Researchers identified unique cryptic peptides in pancreatic cancer cells, showing potential as targets for T-cell therapies to combat this challenging disease.
Researchers at MIT and the Dana-Farber Cancer Institute have made a significant discovery in the fight against pancreatic cancer. They’ve identified a class of peptides known as cryptic peptides that are expressed specifically in pancreatic tumor cells, which could serve as viable targets for T-cell therapies and other innovative treatment modalities.
These cryptic peptides arise from genomic sequences previously believed to be non-coding. While some of these peptides are also present in healthy cells, the study identified around 500 that are predominantly found only in pancreatic tumors, highlighting a unique vulnerability in cancer cells.
The research team successfully generated T cells that target these specific peptides, which demonstrated efficacy by attacking pancreatic tumor organoids derived from patient cells. In animal models, these T cells significantly impeded tumor growth, suggesting a promising direction for future therapeutic strategies.
“Pancreatic cancer is notoriously difficult to treat. Our findings uncover an unexpected weakness in pancreatic cancer cells that could be leveraged for therapeutic benefit,” stated Tyler Jacks, the David H. Koch Professor of Biology at MIT and a member of the Koch Institute for Integrative Cancer Research.
Joining Jacks in this research are senior authors William Freed-Pastor, a physician-scientist at Dana-Farber and assistant professor at Harvard Medical School. Their research article appears in the journal Science and highlights a critical step in potentially enhancing pancreatic cancer treatment options.
With approximately 10% of pancreatic cancer patients surviving beyond five years post-diagnosis, the current treatment landscape primarily involves surgery, chemotherapy, and radiation. Unfortunately, many immunotherapy approaches, like checkpoint inhibitors, have not yielded favorable responses in pancreatic cancer patients. However, engineered T-cell therapies are generating excitement as they enter clinical trial evaluation.
The methodology employed by the MIT and Dana-Farber team involved immunopeptidomics, a sophisticated technique to isolate and identify peptides presented on the surface of cells via mass spectrometry. By examining tumor samples from a cohort of patients, the researchers cultivated organoids as a three-dimensional representation of the pancreas.
Most of the groundbreaking antigens detected in these organoids turned out to be cryptic peptides. While previous studies have hinted at their existence in various tumors, this research marks the first identification of cryptic peptides specifically within pancreatic tissue, which could herald a new era in targeted therapies for this aggressive cancer type.
On average, each tumor exhibited around 250 of these peptides, totaling approximately 1,700 unique cryptic peptides detected. This prompted the researchers to focus on this abundant novel class of antigens, underscoring their potential clinical relevance.
To ensure that these antigens could serve as feasible targets for T-cell therapies, the team presented about 30 cancer-specific antigens to immature T cells, resulting in 12 antigens that effectively promoted the proliferation of targeted T cells. Following this, T cells were engineered to express the T-cell receptors specific for these peptides, demonstrating an ability to eradicate patient-derived tumor organoids in lab settings.
In vivotesting further revealed that when these engineered T cells were introduced to mice implanted with tumor organoids, there was a marked reduction in tumor growth—though full eradication wasn't achieved, the results indicated a promising avenue for future exploration. “This is the first instance of T cells targeting cryptic peptides to actively destroy pancreatic tumor cells,” said Freed-Pastor.
In addition to these T-cell therapies, Freed-Pastor’s laboratory is embarking on developing a vaccine designed around some of the identified cryptic antigens. Such a vaccine could stimulate patients’ T cells to attack tumors expressing these specific antigens, broadening the immunotherapeutic arsenal against pancreatic cancer.
Moreover, the implications of this research extend to other treatment modalities, potentially paving the way for T-cell engagers—antibodies designed to bind to both an antigen on the tumor and a T cell, redirecting immune activity toward tumor destruction.
While any prospective vaccines or T-cell therapies stemming from this research are likely a few years away from clinical trials, this study marks a pivotal step in understanding and potentially targeting pancreatic cancer more effectively as new immunotherapeutic strategies evolve.
This groundbreaking study received support from several esteemed organizations, including the Hale Family Center for Pancreatic Cancer Research, the Lustgarten Foundation, Stand Up To Cancer, and the National Institutes of Health.
Materials provided by Massachusetts Institute of Technology. Original written by Anne Trafton. Note: Content may be edited for style and length.
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