The Relationship Between Cancer and The Cell Life Cycle
During the cell cycle, a cell goes through certain checkpoints. These are points where the cell has to determine whether or not it is ready to proceed forward into mitosis. If something isn’t right with the cell at any checkpoint, it will be stopped until the issue is resolved.
Cancer cells do not respond appropriately to stimuli during checkpoints and continue through to mitosis even when problems should be corrected. This allows cancerous cells to replicate themselves without restraint by becoming immortal.
Scientists have noticed that this feature of cancer cells can also be exploited to defeat cancer itself! An old chemotherapy drug known as Hydroxyurea works by artificially inducing G1-S arrest. That means that instead of allowing your cells to continue to go through the cell cycle, they are suddenly put into a sort of limbo. This causes all your cells – including cancerous ones – to commit suicide en masse.
How are cancer cells formed:
Cancer Cells are in many ways abnormal in their metabolic activities. They have high glycolytic rates, a very active pentose phosphate pathway, low mitochondrial activity, and lactic acid.
These all contribute to the acidic microenvironment that is also characteristic of cancers. The origin of cancer cells is quite interesting. Cancer cells are thought to originate from normal body cells when the DNA in those cells accumulates enough mutations over time that allow them to become cancer cells.
The more cell divisions that occur, the more opportunities for mutations within a given cell lineage there are likely to be. Genetic changes can occur by mutation oncogenes or tumor suppressor genes, deletions in chromosomal regions, or other mechanisms.
How do cancer cells differ from normal cells:
Usually, cell growth and division are tightly controlled by several mechanisms. As the cells divide, each new daughter cell receives one complete copy of the parent cell’s DNA. This allows for the repair of any damaged DNA that was not adequately copied during the previous cycle.
One form of damage commonly found in cancerous cells is an anomaly called chromosomal instability (CIN). CIN cells are defective in their ability to replicate their DNA during each cell division cycle accurately.
At some point in time, they acquired a mutation or, more likely, many mutations throughout different chromosomes within their genome(the entire set of genes contained in the chromosome). These mutations lead to changes in how the cell divides, resulting in uncontrolled growth if left unchecked.
This process is not entirely understood but is thought to be initiated by oxidative stress. Oxidative stress occurs when more reactive oxygen species (ROS) are present than the cell has antioxidants to counteract their harmful effects.
Typically, cells have several lines of defense against oxidative stress. They can use antioxidant enzymes and scavenge for free hydrogen atoms through glycolysis. They are usually contained within a limited environment inside the cell membrane where ROS produced in one section should not affect other cell regions. If these measures fail, then stem cells may mutate into cancer cells as a means of self-defense against genetic damage.
Cancer cells continue to divide without regard for normal growth controls that typically stop division after several cell divisions. The genetic defects from each new generation of cells can be passed on to the next generation when this happens. The result is that the stem cells become cancerous due to accumulated damage in their DNA by simply trying to keep dividing over and over again past what should have been the standard limit of cell division.
what stage of mitosis does cancer occur:
One explanation for this is that cancer cells may be susceptible to chemotherapies to disrupt mitosis. Thus, the first cell cycle after chemotherapy treatment might be particularly vulnerable to damage by ROS, resulting in mutations and ultimately cancer.
What causes these cancer cells:
The process of carcinogenesis (initiation of cancer) requires genetic damage to occur within normal stem cells of the body. Dietary or environmental toxins can cause these initial mutations. They can occur due to random errors during DNA replication that are passed on from parent to daughter cells as it divides.
Most cancers result from DNA mutations occurring in stem cells over decades rather than a single mutation event early in life. Once initiated, the entire DNA of the cancer cell is changed, leading to uncontrolled growth and division.
Some cancers may develop after a single mutation event that results in an abnormal oncogene or tumor suppressor gene. An example of this would be an amplification(increase)of the MYC gene found within many lung cancers. Mutations in the K-RAS oncogene can also lead to lung cancer by creating a constitutively active version that drives cells into excessive growth.
Other mutations cause genetic changes that result in uncontrollable cell division despite standard mechanisms for ending replication once all chromosomes are copied correctly. This type of cancer progression is known as CIN (Chromosomal Instability). As mentioned above, oxidative stress due to ROS damage can play a significant role in causing mutations.
cancer cell division:
Cancer cells (also known as malignant cells) can multiply without control or order. They do not listen to the body’s instructions anymore.
Some cancer cells can invade and destroy tissues and organs. This process is called metastasis, spreading out of the tumor mass into other parts of the organ or to other parts of the body.
All cancer forms:
Cancer is a classifications disease that includes more than 100 different abnormalities at a cellular level. These defects can be inherited through genetics, during prenatal development, or acquired after birth due to exposure to carcinogens such as smoke, radiation, or certain chemicals. External factors also play an essential role in causing cancer, such as exposure to the sun’s ultraviolet rays or a high-fat diet.
How do cancer cells bypass the cell cycle checkpoints:
Many processes control the way cancer cells divide, live, and die. One process is cell division itself. Cancer cells should stop dividing when they sense they have divided an exact number of times (a process called “cellular senescence”). Still, sometimes they can bypass this mechanism and continue to divide even after hitting their limit (a process called “cancer stemness”). Another process is gathering more resources than necessary to make more energy (a process called “hyperplasia”). Some scientists believe that if we understand how these processes work, we might design therapies that target them.
How do cancer cells damage the DNA:
DNA is a molecule inside all cells in our body responsible for keeping all the instructions for creating and sustaining life. Damaged or mutated DNA can lead to many different diseases, including cancer.
Cancer occurs when there is a mutation or damage to the DNA of a dividing (proliferating) cell such as a skin cell, lung cell, bone marrow blood cell, etc. This damage is often caused by exposure to carcinogens such as tobacco smoke and radioactive materials. Other forms of cancer can be inherited from parents. They may include Genes that don’t work correctly (mutations), abnormal numbers of chromosomes (such as an extra chromosome 13), too many growth signals, and old age.