Jane F. Wiesen

Abnormal astrocyte development and neuronal death in mice lacking the epidermal growth factor receptor

Stimulation of the epidermal growth factor receptor (EGF‐R) produces numerous effects on central nervous system (CNS) cells in vitro including neuronal survival and differentiation, astrocyte proliferation and the proliferation of multipotent progenitors. However, the in vivo role of EGF‐R is less well understood. In the present study, we demonstrate that EGF‐R null mice generated on a 129Sv/J Swiss Black background undergo focal but massive degeneration the olfactory bulb, piriform cortex, neocortex, and thalamus between postnatal days 5 and 8 which is due, at least in part, to apoptosis. Some of the neuronal populations that degenerate do not normally express EGF‐R, indicating an indirect mechanism of neuronal death. There were also delays in GFAP expression within the glia limitans and within structures outside the germinal zones in early postnatal ages. At or just prior to the onset of the degeneration, however, there was an increase in GFAP expression in these areas. The brains of EGF‐R −/− animals were smaller but cytoarchitecturally normal at birth and neuronal populations appeared to be intact, including striatal GABAergic and midbrain dopaminergic neurons which have previously been shown to express EGF‐R. Multipotent progenitors and astrocytes derived from EGF‐R −/− mice were capable of proliferating in response to FGF‐2. These data demonstrate that EGF‐R expression is critical for the maintenance of large portions of the postnatal mouse forebrain as well as the normal development of astrocytes. J. Neurosci. Res. 53:697–717, 1998.

B cells regulate macrophage phenotype and response to chemotherapy in squamous carcinomas.

B cells foster squamous cell carcinoma (SCC) development through deposition of immunoglobulin-containing immune complexes in premalignant tissue and Fcγ receptor-dependent activation of myeloid cells. Because human SCCs of the vulva and head and neck exhibited hallmarks of B cell infiltration, we examined B cell-deficient mice and found reduced support for SCC growth. Although ineffective as a single agent, treatment of mice bearing preexisting SCCs with B cell-depleting αCD20 monoclonal antibodies improved response to platinum- and Taxol-based chemotherapy. Improved chemoresponsiveness was dependent on altered chemokine expression by macrophages that promoted tumor infiltration of activated CD8(+) lymphocytes via CCR5-dependent mechanisms. These data reveal that B cells, and the downstream myeloid-based pathways they regulate, represent tractable targets for anticancer therapy in select tumors.

Uterine and vaginal organ growth requires epidermal growth factor receptor signaling from stroma

Estrogens are crucial for growth and function of the female genital tract. Recently, we showed that induction of uterine epithelial proliferation by estradiol is a paracrine event requiring an estrogen receptor-positive stroma. Growth factors [such as EGF (epidermal growth factor) ligands] are likely paracrine mediators, which may directly or indirectly regulate epithelial proliferation in estrogen target organs via cell-cell interactions. In this report, we used mice with a null mutation in their EGF receptor (EGFR) to examine the role of EGFR signaling in growth of the uterus and vagina and in estrogen-induced uterine and vaginal epithelial proliferation. When WT and EGFR-knockout (EGFR-KO) uteri and vaginae were grown as renal capsule grafts in nude mice, growth of uterine and vaginal grafts of EGFR-KO mice was reduced, compared with their WT counterparts. Grafts of both EGFR-KO uteri and vaginae were about one third smaller (wet weight) than their corresponding WT organs, even though differentiation of both epithelium and mesenchyme were normal in both cases. Both wild-type and EGFR-KO vaginal grafts contained within their lumina alternating layers of cornified and mucified epithelial cell layers, indicating cyclic alteration of epithelial differentiation. In response to estradiol treatment, stromal cell labeling index (LI), as assessed by incorporation of 3H-thymidine, was severely depressed in EGFR-KO uterine and vaginal grafts vs. stromal cell LI in WT uterine and vaginal grafts. Unexpectedly, epithelium of both EGFR-KO and wild-type grafts responded comparably to estradiol with a marked elevation (approximately 7-fold overall) of epithelial LI in response to estradiol in uterine and vaginal epithelia. These data supported the hypothesis that overall uterine and vaginal organ growth, in response to estrogen, required EGFR signaling for DNA synthesis in the fibromuscular stroma, whereas EGFR signaling was not essential for estrogen-induced epithelial growth in the uterus and vagina.

Stromal regulation of vessel stability by MMP14 and TGFβ

Innate regulatory networks within organs maintain tissue homeostasis and facilitate rapid responses to damage. We identified a novel pathway regulating vessel stability in tissues that involves matrix metalloproteinase 14 (MMP14) and transforming growth factor beta 1 (TGFβ1). Whereas plasma proteins rapidly extravasate out of vasculature in wild-type mice following acute damage, short-term treatment of mice in vivo with a broad-spectrum metalloproteinase inhibitor, neutralizing antibodies to TGFβ1, or an activin-like kinase 5 (ALK5) inhibitor significantly enhanced vessel leakage. By contrast, in a mouse model of age-related dermal fibrosis, where MMP14 activity and TGFβ bioavailability are chronically elevated, or in mice that ectopically express TGFβ in the epidermis, cutaneous vessels are resistant to acute leakage. Characteristic responses to tissue damage are reinstated if the fibrotic mice are pretreated with metalloproteinase inhibitors or TGFβ signaling antagonists. Neoplastic tissues, however, are in a constant state of tissue damage and exhibit altered hemodynamics owing to hyperleaky angiogenic vasculature. In two distinct transgenic mouse tumor models, inhibition of ALK5 further enhanced vascular leakage into the interstitium and facilitated increased delivery of high molecular weight compounds into premalignant tissue and tumors. Taken together, these data define a central pathway involving MMP14 and TGFβ that mediates vessel stability and vascular response to tissue injury. Antagonists of this pathway could be therapeutically exploited to improve the delivery of therapeutics or molecular contrast agents into tissues where chronic damage or neoplastic disease limits their efficient delivery.

The role of stromelysin-1 in stromal-epithelial interactions and cancer.

Stromelysin-1 was one of the first proteinases found to be associated with cancer. In this review we describe the role of stromelysin-1 in normal mammary gland involution. When stromelysin-1 is overexpressed in transgenic mice the mammary gland undergoes precocious involution and is predisposed to forming a reactive stroma resembling that of a wound site or a tumor. Stromelysin-1 may act as an oncogene because transgenic mice expressing an active form of the enzyme develop mammary tumors. These observations suggest that stromelysin-1 and other matrix metalloproteinases may be useful targets for therapeutic intervention in cancer.

Abstract 4391: CD20 as a target for therapy in solid tumors

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Using the K14-HPV16 mouse model of squamous carcinogenesis (SCC), we previously reported that B cells foster neoplastic progression through deposition of immunoglobulin complexes in premalignant tissue via Fcα receptor-dependent activation of recruited myeloid cells. Here we evaluated therapeutic interventions targeting these pathways in preclinical trials through administration of depleting αCD20 antibody and small molecule inhibitor of Syk kinase. Both approaches harbored efficacy in preventing premalignant progression to the dysplastic/carcinoma in situ state. Screening a diverse spectrum of human solid tumors revealed SCCs of the vulva, head and neck, as well as pancreatic ductal adenocarcinomas (PDAC) as scoring positively for “signatures” of B cell or plasma cell infiltration, i.e. Ig or CD20 mRNA expression, thereby identifying carcinomas potentially amenable to anti-B cell therapies. Accordingly, B cell-deficient mice failed to support growth of either transplantable orthotopic SCC or PDAC. While administration of αCD20 mAB as a single agent was inefficient in impeding growth of preexisting SCCs, when delivered in combination with cytotoxic chemotherapy, e.g., paclitaxel, carboplatin or cisplatin, αCD20 mAb significantly improved chemotherapeutic response and improved survival by a mechanism dependent on CD8+ T cells. These data reveal that blocking protumorigenic programs regulating by humoral immunity, in combination with chemotherapy, effectively reprograms the tumor immune microenvironment and improves outcome. The authors acknowledge generous support from the NIH/NCI (R01CA130980, R01CA13256, R01CA140943, R01CA15531), the Department of Defense (W81XWH-09-1-0342, W81XWH-10-BCRP-EOHS-EXP) and the Susan G Komen Foundation (KG111084) Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4391. doi:1538-7445.AM2012-4391