Mechanism of action of potential anticancer drugs

Traditionally, inoperable or metastatic cancers have been treated by causing massive DNA damage in order to induce self-destruction (apoptosis) of the rapidly multiplying cancer cells. Initially, this strategy works for many cancers, in particular those which express normal p53 tumor suppressor protein. However, most cancers eventually aquire mutations in either p53 or other signaling molecules and fail to initiate apoptosis in response to severe DNA damage. During this study three types of compounds were investigated for their DNA damaging and anticancer effects: a pair of novel metal containing compounds, a pair of natural products, and a known synthetic drug which had been used many years ago for completely different indication. It was shown that all stop the growth of cancer cells and that the latter two classes do not require functional p53 because they work equally well in cells with normal (wildtype), mutant or no p53. The two nickel complexes investigated in this dissertation, differ in their ability to cause DNA damage and cell death. The oxidized form of the nickel complex, [Ni(CR-2H)] 2+ causes DNA damage and cell death at a much lower concentration than its reduced counterpart [Ni(CR)] 2+ . The phenanthridine alkaloids, Sanguinarine and Chelerythine cause high levels of DNA strand breaks and extremely rapid apoptosis which is not due to DNA damage because the quick onset precludes extensive signaling. The effects of the phenanthridines were linked to production of large amounts of reactive oxygen species (ROS), in particular hydrogen peroxide (H 2 O 2 ). The importance of ROS for the action of anticancer drugs as well as antibiotics is increasingly being recognized. In addition we also investigated the thioxanthone Lucanthone or Miracil D (which was used for the treatment of parasitic worms more than 50 years ago). It causes DNA strand breaks and apoptosis. Apoptosis occurs on a timescale consistent with signaling. However, p53 does not seem to be involved and alternative mechanisms are being investigated. This work provides new directions for designing novel anticancer drugs that are not subject to the limitations of DNA damaging agents

Mechanism of action of potential anticancer drugs

Traditionally, inoperable or metastatic cancers have been treated by causing massive DNA damage in order to induce self-destruction (apoptosis) of the rapidly multiplying cancer cells. Initially, this strategy works for many cancers, in particular those which express normal p53 tumor suppressor protein. However, most cancers eventually aquire mutations in either p53 or other signaling molecules and fail to initiate apoptosis in response to severe DNA damage. During this study three types of compounds were investigated for their DNA damaging and anticancer effects: a pair of novel metal containing compounds, a pair of natural products, and a known synthetic drug which had been used many years ago for completely different indication. It was shown that all stop the growth of cancer cells and that the latter two classes do not require functional p53 because they work equally well in cells with normal (wildtype), mutant or no p53. The two nickel complexes investigated in this dissertation, differ in their ability to cause DNA damage and cell death. The oxidized form of the nickel complex, [Ni(CR-2H)] 2+ causes DNA damage and cell death at a much lower concentration than its reduced counterpart [Ni(CR)] 2+ . The phenanthridine alkaloids, Sanguinarine and Chelerythine cause high levels of DNA strand breaks and extremely rapid apoptosis which is not due to DNA damage because the quick onset precludes extensive signaling. The effects of the phenanthridines were linked to production of large amounts of reactive oxygen species (ROS), in particular hydrogen peroxide (H 2 O 2 ). The importance of ROS for the action of anticancer drugs as well as antibiotics is increasingly being recognized. In addition we also investigated the thioxanthone Lucanthone or Miracil D (which was used for the treatment of parasitic worms more than 50 years ago). It causes DNA strand breaks and apoptosis. Apoptosis occurs on a timescale consistent with signaling. However, p53 does not seem to be involved and alternative mechanisms are being investigated. This work provides new directions for designing novel anticancer drugs that are not subject to the limitations of DNA damaging agents

Breaking Up with DNA

Chemotherapy can destroy many cancerous cells but it destroys some healthy cells as well. Some chemicals destroy cancer cells by alkylating DNA. Another method for killing fast growing cancer cells uses the Fenton reaction which involves hydrogen peroxide, a specific pH, and a ferrous iron catalyst. The peroxide reacts to a hydroxide ion and a hydroxyl free radical. The hydroxyl free radical is the primary oxidizing species which oxidizes and breaks apart organic molecules, such as DNA. We have set up Fenton reactions in a test tube and studied the effect on DNA strand breaks. Recently, we have begun investigating a nickel complex that had been shown to cause DNA single strand breaks. In this case, reactions that break up the DNA may be enhanced by the ability of complex to intercalate or slide between the bases of DNA. There may be different methods to cause DNA strand breaks but in any case, antioxidant should be able to prevent it. Antioxidants are molecules that slow down the production of free radicals and oxidation reactions. They can remove radical intermediates and are often called reducing agents. Small amounts of antioxidants may help prevent cancer by preventing DNA strand caused by environmental chemicals. Large amounts of antioxidants or antioxidants taking during chemotherapy may not be helpful. In order be able to study the effect of different amounts of antioxidants on the Fenton reaction and other reactions that cause DNA strand breaks we have been optimizing methods for detecting DNA strand breaks

Breaking Up with DNA

Chemotherapy can destroy many cancerous cells but it destroys some healthy cells as well. Some chemicals destroy cancer cells by alkylating DNA. Another method for killing fast growing cancer cells uses the Fenton reaction which involves hydrogen peroxide, a specific pH, and a ferrous iron catalyst. The peroxide reacts to a hydroxide ion and a hydroxyl free radical. The hydroxyl free radical is the primary oxidizing species which oxidizes and breaks apart organic molecules, such as DNA. We have set up Fenton reactions in a test tube and studied the effect on DNA strand breaks. Recently, we have begun investigating a nickel complex that had been shown to cause DNA single strand breaks. In this case, reactions that break up the DNA may be enhanced by the ability of complex to intercalate or slide between the bases of DNA. There may be different methods to cause DNA strand breaks but in any case, antioxidant should be able to prevent it. Antioxidants are molecules that slow down the production of free radicals and oxidation reactions. They can remove radical intermediates and are often called reducing agents. Small amounts of antioxidants may help prevent cancer by preventing DNA strand caused by environmental chemicals. Large amounts of antioxidants or antioxidants taking during chemotherapy may not be helpful. In order be able to study the effect of different amounts of antioxidants on the Fenton reaction and other reactions that cause DNA strand breaks we have been optimizing methods for detecting DNA strand breaks

Direct detection of intracellular superoxide generation from freshly isolated rat aorta: a novel approach

Although superoxide (O2?) plays an important role in vascular diseases, direct measurement of O2? in viable tissue remains a challenge. The aim of this study was to design and validate a procedure to measure O2? generation using freshly isolated aorta. Method: The 8 mm fresh aortic segments from male and female rats were cut longitudinally in Krebs buffer at 37°C and mounted on the silicon elastomer surface with the lumenal surface facing upward. The segments were incubated with the nitric oxide probe 4,5-diaminofluorescein diacetate (DAF-2DA, 5 ?M) or O2? probe dihydroethidium (DHE, 2.5 ?M), followed by fluorescent recoding at longitudinal edge using Leica DMIRE2 microscope. Acetylcholine-induced increased DAF fluorescence was taken as evidence for the endothelial integrity. To examine the effect of O2? generator, DHE fluorescence was quantified before and after incubation of segments with phorbol myristate acetate (PMA, 0.1 ?M), or PMA in the presence of O2? scavenger (tempol, 100 ?M) for 30 min. Results: The extent of PMA-induced O2? increase was greater in female tissues (9.2 fold) than that in males (2.8 fold), and this was prevented by the presence of tempol. This data was comparable to our recent report on gender difference in PMA-induced O2? production in rat aorta using isometric tension study. Conclusion: This procedure will allow us to detect O2? generation in translucent viable vessels. (Supported by NHLBI

Harnessing the Hidden Antitumor Power of the MLL-AF4 Oncogene to Fight Leukemia

It is unclear whether the antiproliferative/proapoptotic activity of oncogenes can be pharmacologically reactivated in cancer cells. In this issue of Cancer Cell, Liu and colleagues report that a proteasome inhibitor reactivates an MLL-AF4 controlled antitumor program to kill leukemia cells in an oncogene dose- and cell type-dependent manner

Annexe 1

The Memorandum of Understanding Full Text of Memorandum of Understanding between Hizbullah and Free Patriotic Movement declared on February 6th, 2006 Available at http://english.moqawama.org/ Introduction The first meeting ever between the head of the Change and Reform Bloc, MP Michel Aoun, and the Secretary General of Hizbullah, Sayyed Hassan Nasrallah, took place today afternoon at St. Michael Church in Shiah in the presence of Mahmoud Comati and Ghaleb Abu-Zeinab from Hizbullah, and Gebra..

Cytogenetic Studies in Indian Population suspected to have Klinefelter syndrome

Klinfelter syndrome is a genetic condition in which there is a presence of an extra copy of sex chromosome X. It is the most common sex chromosomal abnormality seen in males. The objective of our study was to determine the frequency of Klinfelter syndrome and its various cytogenetic types in cases with clinical suspicion of Klinfelter syndrome received at the Department of Cytogenetics, Metropolis Healthcare Limited, Mumbai, India. The period of our study was 2 years from January-2015 to December-2016. This retrospective study was performed on peripheral blood (2-3 ml) freshly collected in sodium heparin green-top vacutainer tube obtained from 421 patients with clinical suspicion of Klinfelter syndrome. All the samples used in our study were received from all over the India and the test requested was Chromosomal karyotyping (KT). The 72- hour old cultures were set and analysed by GTG–banding at 450-550 band level. Out of 421 samples referred, about 83 (19.71%) showed chromosomal abnormality ,68 (16.15%)cases showed extra copy of chromosome X. While, out of 421 cases17(4.03%) cases were detected with polymorphic variations.  Knowing the cytogenetic status is very important for the genetic Counselor and clinician for the management

Cytogenetic and Genetic counselling in couples with Infertility-Metropolis Healthcare experience

This retrospective study aimed at finding out the different chromosomal abnormalities and patterns in the samples. All the samples received at department of Cytogenetics, Metropolis Healthcare laboratory, Mumbai during the period of Jan2015 to Dec.2016 had a previous clinical history of primary infertility. One thousand one hundred and eighteen couples (1108 females and 1108 males) were evaluated by doing chromosomal karyotyping and 68 (3.06) patients showed chromosomal abnormality in the form of balanced translocations, Robertsonian translocations and sex chromosomal abnormalities. Most of the sex chromosomal abnormality in females were in the form of mosaic pattern whereas most of the sex chromosomal abnormality in males where in the form of numerical form. Genetic counselling is an integral part of dealing with patients with genetic abnormality and appropriate genetic counseling can help the patient to avoid the birth of chromosomally abnormal baby and also opens the option of reproduction considering the overall contribution of cytogenetic abnormalities it is very important to know the chromosomal pattern of the couple as a base line investigation before going for ARTs. This will avoid the costly expenses of ARTs of the patients and help to have a chromosomally normal bab