CANCER DRUG RESISTANCE
Introduction:
• Treatment of cancer varies person to person depending on the variety in individual factors because every cancer has specific pathological and molecular characteristics such as location, health and extent of disease.
• The main part is to destroy the cancerous cells by least harming the normal tissue. Tumors can be present in the parts of the body where drug cannot easily penetrate or could be protected by the local environments due to increase tissue hydrostatic pressure or altered tumor vasculature.
Chemotherapy:
• There are several treatments to combat cancers which can work well alone or in combination with sequentially or simultaneously. Of those treatments the most
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• Today we can talk about drug resistance in two classes, target specific and target nonspecific.
• In old times termed as acquired drug resistance and intrinsic drug resistance respectively.
• Drug resistance in cancer is a term used, which means that a patient having cancer has been resistant to the chemotherapies.
• Drug resistance means the decrease in the efficacy of a drug. Drug resistance may develop at once or the drug becomes ineffective overtime.
• When cancer becomes resistant to a lot of structurally different and unrelated chemotherapies then it is called multidrug resistant cancer.
• It is also known as Antineoplastic resistance and in this the cancerous cells become resistant to drugs by a lot of mechanisms.
Intrinsic drug resistance:
• This type of resistance means that an organism or cell have a characteristic property which make all the normal members of the specie tolerable towards particular drug or any specific chemical change in its environment.
• In that case the feature or property responsible for the resistance is inherent and integral property of the specie which has arisen over the course of evolution.
• All the cells whether normal or cancerous exhibit a degree of intrinsic resistance to the compounds they normally encounter.
• In mammalian cells the rate of division of the cells is also an important in the case of intrinsic cancer drug resistance.
• It is the fact
Significance: understanding the mechanism of drug resistance in cancer leads to developing more potent drugs.
In order to become cancerous a cell has many molecular changes that can occur including: tumor suppressor gene inactivation, oncogene activation, telomerase lengthening, ability to evade apoptosis, and angiogenesis (Mechanisms in Medicine, 2012). There are a few particular
Cancer is described as the abnormal growth of cells. Normal cells are replaced with abnormal cells in which their deoxyribonucleic acid (DNA) has been damaged or augmented (McCance & Huether, 2014). Cancer cells with their various DNA changes are characterized by growing uncontrollably, being immortal with an unlimited lifespan
When treated with a revolutionary drug called: imatinib (Gleevec) the 5-year observed survival is greater than 90%
Cancer is a disease caused by an uncontrolled division of abnormal cells. The DNA sequence in cells can be changed as a result of copying errors during replication. If these changes whatever their cause are left uncorrected, both growing and non-growing somatic cells might gain many mutations that they could no longer function. The relevance of DNA damage and repair to the generation of cancer was obvious when it was recognized that everything that causes cancer also cause a change in the DNA sequence. Tumor suppressor genes are protective genes and normally they limit cell growth by monitoring the speed of cell division, repair mismatched DNA and control when a cell dies. When a tumor suppressor gene is mutated cells grow
Cancer cells displayed marked alterations in pro-growth signaling pathways and key metabolic pathways relative to non-tumorigenic differentiated cells, often due to loss of tumor suppressor genes and oncogenic driver mutations. The remodeled signaling and metabolic profiles of cancer cells support not only their aberrant proliferation, but also their survival. Further factors such as intra-tumoral heterogeneity, altered redox status, and epigenetic modifications all contribute to the ability of certain tumors to develop drug resistance and persist under standard treatments.
Mutations (for most cancers) must appear in both tumour suppressing genes and oncogenes for cancers to form. The tumour suppressing genes and oncogenes act in complementary fashion to one another; one pulls forward, and the other pushes back ensuring that the cell cycle occurs in a controlled manner (Sherr, 2004).
Cancer is a disease in which cells multiply out of control and gradually build a mass of tissue called a tumor. There has been a large amount of research dedicated to the treatment and cure of cancer. Several types of treatments have been developed. The following are just some of the major examples of cancer therapy: surgery, chemotherapy, radiation therapy, biologic therapy, biorhythms, unconventional treatments, and hyperthermia. Each type of treatment is discussed in detail below.
Drug resistance is more likely to develop in a species of bacteria that can double its population every 20 minutes because of the amount of bacteria that that is created in a
“The treatment of cancer involves many different areas,” Dr. Labow said. “It is not just surgery, it’s not just chemotherapy, and it’s not just radiation. It is involving genetics, it is involving nutritionists, it is involving all of these
This article focuses more on tolerance rather than the idea that mutations in the bacteria’s genome allow for resistance which due to its being an evolutionary advantage becomes more frequent in bacterial colonies. To try to explain the way antibiotics work the author Ed Yong uses this metaphor “think of the antibiotics as wrenches thrown into the midst of whirring machines. If the machines are off—their cogs still, their motors silent—the wrenches have no effect.” He tries to explain the concept of tolerance through this metaphor by pointing out that if the machine, the bacteria, are off then the wrenches, the antibiotics, will not affect the machine. These persisters or bacteria that use tolerance slow down or stop its functions until the antibiotic dissipates.
Several methods such as surgery, radiation, and chemotherapy have been used to treat cancers. The cancer patients who are not helped
* Hormonal Therapy: Some cancers need hormones to grow, used to block cancer cells from getting hormones to grow.
Cancer is a genetic disease caused by certain changes to genes that control the way our cells function, especially how they grow and divide. Genes carry the instructions to make proteins, which do much of the work in our cells. Certain gene changes can cause cells to evade normal growth controls and become cancer. Genetic changes that promote cancer can be inherited from our parents if the changes are present in germ cells, which are the reproductive cells of the body (eggs and sperm). Such changes, called germline changes, are found in every cell of the offspring. In general, cancer cells have more genetic changes than normal cells. But each person’s cancer has a unique combination of genetic alterations.
There are many different type of cancers, there are also many different types of treatments. One of the most known types of treatments would be chemotherapy. Chemotherapy can be used for a wide range of different types of cancers and diseases, and each of the different types of cancers or diseases require a different group, and sometimes order, of chemicals to properly treat the cancer or disease. These chemicals include: Alkylating agents, Antimetabolites, Anthracyclines, Topoisomerase inhibitors, mitotic inhibitors, corticosteroids, and more. Each of these drugs previously listed have its own cancer type(s) or disease(s) that it can assist in treating. Some of these cancers include: Leukemia, Lymphoma, Hodgkin disease, multiple