Study sheds light on how cancer spreads in blood
Analysis of particles shed by tumors points to new, less invasive way to diagnose malignancies

Date:
July 9, 2020
Source:
Cedars-Sinai Medical Center
Summary:
A new study sheds light on proteins in particles called
extracellular vesicles, which are released by tumor cells into
the bloodstream and promote the spread of cancer. The findings
suggest how a blood test involving these vesicles might be used
to diagnose cancer in the future, avoiding the need for invasive
surgical biopsies.



FULL STORY ==========================================================================
A new study sheds light on proteins in particles called extracellular
vesicles, which are released by tumor cells into the bloodstream and
promote the spread of cancer. The findings suggest how a blood test
involving these vesicles might be used to diagnose cancer in the future, avoiding the need for invasive surgical biopsies.


==========================================================================
The research is a large-scale analysis of what are known as palmitoylated proteins inside extracellular vesicles, according to Dolores Di Vizio,
MD, PhD, professor of Surgery, Biomedical Sciences and Pathology and
Laboratory Medicine at Cedars-Sinai. Di Vizio is co-corresponding author
of the study, published online June 10 in the Journal of Extracellular Vesicles.

Extracellular vesicles have gained significant attention in the last
decade because they contain proteins and other biologically important
molecules whose information can be transferred from cell to cell. They
are known to help cancer metastasize to distant sites in the body,
but exactly how this happens is not clear.

To learn more about this process, the research team looked into a process called palmitoylation, in which enzymes transfer lipid molecules onto
proteins.

Palmitoylation can affect where proteins are located within cells,
their activities and their contribution to cancer progression.

The investigators examined two types of extracellular vesicles, small and large, in samples of human prostate cancer cells. Using centrifuges, they separated the extracellular vesicles from the other cell materials and
analyzed the levels of palmitoylation and the types of proteins present.

The team found extracellular vesicles derived from the cancer
cells contained palmitoylated proteins that are associated with the
spread of cancer. Further, when the team chemically suppressed the palmitoylation process, the level of some of these proteins went down
in the extracellular vesicles.

"Our results suggest that protein palmitoylation may be involved in
the selective packaging of proteins to different extracellular vesicle populations in the body," Di Vizio said. "This finding raises the
possibility that by examining these proteins in extracellular vesicles
in the bloodstream, we may be able to detect and characterize cancer in
a patient in the future without performing a surgical biopsy." Di Vizio
said the next step in the research is to conduct a study in collaboration
with her Cedars-Sinai colleagues and industry partners that will use
advanced technologies, including mass spectrometry and flow cytometry,
with the goal of identifying clinically significant prostate cancer
at diagnosis.

In addition to Di Vizio, Wei Yang, PhD, associate professor of Surgery
at Cedars-Sinai, and Andries Zijlstra, PhD, are co-corresponding
authors for the study. Zijlstra completed the research while working
at Vanderbilt University Medical Center in Nashville. Javier Mariscal,
PhD, a postdoctoral scientist in Di Vizio's laboratory, is the study's
first author.


========================================================================== Story Source: Materials provided by Cedars-Sinai_Medical_Center. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Javier Mariscal, Tatyana Vagner, Minhyung Kim, Bo Zhou, Andrew Chin,
Mandana Zandian, Michael R. Freeman, Sungyong You, Andries Zijlstra,
Wei Yang, Dolores Di Vizio. Comprehensive palmitoyl-proteomic
analysis identifies distinct protein signatures for large and small
cancer-derived extracellular vesicles. Journal of Extracellular
Vesicles, 2020; 9 (1): 1764192 DOI: 10.1080/20013078.2020.1764192 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200709092501.htm

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