Multifactorial nature of hepatocellular carcinoma drug resistance: could plant polyphenols be helpful?

Abstract

Primary hepatocellular carcinoma (HCC) is a quite frequent tumor which results in high mortality and most often exhibits a poor response to present drug therapies. Clearly, a thorough understanding of the biological bases of this malignancy might suggest new strategies for its treatment. Here we examine the evidences that both "pharmacological" mechanisms (e.g. drug transporter or detoxification enzyme over-expression) and alterations in other critical factors, including the IAPs (Inhibitory of Apoptosis Proteins), involved in enhancement of cell survival and proliferation may determine the therapeutic resistance of HCC; we also underline the possible role in the process of the activation of transcription factors, like NF-kappaB, capable of contemporaneously up-regulating the mechanisms discussed. On this basis, we finally comment on the possible use of natural multi-targeted antitumoral agents like plant polyphenols to achieve sensitization to treatments in HCC.

Figure 1

Some of the principal tumor targets of polyphenols discussed in the text. The agents may directly interfere with the affected molecules (e.g. Telomerase, COX-2 and P-gp) and/or influence their activity or expression due to modifications in an upstream regulatory signal or in factors (e.g. NF-κB) which regulate gene transcription.