Tuesday, May 17th, 2005.

International Journal of Cancer. May 17, 2005. Volume 117, Issue 2, Pages 326 – 332. [Link]

Julien Mazieres ^{1 2}, Liang You ¹, Biao He ¹, Zhidong Xu ¹, Sarah Twogood ¹, Amie Y. Lee ¹, Noemi Reguart ¹, Sonny Batra ¹, Iwao Mikami ¹, David M. Jablons ^{1 *}

¹Thoracic Oncology Laboratory, Department of Surgery, Comprehensive Cancer Center, University of California, San Francisco, CA, USA
²Departement Innovation Therapeutique et Oncologie Moleculaire, INSERM U563, Institut Claudius Regaud, Toulouse Cedex, France

Abstract

Malignant mesothelioma of the pleura (MPM) is a highly aggressive neoplasm with a poor prognosis and limited treatment options. A better understanding of its pathogenesis is essential to developing alternative therapeutic strategies. We previously demonstrated that the Wnt signaling pathway is activated in MPM through the overexpression of disheveled proteins. To extend our knowledge of Wnt signaling activation in MPM, we performed Wnt-specific microarrays in normal pleura and MPM. We found that the most common event in MPM was the upregulation of Wnt2. We inhibited Wnt2 by siRNA and a monoclonal anti-Wnt2 antibody and analyzed their effects on apoptosis and downstream signaling effectors. We then assessed the antiproliferative effects of the Wnt2 antibody and Alimta, one of the current standard treatments of MPM. We confirmed Wnt2 overexpression at the mRNA and protein level in MPM cell lines and tissues. We then demonstrated that inhibition of Wnt2 by siRNA or a monoclonal antibody induces programmed cell death in MPM cells. We next analyzed the effects of the anti-Wnt2 antibody and of Alimta on MPM cell proliferation. We found that although Wnt2 antibody by itself had less antiproliferative potency than Alimta, the two in combination had substantially more activity than Alimta alone. We thus propose that inhibition of Wnt2 is of therapeutic interest in the development of more effective treatments for MPM.

Glossary

Alimta

(pemetrexed) trademarked name under which pemetrexed is marketed. Chemotherapy drug. See: pemetrexed.

prognosis

(prog-no-sis) a prediction of the course of disease; the outlook for the cure of the patient. For example, women with breast cancer that was detected early and who received prompt treatment have a good prognosis.

pleura

(pler-uh) the membrane around the lungs and lining of the chest cavity. (Pleural mesothelioma.)

oncology

(on-call-o-jee) the branch of medicine concerned with the diagnosis and treatment of cancer.

neoplasm

(nee-o-plas-um) an abnormal growth (tumor) that starts from a single altered cell; a neoplasm may be benign or malignant. Cancer is a malignant neoplasm.

cell

the basic unit of which all living things are made. Cells replace themselves by splitting and forming new cells (mitosis). The processes that control the formation of new cells and the death of old cells are disrupted in cancer.

cancer

malignancy; a group of diseases typified by abnormal, generally out-of-control, cell growth.

antibody

a protein in the blood that defends against foreign agents, such as bacteria. These agents contain certain substances called antigens. Each antibody works against a specific antigen. (See also antigen.)

mesothelioma

a tumor derived from mesothelial tissue, such as the peritoneum (lining the abdomen) or pleura (lining the lungs). More on mesothelioma.

apoptosis

a type of cell death in which the cell basically commits suicide; scientists believe some types of cancer may originate from an interruption of this programmed cell death, allowing cells to grow out of control.

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