Radiotherapy and Its Side Effects: Chapter 3 - Modern Technologies in Radiotherapy

 PART II

Chapter 3

Modern Technologies in Radiotherapy (Cont'd)

3. Improvement of radiotherapy by using radioprotectors 

Radioprotection is another important approach in radiotherapy. Basically, a therapeutic agent, radioprotector, is administered to a patient before the patient is treated by radiotherapy. In other words, radioprotectors protect normal tissues against radiation-induced side effects. Ideally, radioprotectors produce or stimulate certain biological reactions/products which then counteract the adverse effects caused by radiation. 

Unfortunately, there has not been any significantly improved radioprotector since the discovery and approval of a popular broad-spectrum radioprotective drug, amifostine (Fig. 2.3), by the FDA. Interestingly, amifostine was originally approved to reduce the cumulative renal toxicity associated with repeated administration of cisplatin in patients with advanced ovarian cancer and non-small cell lung cancer. However, while nephroprotection was observed, amifostine also formed chelation with cisplatin and reduced its anticancer activity. Therefore, its indication for chemoprotection in cisplatin treatment in non-small cell lung cancer was withdrawn in 2005.

Fig. 2.3.   Structure of amifostine (WR2721) and its metabolite

 

 More details about amifostine and other radioprotectors are described in Part III.

© Jiajiu Shaw, 2021

Disclaimer: This blog is written solely for informational purposes. It does not constitute the practice of any medical, nursing or other medical professional health care advice, diagnosis, or treatment. All contents posted are extracted from the book, "SIDE EFFECTS OF CHEMOTHERAPY AND RADIOTHERAPY", prepared by Dr. Jiajiu Shaw, Dr. Frederick Valeriote, and Dr. Ben Chen. 

Chemotherapy and Its Side Effects: Chapter 2 - Antibiotics

Chapter 2

Anticancer Drugs - D. Antibiotics

There are a number of antibiotics being used as anticancer drugs. Examples of antitumor antibiotics include doxorubicin, dactinomycin, epirubicin, and bleomycin. DNA binding agents can have a number of outcomes which result in cell death. They usually are planer in structure and multi-ringed to allow them to non-covalently bind to the bases in DNA (and RNA). Compounds like actinomycin D turn off RNA syntheses once they intercalate with the DNA. Compounds, like bleomycin, create free radicals after intercalating with DNA strands.

In this section, we will focus on a class of anticancer drugs, anthracyclines. Anthracyclines are derived from Streptomyces bacteria. They are used to treat a number of cancers, including breast, ovarian, and lung cancer as well as leukemia. Anthracyclines are known to form intercalation with DNA to achieve anticancer effect although the complete mechanism is somewhat complex (intercalation is a reversible inclusion between two different molecules or groups). Anthracyclines have played a very important role in chemotherapy and have been used in many different types of cancers.

Although anthracyclines are effective against more cancers than most other classes of anticancer drug, anthracyclines do have several adverse effects including cardiotoxicity. A specific example of anthracyclines, Doxorubicin, is described below.

Doxorubicin (trade names: Adriamycin PFS, Adriamycin RDF, or Rubex)

Doxorubicin (Figure 1.11) is closely related to another anthracycline occurred naturally, daunorubicin. Just like all anthracyclines, doxorubicin intercalates with DNA and causes structural distortion of DNA. As a result, replication of DNA is inhibited and cancer cells eventually die. However, this intercalation with DNA can also happen to normal cells and causes significant side effects.

Fig. 1.11  Doxorubicin (left) and daunorubicin (right)

Doxorubicin is commonly used in the treatment of a wide range of cancers, including breast, ovarian, and lung cancer as well as leukemia. Doxorubicin is administered intravenously and its main side effects include cardiomyopathy, myelosuppression, and secondary malignancies.

© Jiajiu Shaw, 2019

Disclaimer: This blog is written solely for informational purposes. It does not constitute the practice of any medical, nursing or other medical professional health care advice, diagnosis, or treatment. All contents posted are extracted from the book, "SIDE EFFECTS OF CHEMOTHERAPY AND RADIOTHERAPY", prepared by Dr. Jiajiu Shaw, Dr. Frederick Valeriote, and Dr. Ben Chen. 

Natural Products for Cancer Prevention/Management (19)

Oleic Acid

Oleic acid is a monounsaturated fatty acid; it is odorless, colorless to slightly yellow. Oleic acid is found in plant oils, including avocados, olives, sesame seeds, pecans, almonds, peanuts, and other nuts. It is also found in animal fats.

      Oleic acid helps lower low density lipoprotein (LDL), which is often referred to as the bad cholesterol.  In addition, Mediterranean diet contains high levels of oleic acid, which was reported to lower cancer risks.  Another report showed that oleic acid is anticancer through the suppression of elevated levels of human epidermal growth factor receptor-2. 


© Jiajiu Shaw, 2017

Disclaimer: This blog is written solely for informational purposes. It does not constitute the practice of any medical, nursing or other medical professional health care advice, diagnosis, or treatment. All contents posted are extracted from the book I wrote, "IS CANCER IN US", published recently.

Natural Products for Cancer Prevention/Management (12)

Resveratrol

Resveratrol is found in grapes and several different berries.  Due to its high demand, most commercial products of resveratrol have been extracted from a Chinese plant, HuQi. 

It has been reported that resveratrol has several positive effects in health, including anti-inflammatory, anticancer, and anti-aging effects.  Although there have been some supportive data for the health benefits of resveratrol from in vitro and animal studies, there has not been a clear conclusion in human clinical studies. 

© Jiajiu Shaw, 2016

Disclaimer: This blog is written solely for informational purposes. It does not constitute the practice of any medical, nursing or other medical professional health care advice, diagnosis, or treatment. All contents posted are extracted from the book I am writing, "IS CANCER IN US", to be published in about two months.

Natural Products for Cancer Prevention/Management (11)

Resveratrol

Resveratrol is found in grapes and several different berries.  Due to its high demand, most commercial products of resveratrol have been extracted from a Chinese plant, HuQi.

It has been reported that resveratrol has several positive effects in health, including anti-inflammatory, anticancer, and anti-aging effects.  Although there have been some supportive data for the health benefits of resveratrol from in vitro and animal studies, there has not been a clear conclusion in human clinical studies. 

© Jiajiu Shaw, 2016

Disclaimer: This blog is written solely for informational purposes. It does not constitute the practice of any medical, nursing or other medical professional health care advice, diagnosis, or treatment. All contents posted are extracted from the book I am writing, "IS CANCER IN US", to be published in about two months.