changes in protein profiles in bortezomib applied multiple myeloma ...

Spot 4, Ubiquitin-conjugating enzyme E2C accepts ubiquitin from the E1
complex and catalyzes its covalent attachment to other proteins. It catalyzes 'Lys-11'-
and 'Lys-48'-linked polyubiquitination in vitro. Morover this protein acts as an essential
factor of the anaphase promoting complex/cyclosome (APC/C), a cell cycle-regulated
ubiquitin ligase that controls progression through mitosis. Acts by initiating 'Lys-11'-
linked polyubiquitin chains on APC/C substrates, leading to the degradation of APC/C
substrates by the proteasome and promoting mitotic exit. As this protein is responsible
for controlling progression and has a role in protein ubiquitination, its expression level
is increasing with the Bortezomib effect.
Spot 34, Ras-related protein Rab-25 is involved in the regulation of cell survival.
Similar to spot 2, 4, and 18, its expression degree increases in response to Bortezomib.
Spot 5, Paxillin is a cytoskeletal protein involved in actin-membrane attachment
at sites of cell adhesion to the extracellular matrix (focal adhesion). With the applying
anticancer agents to the cells, it was lost.
Spot 14, Signaling trashold-regulating transmembrane adapter 1 negatively
regulates TCR (T-cell antigen receptor)-mediated signaling in T-cells. It is also involved
in positive selection of T-cells. It is specifically expressed in T and B-cells and present
in plasma cells but not in germinal center B-cells (at protein level). Furthermore, it is
expressed in T- and B-cell lymphoma. Like spot 5, it was lost with the Bortezomib.
Spot 15, Caspase recruitment domain-containing protein 14 activates NF-κB via
BCL10 and IKK and stimulates the phosphorylation of BCL10. The main goal of
Bortezomib is inhibit the proteasomes for preventing the IκB degredation and
accordingly NF-κB activation, so it is very required to lose of this protein as expected.
Spot 23, NF-κB inhibitor delta may regulate the expression of IL-2, IL-6, and
other cytokines through regulation on NF-κB activity, similarly to spot 15.
Spot 6, Glutathione peroxidase 3 protects cells and enzymes from oxidative
damage, by catalyzing the reduction of hydrogen peroxide, lipid peroxides and organic
hydroperoxide, by glutathione. So, it is an example of newly formed protein after the
Bortezomib effects upon MM U-266 cells.
For spot 7, we obtained two proteins that have the change to be the correct one
after the mass spectrometric analysis. One of them was Mitogen-activated protein
kinase kinase kinase kinase 1 which may play a role in the response to environmental
stress. This protein appears to act upstream of the JUN N-terminal pathway and might
play a role in hematopoietic lineage decisions and growth regulation. As well as, it is
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