January 5, 2005 – Researchers at the Hebrew University
of Jerusalem have succeeded in discovering and isolating
a new protein from the poplar tree with special structural
and qualitative characteristics that could have consequences
for development of future nanocapsules for drug delivery
to cancer cells.
addition to being obtained from plant tissue, the
protein can now also be produced in large quantities
as a recombinant protein in bacteria, making it highly
available for medicinal or other applications.
SP-1, the protein has a nanometric, “bagel-shaped,”
circular form and is extremely stable. It has been
found to be capable of surviving contact with enzymes
that break down proteins or exposure to extreme conditions
such as boiling, excessive acidity, salinity, organic
solvents or detergent solutions.
research was conducted at the Hebrew University’s
Faculty of Agricultural, Food and Environmental Quality
Sciences in Rehovot by Prof. Arie Altman, head of
the faculty’s Institute of Plant Sciences and Genetics
in Agriculture, and Prof. Oded Shoseyov, with the
participation of Dr. Wangxia Wang and Dr. Dan Pelah
and the scientists of Fulcrum SP Ltd.: Dr. Amnon Wolf,
Dr. Ira Marton and Dr. Yonatan Puny.
to Profs. Altman and Shoseyov, the SP-1 protein serves
to assist in creating a properly folded and functioning
structure of other proteins within the plant’s cells.
The SP-1 also has the ability to assemble itself into
a structure composed of 12 identical units, making
it exceptionally resistant to extreme conditions.
These qualities are rarely found among proteins and
make the SP-1 a promising candidate for a multiplicity
of uses in developing medicinal applications in the
rapidly growing field of nanobiotechnology.
nanocapsules will be capable of delivering cell-destroying
drugs specifically to certain types of solid cancer
tumors. The protein’s tiny structure enables this
carrier to penetrate specifically into tumors without
harming healthy tissue and thus enhance the effectiveness
of chemotherapy. This selective penetration is based
on the fact that the blood vessels which feed tumors
are considerably more porous than those reaching healthy
cells. Therefore, the units of SP-1 carrying the drug
would invade only the tumor-feeding blood vessels
and not normal ones.
recently, the three-dimensional structure of the protein
was deciphered by x-ray crystallography. The research
on this was published in the Journal of Biological
Chemistry issue of December 2004, authored by graduate
student Orna Dgany, Prof. Altman and Prof. Shoseyov,
in cooperation with Dr. Orna Almog of Ben-Gurion University
of the Negev and Dr. Sharon Wolf of the Weizmann Institute
of Science and other researchers.
Altman and Prof. Shoseyov are the scientific founders
of the biotech start-up company Fulcrum SP Ltd. that
is developing the SP-1 protein for cancer drug delivery
and other applications.
further information: Jerry Barach, Dept. of Media
Relations, the Hebrew University, tel: 02-588-2904,
or Orit Sulitzeanu, Hebrew University spokesperson,