Scientists have found the cause of the spread of pancreatic cancer

a new study by U.S. scientists suggests that several molecules that nerve cells use to grow during development may help explain why the most common pancreatic cancers are so difficult to contain and make it difficult for patients to survive.
findings from human and mouse cell experiments may lead to new ways to prevent the spread or metastasis of these cancers and reduce the extreme pain that usually accompanies them. The researchers report the findings in the journal Gastroenterology.
An estimated 57,000 Americans are affected by pancreatic catheter cancer (PDA) each year, according to the American Cancer Society, with about 45,000 deaths, making it the fourth leading cause of cancer death in the United States. The cancer has a combined five-year survival rate of 9 percent, lower than other cancer types in the country, explained Zheng Lei, who is an associate professor of oncology and co-director of the Center for Precision Medicine for Pancreatic Cancer at Johns Hopkins University.
the main cause of poor prognosmation of cancer is metastasis, the process by which the cancer grows and spreads to distant organs. Many patients have metastasis at the time of diagnosis, and patients who have not metastasis at the time of diagnosis usually die from metastasis even after surgery and radiotherapy control on the surface of the local lesions.
PDA cases are also marked by a process known as neuro-immersion (PNI), in which the tumor grows into nearby nerves. Although PNI has been identified as an accurate signal of poor prognosm and reduced survival, it is not clear how it occurs and whether it is related to transfer.
to study these issues, Zheng and his colleagues looked closely at axon-guided proteins using human and mouse cell line, a family of biotransmission molecules that are often found in PDAs. The researchers looked further at two of these proteins: SEMA3D and its target PLXND1. Both are involved in the growth of long extensions of nerve cells, called axons. Zheng Lei's laboratory studies show that PDA cells typically secrete large amounts of SEMA3D.
experiments with human pancreatic cancer cells cultured in the lab showed that when researchers genetically fine-tuned the SEMA3D secretions of cancer cells, the cells lost about 30 percent of their ability to invade nearby nerves compared to normally secreted cancer cells.
when the researchers injected modified human pancreatic cancer cells into mice, they found that the nerves that grew into the tumor tripled.
a similar result when Zheng Lei and his colleagues blocked PLXND1 (SEMA3D subject on nerve cells) in a human pancreatic cancer cell laboratory model. "Nerves are not as attractive to these cancer cells." Noelle Jurcak, lead author of the study, said. In addition, when the researchers genetically modified mice to reduce the amount of PLXND1 secretion of their nerves, they made a startling discovery: not only did the nerve growth around tumor cells decrease, but the metastasis rate also dropped sharply, indicating that PNI was essential for the growth of metastatic PDA.
researchers have confirmed the key role of these molecules in human PDA cells. In samples of pancreatic cancer tissue taken from patients, the researchers found that tumors that expressed small amounts of SEMA3D and PLXND1 were 10 times more likely to be far apart from nearby nerves, while tumors containing large amounts of these proteins were associated with high levels of PNI.
Zheng Lei concluded that the results show that SEMA3D and PLXND1 play an important role in PNI and PDA transfer. Finally, the researchers say they may be able to develop targeted drugs for both molecules to reduce cancer-related pain by controlling the PNI. Targeting SEMA3D and PLXND1 may also help prevent or prevent transfers, he added.
researchers caution that it is not clear exactly how these molecules are involved in the spread of cancer, but one possible explanation is that pancreatic cancer cells can hide in nearby nerves even after the primary tumor is removed. If so, new surgical strategies or drugs can help slow the spread of PDA and related cancers, thereby increasing their survival.
"Our next step is to prove whether nerves become micro-environments that accept invading tumor cells," he said. Zheng Lei said, "If tumor cells are hidden there, it could be the source of recurrence." (Source: Zhao Xixi, China Science Journal)
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