Caffeine and Apoptosis - Caffeine: Chemistry, Analysis, Function and Effects - page 394

been a focus of intense research. It appears that AKT lies at the cross-roads of
multiple cellular signaling pathways and acts as a transducer of many functions
initiated by growth factors and other receptors that activate PI3K. One of the
major activities of AKT is to promote cell survival. AKT is activated in response
to UVB irradiation and is frequently activated in human cancers.
p53: also known as protein 53 or tumor protein 53, is a tumor suppressor
protein that in humans is encoded by the TP53 gene. p53 is crucial in
multicellular organisms, where it regulates the cell cycle and apoptosis, and
thus functions as a tumor suppressor that is involved in preventing cancer. As
such, p53 has been described as ''the guardian of the genome'', the ''guardian
angel gene'', and the ''master watchman'', referring to its role in conserving
stability by preventing genome mutation.
Caffeine: Caffeine is a drug that stimulates the central nervous system. Caffeine
is found naturally in coffee, tea, and chocolate. For many years, caffeine has
been generally believed to induce cell apoptosis, suppress cell proliferation,
abolish chemical- or radiation-induced delays in cell cycle progression and
enhance the toxicity of radiation and anti-cancer agents. Caffeine has also been
shown to inhibit ultraviolet B (UVB)-induced skin cancer in mice.
Cell cycle: The sequence of events within the cell during cell divisions. The cell
cycle is traditionally divided into the following phases:
N

d n 0 t 2 n g | 2

G0 (G zero, the G standing for gap)

N

G1, (G one, the first gap)

N

S (synthesis phase during which the DNA is synthesized, replicated)

N

G2 (G two, the second gap)

N

M (standing for mitosis, cell division).

Cells that are not destined to divide again are considered to be in G0. The
transition from G0 to G1 is thought to commit the cell to completing the cell
cycle and dividing.
DNA damage: Drug- or radiation-induced injuries in DNA that introduce
deviations from its normal double-helical conformation. These changes include
structural distortions which interfere with replication and transcription, as well
as point mutations which disrupt base pairs and wield damaging effects on
prospective generations through changes in the DNA sequence. If the damage
is insignificant, it can often be repaired (DNA REPAIR). If the damage is
extensive, it can induce apoptosis.

List of Abbreviations
1. 293T cell a cell line derived from human embryonic kidney cells

2. E-BP1 eukaryotic initiation factor 4E binding protein 1

3. -OHDA 6-Hydroxydopamine

4. ATM Ataxia-telangiectasia mutated

5. ATR ATM and RAD3-related