postdoc

Unlocking the potential to better target cancer with immunotherapy

Monash University-led research is unlocking new ways for immunotherapy to better target cancer.

Cancer immunotherapy has revolutionised treatment for patients, whereby the body’s own immune system is harnessed to destroy cancer cells.

Typically, several molecules restrain the ability of T cells to target cancer cells and developing approaches to limit this restraining effect can lead to improved effectiveness of cancer immunotherapy.

Research published in Science Immunology has determined the structure of how an inhibitory molecule, LAG3, interacts with its main ligand and provides a new targeted approach to improving the effectiveness of immunotherapy for certain forms of cancer.

The publication is the first to show the crystal structure of a human LAG-3/HLA-II complex and provides a better foundation for development of blocking LAG-3 therapeutics.

Led by Professor Jamie Rossjohn at Monash University’s Biomedicine Discovery Institute (BDI), in collaboration with Immutep, this research resolves how the human LAG-3 receptor binds to HLA II molecules.

First author Dr Jan Petersen said: “The way the PD-1 and CTLA-4 immune checkpoint molecules bind to their respective ligands has been resolved for many years.

“However, the resolution of the interface between another important checkpoint molecule, LAG-3, and its main ligands, HLA-II molecules, has remained elusive.

“Solved using data collected at the Australian Synchrotron, a structure of a LAG-3/HLA-II complex provides a structural foundation to harness rationally for future development of antibodies and small molecule therapeutics designed to block LAG-3 activity.”

A diagram of a cell

Description automatically generated with medium confidence

Figure 1: Human LAG-3 homodimer (with domains D1, D2, D3 and D4) binding to two separate HLA-II (MHC-II) molecules on the surface of an antigen-presenting cell (APC), imposing a distinct 38° offset angle.

Dr Frédéric Triebel, Immutep’s CSO, added: “These findings add to the strong foundation of our work with Professor Rossjohn and his team to develop a deeper understanding of the structure and function of the LAG-3 immune control mechanism, particularly as it relates to our anti-LAG-3 small molecule program.”

Read the full paper published in Science Immunology, titled Crystal Structure of the Human LAG-3–HLA-DR1–Peptide Complex 

 

About the Monash Biomedicine Discovery Institute
Committed to making the discoveries that will relieve the future burden of disease, the Monash Biomedicine Discovery Institute (BDI) at Monash University brings together more than 120 internationally-renowned research teams. Spanning seven discovery programs across Cancer, Cardiovascular Disease, Development and Stem Cells, Infection, Immunity, Metabolism, Diabetes and Obesity, and Neuroscience, Monash BDI is one of the largest biomedical research institutes in Australia. Our researchers are supported by world-class technology and infrastructure, and partner with industry, clinicians and researchers internationally to enhance lives through discovery.

About Immutep
Immutep is a clinical-stage biotechnology company developing novel LAG-3 immunotherapy for cancer and autoimmune disease. We are pioneers in the understanding and advancement of therapeutics related to Lymphocyte Activation Gene-3 (LAG-3), and our diversified product portfolio harnesses its unique ability to stimulate or suppress the immune response. Immutep is dedicated to leveraging its expertise to bring innovative treatment options to patients in need and to maximise value for shareholders. For more information, please visit www.immutep.com.

DOI: 10.1126/sciimmunol.ads5122

Original article

Monash study unravels another piece of the puzzle in how cancer cells may be targeted by the immune system

Effective immunity hinges on the ability to sense infection and cellular transformation. In humans, there is a specialised molecule on the surface of cells termed MR1. MR1 allows sensing of certain small molecule metabolites derived from cellular and microbial sources; however, the breadth of metabolite sensing is unclear.

Published in PNAS, researchers at the Monash University Biomedicine Discovery Institute (BDI) have identified a form of Vitamin B6 bound to MR1 as a means of engaging tumour-reactive immune cells. The work involved an international collaborative team co-led by researchers from the University of Melbourne.

 

Monash BDI authors on the study (L-R): Dr Patricia Illing, Dr Wael Awad, Dr Mitchell McInerney .

Monash BDI authors on the study (L-R): Dr Patricia Illing, Dr Wael Awad, Dr Mitchell McInerney .

According to Dr Illing, “Our findings suggest that Vitamin B6 molecules displayed by MR1 represent a means for the immune system to detect altered cellular metabolism/metabolite levels that may distinguish cancer cells,” she said.

“Identification of small molecules/metabolites able to activate immune cells with cancer reactivity is a key step in understanding how small molecule sensing might contribute to anti-cancer immunity.”

Central to this study were the unbiased mass spectrometry analysis of small molecules bound to MR1, the structural resolution of the interactions between MR1 and Vitamin B6, and immunological assays performed by lead authors Dr Mitchell McInerney and Dr Wael Awad at Monash Biomedicine Discovery Institute, and Dr Michael Souter and Mr Yang Kang at the University of Melbourne, Peter Doherty Institute.

While it’s not yet clear if the Vitamin B6 molecule can be utilised in therapeutics, “understanding the breadth of MR1 mediated immunity has the capacity to illuminate routes for therapeutic intervention,” Dr Illing said.

An important aspect of the finding is that MR1 differs very little across individuals – with few known genetic variants in the human population. “Thus, understanding immune activation mediated via MR1 may pave the way for therapeutic interventions with broad utility,” Dr Illing said.

She added that next steps for investigation will confirm whether Vitamin B6 and related molecules are displayed by the MR1 of cancer cells at altered levels to healthy body cells, thus enabling specific cancer targeting, or if other small molecules displayed by MR1 may help differentiate cancerous and healthy cells.

Read the full paper published in PNAS, titled MR1 presents vitamin B6–related compounds for recognition by MR1-reactive T cells
DOI: 10.1073/pnas.2414792121

Original article