Stephanie N. Shishido

Humoral innate immune response and disease.

Abstract The humoral innate immune response consists of multiple components, including the naturally occurring antibodies (NAb), pentraxins and the complement and contact cascades. As soluble, plasma components, these innate proteins provide key elements in the prevention and control of disease. However, pathogens and cells with altered self proteins utilize multiple humoral components to evade destruction and promote pathogy. Many studies have examined the relationship between humoral immunity and autoimmune disorders. This review focuses on the interactions between the humoral components and their role in promoting the pathogenesis of bacterial and viral infections and chronic diseases such as atherosclerosis and cancer. Understanding the beneficial and detrimental aspects of the individual components and the interactions between proteins which regulate the innate and adaptive response will provide therapeutic targets for subsequent studies.

Gap Junction Enhancer Increases Efficacy of Cisplatin to Attenuate Mammary Tumor Growth

Cisplatin treatment has an overall 19% response rate in animal models with malignant tumors. Increasing gap junction activity in tumor cells provides the targets to enhance antineoplastic therapies. Previously, a new class of substituted quinolines (PQs) acts as gap junction enhancer, ability to increase the gap junctional intercellular communication, in breast cancer cells. We examined the effect of combinational treatment of PQs and antineoplastic drugs in an animal model, showing an increase in efficacy of antineoplastic drugs via the enhancement of gap junctions. Mice were implanted with estradiol-17ß (1.7 mg/pellet) before the injection of 1×107 T47D breast cancer cells subcutaneously into the inguinal region of mammary fat pad. Animals were treated intraperitoneally with DMSO (control), cisplatin (3.5 mg/kg), PQ (25 mg/kg), or a combining treatment of cisplatin and PQ. Cisplatin alone decreased mammary tumor growth by 85% while combinational treatment of cisplatin and PQ1 or PQ7 showed an additional reduction of 77% and 22% of tumor growth after 7 treatments at every 2 days, respectively. Histological results showed a significant increase of gap junction proteins, Cx43 and Cx26, in PQ-treated tissues compared to control or cisplatin. Furthermore, evidence of highly stained caspase 3 in tumors of combinational treatment (PQ and cisplatin) was seen compared to cisplatin alone. We have showed for the first time an increase in the efficacy of antineoplastic drugs through a combinational treatment with PQs, a specific class of gap junction enhancers.

The anticancer effect of PQ1 in the MMTV-PyVT mouse model

Animal models are commonly used to analyze the mechanism of carcinogenesis as well as the development and screening of potent drugs. Here the transgenic strain FVB/N‐Tg(MMTV‐PyVT)634Mul/J (also known as PyVT) was used as a model system for measuring tumor burden, drug sensitivity, and metastasis of mammary carcinomas. Loss of gap junctional intercellular communication and the down regulation of connexin expression are characteristic of neoplastic cells. The substituted quinoline, 6‐methoxy‐8‐[(3‐aminopropyl)amino]‐4‐methyl‐5‐(3‐trifluoromethyl‐phenyloxy)quinolone (PQ1), has been shown to restore GJIC and increase connexin expression in breast cancer cell lines while not affecting normal mammary cells, suggesting that it may provide effective anticancer treatment with less detrimental effects. The PyVT spontaneous mammary tumor mouse model was used to determine the biological and histological effects of PQ1 on tumorigenesis and metastasis at three stages of development: Pretumor, early tumor and late tumor formation. Treatment with PQ1 at all three stages of development significantly reduced tumor growth. PQ1 treatment further increased Cx43 expression during pre‐ and early‐tumor formation, while it prevented an increase in Cx46 expression during late stage tumor formation. This study shows that Cx43 expression and neoplastic cellular growth are inversely related, but that PQ1 can alter tumor growth through targeting gap junction proteins to prove clinical efficacy in the treatment of spontaneous mammary tumors.

Induction of Apoptosis by PQ1, a Gap Junction Enhancer that Upregulates Connexin 43 and Activates the MAPK Signaling Pathway in Mammary Carcinoma Cells

The mechanism of gap junction enhancer (PQ1) induced cytotoxicity is thought to be attributed to the change in connexin 43 (Cx43) expression; therefore, the effects of Cx43 modulation in cell survival were investigated in mammary carcinoma cells (FMC2u) derived from a malignant neoplasm of a female FVB/N-Tg(MMTV-PyVT)634Mul/J (PyVT) transgenic mouse. PQ1 was determined to have an IC50 of 6.5 µM in FMC2u cells, while inducing an upregulation in Cx43 expression. The effects of Cx43 modulation in FMC2u cell survival was determined through transfection experiments with Cx43 cDNA, which induced an elevated level of protein expression similar to that seen with PQ1 exposure, or siRNA to silence Cx43 protein expression. Overexpression or silencing of Cx43 led to a reduction or an increase in cell viability, respectively. The mitogen-activated protein kinase (MAPK) family has been implicated in the regulation of cell survival and cell death; therefore, the gap junctional intercellular communication (GJIC)-independent function of PQ1 and Cx43 in the Raf/Mitogen-activated protein kinase/ERK kinase/extracellular-signal-regulated kinase (Raf-MEK-ERK) cascade of cellular survival and p38 MAPK-dependent pathway of apoptosis were explored. PQ1 treatment activated p44/42 MAPK, while the overexpression of Cx43 resulted in a reduced expression. This suggests that PQ1 affects the Raf-MEK-ERK cascade independent of Cx43 upregulation. Both overexpression of Cx43 and PQ1 treatment stimulated an increase in the phosphorylated form of p38-MAPK, reduced levels of the anti-apoptotic protein Bcl-2, and increased the cleavage of pro-caspase-3. Silencing of Cx43 protein expression led to a reduction in the phosphorylation of p38-MAPK and an increase in Bcl-2 expression. The mechanism behind PQ1-induced cytotoxicity in FMC2u mammary carcinoma cells is thought to be attributed to the change in Cx43 expression. Furthermore, PQ1-induced apoptosis through the upregulation of Cx43 may depend on p38 MAPK, highlighting that the effect of PQ1 on gap junctions as well as cellular survival via a MAPK-dependent pathway.

Quantitative electrochemical detection of cathepsin B activity in breast cancer cell lysates using carbon nanofiber nanoelectrode arrays toward identification of cancer formation

UNLABELLED The proteolytic activity of cathepsin B in complex breast cell lysates has been measured with alternating current voltammetry (ACV) using ferrocene (Fc)-labeled-tetrapeptides immobilized on nanoelectrode arrays (NEAs) fabricated with vertically aligned carbon nanofibers (VACNFs). Four types of breast cells have been tested, including normal breast cells (HMEC), transformed breast cells (MCF-10A), breast cancer cells (T47D), and metastatic breast cancer cells (MDA-MB-231). The detected protease activity was found increased in cancer cells, with the MDA-MB-231 metastatic cancer cell lysate showing the highest cathepsin B activity. The equivalent cathepsin B concentration in MDA-MB-231 cancer cell lysate was quantitatively determined by spiking recombinant cathepsin B into the immunoprecipitated MDA-MB-231 lysate and the HMEC whole cell lysate. The results illustrated the potential of this technique as a portable multiplex electronic device for cancer diagnosis and treatment monitoring through rapid profiling the activity of specific cancer-relevant proteases. FROM THE CLINICAL EDITOR Breast cancer is the most common cancer in women. In this report, the authors applied the technique of nanoelectrode arrays to try to detect and compare cathepsin B activities in normal and breast cancer cells. It was found that protease activity correlated positively with the degree of malignancy cancer cells. Taking this further, this technique may be useful for rapid diagnosis of cancer in the future.

Bioavailability and efficacy of a gap junction enhancer (PQ7) in a mouse mammary tumor model.

The loss of gap junctional intercellular communication is characteristic of neoplastic cells, suggesting that the restoration with a gap junction enhancer may be a new therapeutic treatment option with less detrimental effects than traditional antineoplastic drugs. A gap junction enhancer, 6-methoxy-8-[(2-furanylmethyl) amino]-4-methyl-5-(3-trifluoromethylphenyloxy) quinoline (PQ7), on the normal tissue was evaluated in healthy C57BL/6J mice in a systemic drug distribution study. Immunoblot analysis of the vital organs indicates a reduction in Cx43 expression in PQ7-treated animals with no observable change in morphology. Next the transgenic strain FVB/N-Tg(MMTV-PyVT) 634Mul/J (also known as PyVT) was used as a spontaneous mammary tumor mouse model to determine the biological and histological effects of PQ7 on tumorigenesis and metastasis at three stages of development: Pre tumor, Early tumor, and Late tumor formation. PQ7 was assessed to have a low toxicity through intraperitoneal administration, with the majority of the compound being detected in the heart, liver, and lungs six hours post injection. The treatment of tumor bearing animals with PQ7 had a 98% reduction in tumor growth, while also decreasing the total tumor burden compared to control mice during the Pre stage of development. PQ7 treatment increased Cx43 expression in the neoplastic tissue during Pre-tumor formation; however, this effect was not observed in Late stage tumor formation. This study shows that the gap junction enhancer, PQ7, has low toxicity to normal tissue in healthy C57BL/6J mice, while having clinical efficacy in the treatment of spontaneous mammary tumors of PyVT mice. Additionally, gap junctional intercellular communication and neoplastic cellular growth are shown to be inversely related, while treatment with PQ7 inhibits tumor growth through targeting gap junction expression.

The Effect of Antineoplastic Drugs in a Male Spontaneous Mammary Tumor Model

Male breast cancer is a rare disease. The limited number of clinical cases has led to the primary treatments for men being derived from female breast cancer studies. Here the transgenic strain FVB/N-Tg(MMTV-PyVT)634Mul/J (also known as PyVT) was used as a model system for measuring tumor burden and drug sensitivity of the antineoplastic drugs tamoxifen, cisplatin, and paclitaxel on tumorigenesis at an early stage of mammary carcinoma development in a male mouse model. Cisplatin treatment significantly reduced tumor volume, while paclitaxel and tamoxifen did not attenuate tumor growth. Cisplatin treatment was shown to induce apoptosis, grossly observed by reduced tumor formation, through reduced Bcl-2 and survivin protein expression levels with an increase in caspase 3 expression compared to control tumors. Tamoxifen treatment significantly altered the hormone receptor expression levels of the tumor, while additionally upregulating Bcl-2 and Cyclin D1. This suggests an importance in hormonal signaling in male breast cancer pathogenesis. The results of this study provide valuable information toward the better understanding of male breast cancer and may help guide treatment decisions.

Abstract 519: Attenuation of mammary tumor growth by gap junction enhancer.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Normal cells have functional gap junctional intercellular communication (GJIC), while cancer cells exhibit many defects in cellular communication that contribute to the loss of tissue homeostasis. It is believed that restoring GJIC is linked to drug sensitivity and reduction of tumorigenicity. Previous studies show that GJIC and neoplastic cellular growth are inversely related and small molecule targeting gap junction can alter tumor growth. A dose of 25 mg/kg gap junction enhancer (PQ) can cause a 77% decrease of xenograft T47D breast tumors. In addition these small molecules can induce a decrease of tumor growth by 110%, 129%, and 73% in the pre, early, and late stages of tumor development of the transgenic mouse strain, FVB/N-Tg(MMTV-PyVT)634Mul/J. Western blot analysis shows that the gap junction protein, Cx43, was highly expressed in the PQ-treated tumors compared to the controls. Data suggests that enhancement of GJIC attenuates tumor growth; specifically Cx43 plays a significant role in tumorigenesis. Establishment of a continuous line of mammary tumor cells from the malignant neoplasm of a female transgenic mouse demonstrates that PQs can cause an increase of Cx43 expression and subsequently trigger a decrease of cell viability. Overall, targeting gap junction by small molecule PQ has shed light to the dynamic of connexins and gap junctions in mammary tumors. Citation Format: Stephanie N. Shishido, Thu A. Nguyen. Attenuation of mammary tumor growth by gap junction enhancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 519. doi:10.1158/1538-7445.AM2013-519

Abstract 3268: Histological and biological effects of substituted quinolines (gap junction enhancers) in a spontaneous mammary tumor model

Effective use of antineoplastic drugs depends on the ability to balance the killing of tumor cells against the inherent toxicity to the host. Antineoplastic agents that act primarily on rapidly dividing and growing cells produce multiple side effects and are dose limiting. In recent years, there has been the development of biologic response modifiers aimed at enhancing innate anti-tumor defense mechanisms. Previous publications showed that substituted quinolines possess potent inhibitory activities against breast cancer cells through the enhancement of gap junction intercellular communication. These drugs decrease 71% of xenograft breast tumors in nude mice. The objective of this project is to evaluate the effect of substituted quinolines in a spontaneous mouse mammary tumor model (PyVT). PyVT mice were used at three different stages (pre, early and late) to characterize histological and biological changes in the treated animals compared to controls. Substituted quinolines cause a decrease of tumor growth rate by 112%, 77%, and 57% in the pre, early, and late stages of tumor development, respectively. Treatment during the pre and early stages of tumor formation also resulted in a decrease in the total number of tumors. Western blot analysis of the pre stage tumors show that the gap junction protein connexin 43 is more expressed in treated animals compared to control and the contrary for connexin 46. In the early and late stages, connexin 43 is expressed less in treated mice than controls, and vice versa for connexin 46. The expression of these connexins in control tissue suggests that this is due to an overall increase in connexin 43 and a decrease in connexin 46 during tumor development and metastasis. Histology of vital organs showed no significant alteration in treated animals compared to controls. These findings provide evidence that substituted quinolines cause a significant tumor reduction in a spontaneous mammary tumor model with no obvious adverse effects. 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 3268. doi:1538-7445.AM2012-3268

Abstract LB-54: Gap Junction Enhancer Increases Efficacy of Cisplatin to Attenuate Mammary Tumor Growth

INTRODUCTION : Cisplatin treatment has an overall 19% response rate in animal models with malignant tumors (Knapp et al. 1988). Increasing gap junction activity or enhancing GJIC in tumor cells provides the targets to enhance antineoplastic therapies. A new class of substituted quinolines (PQs) possesses inhibitory activities against breast cancer cells through the enhancement of gap junctional intercellular communication. We examined the effect of combinational treatment of PQ and antineoplastic drugs in an animal model to show an increase in efficacy of antineoplastic drugs via the enhancement of gap junctions. MATERIALS AND METHODS : Mice were implanted with estradiol-17s (1.7 mg/pellet) before the injection of 1 × 10 7 T47D breast cancer cells subcutaneously into the inguinal region of mammary fat pad. Animals were treated intraperitoneally with DMSO (control), Cisplatin (3.5mg/kg), PQ (25mg/kg), or a combining treatment of Cisplatin and PQ. RESULTS : Cisplatin alone decreased mammary tumor growth by 29% while combinational treatment of Cisplatin and PQ showed a 36% reduction after 7 treatments at every 2 days. Histological results showed a significant increase of gap junction proteins, Cx43 and Cx26, in PQ-treated tissues compared to control or Cisplatin. Furthermore, evidence of highly stained caspase 3 in tumors of combinational treatment (PQ and Cisplatin) was seen compared to Cisplatin alone. CONCLUSIONS : We have showed for the first time an increase in the efficacy of antineoplastic drugs via the enhancement of gap junctions with PQs, a specific class of gap junction enhancers. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-54. doi:10.1158/1538-7445.AM2011-LB-54