The document summarizes a study that examined how cancer cells with different adaptive antioxidant responses proliferate when exposed to fatty acid oxidation in mitochondria. The study found that fatty acid treatment reduced proliferation in HepG2 cells, which increased mitochondrial and antioxidant enzymes, while increasing proliferation in HeLa cells, which decreased these enzymes. Reducing antioxidant enzymes in HepG2 eliminated the anti-proliferative effect of fatty acid treatment by increasing reactive oxygen species and decreasing mitochondria through mitophagy. The results suggest that cancer cells with higher antioxidant capacity can use fatty acids for energy without reactive oxygen species side effects, whereas lower antioxidant cells experience proliferative effects from fatty acid-induced reactive oxygen species signaling.
2. Introduction
Cancer is a disease in which some of the body’s
cells grow damaged and spread to other parts of
the organism.
When normal cells grow old or lose their
function, they die, and new cells take their place.
Sometimes this process isn’t effective, and
damaged cells grow and multiply. These cells
may form tumors, which are lumps of tissue.
Tumors can be malignant or benign.
3. Introduction
Cancer cells act different depending on where they are. They
adapt and take functions from the original cell line.
The use of FAs can be a pro-tumor or anti-tumor factor. A cancer
cell with higher mitochondrial capacity can oxidate FAs without
the side effects of ROS.
Whereas FAs oxidation causes ROS accumulation in cancer
cells with lower antioxidant response. In this case, ROS act as
signaling molecules that activate proliferative pathways.
4. General Objective
Illustrate if adaptive antioxidant response to mitochondrial
fatty acid oxidation determines the proliferative outcome of
different cancer cells.
5. Methods
Western Blot analysis
Is a technique used to detect a specific protein
in a sample. It involves using electrophoresis
to separate the sample's proteins and transfer
it out to the surface of a membrane.
This test was used to determine the
concentration of mitochondrial enzymes in
cancer cells involved in the FAs oxidation.
Some proteins involved in the glucose
metabolism were analyzed too.
Cell proliferation and viability assays
This test monitors the cancer cells over time, the
number of cell divisions, metabolic activity and DNA
synthesis.
The cell counting was made by using Trypan blue, a
dye exclusion test which provide both the rate of
proliferation and the percentage of viable cells.
It helps to differentiate viable cells from dead cells.
6. Methods
Fluorescence microscopy analyses
Is a tool for studying complex processes inside
living cells. It helps to image cells from many genetic
and environmental backgrounds.
At the end of the experiment, this technique was
used to get fluorescent images of cells. A 535 nm
filter was used to acquire green fluorescence and a
590 nm filter was used for red fluorescence
ROS evaluation
This test measures ROS directly in live cells. It
uses DHE as a fluorescent probe for the
detection of ROS generation and is specific for
superoxide and hydrogen peroxide.
The shift in fluorescence intensity of the cell
population marked with DHE was used to
quantify superoxide.
7. Results
Treatment with HA reduced the proliferation of HepG2 and
increased the proliferation rate of HeLa. These results were well
correlated with an increase in mitochondrial markers in HepG2
(Reduced proliferation) and a decrease in the same markers in
HeLa (Increased proliferation) .
They analyzed enzymatic and non-enzymatic antioxidants
upon HA treatment. It showed that HA increased the
expression of SOD1, SOD2, and catalase in cancer cells that
showed reduced proliferation (HepG2), while these enzymes
were down-regulated in cancer cells with an increased
proliferation rate (HeLa).
In order to determine the response of cancer cells to mitochondrial FAs oxidation, they
used HA to treat different cell lines, including HepG2 and HeLa cells, which demonstrated
different responses to lipid catabolism.
8. Results
By reducing the expression of SOD1 (Antioxidant)
in HepG2 cells, there was an increase in
intracellular ROS and the antiproliferative effect of
HA was reduced.
HA was no longer able to raise the mass of
mitochondria, which was decreased by mitophagy
(Degradation of mitochondria), as observed by the
accumulation of mitochondrial markers after Cq
(autophagy inhibitor) treatment.
9. Discussion
Author What did they said? Did they agree?
S. Castelli
The other side of the coin of mitochondrial
metabolism is ROS production, which can have the
function of signaling molecules that activate
downstream transcriptional factors, many of which
are pro-glycolytic or capable of modulating redox
balance.
Yes
S.A. Rial
This result is consistent with another study showing
that HA does not induce the accumulation of
cytotoxic ROS in HepG2 cells and preserves
mitochondrial integrity.
Yes
V. Bhardwaj
Moreover, cancer cells have higher levels of
intracellular ROS than normal cells.
Yes
10. Conclusions
Thanks to Molecular Biology we have the tools to examine the concentration ROS and fat
acids in a damaged cell and find a way to prevent it from multiplying.
Most of the resources used in the experiment involve biology, so this is a science that can
be used for the treatment of cancer and other cell or mitochondrial-based diseases.
