New strategy for multiple myeloma immunotherapy

November 27, 2017

Osaka - In recent decades monoclonal antibody-based treatment of cancer has been established as one of the most successful therapeutic strategies for both solid tumors and blood cancers. Monoclonal antibodies (mAb), as the name implies, are antibodies that are made by clonal cells derived from a single parent cells and therefore share the identical amino acid sequences.

One of the leading technologies to emerge in mAb-based treatment is CAR-T, where CAR stands for "chimeric antigen receptor", and T represents T cells, a type of white blood cells that have pivotal roles in immune defenses. CARs are produced by combining together the gene for an antibody that recognizes a tumor antigen with the gene for a receptor that resides on the surface of the T cells; insert this new gene into a T cell and it will be precisely targeted at the tumor.

Theoretically, new antigens - molecules capable of inducing an immune response to produce an antibody - that arise from cancer-specific mutations of cell-surface proteins are excellent targets. However, mAb therapy targeting such antigens is impractical because of these proteins' vast diversity within and between individual tumors, which renders identifying new cancer-specific target antigens difficult.

However, such challenges have driven researchers centered at Japan's Osaka University to think outside of the box; cancer-specific antigen formed by the modification of proteins during or after synthesis, such as glycosylation (attachment of sugar moieties to protein) or conformational changes, might have been missed in previous analyses. The team believed new antigen epitopes, which is the part of an antigen recognized by the immune cells, could be discovered by thoroughly searching for cancer-specific mAbs and characterizing the antigens they recognize.

"We applied this strategy to identify novel therapeutic targets for multiple myeloma (MM), a cancer that forms in a type of white blood cell called a plasma cell," explains Naoki Hosen, lead author of the study, which was recently published in Nature Medicine. "Despite advances in MM treatment, relapse remains common. As such, there is an ongoing need for new therapeutic approaches, including mAb-based therapies."

The team screened more than 10,000 anti-MM mAb clones and identified MMG49 as an MM-specific mAb specifically recognizing a subset of integrin β7, a cell-surface receptors that facilitate cell-extracellular matrix adhesion. MMG49 reacted to MM cells, but not other bone marrow cell types in MM patient samples. This prompted the researchers to design a CAR that incorporates a fragment derived from MMG49. The resulting MMG49 CAR T was found to have anti-MM effects without damaging normal blood cells.

"Our results also demonstrate that the active conformer of integrin β7 can serve as an immunotherapeutic target against MM, even though the expression of the protein itself is not specific to MM," study coauthor Yukiko Matsunaga says. "Therefore it's highly plausible that there are other cancer immunotherapeutic targets that have yet to be identified in many cell-surface proteins that undergo conformational changes, even if the expression of the proteins themselves is not cancer-specific."
-end-


Osaka University

Related Cancer Articles from Brightsurf:

New blood cancer treatment works by selectively interfering with cancer cell signalling
University of Alberta scientists have identified the mechanism of action behind a new type of precision cancer drug for blood cancers that is set for human trials, according to research published in Nature Communications.

UCI researchers uncover cancer cell vulnerabilities; may lead to better cancer therapies
A new University of California, Irvine-led study reveals a protein responsible for genetic changes resulting in a variety of cancers, may also be the key to more effective, targeted cancer therapy.

Breast cancer treatment costs highest among young women with metastic cancer
In a fight for their lives, young women, age 18-44, spend double the amount of older women to survive metastatic breast cancer, according to a large statewide study by the University of North Carolina at Chapel Hill.

Cancer mortality continues steady decline, driven by progress against lung cancer
The cancer death rate declined by 29% from 1991 to 2017, including a 2.2% drop from 2016 to 2017, the largest single-year drop in cancer mortality ever reported.

Stress in cervical cancer patients associated with higher risk of cancer-specific mortality
Psychological stress was associated with a higher risk of cancer-specific mortality in women diagnosed with cervical cancer.

Cancer-sniffing dogs 97% accurate in identifying lung cancer, according to study in JAOA
The next step will be to further fractionate the samples based on chemical and physical properties, presenting them back to the dogs until the specific biomarkers for each cancer are identified.

Moffitt Cancer Center researchers identify one way T cell function may fail in cancer
Moffitt Cancer Center researchers have discovered a mechanism by which one type of immune cell, CD8+ T cells, can become dysfunctional, impeding its ability to seek and kill cancer cells.

More cancer survivors, fewer cancer specialists point to challenge in meeting care needs
An aging population, a growing number of cancer survivors, and a projected shortage of cancer care providers will result in a challenge in delivering the care for cancer survivors in the United States if systemic changes are not made.

New cancer vaccine platform a potential tool for efficacious targeted cancer therapy
Researchers at the University of Helsinki have discovered a solution in the form of a cancer vaccine platform for improving the efficacy of oncolytic viruses used in cancer treatment.

American Cancer Society outlines blueprint for cancer control in the 21st century
The American Cancer Society is outlining its vision for cancer control in the decades ahead in a series of articles that forms the basis of a national cancer control plan.

Read More: Cancer News and Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.