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Walter Eckhart

 

Walter Eckhart

Walter Eckhart

Professor and Laboratory Head
Molecular and Cell Biology Laboratory

"The overall interest of my laboratory has been the regulation of cell growth, including the action of cancer-causing genes, communication between cells, and the effects of growth factors on the development of breast cancer."

The growth of cells is tightly controlled, but cancer cells turn a deaf ear to signals that cause normal cells to stop dividing. Eckhart and his team identified and characterized genes in tumor viruses—so-called viral oncogenes—that override normal cell cycle controls. The viral genes he studied stimulate cellular growth signaling pathways, allowing the cells to divide continuously. Identification of growth signaling pathways has led to the development of drugs that inhibit the growth of cancer cells.

Cancer cells also lose the ability to communicate with each other through the exchange of materials through channels called gap junctions. This communication is important for coordinating the activities of cells in tissues, including normal regulation of cell growth. The proteins that form the channels are called connexins. Eckhart found that the addition of a phosphate molecule to a particular site in the connexin protein caused the channel to close. Some cancer-causing genes stimulate this addition, thereby shutting off communication between adjacent cells and disrupting normal growth. Restoration of communication allows the cells to grow normally again, suggesting that agents that regulate cellular communication might help in reversing cancer. Eckhart also studied the effects of a growth factor, insulin-like growth factor-1 (IGF-1), on human mammary epithelial cells growing in a three-dimensional culture system that mimics the environment of the body. These cells spontaneously develop into hollow structures resembling tiny milk ducts, the most common site where invasive cancer arises. Abnormal signaling by IGF-1 changed the clearly defined hollow tubes into a misshapen blob of cells, similar to what happens during early tumor development. Studies like these can help in understanding how changes in genes and growth signaling can lead to breast cancer.

Eckhart recently phased out his laboratory research program. In his capacity as head of the Molecular and Cell Biology Laboratory (MCBL), he continues to work with Suzanne Simon, lab coordinator and administrator of the Salk Institute Cancer Center, to facilitate the research in MCBL.

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Walter Eckhart and Susie Simon

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Walter Eckhart

Faculty

Walter Eckhart

Walter Eckhart

Professor and Laboratory Head
Molecular and Cell Biology Laboratory

Walter Eckhart is a professor and director of the Salk Institute Cancer Center and head of the Molecular and Cell Biology Laboratory. He has studied regulation of cell growth, including the action of cancer causing genes (oncogenes) and the effects of communication between adjacent cells (gap junctional intercellular communication). Recently, he and his colleagues have studied growth signaling through the type I insulin-like growth factor receptor (IGFIR) using three-dimensional cultures of human mammary epithelial cells. Overexpression of the IGFR induces proliferation and anti-apoptotic signaling reminiscent of early pathological changes in breast cancer.

Dr. Eckhart will be phasing out his laboratory research program in the near future to focus on his other responsibilities.

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