Transcript Expressing Surface Proteins to Target Cancer Cells

Expressing Surface
Proteins to Target Cancer
Cells
Joe and Bobby
Goal

To localize medicine-carrying bacteria
to cancer cells
Cancer antigens

Tumor cells express surface
molecules mostly specific to cancer
= antibody targets
1. Detection of tumors
2. Antibody-dependent cellular
cytotoxicity (ADCC)
3. Payload delivery
http://www.antibody.com
Current Antibody-based Cancer
Therapy

Herceptin (trastuzumab)
• Monoclonal antibody that binds to
HER2/neu receptor in early-stage breast
cancer cells

Rituxan (rituximab)
• Antibody that binds to CD20, a protein
expressed by B cells (normal &
malignant)
• Used to combat B cell non-Hodgkin’s
lymphoma, B-cell leukemias

Erbitux (cetuximab)
• Attaches to external growth factor
receptor (EGFR), mediates ADCC
• $30k for 8 weeks
Purpose of Our Antibody

Cancer-seeking antibody is
expressed on surface of bacteria
carrying a payload (medicine)
Process
1.
2.
3.
4.
Discover effective monoclonal
antibody
Find gene sequence
Transform gene into bacteria
Bacteria then expresses antibody
1. Discover effective antibody


Find cancer cells that express
exclusive antigens
Steps
1. Immunization (mice, rats): generate
antibody response
2. Immortalize antibody response as
hybridomas
3. Create monoclonal antibodies from
hybridomas; screen antibodies
http://www.antibody.com
2. Find gene sequence

Identify gene that codes for the
antibody
2.5. Alternatively

Use an antibody that has already
been identified/matched to type of
cancer cell
3. Transform gene into bacteria


Standard procedures
Listeria or E. coli
4. Bacteria then expresses
antibody


Bacteria (which holds a payload of
medicine/toxins/whatever) expresses
cancer-specific antibody
Cancer cells take up bacteria
Interesting?


Monoclonal antibody therapy of
cancer
http://www.nature.com/nbt/journal/
v23/n9/full/nbt1137.html
Antibody Solutions Inc
(www.antibody.com) based in
Mountain View