Description of Research Expertise

Research Interests:
Study of B-cell response to tumors and B-cell interactions with innate immunity in the tumor microenvironment; development and evaluation of affinity reagents for diagnostic and targeted-imaging of cancer and therapy for ovarian cancer.

Key words:
Tumor microenvironment, ovarian cancer, innate and humoral immunity, recombinant antibodies, yeast-display scFv, targeted-nanoparticles.

Research Summary:
A/ Study of B-cell responses to tumors and B-cell interactions with innate immunity in the tumor microenvironment

The central hypothesis of my work is that B-cells play a pivotal, yet underappreciated, role in tumor formation and progression, and thus offer unique therapeutic opportunities for ovarian cancer. In my lab we have used a transgenic mouse model of ovarian cancer to better understand the role of B-cells and characterize the underlying mechanisms. We have observed that these tumors are infiltrated early on by B lymphocytes (TIL-B) and by macrophages. My lab is currently focused on understanding the role of different subsets of TIL-B and determining their relative frequency in ovarian cancer, and designing stimulation therapies that are able to activate all classes of TIL-B toward tumor rejection.
In the past year we also investigated the link between B-cell infiltration in tumors and innate immunity and the complement system. We have discovered that complement activation in tumors is critical for TIL-B function. This finding generates important opportunities to understand the role of B-cells but also to develop therapeutic tools.
Given the role of macrophages in tumor growth and their temporal association with B-cell infiltration in tumors, we are investigating whether macrophage depletion or repolarization could prevent some of the effects of TIL-B on tumor growth and are developing tools to repolarize tumor macrophages. Given my expertise in developing antibodies, we developed functional recombinant antibodies (scFv) against MR and showed that these novel anti-MR scFv could abrogate macrophage phenotype shift. My lab is now conducting in vivo experiments with MR knock-out mice which could lead to a novel therapeutic strategy able to redirect the tumor microenvironment toward an anti-tumor response by stabilizing the phenotype of M1 macrophages.

B/ Development and evaluation of affinity reagents for diagnostic and targeted-imaging and therapy of cancer

I have a long-standing expertise in the field of antibody development. The ELISA assay I developed against Mesothelin and published in 1999 in PNAS is now commercialized by Fujirebio, Inc as MesomarkTM. The scFv assays developed for diagnostic and functional tests directed to Mesothelin and its binding partner, CA125, as well as HE4 and other candidate biomarkers, are central to several epidemiological studies. My work in this area continues and I am exploring the potential of a combination of anti-Mesothelin and anti-CA125 mAbs to prevent peritoneal micrometastases.
Capitalizing on my expertise in antibody engineering, I have established a team at the University of Pennsylvania to create and screen novel yeast-display recombinant antibody (scFv) libraries derived from patients. My lab has created two new libraries of yeast-display scFv and identified several target-specific scFv. We are pursuing these important newly developed tools in different clinically relevant applications in various collaborative works at Penn and extramurally, ranging from functionalizing nanoparticles for organ-specific delivery of nucleic acids and contrast imaging agents and/or cytotoxic reagents, to physically active nanoparticles such as nanorods. ScFv are also being tested for direct radiolabelling and to engineer T-cells redirected to target through scFv. My lab is currently invested in deriving additional scFv against critical tumor-associated targets and to test their application in concrete disease models, including ovarian and breast cancers.

Rotation projects:
Study the mechanisms involved in early events in the genesis of ovarian cancer and specifically the role of B-cells and innate immunity.
Identify novel recombinant antibodies of translational interest for targeted-imaging and therapy in preclinical models of ovarian cancer.

Lab members:
Yi Cheng – Lab Manager (chengyi@mail.med.upenn.edu)
Selene Nunez-Cruz – Research Associate (selene@mail.med.upenn.edu)
Aizhi Zhao – Post-doctoral Fellow (zha@mail.med.upenn.edu)
Andrew Prantner – Post-doctoral Fellow (prantner@mail.med.upenn.edu)
Denarda Dangaj – Graduate Student (ddangaj@mail.med.upenn.edu)

Research Techniques:
Cellular biology: in vitro culture and maturation of human and murine B cells and macrophages, cell functional assays, magnetic and flow sortings, immunohistochemistry.
Molecular biology: engineering and screening of yeast-display scFv libraries, yeast expression of in vivo biotinylated proteins, mammalian expression of recombinant proteins.
Animal models of ovarian cancer in various genetic backgrounds, in vivo tumor imaging, targeted-imaging and therapy.