Boron Chemistry And Applications To Cancer Treatment.pdf
Boron Chemistry and Its Applications to Cancer Therapy: What You Need to Know
Boron is a chemical element that has many interesting properties and applications in various fields, including medicine. Boron compounds, such as carboranes, dodecaborates, metallacarboranes and metallaboranes, have been studied for their potential use in cancer treatment, especially in a technique called boron neutron capture therapy (BNCT).
Boron Chemistry And Applications To Cancer Treatment.pdf
What is Boron Neutron Capture Therapy?
Boron neutron capture therapy is a type of radiotherapy that uses boron atoms to selectively target and destroy cancer cells. The principle of BNCT is based on the nuclear reaction that occurs when boron-10, a stable isotope of boron, absorbs a low-energy neutron and splits into two highly energetic particles: an alpha particle and a lithium-7 nucleus. These particles have a very short range in tissue, about 5-9 micrometers, which is comparable to the diameter of a single cell. Therefore, if boron-10 atoms are delivered to cancer cells and irradiated with neutrons, they can cause lethal damage to the tumor cells without harming the surrounding healthy tissue.
How are Boron Compounds Delivered to Cancer Cells?
The challenge of BNCT is to deliver enough boron-10 atoms to the tumor cells and avoid accumulation in normal cells. This requires the design of boron-containing compounds that have high affinity and specificity for cancer cells, as well as good pharmacokinetic and biodistribution properties. Several types of boron compounds have been developed and tested for BNCT, such as:
Carboranes: These are organometallic compounds that contain carbon, boron and hydrogen atoms arranged in polyhedral cages. Carboranes can be modified with various functional groups to enhance their solubility, stability and targeting ability. For example, carboranyl porphyrins can bind to tumor cells via transferrin receptors, while carboranyl amino acids can be incorporated into peptides or proteins that recognize specific receptors or antigens on cancer cells.
Dodecaborates: These are anionic compounds that contain 12 boron atoms and 10 hydrogen atoms in a closo structure. Dodecaborates can be conjugated with biomolecules such as antibodies, hormones or nucleic acids to target cancer cells. For example, BSH (sodium borocaptate) and BPA (p-boronophenylalanine) are two dodecaborate derivatives that have been used clinically for BNCT of brain tumors and melanoma.
Metallacarboranes: These are hybrid compounds that contain a metal atom (such as cobalt, iron or nickel) coordinated to one or more carborane ligands. Metallacarboranes can exhibit magnetic, optical or catalytic properties that can be exploited for imaging or therapy purposes. For example, cobalt bis(dicarbollide) can act as a MRI contrast agent or a neutron capture agent for BNCT.
Metallaboranes: These are similar to metallacarboranes but contain one or more boron atoms instead of carbon atoms in the ligands. Metallaboranes can also have various biological applications depending on the metal and the ligand. For example, ruthenium metallaboranes can induce apoptosis in cancer cells by generating reactive oxygen species.
What are the Advantages and Limitations of BNCT?
BNCT has some advantages over conventional radiotherapy, such as:
Selectivity: BNCT can target only the tumor cells that have accumulated boron compounds and spare the normal cells that have low or no boron uptake.
Efficacy: BNCT can kill tumor cells that are resistant to other treatments, such as chemotherapy or radiation.
Safety: BNCT can use low-energy neutrons that have minimal side effects on healthy tissue and do not cause secondary radiation.
However, BNCT also faces some limitations, such as:
Availability: BNCT requires a neutron source that can provide a sufficient
Boron Chemistry and Its Applications to Cancer Therapy: What You Need to Know
Boron is a chemical element that has many interesting properties and applications in various fields, including medicine. Boron compounds, such as carboranes, dodecaborates, metallacarboranes and metallaboranes, have been studied for their potential use in cancer treatment, especially in a technique called boron neutron capture therapy (BNCT).
What is Boron Neutron Capture Therapy?
Boron neutron capture therapy is a type of radiotherapy that uses boron atoms to selectively target and destroy cancer cells. The principle of BNCT is based on the nuclear reaction that occurs when boron-10, a stable isotope of boron, absorbs a low-energy neutron and splits into two highly energetic particles: an alpha particle and a lithium-7 nucleus. These particles have a very short range in tissue, about 5-9 micrometers, which is comparable to the diameter of a single cell. Therefore, if boron-10 atoms are delivered to cancer cells and irradiated with neutrons, they can cause lethal damage to the tumor cells without harming the surrounding healthy tissue.
How are Boron Compounds Delivered to Cancer Cells?
The challenge of BNCT is to deliver enough boron-10 atoms to the tumor cells and avoid accumulation in normal cells. This requires the design of boron-containing compounds that have high affinity and specificity for cancer cells, as well as good pharmacokinetic and biodistribution properties. Several types of boron compounds have been developed and tested for BNCT, such as:
Carboranes: These are organometallic compounds that contain carbon, boron and hydrogen atoms arranged in polyhedral cages. Carboranes can be modified with various functional groups to enhance their solubility, stability and targeting ability. For example, carboranyl porphyrins can bind to tumor cells via transferrin receptors, while carboranyl amino acids can be incorporated into peptides or proteins that recognize specific receptors or antigens on cancer cells.
Dodecaborates: These are anionic compounds that contain 12 boron atoms and 10 hydrogen atoms in a closo structure. Dodecaborates can be conjugated with biomolecules such as antibodies, hormones or nucleic acids to target cancer cells. For example, BSH (sodium borocaptate) and BPA (p-boronophenylalanine) are two dodecaborate derivatives that have been used clinically for BNCT of brain tumors and melanoma.
Metallacarboranes: These are hybrid compounds that contain a metal atom (such as cobalt, iron or nickel) coordinated to one or more carborane ligands. Metallacarboranes can exhibit magnetic, optical or catalytic properties that can be exploited for imaging or therapy purposes. For example, cobalt bis(dicarbollide) can act as a MRI contrast agent or a neutron capture agent for BNCT.
Metallaboranes: These are similar to metallacarboranes but contain one or more boron atoms instead of carbon atoms in the ligands. Metallaboranes can also have various biological applications depending on the metal and the ligand. For example, ruthenium metallaboranes can induce apoptosis in cancer cells by generating reactive oxygen species.
What are the Advantages and Limitations of BNCT?
BNCT has some advantages over conventional radiotherapy, such as:
Selectivity: BNCT can target only the tumor cells that have accumulated boron compounds and spare the normal cells that have low or no boron uptake.
Efficacy: BNCT can kill tumor cells that are resistant to other treatments, such as chemotherapy or radiation.
Safety: BNCT can use low-energy neutrons that have minimal side effects on healthy tissue and do not cause secondary radiation.
However, BNCT also faces some limitations, such as:
Availability: BNCT requires a neutron source that can provide a sufficient flux
Boron Chemistry and Its Applications to Cancer Therapy: What You Need to Know
Boron is a chemical element that has many interesting properties and applications in various fields, including medicine. Boron compounds, such as carboranes, dodecaborates, metallacarboranes and metallaboranes, have been studied for their potential use in cancer treatment, especially in a technique called boron neutron capture therapy (BNCT).
What is Boron Neutron Capture Therapy?
Boron neutron capture therapy is a type of radiotherapy that uses boron atoms to selectively target and destroy cancer cells. The principle of BNCT is based on the nuclear reaction that occurs when boron-10, a stable isotope of boron, absorbs a low-energy neutron and splits into two highly energetic particles: an alpha particle and a lithium-7 nucleus. These particles have a very short range in tissue, about 5-9 micrometers, which is comparable to the diameter of a single cell. Therefore, if boron-10 atoms are delivered to cancer cells and irradiated with neutrons, they can cause lethal damage to the tumor cells without harming the surrounding healthy tissue.
How are Boron Compounds Delivered to Cancer Cells?
The challenge of BNCT is to deliver enough boron-10 atoms to the tumor cells and avoid accumulation in normal cells. This requires the design of boron-containing compounds that have high affinity and specificity for cancer cells, as well as good pharmacokinetic and biodistribution properties. Several types of boron compounds have been developed and tested for BNCT, such as:
Carboranes: These are organometallic compounds that contain carbon, boron and hydrogen atoms arranged in polyhedral cages. Carboranes can be modified with various functional groups to enhance their solubility, stability and targeting ability. For example, carboranyl porphyrins can bind to tumor cells via transferrin receptors, while carboranyl amino acids can be incorporated into peptides or proteins that recognize specific receptors or antigens on cancer cells.
Dodecaborates: These are anionic compounds that contain 12 boron atoms and 10 hydrogen atoms in a closo structure. Dodecaborates can be conjugated with biomolecules such as antibodies, hormones or nucleic acids to target cancer cells. For example, BSH (sodium borocaptate) and BPA (p-boronophenylalanine) are two dodecaborate derivatives that have been used clinically for BNCT of brain tumors and melanoma.
Metallacarboranes: These are hybrid compounds that contain a metal atom (such as cobalt, iron or nickel) coordinated to one or more carborane ligands. Metallacarboranes can exhibit magnetic, optical or catalytic properties that can be exploited for imaging or therapy purposes. For example, cobalt bis(dicarbollide) can act as a MRI contrast agent or a neutron capture agent for BNCT.
Metallaboranes: These are similar to metallacarboranes but contain one or more boron atoms instead of carbon atoms in the ligands. Metallaboranes can also have various biological applications depending on the metal and the ligand. For example, ruthenium metallaboranes can induce apoptosis in cancer cells by generating reactive oxygen species.
What are the Advantages and Limitations of BNCT?
BNCT has some advantages over conventional radiotherapy, such as:
Selectivity: BNCT can target only the tumor cells that have accumulated boron compounds and spare the normal cells that have low or no boron uptake.
Efficacy: BNCT can kill tumor cells that are resistant to other treatments, such as chemotherapy or radiation.
Safety: BNCT can use low-energy neutrons that have minimal side effects on healthy tissue and do not cause secondary radiation.
However, BNCT also faces some limitations, such as:
Availability: BNCT requires a neutron source that can provide a sufficient flux
Conclusion
BNCT is a promising technique for cancer treatment that can selectively target and destroy tumor cells without damaging normal tissue. BNCT relies on the delivery of boron compounds to cancer cells and the irradiation of neutrons to trigger the nuclear fission of boron atoms. Various types of boron compounds have been developed and tested for BNCT, such as carboranes, dodecaborates, metallacarboranes and metallaboranes. However, there are still some challenges and limitations that need to be overcome before BNCT can be widely applied in clinical practice. These include the availability of neutron sources, the optimization of boron delivery agents, the measurement of boron concentration and dose, and the evaluation of the long-term effects and safety of BNCT. Future research and development should focus on these aspects and explore the potential of BNCT for different types of cancers and in combination with other therapies. d282676c82