Apoptosis, matters of life and death

The role of apoptosis in oral disease: mechanisms; aberrations in neoplastic, autoimmune, infectious, hematologic, and developmental diseases; and therapeutic opportunities

Apoptosis is a genetically programmed form of cell death, which primarily functions to eliminate senescent or altered cells that are useless or harmful for the multicellular organism. Contrary to necrosis, apoptosis represents a physiologic cellular mechanism, normal function and control of which are critical for the development and homeostasis of multicellular organisms. In contrast, aberrations of the apoptotic mechanisms that cause excessive or deficient programmed cell death have been linked to a wide array of pathologic conditions. This review briefly summarizes the major apoptotic pathways and molecules and presents the most important oral diseases that are related to dysregulation of apoptosis. Knowledge of the association between aberrations in apoptotic mechanisms and human pathology hopefully will be implemented for the design of improved diagnostic and prognostic assays and the development of novel, more efficient, therapeutic strategies.

Green tea and prostate cancer

Many laboratory studies and human epidemiological data suggest that most prostate cancer deaths are attributable to lifestyle, including nutritional factors where diet plays a major role in initiation as well as subsequent progression of the disease. Under these circumstances, chemoprevention seems to be a logical and obvious strategy. Because of its long latency and high incidence, prostate cancer is an ideal disease for chemoprevention. The suitable agent(s) for prostate cancer chemoprevention should be the one(s) that has efficacy in the laboratory experiments on one hand, and also possesses proven epidemiological basis on the other hand. In this article, we address the use of green tea for prostate cancer chemoprevention. Experimental as well as the epidemiological basis for this possibility is provided.

Cisplatin-induced apoptosis of mesothelioma cells is affected by potassium ion flux modulator amphotericin B and bumetanide

Chemotherapeutic anti-cancer drugs induce cell death by the process of apoptosis. Efflux of potassium ions (K(+)) is necessary for cell volume reduction during apoptosis and increased inward pumping of K(+) thus counteracts apoptosis. Potassium flux modulation could therefore interact with apoptosis and affect the efficiency of cancer chemotherapeutics. We explored if the K(+) efflux stimulator amphotericin B, with or without the Na(+), K(+), 2Cl(-)-cotransport (K(+) influx) blocker bumetanide, could affect cisplatin- and carboplatin-induced apoptosis and cytotoxicity in the pulmonary mesothelioma cell line (P31). Apoptosis was determined by quantifying free nucleosomes and caspase-3 activity, and cytotoxicity was determined by clone formation and a fluorometric assay. The pan-caspase enzyme inhibitor Boc-D-FMK was used to further determine the role of caspase activity in K(+)-flux-modulated cisplatin-/carboplatin-induced apoptosis and cytotoxicity. Amphotericin B (3.2 micromol/L) combined with bumetanide (100 micromol/L) potentiated cisplatin-induced free nucleosome and caspase-3 activity. The combination of the K(+) modulators did not, however, increase cisplatin cytotoxicity. The caspase inhibitor Boc-D-FMK, but unexpectedly also bumetanide, markedly reduced cisplatin cytotoxicity and annihilated the augmented cytotoxicity of cisplatin in the presence of amphotericin B. Carboplatin cytotoxicity was reduced by bumetanide, but not affected by amphotericin B. Carboplatin and carboplatin/bumetanide cytotoxicity was further reduced by Boc-D-FMK. We conclude that the ability of cisplatin, and to a lesser extent carboplatin, to induce apoptosis is indeed influenced by cellular potassium flux modulators. We suggest that K(+) ionophores such as amphotericin B, and K(+) influx blockers such as bumetanide, alone or in combination, should be further evaluated for their potential clinical usefulness in influencing tumor cell apoptosis induced by cisplatin and other cancer chemotherapeutics.