(4ec) Biochemical Engineering of Cancer Immunotherapeutics

Despite the success of modern surgical techniques and
chemotherapeutic strategies in treating primary tumors, the insidious process
of cancer metastasis remains the most elaborate barrier to overcome in the cure
of the disease. With accumulating evidence of inflammation underpinning
metastatic progression, the integration of engineering fundamentals with
biochemistry, biomaterials and molecular biology as it pertains to the
inflammatory mediators of cell migration in immunity and metastasis is
essential to cancer therapeutic development.

Cancer metastasis is a highly coordinated process in
which cancerous cells "hijack" the homing mechanisms of immune cells in order to
invade and colonize distant tissues. Selectins facilitate this process by
mediating specific interactions between selectin-expressing immune and vascular
cells and selectin ligands presented by tumor cells. My research led to the
discovery of new surface adhesion molecules CD44v, carcinoembryonic antigen
(CEA), and podocalyxin-like protein (PCLP), which are glycoproteins irregularly
expressed by metastatic cells and function as selectin ligands in dynamic shear
environment of the vasculature. Furthermore, we characterized and correlated the
efficiency of selectin binding activity with their "metastatic-glycan
fingerprint". Stable, specific knockdown of CD44v and CEA mediated by siRNA led
to a significant reduction in interactions between colon carcinoma cells and
immobilized selectins, implicating these molecules in metastases-targeting
therapeutic applications.

Contemporary therapies to combat metastases increasingly
focus on harnessing the immune system. However, methods to elicit potent adaptive
immune responses that are cancer cell-specific yet safe remain elusive. Hence,
I am currently applying engineering fundamentals to the development of cancer
immunotherapeutics using a
nanobiotechnology approach for optimal lymphoid tissue targeting and adjuvancy.
First, using a mouse model of impaired fluid drainage
and immune cell migration, we establish that delivery of antigen to the lymph
node is crucial for efficient humoral but not T cell immunity in response to
vaccination as well as to the process of toleragenesis. These data implicate
that optimal priming of cancer specific cytotoxic T cells may be achieved via
splenic targeting of cancer vaccines while strategies to reverse tumor
tolerance should target the lymph nodes. Next,
accumulating evidence suggests that complement is an important
regulator of adaptive immune responses to vaccination as well as tumor immunity.
Harnessing the inherent biochemistry of polymeric nanoparticle surfaces, activation
and regulation of complement is achieved such that we might exploit its
immunological functions for use in material-based vaccines. Indeed, immunization
of mice with OVA-conjugated nanoparticle with surface chemistries that induce efficient
complement opsonization enhanced anti-OVA immune responses. Cumulatively, these studies underscore how rational
design of targeting strategies and biomaterial properties are fundamental to
the development of effective immunotherapeutic strategies.

1.    Thomas, S.N., van der
Vlies, A.J., O'Neil, C.P., Yu, S.S., Giorgio, T.D., Swartz, M.A., Hubbell, J.A., Engineering complement
activation on polypropylene sulfide vaccine nanoparticles. Submitted to Biomaterials.

2.    Thomas, S.N., Rutkowski,
J.M., Pasquilier, M., Kuan, E., Alitalo, K., E, Randolph, G., Swartz, M.A., Weak humoral immunity and acquired autoimmunity in
mice with impaired dermal lymphatic drainage. Submitted
to Journal of Clinical Investigation.

3.    Thomas, S.N., Swartz, M.A., Hubbell, J.A. Chemotherapeutic-loaded nanoparticles as vaccine
adjuvants. In preparation.

4.    Velutto, D., Thomas,
S.N., Simeoni, E., Swartz, M.A., Hubbell, J.A. Mixed micelles as 30
nm Nonviral DNA Vectors: Design and Demonstration in Tumor Microenvironment
Modulation and Immunotoxicity. In
preparation.

5.    Dallas, M., Liu, G., Thomas, S.N., Huso, D., Konstantopoulos,
K. Divergent
roles of CD44 and CEA in cancer metastasis. In preparation.

6.    Konstantopoulos, K., Thomas, S.N. Hematogenous Metastasis: Roles of CD44v and
Alternative Sialofucosylated Selectin Ligands. Advances in Experimental Medicine and Biology: Molecular Immunology of
Complex Carbohydrates 3. In Press.

7.    Hubbell, J.A., Thomas, S.N., Swartz, M.A.,
2009. Materials engineering for immunomodulation. Nature, 462
(7272): 449-460.

8.    Thomas,
S.N.*, Tong, Z.Q.*, Stebe, K.,
Konstantopoulos, K. 2009. Identification, characterization and utilization of
tumor cell selectin ligands in the design of colon cancer diagnostics. Biorheology. 46:207-25. *Equally
contributing.

9.    Konstantopoulos, K., Thomas, S.N. 2009. Cancer
Cells in Transit: The Vascular Interactions of Tumor Cells. Annual Review of Biomedical
Engineering.
11:177–202.

10. Thomas, S.N., Schnaar, R.L., Konstantopoulos, K.
2009. Podocalyxin-like protein is an E-/L-selectin ligand
on colon carcinoma cells: Comparative biochemical properties of selectin ligands
in host and tumor cells. Am J Physiol Cell
Physiol. 296: C505-C513.

11. Thomas, S.N., Zhu, F., Schnaar, R.L., Alves, C.S.,
Konstantopoulos, K. 2008. Carcinoembryonic antigen and CD44
variant isoforms cooperate to mediate colon carcinoma cell adhesion to E- and
L-selectin in shear flow. Journal of Biological
Chemistry 283(23): 15647-55.

12. Alves, C.S., Burdick, M.M.,
Thomas, S.N., Pawar, P.,
Konstantopoulos, K. 2008. The Dual Role of CD44 as a
Functional P-selectin and Fibrin Counter-receptor. Am J Physiol Cell Physiol 294(4): C907-16.

13. Napier, S.L., Healy, Z.R., Schnaar,
R.L., Konstantopoulos, K.  2007. Selectin ligand expression regulates the initial
vascular interactions of colon carcinoma cells: the roles of CD44v and alternate sialofucosylated
selectin ligands. Journal of Biological Chemistry 282(6); 3433-3441.
(Noted as recommended reading and a paper of special interest: Taylor, M. E.,
Drickamer, K. 2007 Current Opinion in Cell Biology 19: 572-577.)

14. Hanley, W., Napier, S., Burdick, M.M., Schnaar, R., Sackstein, R.,
Kostantopoulos, K. 2006. Variant isoforms of CD44 are P- and L-selectin ligands on
colon carcinoma cells. FASEB J. 20(2): 337-9.

15. Ahn, K.C., Jun, A.J.,
Pawar, P., Jadhav, S., Napier, S., McCarty, O.J., Konstantopoulos, K.
2005. Preferential Binding of Platelets
to Monocytes over Neutrophils Under Flow. Biochem Biophys Res Commun. 1;329(1):
345-55.

16. Cantor, R.M., Yuan, J., Napier, S., Kono, N., Grossman, J.M., Hahn,
B.H., Tsao B.P. 2004. Systemic Lupus Erythematosus Genome Scan:  Support for Linkage at 1q23, 2q33, 16q12–13, and
17q21–23 and Novel Evidence at 3p24, 10q23–24, 13q32, and
18q22–23. Arthritis and Rheumatism. 50: 3203-3210.

17. Cantor, R.M., de Bruin, T., Kono, N., Napier, S., van Nas, A.,
Allayee, H., Lusis, A.J. 2004. Quantitative Trait Loci for Apolipoprotein B, Cholesterol,
and Triglycerides in Familial Combined Hyperlipidemia Pedigrees. Arterioscler
Thromb Vasc Biol. 24: 1935-1941.