Targeting Breast Cancer

A new component, which is a protein that stimulates the immune system to attack HER2-positive breast cancer cells, has been added to a nanoscale drug. This drug can carry a variety of weapons and sneak into cancer cells to break them down from the inside has a new component.  The multi-pronged approach directly attacks cancer cells and blocks the growth of cancer-supporting blood vessels and stimulates an anti-tumor immune response.
The research team, led by scientists at the Nanomedicine Research Center, part of the Maxine Dunitz Neurosurgical Institute in the Department of Neurosurgery at Cedars-Sinai Medical Center, conducted the study in laboratory mice with implanted human breast cancer cells.  Mice receiving the drug lived significantly longer than untreated counterparts and those receiving only certain components of the drug.
Drugs often injure normal cells as a side effect, but this drug is unlike other drugs that target cells from the outside.  This new therapy consists of multiple drugs chemically bonded to a “nanoplatform” that functions as a transport vehicle.
HER2-positive cancers, which consists of approximately 25% to 30% of breast and ovarian cancers  tend to be more aggressive and less responsive to treatment  because the overactive HER2 gene makes excessive amounts of a protein that promotes cancer growth.  Herceptin is an antibody to the HER2 gene.  Herceptin naturally seeks out this protein, and so the research team used key parts of Herceptin to guide the nanodrug into HER2-positive cancer cells.  This commonly used drug is often effective for a while; but many tumors become resistant within the first year of treatment and the drug can injure normal organs it contacts.
A ‘fusion-gene’ was genetically prepared that consists of an immune-stimulating protein, interleukin-2, and a gene of Herceptin.  Interleukin-2 activates a variety of immune cells but is not stable in blood plasma and does not home specifically to tumor cells.  By attaching the new fusion antibody to the nanoplatform, the scientists were able to deliver Herceptin directly to HER2-positive cancer cells, at the same time transporting IL-2 to the tumor site to stimulate the immune system.  Attaching IL-2 to the platform helped stabilize the protein and allowed us to double the dosage that could be delivered to the tumor.
The researchers also attached other components, such as molecules to block a protein (laminin-411) that cancer cells need to make new blood vessels for growth.
The nanodrug, Polycefin, is in an emerging class called nanobiopolymeric conjugates, nanoconjugates or nanobioconjugates.  They are the latest evolution of molecular drugs designed to slow or stop cancers by blocking them in multiple ways.  Polycefin is intended to slow their growth by entering cells and altering defined targets.   The new version also stimulates the immune system to further weaken cancers.
One of the researched commented that they believe this is the first time a drug has been designed for nano-immunology anti-cancer treatment.
More study is needed to confirm the findings, improve the effectiveness of this approach and shed light on the anti-cancer mechanisms at work, but it appears that the nanobioconjugate may represent a new generation of cancer therapeutics in which we launch a multipronged attack that directly kills cancer cells, blocks the growth of cancer-supporting blood vessels and stimulates a powerful antitumor immune response.  Previous animal studies have found the nanodrug to be a safe and efficient delivery platform.
Nano researchers manipulate substances and materials at the atomic level, generally working with substances smaller than 100 nanometers.  . A human hair is 80,000 to 100,000 nanometers wide. Cedars-Sinai’s nanoconjugate is estimated to be about 27 nanometers wide.