptor photobleaching techniques showed that the caspase-3 was not activated by taxol for the cytoplastic vacuoliazation cells expressed stably with scat3 plasmid, suggesting that caspase-3 is not involved in the taxol-inducecd cell swelling, cytoplasmatic vacuolization and cell death. These results show that taxol can induce a novel nonapoptotic PCD resembling the paraptosis in ASTC-a-1 cells.
Guang pu xue yu guang pu fen xi = Guang pu 12/2008; 28(11):2623-7. · 0.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: High concentration of taxol was found to induce programmed cell death (PCD) and cytoplasm vacuolization in human lung adenocarcinoma (ASTC-a-1) cells. To elucidate the relationship between the PCD and cytoplasm vacuolization, confocal fluorescence microscopy was performed on the cytoplasm vacuolization, endoplasmic reticulum (ER) and mitochondria swelling after taxol treatment in living cells. erRFP plasmid was used to probe the ER distribution, and SCAT3 plasmid was used to monitor the caspase-3 activation in living cells. Our results showed that taxol induced concentration-dependent and caspases-independent cytoplasm vacuolization and cell death through ER and mitochondria swelling. Live confocal imaging of ASTC-a-1 cells stably expressing SCAT3 further verified that taxol-induced cytoplasm vacuolization and cell death was caspase-3-independent. In conclusion, we found for the first time that taxol induces a paraptosis-like PCD in the ASTC-a-1 cells by cytoplasm vacuolization due to the swelling of both ER and mitochondria without activating the caspase enzymes.
Cancer letters 07/2008; 270(1):164-72. · 4.86 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The CCK-8 was used to measure the inhibition effect of Xiao-Ai-Ping (XAP), a traditional medicine, on the human lung adenocarcinoma (ASTC-a-1) cells viability. The ASTC-a-1 cells expressing stably with SCAT3, a fluorescence resonance energy transfer (FRET) plasmid based on the green fluorescent protein mutants (GFPs), was verified using confocal fluorescence scanning microscopy imaging, fluorescence emission spectra and FRET acceptor photobleaching techniques. The caspase-3 activation can be monitored by the fluorescence emission spectra of SCAT3 inside living cells. The cells expressing stably with SCAT3 were cultured with XAP for 96 hours, and the fluorescence emission spectra of the SCAT3 inside living cells were measured at the time of 0, 24, 72, and 96 hours, respectively. Experimental results showed that: (1)XAP inhibited obviously the proliferation of ASTC-a-1 cells and induced the cell death. The inhibition of XAP on the cells was dose-dependent; (2)the SCAT3 inside living cells was cleaved completely 72 hours after the XAP treatment, implying that a great deal of pro-caspase-3 was activated by XAP; (3)24 hours after XAP treatment, the emission spectra of SCAT3 inside living cells cultured in DMEM without XAP for 48 and 72 hours did not change greatly, implying that XAP did not activate obviously caspase-3 within 24 hours.
Guang pu xue yu guang pu fen xi = Guang pu 07/2008; 28(6):1327-31. · 0.84 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Taxol (paclitaxel), one of the most active cancer chemotherapeutic agents, can cause programmed cell death (PCD) and cytoplasmic vacuolization. The objective of this study was to analyze the morphological characteristics induced by taxol. Human lung adenocarcinoma (ASTC-a-1) cells were exposed to various concentration of taxol. CCK-8 was used to assay the cell viability. Atomic force microscopy (AFM), plasmid transfection and confocal fluorescence microscopy were performed to image the cells morphological change induced by taxol. Fluorescence resonance energy transfer (FRET) was used to monitor the caspase-3 activation in living cells during taxol-induced cell death. Cells treated with taxol exhibited significant swelling and cytoplasmic vacuolization which may be due to endoplasmic reticulum (ER) vacuolization. Caspase-3 was not activated during taxol-induced cytoplasmic vacuolization and cell death. These findings suggest that taxol induces caspase-3-independent cytoplasmic vacuolization, cell swelling and cell death through ER vacuolization.
Micron 05/2008; 39(8):1216-21. · 1.53 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Molecular biological methods were applied to analyze the genetic diversity of microbe community in biofilter. V3 variable fragments of genes coding for 16S rRNA were amplified by Polymerase Chain Reaction. Then PCR-DGGE combined technique were used to analyze the microbial population composition and phylogeny of deodorant biofilter. The results indicate that there are prominent differences in microbial diversity and abundance between acid and neutral conditions. Owing to the selective pressure of extreme acidity, there is less diversity of microbe compared with that in neutral environment. It is demonstrated the obvious distinction of spacial diversity in different biofilter bed as well. PCR and T-vector cloning sequencing results shows that the sulfur-oxidizing bacteria are the predominant population. The research offers the valid scientific basis for better treatment of odorant gas and the theoretical foundation for application of bio-deodorization.
ACTA MICROBIOLOGICA SINICA 07/2005; 45(3):446-50.
-
[show abstract]
[hide abstract]
ABSTRACT: Background and Objectives
Low-power laser irradiation (LPLI) has been used for therapies such as curing spinal cord injury, healing wound etc. Yet, the mechanism of LPLI remains unclear. In order to determine the effects of high fluence LPLI on cell growth and caspase-3 activity, we have measured the dynamics of caspase-3 activity during cell apoptosis induced by high fluence LPLI treatment.Study Design/Materials and Methods
He–Ne laser was used to irradiate human lung adenocarcinoma cells (ASTC-a-1). Cell Counting Kit-8 was used for cytotoxicity assay. A fluorescent microscope was used to perform fluorescence resonance energy transfer (FRET) imaging. A luminescence spectrometer was used to acquire the fluorescent emission spectrum. Statistical analysis was performed with Student's paired t-test.ResultsCytotoxicity assay showed that when light irradiation fluence exceeded 60 J/cm2, LPLI treatment induced ASTC-a-1 cell apoptosis in a fluence-dependent manner. FRET imaging and spectrofluorometric analysis demonstrated that caspase-3 was activated during high fluence LPLI-induced cell apoptosis.Conclusions
Using FRET technique, we have reported that high fluence LPLI can induce human lung adenocarcinoma cells (ASTC-a-1) apoptosis. The activation of caspase-3 plays an important role in the apoptotic process. Lasers Surg. Med. 36:2–7, 2005. © 2005 Wiley-Liss, Inc.
Lasers in Surgery and Medicine 12/2004; 36(1):2 - 7. · 2.75 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Combination of green fluorescent protein (GFP) and two-photon excitation fluorescence microscopy (TPE) has been used increasingly to study dynamic biochemical events within living cells, sometimes even in vivo. However, the high photon flux required in TPE may lead to higher-order photobleaching within the focal volume, which would introduce misinterpretation about the fine biochemical events. Here we first studied the high-order photobleaching rate of GFP inside live cells by measuring the dependence of the photobleaching rate on the excitation power. The photobleaching rate under one- and two-photon excitation increased with 1-power and 4-power of the incident intensity, respectively, implying the excitation photons might interact with excited fluorophore molecules and increase the probability of photobleaching. These results suggest that in applications where two-photon imaging of GFP is used to study dynamic molecular process, photobleaching may ruin the imaging results and attention should be paid in interpreting the imaging results.
Biochemical and Biophysical Research Communications 04/2002; 291(5):1272-5. · 2.48 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Dihydroartemisinin (DHA), a front-line antimalarial herbal compound, has been shown to possess promising anticancer activity with low toxicity. We have previously reported that DHA induced caspase-3-dependent apoptosis in human lung adenocarcinoma cells. However, the cellular target and molecular mechanism of DHA-induced apoptosis is still poorly defined. We use confocal fluorescence microscopy imaging, fluorescence resonance energy transfer, and fluorescence recovery after photobleaching techniques to explore the roles of DHA-elicited reactive oxygen species (ROS) in the DHA-induced Bcl-2 family proteins activation, mitochondrial dysfunction, caspase cascade, and cell death. Cell Counting Kit-8 assay and flow cytometry analysis showed that DHA induced ROS-mediated apoptosis. Confocal imaging analysis in a single living cell and Western blot assay showed that DHA triggered ROS-dependent Bax translocation, mitochondrial membrane depolarization, alteration of mitochondrial morphology, cytochrome c release, caspase-9, caspase-8, and caspase-3 activation, indicating the coexistence of ROS-mediated mitochondrial and death receptor pathway. Collectively, our findings demonstrate for the first time that DHA induces cell apoptosis by triggering ROS-mediated caspase-8/Bid activation and the mitochondrial pathway, which provides some novel insights into the application of DHA as a potential anticancer drug and a new therapeutic strategy by targeting ROS signaling in lung adenocarcinoma therapy in the future.
Journal of Biomedical Optics 15(4):046028. · 3.16 Impact Factor
