Elucidation of underlying molecular mechanism of 5-Fluorouracil chemoresistance and its restoration using fish oil in experimental colon carcinoma

The role of the natural compound naringenin in AMPK-mitochondria modulation and colorectal cancer inhibition

BACKGROUND

Although AMP-activated protein kinase (AMPK) has been extensively studied in cellular processes, the understanding of its substrates, downstream functions, contributions to cell fate and colorectal cancer (CRC) progression remains incomplete.

PURPOSE

The aim of this study was to investigate the effects and mechanisms of naringenin on CRC.

METHODS

The biological and cellular properties of naringenin and its anticancer activity were evaluated in CRC. In addition, the effect of combined treatment with naringenin and 5-fluorouracil on tumor growth in vitro and in vivo was evaluated.

RESULTS

The present study found that naringenin inhibits the proliferation of CRC and promote its apoptosis. Compared with the naringenin group, naringenin combined with 5-fluorouracil had significant effect on inhibiting cell proliferation and promoting its apoptosis. It is showed that naringenin activates AMPK phosphorylation and mitochondrial fusion in CRC. Naringenin combined with 5-fluorouracil significantly reduces cardiotoxicity and liver damage induced by 5-fluorouracil in nude mice bearing subcutaneous CRC tumors, and attenuates colorectal injuries in azoxymethane/DSS dextran sulfate (AOM/DSS)-induced CRC. The combination of these two drugs alters mitochondrial function by increasing reactive oxygen species (ROS) levels and decreasing the mitochondrial membrane potential (MMP), thereby stimulating AMPK/mTOR signaling. Mitochondrial dynamics are thereby regulated by activating the AMPK/p-AMPK pathway, and mitochondrial homeostasis is coordinated through increased mitochondrial fusion and reduced fission to activate apoptosis in cancer cells.

CONCLUSIONS

Our data suggest that naringenin is important for inhibiting CRC proliferation, possibly through the AMPK pathway, to regulate mitochondrial function and induce apoptosis in CRC.

The Salmon Oil OmeGo Reduces Viability of Colorectal Cancer Cells and Potentiates the Anti-Cancer Effect of 5-FU

Colorectal cancer (CRC) is one of the most common cancer types worldwide. Chemotherapy is toxic to normal cells, and combinatory treatment with natural well-tolerated products is being explored. Some omega-3 polyunsaturated fatty acids (n-3 PUFAs) and marine fish oils have anti-cancer effects on CRC cells. The salmon oil OmeGo (Hofseth BioCare) contains a spectrum of fatty acids, including the n-3 PUFAs docosahexaenoic acid (DHA) and eicosahexaenoic acid (EPA). We explored a potential anti-cancer effect of OmeGo on the four CRC cell lines DLD-1, HCT-8, LS411N, and LS513, alone and in combination with the chemotherapeutic agent 5-Fluorouracil (5-FU). Screening indicated a time- and dose-dependent effect of OmeGo on the viability of the DLD-1 and LS513 CRC cell lines. Treatment with 5-FU and OmeGo (IC20-IC30) alone indicated a significant reduction in viability. A combinatory treatment with OmeGo and 5-FU resulted in a further reduction in viability in DLD-1 and LS513 cells. Treatment of CRC cells with DHA + EPA in a concentration corresponding to the content in OmeGo alone or combined with 5-FU significantly reduced viability of all four CRC cell lines tested. The lowest concentration of OmeGo reduced viability to a higher degree both alone and in combination with 5-FU compared to the corresponding concentrations of DHA + EPA in three of the cell lines. Results suggest that a combination of OmeGo and 5-FU could have a potential as an alternative anti-cancer therapy for patients with CRC.

Fatty acids in cancer chemoresistance

Despite the remarkable clinical success of immunotherapy and molecular targeted therapy in patients with advanced tumors, chemotherapy remains the most commonly used treatment for most tumor patients. Chemotherapy drugs effectively inhibit tumor cell proliferation and survival through their remarkable mechanisms. However, tumor cells often develop severe intrinsic and acquired chemoresistance under chemotherapy stress, limiting the effectiveness of chemotherapy and leading to treatment failure. Growing evidence suggests that alterations in lipid metabolism may be implicated in the development of chemoresistance in tumors. Therefore, in this review, we provide a comprehensive overview of fatty acid metabolism and its impact on chemoresistance mechanisms. Additionally, we discuss the potential of targeting fatty acid metabolism as a therapeutic strategy to overcome drug resistance.

Synthesis and performance evaluation of 5-fluorouracil-loaded zwitterionic poly(4-vinylpyridine) nanoparticles

After polymerizing 4-vinylpyridine, the obtained polymer was converted into zwitterionic nanoparticles containing 5-fluorouracil. Their potential for long-term blood circulation was investigated by in vitro and in vivo experiments.