Regulation of the calcium-channelI min/I crac activity in human epidermal carcinoma A431 cells

2000 ◽  
Vol 32 (3) ◽  
pp. 149-149
Author(s):  
K. O. Gusev ◽  
E. V. Kaznacheyeva ◽  
A. N. Zubov ◽  
G. N. Mozhayeva
Keyword(s):  
A431 Cells ◽  
Epidermal Carcinoma

Apoptotic signalling cascade in photosensitized human epidermal carcinoma A431 cells: involvement of singlet oxygen, c-Jun N-terminal kinase, caspase-3 and p21-activated kinase 2

2000 ◽  
Vol 351 (1) ◽  
pp. 221-232 ◽  
Author(s):  
Wen-Hsiung CHAN ◽  
Jau-Song YU ◽  
Shiaw-Der YANG
Keyword(s):  
Singlet Oxygen ◽  
Caspase 3 ◽  
Early Stage ◽  
A431 Cells ◽  
Caspase Family ◽  
P21 Activated Kinase ◽  
Induced Apoptosis ◽  
Jnk Activation ◽  
Epidermal Carcinoma ◽  
Signalling Cascade

Photodynamic treatment (PDT) elicits diverse cellular responses and can also cause apoptosis. In the present study the cascade of signalling events involved in PDT-induced apoptosis was investigated using Rose Bengal (RB) as the photosensitizer, and human epidermal carcinoma A431 cells as the cell model. We show that a 36-kDa kinase detected by an in-gel kinase assay is markedly activated during PDT-triggered apoptosis. Immunoblot analysis revealed that this 36-kDa kinase represents the C-terminal catalytic fragment of p21-activated kinase (PAK)2. Generation of this active fragment of PAK2 is mediated by the caspase family of proteases, which are activated by PDT. The specific caspase inhibitors (acetyl-Asp-Glu-Val-Asp-aldehyde and acetyl-Tyr-Val-Ala-Asp-chloromethylketone) block the PDT-induced caspase-3 activation and subsequent PAK2 cleavage/activation, indicating a major role for the caspase family proteases in PDT-induced apoptosis. Both PDT-induced caspase-3 activation and PAK2 cleavage/activation can be inhibited by the singlet oxygen scavengers, L-histidine and α-tocopherol, but not the hydroxyl radical scavenger, mannitol, demonstrating that singlet oxygen is an immediate early-apoptotic signal generated by PDT. In addition, PDT can induce a two-stage activation of the c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) in A431 cells; the early-stage JNK activation is singlet oxygen-dependent, whereas the late-stage JNK activation is mediated by the singlet oxygen-triggered caspase activation. Experiments using anti-sense oligonucleotides against JNK1 and PAK2 further show that during PDT-induced apoptosis the early-stage JNK activation is required for caspase activation, and that the late-stage JNK activation is regulated by the caspase-mediated cleavage/activation of PAK2. Collectively, a model for the PDT-triggered apoptotic signalling cascade with RB is proposed, which involves singlet oxygen, JNK, caspase-3 and PAK2, sequentially.

scholarly journals Site-Specific Dual-Labeling of a VHH with a Chelator and a Photosensitizer for Nuclear Imaging and Targeted Photodynamic Therapy of EGFR-Positive Tumors

Cancers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 428
Author(s):  
Emma Renard ◽  
Estel Collado Camps ◽  
Coline Canovas ◽  
Annemarie Kip ◽  
Martin Gotthardt ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Fluorescence Imaging ◽  
Ex Vivo ◽  
Growth Factor Receptor ◽  
Nuclear Imaging ◽  
A431 Cells ◽  
Site Specific ◽  
Variable Domains ◽  
Diagnostic Probe

Variable domains of heavy chain only antibodies (VHHs) are valuable agents for application in tumor theranostics upon conjugation to both a diagnostic probe and a therapeutic compound. Here, we optimized site-specific conjugation of the chelator DTPA and the photosensitizer IRDye700DX to anti-epidermal growth factor receptor (EGFR) VHH 7D12, for applications in nuclear imaging and photodynamic therapy. 7D12 was site-specifically equipped with bimodal probe DTPA-tetrazine-IRDye700DX using the dichlorotetrazine conjugation platform. Binding, internalization and light-induced toxicity of DTPA-IRDye700DX-7D12 were determined using EGFR-overexpressing A431 cells. Finally, ex vivo biodistribution of DTPA-IRDye700DX-7D12 in A431 tumor-bearing mice was performed, and tumor homing was visualized with SPECT and fluorescence imaging. DTPA-IRDye700DX-7D12 was retrieved with a protein recovery of 43%, and a degree of labeling of 0.56. Spectral properties of the IRDye700DX were retained upon conjugation. 111In-labeled DTPA-IRDye700DX-7D12 bound specifically to A431 cells, and they were effectively killed upon illumination. DTPA-IRDye700DX-7D12 homed to A431 xenografts in vivo, and this could be visualized with both SPECT and fluorescence imaging. In conclusion, the dichlorotetrazine platform offers a feasible method for site-specific dual-labeling of VHH 7D12, retaining binding affinity and therapeutic efficacy. The flexibility of the described approach makes it easy to vary the nature of the probes for other combinations of diagnostic and therapeutic compounds.

scholarly journals Natural Compounds Isolated from Stachybotrys chartarum Are Potent Inhibitors of Human Protein Kinase CK2

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4453
Author(s):  
Samer Haidar ◽  
Franziska M. Jürgens ◽  
Dagmar Aichele ◽  
Annika Jagels ◽  
Hans-Ulrich Humpf ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Natural Compounds ◽  
Breast Adenocarcinoma ◽  
Stachybotrys Chartarum ◽  
Mcf7 Cells ◽  
A431 Cells ◽  
Ic50 Values ◽  
Human Lung Carcinoma ◽  
Kinase Ck2

A large number of secondary metabolites have been isolated from the filamentous fungus Stachybotrys chartarum and have been described before. Fourteen of these natural compounds were evaluated in vitro in the present study for their inhibitory activity towards the cancer target CK2. Among these compounds, stachybotrychromene C, stachybotrydial acetate and acetoxystachybotrydial acetate turned out to be potent inhibitors with IC50 values of 0.32 µM, 0.69 µM and 1.86 µM, respectively. The effects of these three compounds on cell proliferation, growth and viability of MCF7 cells, representing human breast adenocarcinoma as well as A427 (human lung carcinoma) and A431 (human epidermoid carcinoma) cells, were tested using EdU assay, IncuCyte® live-cell imaging and MTT assay. The most active compound in inhibiting MCF7 cell proliferation was acetoxystachybotrydial acetate with an EC50 value of 0.39 µM. In addition, acetoxystachybotrydial acetate turned out to inhibit the growth of all three cell lines completely at a concentration of 1 µM. In contrast, cell viability was impaired only moderately, to 37%, 14% and 23% in MCF7, A427 and A431 cells, respectively.

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