Related Experiment Videos
Mitochondria-targeted metformins: anti-tumour and redox signalling mechanisms
Balaraman Kalyanaraman1, Gang Cheng1, Micael Hardy2
1Department of Biophysics and Free Radical Research , Medical College of Wisconsin , Milwaukee, WI , USA.
Abstract:
Reports suggest that metformin exerts anti-cancer effects in diabetic individuals with pancreatic cancer. Thus, metformin is currently being repurposed as a potential drug in cancer treatment. Studies indicate that potent metformin analogues are required in cancer treatment because of the low bioavailability of metformin in humans at conventional antidiabetic doses. We proposed that improved mitochondrial targeting of metformin by attaching a positively charged lipophilic triphenylphosphonium group will result in a new class of mitochondria-targeted metformin analogues with significantly enhanced anti-tumour potential. Using this approach, we synthesized various mitochondria-targeted metformin analogues with different alkyl chain lengths. Results indicate that the antiproliferative effects increased with increasing alkyl chain lengths (100-fold to 1000-fold). The lead compound, mito-metformin10, potently inhibited mitochondrial respiration through inhibition of complex I, stimulation of superoxide and hydrogen peroxide formation and activation of AMPK. When used in combination with ionizing radiation, mito-metformin10 acted as a radiosensitizer of pancreatic cancer cells. Because of the 1000-fold-higher potency of mitochondria-targeted metformin10, therapeutically effective plasma concentrations likely can be achieved in cancer patients.
Insights
New metformin analogues targeting mitochondria show significantly enhanced anti-cancer effects. The lead compound, mito-metformin10, is 1000-fold more potent, offering potential for effective pancreatic cancer treatment.
Area of Science:
- Biochemistry
- Pharmacology
- Oncology
Background:
- Metformin shows anti-cancer effects in diabetic patients with pancreatic cancer, leading to its repurposing for cancer treatment.
- Metformin analogues with improved bioavailability and potency are needed for effective cancer therapy due to metformin's low bioavailability.
- Mitochondrial targeting is proposed to enhance metformin's anti-tumour potential.
Purpose of the Study:
- To synthesize novel mitochondria-targeted metformin analogues with enhanced anti-tumour activity.
- To evaluate the antiproliferative effects and mechanism of action of these analogues.
- To assess the radiosensitizing potential of the lead compound in pancreatic cancer cells.
Main Methods:
- Synthesis of mitochondria-targeted metformin analogues with varying alkyl chain lengths.
- Assessment of antiproliferative effects and mitochondrial respiration inhibition (Complex I).
- Evaluation of superoxide and hydrogen peroxide formation, AMPK activation, and radiosensitization in pancreatic cancer cells.
Main Results:
- Antiproliferative effects increased with longer alkyl chains, showing 100-fold to 1000-fold enhancement.
- The lead compound, mito-metformin10, potently inhibited mitochondrial respiration and activated AMPK.
- Mito-metformin10 demonstrated radiosensitizing effects on pancreatic cancer cells when combined with ionizing radiation.
Conclusions:
- Mitochondria-targeted metformin analogues, particularly mito-metformin10, exhibit significantly enhanced anti-tumour potency.
- Mito-metformin10's mechanism involves mitochondrial respiration inhibition and AMPK activation.
- The high potency of mito-metformin10 suggests potential for achieving therapeutic plasma concentrations in cancer patients.