Selective estrogen receptor modulators inhibit growth and progression of premalignant lesions in a mouse model of ductal carcinoma in situ

INTRODUCTION: Ductal carcinoma in situ (DCIS) is a noninvasive premalignant lesion and is considered a precursor to invasive carcinoma. DCIS accounts for nearly 20% of newly diagnosed breast cancer, but the lack of experimentally amenable in vivo DCIS models hinders the development of treatment strategies. Here, we demonstrate the utility of a mouse transplantation model of DCIS for chemoprevention studies using selective estrogen receptor modulators (SERMs). This model consists of a set of serially transplanted lines of genetically engineered mouse mammary intraepithelial neoplasia (MIN) outgrowth (MIN-O) tissue that have stable characteristics. We studied the ovarian-hormone-responsiveness of one of the lines with a particular focus on the effects of two related SERMs, tamoxifen and ospemifene. METHODS: The estrogen receptor (ER) status and ovarian-hormone-dependence of the mouse MIN outgrowth tissue were determined by immunohistochemistry and ovarian ablation. The effects of tamoxifen and ospemifene on the growth and tumorigenesis of MIN outgrowth were assessed at 3 and 10 weeks after transplantation. The effects on ER status, cell proliferation, and apoptosis were studied with immunohistochemistry. RESULTS: The MIN-O was ER-positive and ovarian ablation resulted in reduced MIN-O growth and tumor development. Likewise, tamoxifen and ospemifene treatments decreased the MIN growth and tumor incidence in comparison with the control (P < 0.01). Both SERMs significantly decreased cell proliferation. Between the two SERM treatment groups, there were no statistically significant differences in MIN-O size, tumor latency, or proliferation rate. In contrast, the ospemifene treatment significantly increased ER levels while tamoxifen significantly decreased them. CONCLUSION: Tamoxifen and ospemifene inhibit the growth of premalignant mammary lesions and the progression to invasive carcinoma in a transplantable mouse model of DCIS. The inhibitory effects of these two SERMs are similar except for their effects on ER modulation. These differences in ER modulation may suggest different mechanisms of action between the two related SERMs and may portend different long-term outcomes. These data demonstrate the value of this model system for preclinical testing of antiestrogen or other therapies designed to prevent or delay the malignant transformation of premalignant mammary lesions in chemoprevention

Pilot Randomized Controlled Trial of an Integrative Intervention with Methamphetamine-Using Men Who Have Sex with Men

Contingency management (CM) is an evidence-based intervention that provides tangible rewards as positive reinforcement for biologically confirmed abstinence from substance use. Integrative approaches targeting positive affect regulation could boost the effectiveness of CM by sensitizing individuals to non-drug-related sources of reward and assisting them with effectively managing symptoms of withdrawal. This pilot randomized controlled trial with 21 methamphetamine-using men who have sex with men (MSM) examined the feasibility and accept-abilityofa5-session, positive affect intervention delivered during CM-Affect Regulation Treatment to Enhance Methamphetamine Intervention Success (ARTEMIS). After completing 4 weeks of a 12-week CM program, participants were randomized to receive ARTEMIS+CM (n=12) or CM-only (n=9). Those randomized to receive the ARTEMIS positive affect intervention completed 98% of sessions and reported marginally significant increases in positive affect over the five sessions. In exit interviews with ARTEMIS+CM participants, individuals noted that the positive affect regulation skills increased self-awareness and led to greater engagement in the recovery process. ARTEMIS+CM participants reported significant increases in positive affect and CM-only participants reported significant reductions in negative affect over a 2-month follow-up. These affective changes were not maintained, and no concurrent effects on stimulant use or sexual risk taking were observed over the 6-month follow-up. More definitive clinical research is necessary to ex-amine the efficacy of ARTEMIS+CM with methamphetamine-using MSM