Friday, April 27, 2012
Your $ Making Progress on LMS
From Sharon Anderson
Hi Steve,
Please share the attached research article with family and friends who contributed to Rebecca's fundraising efforts. Her contributions funded the mice studies, which had dramatic results. We can't thank everyone enough.
L,
Sharon
I can't attach the article but can include the following:
Press Release from Stanford on CD47 Antibody and LMS discovery
http://www.eurekalert.org/pub_releases/2012-03/sumc-sas032112.php
Single antibody shrinks variety of human tumors transplanted into
mice, Stanford study shows
STANFORD, Calif. — Human tumors transplanted into laboratory mice
disappeared or shrank when scientists treated the animals with a
single antibody, according to a new study from the Stanford University
School of Medicine. The antibody works by masking a protein flag on
cancer cells that protects them from macrophages and other cells in
the immune system. The scientists achieved the findings with human
breast, ovarian, colon, bladder, brain, liver and prostate cancer
samples.
It is the first antibody treatment shown to be broadly effective
against a variety of human solid tumors, and the dramatic response —
including some overt cures in the laboratory animals — has the
investigators eager to begin phase-1 and -2 human clinical trials
within the next two years.
"Blocking this 'don't-eat-me' signal inhibits the growth in mice of
nearly every human cancer we tested, with minimal toxicity," said
professor of pathology Irving Weissman, MD, who also directs
Stanford's Institute of Stem Cell Biology and Regenerative Medicine
and the Ludwig Center for Cancer Stem Cell Research at Stanford. "This
shows conclusively that this protein, CD47, is a legitimate and
promising target for human cancer therapy."
The antibody treatment also significantly inhibited the ability of the
tumors to metastasize throughout the animals' bodies.
"This is exciting work and will surely trigger a worldwide wave of
research designed to convert this strategy into useful therapies,"
said Robert Weinberg, PhD, a professor of biology at the Whitehead
Institute for Biomedical Research in Massachusetts who was not
involved in the research. "Mobilizing the immune system to attack
solid tumors has been a longstanding goal of many cancer researchers
for decades."
The research will be published online March 26 in the Proceedings of
the National Academy of Sciences. Weissman, who is the Virginia & D.K.
Ludwig Professor for Clinical Investigation in Cancer Research at
Stanford and a member of the Stanford Cancer Institute, is the senior
author of the research. Postdoctoral scholars Stephen Willingham, PhD,
and Jens-Peter Volkmer, MD, are the co-first authors of the study.
Previous work in Weissman's lab has shown that CD47 is normally
expressed on the surfaces of circulating blood stem cells to protect
them from immune cells called macrophages. Macrophages patrol the body
looking for signs of trouble in the form of invaders or rogue cells,
but they sometimes latch onto the wrong targets. CD47 prompts them to
release cells they've grabbed by mistake.
Weissman and his colleagues also showed previously that some types of
cancer cells — particularly those of blood cancers such as leukemia
and lymphoma — have figured out a way to game the system and use this
"don't-eat-me signal" to their advantage by expressing CD47 on their
own surfaces. In 2010, they found that blocking CD47 with a specific
antibody (plus adding another to further stimulate the macrophages'
killing instinct) can cure some cases of human non-Hodgkin's lymphoma
in mice. But it wasn't known until now how widespread or clinically
important the phenomenon would be in human solid tumors.
In the current study, Willingham and Volkmer collected surgical
samples of a variety of human tumors, including ovarian, breast,
colon, bladder, brain, liver and prostate. To do so, they enlisted the
help of clinical experts from across the School of Medicine, including
those specializing in oncology, urology, obstetrics and gynecology,
radiation oncology, neurosurgery, hematology, pathology,
otolaryngology and hepatology.
They showed that nearly every human cancer cell they examined
expressed CD47 — usually at higher levels (on average, about three
times more) than did non-cancerous cells. Furthermore, people whose
cancer cells express a lot of CD47 tend to have shorter life spans
than people with similar cancers that express less CD47. This suggests
that an analysis of the levels of CD47 expression in some types of
tumors could be a valuable prognostic tool for patients and their
doctors.
Willingham and Volkmer then implanted the different human tumor cells
into matching locations in the bodies of mice — breast cancer tumors
into the mammary fat pads, and ovarian cancer tumors into the abdomen,
for example. Once the tumors were well-established (after two weeks or
more), they treated the animals with the anti-CD47 antibody.
The researchers saw that most of the established tumors begin to
shrink and even, in some cases, disappear within weeks of treatment
with the antibody. In one case, antibody treatment cured five mice
injected with the same human breast cancer cells. When the tumor was
gone, the treatment was discontinued; the mice were monitored for four
months with no signs of recurrence.
"These results indicate that anti-CD47 antibodies can dramatically
inhibit the growth of human solid tumors by blocking the ability of
CD47 to transmit the 'don't-eat-me' signal to macrophages," concluded
the authors.
"If the tumor was highly aggressive," said Weissman, "the antibody
also blocked metastasis. It's becoming very clear that, in order for a
cancer to survive in the body, it has to find some way to evade the
cells of the innate immune system." The innate immune system is the
body's first line of defense against pathogens like bacteria and
viruses. Unlike the adaptive immunity conferred by antibodies and T
cells that recognize and battle specific molecules, cells of the
innate immune system, like macrophages, respond non-specifically to a
variety of threats.
The researchers' approach didn't work in every animal, though. A set
of mice with breast cancer cells from a one human patient experienced
no benefit from antibody treatment. "There's certainly more to learn,"
said Weissman. "We need to learn more about the relationship between
macrophages and tumor cells, and how to draw more macrophages to the
tumors." He suggested that reducing the size of a tumor with surgery
or radiotherapy before antibody treatment could make the treatment
more effective. Another option, he added, would be to use a second
antibody in addition to CD47 that would further stimulate the ability
of the macrophages or other immune cells to kill the cancer cells.
While treatment modifications may be beneficial, the findings about
the effect of the single antibody are promising in their own right and
set the stage for advancing the research. "We believe these results
show that we should move forward quickly but cautiously into human
clinical trials for many types of solid tumors," Weissman said.
[Continue article at the above link]
Below is summary of the work on LMS by Dr. Matt van de Rijn at
Stanford. This is incredible news and the next stage will be a
clinical trial to test this vaccine in humans.
Sharon
..................................................................................
Protein blocking frees macrophages to attack LMS tumors
Leiomyosarcoma (LMS) is a rare and aggressive cancer that affects
smooth muscle cells such as those found in the uterus and soft tissues
throughout the body. Previous studies have linked poor clinicals
outcomes of the disease with the presence of immune system cells
known as tumor associated macrophages (TAMs), suggesting that TAMs
promote LMS tumors.
Badreddin Edris et al. (pp. 6656–6661) investigated a technique that
interferes with the mechanism that hides cancerous LMS cells from the
immune system and turns the
presence of TAMs against LMS tumors. The authors used antibodies
against CD47, a protein that inhibits the process known as phagocytos
is , whereby macrophages engulf and ingest dis eas ed cells .
In trials with two human cell lines interfering with CD47 increased
phagocytosis in vitro, according to the authors. To evaluate the
technique in vivo, the authors transplanted LMS cells into mice and
after 6 weeks treated randomized animals for 1 week with a humanized
anti-CD47 antibody. After treatment, the authors found that the test
subjects exhibited striking decreases in the size of primary tumors
and the number of metastatic sites. The findings suggest that
therapies with anti-CD47 antibodies can potentially both reduce tumor
size and inhibit LMS metastasis, according to the authors. — T.J.
Reprinted from
Proceedings of the National Academy of Sciences
www.pnas.org
doi: 10.1073/iti1712109
PNAS April 24, 2012 vol. 109 no. 17 6355-6356
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