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as it buds before dividing
Image by Carolyn Larabell
L-asparaginase derived from baker’s yeast has shown early promise for treating acute lymphoblastic leukemia (ALL), according to researchers.
The team isolated L-asparaginase from Saccharomyces cerevisiae and found the enzyme could kill ALL cells in vitro, while largely sparing healthy control cells.
Gisele Monteiro de Souza, PhD, of the University of São Paulo in São Paulo, Brazil, and her colleagues detailed these findings in Scientific Reports.
“In this study, we characterized the enzyme L-asparaginase from S cerevisiae,” Dr Souza said. “The results show this protein can efficiently annihilate leukemia cells with low cytotoxicity to healthy cells.”
She and her colleagues conducted this study in search of alternatives to L-asparaginase extracted from bacteria (Escherichia coli and Erwinia chrysanthemi).
“Our goal in this project wasn’t to produce the enzyme, but rather to find a new source of the biodrug in microorganisms for use in patients who develop resistance to the bacterial enzyme,” said study author Marcos Antonio de Oliveira, of São Paulo State University in São Vicente, Brazil.
To this end, the researchers isolated fungi from several different Brazilian environments as well as marine and land environments in Antarctica. According to Oliveira, these organisms often secrete asparaginase into the extracellular medium in response to a shortage of nitrogen.
“This lowers the cost of purifying the molecule for drug production, an important factor from an industrial standpoint,” he said.
The group also used bioinformatics tools to mine information on the genomes of several microorganisms from international databases.
In this way, they identified a gene responsible for producing an enzyme that closely resembles the enzymes found in E coli and E chrysanthemi, but with a number of advantages, in the genome of S cerevisiae.
The gene of interest from L-asparaginase was cloned, and the researchers used genetic engineering to make E coli express large amounts of the enzyme originally found in yeast.
“We were able to obtain the recombinant protein,” said study author Iris Munhoz Costa, of the University of São Paulo.
“We then performed studies to characterize its secondary structure and identify important regions called catalytic sites. Finally, we evaluated its efficacy in vitro.”
The enzyme was tested in 3 different cell lines: ALL cells incapable of producing asparagine at normal levels (MOLT4), another ALL cell line capable of producing asparagine at normal levels (REH), and non-malignant control cells (HUVECs).
These 3 cell lines were subdivided into 2 groups. One was treated with L-asparaginase derived from E coli enzyme, and the other was treated with L-asparaginase from yeast.
“The bacterial enzyme killed about 90% of the MOLT4 human leukemia cells and displayed low toxicity to the healthy HUVEC cells, killing only 10%,” Dr Souza said.
“The yeast enzyme killed between 70% and 80% of the MOLT4 cells and displayed less than 10% toxicity for HUVEC cells. Neither was significantly effective against REH cells.”
In her view, the results are encouraging, in contrast with those of studies performed with the same enzyme in the 1970s. At that time, the tests involved a version of the protein extracted directly from yeast and containing many impurities.
The group’s next step is to perform new in vitro trials with different cell types to evaluate the immune response and toxicity. If the results are positive, the first tests in animals may be next.
The researchers are also studying possible modifications that could be made to the molecule’s structure to increase antitumor activity and extend the enzyme’s half-life. 
as it buds before dividing
Image by Carolyn Larabell
L-asparaginase derived from baker’s yeast has shown early promise for treating acute lymphoblastic leukemia (ALL), according to researchers.
The team isolated L-asparaginase from Saccharomyces cerevisiae and found the enzyme could kill ALL cells in vitro, while largely sparing healthy control cells.
Gisele Monteiro de Souza, PhD, of the University of São Paulo in São Paulo, Brazil, and her colleagues detailed these findings in Scientific Reports.
“In this study, we characterized the enzyme L-asparaginase from S cerevisiae,” Dr Souza said. “The results show this protein can efficiently annihilate leukemia cells with low cytotoxicity to healthy cells.”
She and her colleagues conducted this study in search of alternatives to L-asparaginase extracted from bacteria (Escherichia coli and Erwinia chrysanthemi).
“Our goal in this project wasn’t to produce the enzyme, but rather to find a new source of the biodrug in microorganisms for use in patients who develop resistance to the bacterial enzyme,” said study author Marcos Antonio de Oliveira, of São Paulo State University in São Vicente, Brazil.
To this end, the researchers isolated fungi from several different Brazilian environments as well as marine and land environments in Antarctica. According to Oliveira, these organisms often secrete asparaginase into the extracellular medium in response to a shortage of nitrogen.
“This lowers the cost of purifying the molecule for drug production, an important factor from an industrial standpoint,” he said.
The group also used bioinformatics tools to mine information on the genomes of several microorganisms from international databases.
In this way, they identified a gene responsible for producing an enzyme that closely resembles the enzymes found in E coli and E chrysanthemi, but with a number of advantages, in the genome of S cerevisiae.
The gene of interest from L-asparaginase was cloned, and the researchers used genetic engineering to make E coli express large amounts of the enzyme originally found in yeast.
“We were able to obtain the recombinant protein,” said study author Iris Munhoz Costa, of the University of São Paulo.
“We then performed studies to characterize its secondary structure and identify important regions called catalytic sites. Finally, we evaluated its efficacy in vitro.”
The enzyme was tested in 3 different cell lines: ALL cells incapable of producing asparagine at normal levels (MOLT4), another ALL cell line capable of producing asparagine at normal levels (REH), and non-malignant control cells (HUVECs).
These 3 cell lines were subdivided into 2 groups. One was treated with L-asparaginase derived from E coli enzyme, and the other was treated with L-asparaginase from yeast.
“The bacterial enzyme killed about 90% of the MOLT4 human leukemia cells and displayed low toxicity to the healthy HUVEC cells, killing only 10%,” Dr Souza said.
“The yeast enzyme killed between 70% and 80% of the MOLT4 cells and displayed less than 10% toxicity for HUVEC cells. Neither was significantly effective against REH cells.”
In her view, the results are encouraging, in contrast with those of studies performed with the same enzyme in the 1970s. At that time, the tests involved a version of the protein extracted directly from yeast and containing many impurities.
The group’s next step is to perform new in vitro trials with different cell types to evaluate the immune response and toxicity. If the results are positive, the first tests in animals may be next.
The researchers are also studying possible modifications that could be made to the molecule’s structure to increase antitumor activity and extend the enzyme’s half-life.
as it buds before dividing
Image by Carolyn Larabell
L-asparaginase derived from baker’s yeast has shown early promise for treating acute lymphoblastic leukemia (ALL), according to researchers.
The team isolated L-asparaginase from Saccharomyces cerevisiae and found the enzyme could kill ALL cells in vitro, while largely sparing healthy control cells.
Gisele Monteiro de Souza, PhD, of the University of São Paulo in São Paulo, Brazil, and her colleagues detailed these findings in Scientific Reports.
“In this study, we characterized the enzyme L-asparaginase from S cerevisiae,” Dr Souza said. “The results show this protein can efficiently annihilate leukemia cells with low cytotoxicity to healthy cells.”
She and her colleagues conducted this study in search of alternatives to L-asparaginase extracted from bacteria (Escherichia coli and Erwinia chrysanthemi).
“Our goal in this project wasn’t to produce the enzyme, but rather to find a new source of the biodrug in microorganisms for use in patients who develop resistance to the bacterial enzyme,” said study author Marcos Antonio de Oliveira, of São Paulo State University in São Vicente, Brazil.
To this end, the researchers isolated fungi from several different Brazilian environments as well as marine and land environments in Antarctica. According to Oliveira, these organisms often secrete asparaginase into the extracellular medium in response to a shortage of nitrogen.
“This lowers the cost of purifying the molecule for drug production, an important factor from an industrial standpoint,” he said.
The group also used bioinformatics tools to mine information on the genomes of several microorganisms from international databases.
In this way, they identified a gene responsible for producing an enzyme that closely resembles the enzymes found in E coli and E chrysanthemi, but with a number of advantages, in the genome of S cerevisiae.
The gene of interest from L-asparaginase was cloned, and the researchers used genetic engineering to make E coli express large amounts of the enzyme originally found in yeast.
“We were able to obtain the recombinant protein,” said study author Iris Munhoz Costa, of the University of São Paulo.
“We then performed studies to characterize its secondary structure and identify important regions called catalytic sites. Finally, we evaluated its efficacy in vitro.”
The enzyme was tested in 3 different cell lines: ALL cells incapable of producing asparagine at normal levels (MOLT4), another ALL cell line capable of producing asparagine at normal levels (REH), and non-malignant control cells (HUVECs).
These 3 cell lines were subdivided into 2 groups. One was treated with L-asparaginase derived from E coli enzyme, and the other was treated with L-asparaginase from yeast.
“The bacterial enzyme killed about 90% of the MOLT4 human leukemia cells and displayed low toxicity to the healthy HUVEC cells, killing only 10%,” Dr Souza said.
“The yeast enzyme killed between 70% and 80% of the MOLT4 cells and displayed less than 10% toxicity for HUVEC cells. Neither was significantly effective against REH cells.”
In her view, the results are encouraging, in contrast with those of studies performed with the same enzyme in the 1970s. At that time, the tests involved a version of the protein extracted directly from yeast and containing many impurities.
The group’s next step is to perform new in vitro trials with different cell types to evaluate the immune response and toxicity. If the results are positive, the first tests in animals may be next.
The researchers are also studying possible modifications that could be made to the molecule’s structure to increase antitumor activity and extend the enzyme’s half-life.