Tumor various protein antibodies. It was determined that

Tumor
necrosis factor-alpha (TNF-?) acts through tumor necrosis factor receptor type
2 (TNFR2) and tumor necrosis factor receptor type 1 (TNFR1) which both react
with an important inflammatory cytokine: tumor necrosis factor (TNF). This
interaction launches an immune response with TNFR1 more generally expressed in
tissues all over the body and TNFR2 expressed more precisely in T cells,
oligodendrocytes, and endothelial cells. Most importantly, TNFR2 appears to
have an essential role in the activation and regulatory activity of T cells. It
is especially vital in promoting proliferation, migration, and angiogenesis in
several cancers including bladder, breast, head and neck squamous cell, kidney,
lung squamous cell, prostate, melanoma, and uterine carcinoma (1,2). Using an ELISpot
test along with flow cytometry the reactive cells of TNF-? were found to have an
important function in controlling infection and growth of tumor cells in
HPV-caused cervical cancer. When TNF-? expression increases so does the
expression of TNFR2 which allows this expression to have an anti-tumor effect (3).
Lung cancer tumor samples were also analyzed using flow cytometry and stained
with various protein antibodies. It was determined that TNFR2 expression was
found in regulatory T (Treg) and effector T (Teff) cells
in lung tumor (1). Furthermore, Treg can be inhibited by TNFR2
antibody antagonists with more force in cancer tissues vs healthy tissues such
as to cause inhibition of the receptor. One recent technique has resulted in
hexagonal lattice of antiparallel dimers to stabilize the receptor inhibitory
state using TNFR2 antagonism (4). TNFR2 activates canonical NF-?B and JNK MAP
and non-canonical NF-?B kinase signaling. Blocking the activation of the
non-canonical NF-?B pathway can cause problems with the activation of T cells
possibly leading to apoptosis and increased cancer cell invasion (5). A
representative model of this has been difficult to obtain, and therefore, TNFR2
signal transduction along with its adaptor molecules is not well characterized.
Using proteomics, TNFR2 was bound to TNF resulting in the end product of the
ligand-TNFR2 complex. This complex causes the initiation of downstream signal
transduction causing accumulation of cytosolic signaling proteins. Analysis of
these proteins revealed that mitochondrial aminopeptidase P3 (APP3m) bind to
TNFR2 and thus is a vital adaptor molecule (6). Similarly, two signaling
proteins, Bid and Bim are downstream of TNFR2. These two molecules were found
through RNA isolation and RT-PCR to help induce cell apoptosis through TNFR2 in
vitro (7). A phage library was used to further characterize this expression by
producing an agonistic TNF mutant which binds to mTNFR2. This mutant’s binding
kinetics was tested with surface plasmon resonance (SPR) revealing that association
and dissociation was quicker in the mutant (8). A different TNF mutant was also
created with disulfide cross-links making the trimeric TNF complex more rigid
which increased the inhibitory effect of TNFR2 allowing for higher binding with
TNFR1 for antagonistic behavior (9). Similarly, exploration of TNFR2 in
enzyme-instructed self-assembly (EISA) of cholesterol and phosphotyrosine conjugate
molecules in order to fight cancers has resulted in drug treatment capable of
avoiding targeting TNFR2 and the immune cells while selectively binding to
TNFR1 to cause cancer cell death (10). Also, silencing of TNFR2 was shown to
inhibit poly (ADP-ribose) polymerase (PARP) which has been hypothesized to mean
that TNFR2 is trying to block some of the DNA damage by inhibiting PARP
expression (2). More research is needed to fully characterize TNFR2 function in
repairing DNA damage. Overall, TNFR2 and further investigation into its role is
important in the field of cancer research, especially concerning anti-cancer
drug research.