Unmasking cancer’s mitochondrial heist
Cancer, originating from the Greek word karkinos, or crab, defines a group of diseases responsible for almost 10 million lives lost worldwide every year[1]. Our body is composed of 30-40 trillion cells. Each time a cell divides, approximately 3 million base pairs of DNA (the molecule that carries our genetic blueprint) are meticulously copied by tightly controlled reactions, ensuring each descendant receives an error-free copy of the information. However, lurking amongst these trillions of cells, one cell committed a serious offence — it failed to detect a mistake in the DNA sequence. Instead of fixing the problem, or initiating programmed cell death (apoptosis), the mutation remained in the blueprint and was packaged up for the next generation of cells. As these mutations accumulated, the finely tuned symphony of cell division was irreparably hijacked, and this once healthy cell became an unstoppable dividing machine that started to invade and strangle healthy tissue: this is cancer.
Treating cancer is complicated because it is a disease of self, a normal cell gone rogue. Luckily for us, our bodies search for abnormal cells, assembling a taskforce of specialised immune cells called T-cells to hunt and destroy them. However, when these elite hunters arrive at the battleground, they encounter harsh terrain. Low energy and oxygen supplies, combined with exposure to molecular weapons (like reactive oxygen species (ROS)) compromise their ability to work[2],[3]. As they struggle to contain the situation, these T-cells can burnout, leaving cancer free to conquer.
Recent research reveals that specific cancerous cells also avoid T-cell attacks by poaching supplies from within enemy lines[4]. They burrow into T-cells using tiny tunnels called nanotubes to extract the very factories that make cellular energy, the mitochondria[5]. But what are the consequences of mitochondria theft for cancer patients? Using a statistical approach, scientists scored patient tumours based on a specific pattern of gene expression (how information in DNA is translated into function) to identify cancer cells with pilfered mitochondria[4]. Most tumours had high scores compared to normal tissue. Shockingly, in tumours with higher scores, the seized mitochondria were likely exploited to make energy for their captors, as these tumours had evidence of an enhanced ability to grow and divide. Adding insult to injury, higher scores also correlated with reduced patient survival.
Though these findings complicate our war on cancer, future investigations in this area with no doubt uncover novel strategies to fight back against this molecular thievery.
[1] https://www.who.int/news-room/fact-sheets/detail/cancer%5b/ref
[2] https://www.sciencedirect.com/science/article/pii/S1550413121000668#:~:text=The%20accumulation
[3] www.frontiersin.org/articles/10.3389/fimmu.2023.1151632/full%5b/ref
[4] https://www.sciencedirect.com/science/article/pii/S1535610823003197?via%3Dihub
[5] https://www.pnas.org/doi/full/10.1073/pnas.0510511103
Edited by Despoina Allagioti
Copy-edited by Rachel Shannon
