scholarly journals Intracellular Amplifiers of Reactive Oxygen Species Affecting Mitochondria as Radiosensitizers

Cancers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 208
Author(s):  
Hong-Gui Xu ◽  
Viktor Reshetnikov ◽  
Marit Wondrak ◽  
Lisa Eckhardt ◽  
Leoni A. Kunz-Schughart ◽  
...  

Radiotherapy (RT) efficacy can be improved by using radiosensitizers, i.e., drugs enhancing the effect of ionizing radiation (IR). One of the side effects of RT includes damage of normal tissue in close proximity to the treated tumor. This problem can be solved by applying cancer specific radiosensitizers. N-Alkylaminoferrocene-based (NAAF) prodrugs produce reactive oxygen species (ROS) in cancer cells, but not in normal cells. Therefore, they can potentially act as cancer specific radiosensitizers. However, early NAAF prodrugs did not exhibit this property. Since functional mitochondria are important for RT resistance, we assumed that NAAF prodrugs affecting mitochondria in parallel with increasing intracellular ROS can potentially exhibit synergy with RT. We applied sequential Cu+-catalyzed alkyne-azide cycloadditions (CuAAC) to obtain a series of NAAF derivatives with the goal of improving anticancer efficacies over already existing compounds. One of the obtained prodrugs (2c) exhibited high anticancer activity with IC50 values in the range of 5–7.1 µM in human ovarian carcinoma, Burkitt’s lymphoma, pancreatic carcinoma and T-cell leukemia cells retained moderate water solubility and showed cancer specificity. 2c strongly affects mitochondria of cancer cells, leading to the amplification of mitochondrial and total ROS production and thus causing cell death via necrosis and apoptosis. We observed that 2c acts as a radiosensitizer in human head and neck squamous carcinoma cells. This is the first demonstration of a synergy between the radiotherapy and NAAF-based ROS amplifiers.

2021 ◽  
Vol 83 (5) ◽  
Author(s):  
Rajangam Pushpalatha ◽  
Ganapathy Sindhu ◽  
Ramalingam Sharmila ◽  
G. Tamizharasi ◽  
Lakshmanan Vennila ◽  
...  

2019 ◽  
Vol 18 (9) ◽  
pp. 1313-1322 ◽  
Author(s):  
Manjula Devi Ramamoorthy ◽  
Ashok Kumar ◽  
Mahesh Ayyavu ◽  
Kannan Narayanan Dhiraviam

Background: Reserpine, an indole alkaloid commonly used for hypertension, is found in the roots of Rauwolfia serpentina. Although the root extract has been used for the treatment of cancer, the molecular mechanism of its anti-cancer activity on hormonal independent prostate cancer remains elusive. Methods: we evaluated the cytotoxicity of reserpine and other indole alkaloids, yohimbine and ajmaline on Prostate Cancer cells (PC3) using MTT assay. We investigated the mechanism of apoptosis using a combination of techniques including acridine orange/ethidium bromide staining, high content imaging of Annexin V-FITC staining, flow cytometric quantification of the mitochondrial membrane potential and Reactive Oxygen Species (ROS) and cell cycle analysis. Results: Our results indicate that reserpine inhibits DNA synthesis by arresting the cells at the G2 phase and showed all standard sequential features of apoptosis including, destabilization of mitochondrial membrane potential, reduced production of reactive oxygen species and DNA ladder formation. Our in silico analysis further confirmed that indeed reserpine docks to the catalytic cleft of anti-apoptotic proteins substantiating our results. Conclusion: Collectively, our findings suggest that reserpine can be a novel therapeutic agent for the treatment of androgen-independent prostate cancer.


2020 ◽  
Vol 22 (1) ◽  
pp. 154
Author(s):  
Fasih Bintang Ilhami ◽  
Kai-Chen Peng ◽  
Yi-Shiuan Chang ◽  
Yihalem Abebe Alemayehu ◽  
Hsieh-Chih Tsai ◽  
...  

Development of stimuli-responsive supramolecular micelles that enable high levels of well-controlled drug release in cancer cells remains a grand challenge. Here, we encapsulated the antitumor drug doxorubicin (DOX) and pro-photosensitizer 5-aminolevulinic acid (5-ALA) within adenine-functionalized supramolecular micelles (A-PPG), in order to achieve effective drug delivery combined with photo-chemotherapy. The resulting DOX/5-ALA-loaded micelles exhibited excellent light and pH-responsive behavior in aqueous solution and high drug-entrapment stability in serum-rich media. A short duration (1–2 min) of laser irradiation with visible light induced the dissociation of the DOX/5-ALA complexes within the micelles, which disrupted micellular stability and resulted in rapid, immediate release of the physically entrapped drug from the micelles. In addition, in vitro assays of cellular reactive oxygen species generation and cellular internalization confirmed the drug-loaded micelles exhibited significantly enhanced cellular uptake after visible light irradiation, and that the light-triggered disassembly of micellar structures rapidly increased the production of reactive oxygen species within the cells. Importantly, flow cytometric analysis demonstrated that laser irradiation of cancer cells incubated with DOX/5-ALA-loaded A-PPG micelles effectively induced apoptotic cell death via endocytosis. Thus, this newly developed supramolecular system may offer a potential route towards improving the efficacy of synergistic chemotherapeutic approaches for cancer.


Sign in / Sign up

Export Citation Format

Share Document