Nucleic Aptamer Selection Against S100A4 for Prevention of Cancer Metastasis

The full proposal has been posted on Dropbox.

S100A4 (also known as calvasculin) belongs to the S100 family of Ca2+-binding proteins. S100 proteins are localized in the cytoplasm and/or nucleus of a wide range of cells, and involved in the regulation of a number of cellular processes such as cell cycle progression and differentiation. Calvasculin is a polypeptide of 100 amino acids, excluding the initiating N-terminal methionine. The molecular mass of the natural protein, determined by electrospray ionisation mass spectrometry, is 11,646 Da. (Barraclough 1998). The protein has many functions, such as induction of angiogenesis, stimulation of neurite outgrowth and protection of cells from proapoptotic stimuli (Hua et al. 2009). S100A4 may also function in motility, invasion, and tubulin polymerization. Chromosomal rearrangements and overexpression of this protein have been implicated in the motility and metastasis of cancer through interactions with cytoskeletal constituents.
S100A4 signaling can focus on factors associated with normal and abnormal proliferation, apoptosis and growth, and differentiation. Therefore, it is arguably a molecular target of considerable potential possessing a wide ranging biological activity that can alter and regulate the major phenotypic features of cancer (Sherbet 2008). RNA ligands, called aptamers act as a promising means to inhibit S100A4. Aptamers bind with high specificity and high affinity to their protein targets and are powerful tools in diagnostics and therapeutics (Stoltenburg et al. 2008). Aptamers against S100A4 are expected to provide a major defense against metastasis of cancer and tumor cells.
Specific Aim 1: Selection of RNA aptamers against S100A4
S100A4 promotes cell progression through angiogenesis and allows tumor neovascularization and cell progression of cancer cells (Sherbet 2008). Therefore decreased levels of this protein correlate to decreased metastasis. Selection of RNA aptamers against S100A4 will decrease metastasis of cancer and tumor cells and since S100A4 also protects from apoptotic stimuli may also induce apoptosis in these malignant cells.

Barraclough, R. 1998. Calcium-binding protein S100A4 in health and disease. Biochimica et Biophysica Acta (BBA) - Molecular Cell Research, 1448(2): 190-199.
Hua J., D. Chen, H. Fu, R. Zhang, W. Shen, S. Liu, K. Sun, and X. Sun. 2009. Short hairpin RNA–mediated inhibition of S100A4 promotes apoptosis and suppresses proliferation of BGC823 gastric cancer cells in vitro and in vivo. Cancer Letters, 292 (1): 41-47.
Sherbet, G.V. 2008. Metastasis promoter S100A4 is a potentially valuable molecular target for cancer therapy. Cancer Letters, 280(1): 15-30.
Stoltenburg, R., C. Reinemann, and B. Strehlitz. SELEX--a (r)evolutionary method to generate high-affinity nucleic acid ligands. Biomolecular Engineering 24 (4): 381-403.


Gwen Stovall said...

Nice abstract. Sounds like a good project. Please consider adding a sentence about how to obtain the protein.

Gwen Stovall said...

Do you have a reference for this, "Therefore decreased levels of this protein correlate to decreased metastasis"? Or - is this one of your hypotheses? Clarify this statement.

Amanda C. Romero said...

This sounds like a really interesting project, we have the same kind of end goal!

Mimi Le said...

This sounds like a good project. However, if the body requires S100A4 for normal cell functions (motility and polymerization), how would you be able to regulate the amount of inhibition (by RNA aptamers) to the point where it becomes beneficial to the cell?

Nia_Fernandez said...

"Chromosomal rearrangements and overexpression of this protein have been implicated in the motility and metastasis of cancer through interactions with cytoskeletal constituents." -- > source?

It seems to encompass a wide range of issues. It may be better to focus the purpose some more.

It has very thorough protein information!!

Stephanie Philip said...

Gwen and Nia: Both of those I believe have sources - I have to double check if I just neglected to cite them in paragraph - they should be in the bibliography. Thanks for the heads up though!

Mimi: Hmm, you make an good point, I definitely need to continue research on the protein - thanks for the heads up!

Kamaxi Patel said...

You have a lot of interesting information about your protein! It provides a nice background and leads up to your specific point.

Maybe you can provide some examples of things that have been done in the past using your protein and their results.

Brad Hall said...

@Kamaxi, I think the level of background in this abstract is appropriate, and anything more should be in the actual proposal.

@Stephanie, this target is actually quite expensive. I found it from Genway, Cat# 10-663-46724, 20ug for $165. That means you only get 1449pmol. If you are really set on this protein, you can work with it. If you are set on cancer prevention, then work with another student on their target or find another target on your own. Other students are working with S100 related targets (see Kamaxi and Emma) and Amanda is working with CXCL1.

Brad Hall said...

I wrote Roger an e-mail checking on this target.

Nia_Fernandez said...

To perform your calculations:

Since your company did not provide you with preferred resuspension volume nor final concentration we used

10 ul = 100 pmol for your calculations

13,800 g/mol

0.00002g * (mol/ 13,800g) * 1e12 = 1449.28 pmol/ 100 pmol/ aliquot =
14.49 aliquots

14.49 aliquots * (10 ul/ aliquot) =
145 ul 1X Tris

Luis Fernando Reyes said...

i love this i blog im doing my post-doc on aptamers!