Drug delivery systemwith anaerobic bacteria
for cancer therapy
2019/10/17
M2 Takahashi Kazuki

1

Contents
1. Well-known cancer therapies
2. Anaerobic condition in solid cancer tumors

3. Bacterial immunotherapy for cancer
4. Applications of anaerobic bacteria as a novel drugdelivery system
5. Summary

2

Contents
1. Well-known cancer therapies
2. Anaerobic condition in solid cancer tumors

3. Bacterial immunotherapy for cancer
4. Applications of anaerobic bacteria as a novel drugdelivery system
5. Summary3Orthodox method to treat cancers
Photo by JAFAR AHMED on Unsplash
Downleft: scienceblog.cancerresearchuk

SurgeryRadiotherapy

Chemotherapy• Surgery is performed in the limited areas in the body.
4• Some solid tumors are resistant to radio- & chemotherapy.

Immunotherapy• Dendritic cell therapy• Cancer vaccine

https://serenclinic.jp/dc/vaccell/vacell02.php• Cytokine therapy• Antibody therapy• Antibody-dependent
cellular cytotoxicity

https://en.wikipedia.org/wiki/Antibody-dependent_cellular_cytotoxicity• Immune checkpoints• Interferon• Interleukin(IL-2)
Glenn Dranoff,
Nature Reviews Cancer,2004, 4, 11

がん免疫.jp5Drug delivery systems to solid tumors• Nanoparticle (NP)
Matsumura Y, et al., Cancer Sci., 2009, 100, 572• Antibody-Drug Conjugate (ADC)

Nejadmoghaddam MR, et al., Avicenna J Med Biotechnol, 2019, 11, 3• These drug delivery systems are not effective for somesolid tumors.
• A novel DDS is required to be invented to cope with any
6solid tumors

Summary of Well-known cancer therapies• Many types of cancer therapy were developed andare being developed now.
• Some solid tumors are resistant to various therapies.
• A new type of DDS is required to be established tocope with the solid tumors.

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Contents
1. Well-known cancer therapies
2. Anaerobic condition in solid cancer tumors

3. Bacterial immunotherapy for cancer
4. Applications of anaerobic bacteria as a novel drugdelivery system
5. Summary8

Solid tumor characteristics• Hypoxia: anaerobic environment• Oxygen pressure• Normal tissues: 3-5% and 20-100 mmHg
• Solid cancer tissues: <1% and 0-20 mmHg

• Angiogenesis: supplying several nutrients and oxygenand metastasis.
• How is such a low oxygen condition created despiteangiogenesis in evident enhancement of malignanttumors?
9Solid tumor characteristics• Hypoxia: anaerobic environment• Oxygen pressure• Normal tissues: 3-5% and 20-100 mmHg
• Solid cancer tissues: <1% and 0-20 mmHg

• Angiogenesis: supplying several nutrients and oxygenand metastasis.
• The angiogenesis is outpaced by the tumor growth.
• The blood vessels formed by angiogenesis don’t haveability to supply enough O2.
10Hypoxia• HIF-1 (Hypoxia-inducible factors)• Stabilized by hypoxic conditions• Upregulates glycolysis enzymes and VEGF
glycolysis enzymes → ATP synthesis
vascular endothelial growth factor (VEGF) → angiogenesis.

the 2019 Nobel Prize in Physiology or Medicine
William G. Kaelin Jr., Sir Peter J. Ratcliffe
and Gregg L. Semenza
for their discoveries of how cells sense and adapt
to oxygen availability
Announcement of the Nobel Prize in Physiology or Medicine 201911

Contents
1. Well-known cancer therapies
2. Anaerobic condition in solid cancer tumors

3. Bacterial immunotherapy for cancer
4. Applications of anaerobic bacteria as a novel drugdelivery system
5. Summary12

Bacterial therapy for cancer• The original observation of tumor spontaneousrecovery and regression of certain cancer patientsfrom concurrent bacterial infections was made over
300 years ago.
• Numerous case reports, review papers and bookchapters on the subject have been published,including about 1000 cases by the year 1987 andmean 10 reports per year by 2003.
M.Q Wei et al., Cancer Letters, 2008, 259, 1613

Bacterial therapy for cancer• Concept14

Phase 1 study of Salmonella VNP20009• 25 patients received an intravenous dose of VNP20009.
• the maximum tolerated dose (3x108 cfu/m2)• Shrinking of the tumor was not observed in any case.
• The existence of bacteria in the tumor was detected inonly three patients.
• In four patients, bacteriosis was observed but thebacteria were not detected in the tumors.
John F. T, et al., J. Clin. Oncol., 2002, 20, 142

This clinical test was failed.
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Anaerobic bacteria grows in tumors only.
• Clostridium tetani produces
toxins.
• The injection of Cl. tetani
spores resulted in tetanic
death in the tumor-bearing
host in approximately 48hours, regardless of thetumor size, the tumor type,or the spore dose.
Malmgren RA, Flanigan CC, Cancer Res, 1955, 15, 473

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Anaerobic bacteria grows in tumors only.
• Clostridium tetani grew a lot in
the tumors only.
• Numbers of the bacteria inother organs were notdifferent between in tumorbearing mice and non- tumorbearing mice.

Malmgren RA, Flanigan CC, Cancer Res, 1955, 15, 473

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Bifidobacterium

Bifidobacterium bifidum
https://www.yakult.co.jp/products/item0228.html

https://institute.yakult.co.jp/bacteria/4230/• Bifidobacterium has long been prescribed for infantpatients in Japan.
• It was considered as safe bacteria injected intravenously.
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Bifidobacterium grows only in tumor tissues

Bifidobacterium bifidum grows only in tumor tissues.
Kimura NT, et al., Cancer Res, 1980, 40, 2061

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B. bifidum (Lac B) & lactulose

Lactulose:
A synthesized disaccharide from lactose.
It is not metabolized by mammalian tissue cells.

Lactulose in vivo stimulates the growth of B. bifidumin the tumor.
Kimura NT, et al., Cancer Res, 1980, 40, 2061

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The non-pathogenicity of B. bifidum (Lac B)• The animals expressed no visible adverse symptoms.
• It was confirmed that B. bifidum is safe bacteria
injected intravenously.
Kimura NT, et al., Cancer Res, 1980, 40, 2061

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Anaerobic bacteria characteristics

M.Q Wei et al.,Cancer Letters, 2008, 259, 16
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Summary of Anaerobic bacteria characteristics• Obligate anaerobic bacteria intravenously injectedaccumulates only in tumor cells.
• Bifidobacterium is non-pathogenic, but it doesn’t show
oncolytic effect.
• Clostridium extensive oncolytic effect, but some strains
are pathogenic.

• Facultative anaerobic bacteria shows pathogenic or
toxic effect on both tumor cells and normal cells.
• Streptococcus, Salmonella, Listeria, E. coli, etc…

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Summary of bacterial therapy for cancer• The original bacterial therapy for cancer wasperformed over 300 years ago.
• Obligate anaerobic bacteria intravenously injected
accumulates only in tumor cells.
• Obligate anaerobic bacteria (Clostridium andBifidobacterium) treatment alone was not enoughto control tumor significantly.

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Contents
1. Well-known cancer therapies
2. Anaerobic condition in solid cancer tumors

3. Bacterial immunotherapy for cancer
4. Applications of anaerobic bacteria as a novel drugdelivery system
5. Summary25

Bifidobacterium used for a novel DDS• Bifidobacterium are non-invasive bacteria.
• Expression vector insertion enables to carry thedesired peptides and proteins into the solid tumors.
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Examples of Bifidobacterium DDSs
• Anti-PD-1 antibody scFv producing B. longum
Abstract only

• Trastuzumab scFv producing B. longum

T. Kikuchi, et al., Biochem. Biophys. Res. Commun., 2017, 493, 30

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5-Fluorouracil (5-FU)• 5-FU• a medication used to treat cancer.
• a thymidylate synthase (TS) inhibitor.

• Mechanism• 5-FU inhibits Thymidylate synthase resulting in impaired
DNA synthesis.

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Cytosine deaminase (CD)• Cytosine deaminase (CD)• CD converts low-toxic 5-fluorocytosine (5FC) to active 5fluorouracil (5FU)• The cytosine deaminase of Escherichia coli (e-CD)
was inserted into the plasmid under the promoter
region of the plasmid.
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CD producing B. longum• Concept• 5-FC is produced and activated in tumor cells only.

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CD producing B. longum
Rats

Nude mice• Suppression of tumor growth was observed in thegroups treated with i.v. injection of the bacteria andthe prodrug 5-FC given orally.
Sasaki T, et al., Cancer Sci., 2006, 97, 649

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Anaeropharma Science• Anaeropharma Science was established in Tokyo, Japanin 2004.

• The Phase I/II trial of APS001F is currently ongoing in US.

• This company works on a joint development projectwith Eisai Co., Ltd. and Astellas Pharma Inc. respectively.
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Contents
1. Well-known cancer therapies
2. Anaerobic condition in solid cancer tumors

3. Bacterial immunotherapy for cancer
4. Applications of anaerobic bacteria as a novel drugdelivery system
5. Summary

33

Summary• Obligate anaerobic bacteria intravenously injected
accumulates only in tumor cells because of its
anaerobic condition.
• Obligate anaerobic bacteria (Clostridium andBifidobacterium) treatment alone was not enoughto control tumor significantly.
• Bifidobacterium is being used to treat cancer as anovel DDS, or a safety carrier of the therapeuticproteins.
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Clinical trial of Salmonella VNP20009← Patients’ information

個数↓Results of counting No.
→of bacteria in tumors

FNA: fine needle aspiration cytology
穿刺吸引細胞診36