This picture shows a tumor within a tadpole embryo that has been labeled with red fluorescence to allow tracking; © Brook Chernet
Biologists at Tufts University School of Arts and Sciences have discovered a bioelectric signal that can identify cells that are likely to develop into tumors.
The researchers also found that they could lower the incidence of cancerous cells by manipulating the electrical charge across cells' membranes. "The news here is that we have established a bioelectric basis for the early detection of cancer," says Brook Chernet.
Doctor Michael Levin says, "We have shown that electric events tell the cells what to do. The voltage changes are not merely a sign of cancer. They control and direct whether the cancer occurs or not."
Bioelectric signals underlie an important set of control mechanisms that regulate how cells grow and multiply. Chernet and Levin investigated the bioelectric properties of cells that develop into tumors in Xenopus laevis frog embryos.
In previous research, the scientists have shown how manipulating membrane voltage can influence or regulate cellular behavior such as cell proliferation, migration, and shape in vivo, and be used to induce the formation or regenerative repair of whole organs and appendages. In this study, the researchers hypothesized that cancer can occur when bioelectric signaling networks are perturbed and cells stop attending to the patterning cues that orchestrate their normal development.
The researchers induced tumor growth in the frog embryos by injecting the samples with mRNAs (messenger RNA) encoding well-recognized human oncogenes Gli1, KrasG12D, and Xrel3. The embryos developed tumor-like growths that are associated with human cancers such as melanoma, leukemia, lung cancer, and rhabdomyosarcoma (a soft tissue cancer that most often affects children).
When the researchers analyzed the tumor cells using a membrane voltage-sensitive dye and fluorescence microscopy, they made an exciting discovery. "The tumor sites had unique depolarized membrane voltage relative to surrounding tissue," says Chernet. "They could be recognized by this distinctive bioelectric signal.
The biologists were also able to show that changing the bioelectric code to hyperpolarize tumor cells suppressed abnormal cell growth. "We hypothesized that the appearance of oncogene-induced tumors can be inhibited by alteration of membrane voltage," says Levin, "and we were right."
To counteract the tumor-inducing depolarization, they injected the cells with mRNA encoding carefully-chosen ion channels (proteins that control the passage of ions across cell membranes).
MEDICA.de; Source: Tufts University