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Research Projects

Huber Lab

Chemoprevention by coffee and coffee components

Although "chemical compounds" are often rather perceived as pro-carcinogenic in the eyes oft the public, it has to be strongly emphasized that many of these compounds may also protect against cancer. The intake of such substances is at times caused by life-style but can also occur in the frame of targeted intervention measures.

The protective mechanisms involved are summarized as "chemoprevention" (other than chemotherapy) whenever they are effective before diagnosis and thus usually before the onset of symptoms of the disease. Since cancer is mostly diagnosed at a rather late time point in the carcinogenic process, chemopreventive mechanisms may be aimed at various stages of carcinogenesis (e.g. carcinogen-activation, tumor initiation, tumor promotion) and equally at many different mechanistic systems. Thus, a varied field of action for chemoprevention research at different levels is provided

Since epidemiological studies had repeatedly revealed lower rates of colon and liver cancers in coffee drinkers we made potential protective mechanisms of coffee and its components a specific focus in our research activity.

Our main interest is directzed towards the diterpenes kahweol and cafestol which are contained in the coffee bean and in several types of coffee. Indeed, we have observed more than one beneficial effect as a consequence of their intake. For instance, carcinogen-detoxfying enzymes are induced whereas carcinogen-activating enzymes are at the same time inhibited. There is also enhancement of an important system that repairs alkylated DNA and protection against oxidative stress is increased at several levels.

Investigation of all of these systems of protection is presently being continued in order to achieve a more thorough characterization of the involved mechanisms and to find new approaches. In this context, we are particularly intertested in redox effects on thious pols such as glutathione and thioredoxin which may, just like "switches", influence the function of numerroteins. In addition, other potentially chemopreventive compounds (e.g. xanthumol oder quercetin) are/were targets in our studies.

Effects of rancid fat on the redox system

The so-called "Western Diet", the typical fat-enriched diet of the Western world, is associated with an elevated rate of cancers of for instance the liver.

Liver cancer is frequently a consequence of cirrhosis for which inflammation appears to be a requirement, a classical trigger for such inflammation being alcohol abuse. However, the recently increasing appearance of NASH ("non-alcoholic steatohepatitis") in people who are overweighed but not alcohol consumers suggests that overnutrition alone is capable of causing liver cirrhosis and liver cancer, so that Western Diet appears to trigger inflammatory mechanisms by itself.

Of great interest in this connection are the consequences of exposure to rancid, i.e. peroxidized fat, as it occurs when fried fast food is being consumed.

Application of bacterial "ghosts" in cancer prevention

Bacteria may be converted to so-called "ghosts", i.e. essentially be reduced to their inner and outer membranes.

Thus, the pathogenic functions are eliminated whereas the capacity to cell invasion is preserved. Ghosts can be loaded with a variety of substances and thus be used for a more efficient application of these substances at the cellular level.

In cooperation with Professor Werner Lubitz (Dept. Medical/Pharmaceutical Chemistry, University of Vienna) we investigate the possibilties of this system in chemoprevention strategies.