Christensen, John D.

Abstract Objective: Transgender and gender-diverse individuals are at risk of insufficient treatment of endocrine diseases due to a number of barriers to care. There are currently no data evaluating the prevalence of thyroid disease in this population, and it is unknown if gender-affirming hormone therapy affects treatment of thyroid disease in these individuals. Methods: Utilizing a registry of 676 patients over 18 years of age who were seen in our Transgender and Intersex Specialty Care Clinic from 2015-2019, we identified 554 individuals seeking medical therapy for gender dysphoria/incongruence. Of these, 56 patients were taking thyroid hormone or antithyroid medications or had a coded diagnosis of thyroid disease; 2 were excluded as they were receiving thyroid hormone as adjunctive therapy for refractory depression. 54 patients were therefore analyzed with respect to thyroid disease (TD+), and compared to those 498 patients without thyroid disease (TD-) with regard to average vital signs, demographics, and presence of common comorbidities. Results: Fifty percent of our TD+ patients were recorded female sex at birth, and 98% were Caucasian. TD+ patients were much more likely to have essential hypertension (OR 5.99), to use tobacco (OR 2.23), and to be overweight or obese (OR 2.16) than TD- patients. Due to the evolving natural history of disease, some TD+ patients belonged to multiple categories: 48 patients, 26 trans feminine and 21 trans masculine, had hypothyroidism, of whom 41 had overt hypothyroidism and 2 patients had subacute thyroiditis that progressed to the hypothyroid phase of illness. 5 patients (3 trans masculine and 2 trans feminine) demonstrated hyperthyroidism, 4 of whom had Graves’ Disease. 2 patients had multinodular goiter, both trans masculine. 2 patients had thyroid malignancies, both trans feminine, of whom one had proven follicular thyroid carcinoma and the other had unspecified thyroid malignancy. Among hypothyroid patients, there was a slight non-significant trend toward increased thyroid hormone requirements while receiving treatment with estradiol or testosterone. Conclusion: To our knowledge, this represents the first attempt to characterize the prevalence of various thyroid disease states in the gender diverse population. Our data corresponded to a prevalence of hypothyroidism of approximately 8.7%, which is higher than previously published estimates of 3-5% in the general population. Whether this represents actual increased prevalence or assessment bias is uncertain. It is important for all health professionals who care for gender diverse people to identify and appropriately treat thyroid disease, and to monitor thyroid function closely if gender-affirming hormone therapy is initiated.

Abstract Cancer-associated fibroblasts (CAF) are abundant in the stroma of desmoplastic cancers where they promote tumor progression. CAFs are “activated” and as such may be uniquely susceptible to apoptosis. Using cholangiocarcinoma as a desmoplastic tumor model, we investigated the sensitivity of liver CAFs to the cytotoxic drug navitoclax, a BH3 mimetic. Navitoclax induced apoptosis in CAF and in myofibroblastic human hepatic stellate cells but lacked similar effects in quiescent fibroblasts or cholangiocarcinoma cells. Unlike cholangiocarcinoma cells, neither CAF nor quiescent fibroblasts expressed Mcl-1, a known resistance factor for navitoclax cytotoxicity. Explaining this paradox, we found that mitochondria isolated from CAFs or cells treated with navitoclax both released the apoptogenic factors Smac and cytochrome c, suggesting that they are primed for cell death. Such death priming in CAFs appeared to be due, in part, to upregulation of the proapoptotic protein Bax. Short hairpin RNA-mediated attenuation of Bax repressed navitoclax-mediated mitochondrial dysfunction, release of apoptogenic factors, and apoptotic cell death. In a syngeneic rat model of cholangiocarcinoma, navitoclax treatment triggered CAF apoptosis, diminishing expression of the desmoplastic extracellular matrix protein tenascin C, suppressing tumor outgrowth, and improving host survival. Together, our findings argue that navitoclax may be useful for destroying CAFs in the tumor microenvironment as a general strategy to attack solid tumors. Cancer Res; 73(2); 897–907. ©2012 AACR.

Abstract Background and Aims: Cholangiocarcinomas (CCA) are highly desmoplastic tumors containing abundant cancer associated myofibroblasts (CAF). An inverse association between the abundance of CAF and survival has been demonstrated in CCA, suggesting that CAF play a pivotal role in CCA development and progression. The CAF phenotype represents an ‘activated cell state’ and as such may be uniquely susceptible to apoptosis. BH3 mimetics induce apoptosis in cells ‘primed’ for cell death, representing a therapeutic strategy for cancer. Herein we examine whether CAF display a selective sensitivity to the BH3 mimetic ABT-263 and whether ABT-263 induced ablation of CAF reduces tumor growth and progression. Methods: We employed human and rat CAF, myofibroblastic human LX2 cells, human and rat control fibroblasts, the rat cholangiocarcinoma cell line BDEneu and human CCA cell lines for these studies. In-vivo experiments were conducted using a syngeneic, orthotopic rat CCA model. Results: We observed a significant and dose dependent induction of apoptosis by ABT-263 in human and rat primary CAF as well as activated LX2 cells as compared to rat BDEneu and human CCA cell lines. Comparison of Bcl-2 protein expression in quiescent fibroblasts versus CAF demonstrated a consistent upregulation of Bax in the CAF, likely explaining their enhanced sensitivity to pro-death stimuli. Indeed, ABT-263 treatment of CAF was associated with Bax activation as compared to human CCA cell lines. Finally, administration of ABT-263 decreased tumor size and metastasis in a human-like in-vivo rat model of CCA. Analysis of the rat tumors revealed a decrease in Tenascin C positive tumor stroma and an increase of TUNEL-positive apoptotic stromal cells. Conclusions: CCA associated CAF appear to be ‘primed’ for cell death, possibly due to overexpression of the pro-apoptotic Bcl-2 protein Bax. Consequently CAF display increased sensitivity to the BH3 mimetic ABT-263, which selectively depletes them from a rat in-vivo model of CCA, thereby reducing tumor growth and metastasis. Thus targeting CCA tumor stroma by inducing apoptosis in CAF may represent a new therapeutic approach in human CCA. 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 4905. doi:1538-7445.AM2012-4905