MicroRNAs (miRNAs) are small (∼22 nucleotide) non-coding RNAs that regulate a myriad of biological processes and are frequently dysregulated in cancer. Cancer-associated microRNAs have been detected in serum and plasma and hold promise as minimally invasive cancer biomarkers, potentially for assessing disease characteristics in patients with metastatic disease that is difficult to biopsy. Here we used miRNA profiling to identify cancer-associated miRNAs that are differentially expressed in sera from patients with metastatic castration resistant prostate cancer (mCRPC) as compared to healthy controls. Of 365 miRNAs profiled, we identified five serum miRNAs (miR-141, miR-200a, miR-200c, miR-210 and miR-375) that were elevated in cases compared to controls across two independent cohorts. One of these, miR-210, is a known transcriptional target of the hypoxia-responsive HIF-1α signaling pathway. Exposure of cultured prostate cancer cells to hypoxia led to induction of miR-210 and its release into the extracellular environment. Moreover, we found that serum miR-210 levels varied widely amongst mCRPC patients undergoing therapy, and correlated with treatment response as assessed by change in PSA. Our results suggest that (i) cancer-associated hypoxia is a frequent, previously under-appreciated characteristic of mCRPC, and (ii) serum miR-210 may be further developed as a predictive biomarker in patients with this distinct disease biology.

Colonization with Oxalobacter formigenes may reduce the risk of calcium oxalate kidney stone disease. To improve our limited understanding of host-O. formigenes and microbe-O. formigenes interactions, germfree mice and mice with altered Schaedler flora (ASF) were colonized with O. formigenes. Germfree mice were stably colonized with O. formigenes, which suggests that O. formigenes does not require other organisms to sustain its survival. Examination of intestinal material indicated no viable O. formigenes in the small intestine and ϳ4 ؋ 10 6 CFU O. formigenes per 100 mg contents in the cecum and proximal colon, with ϳ0.02% of total cecal O. formigenes cells being tightly associated with the mucosa. O. formigenes did not alter the overall microbial composition of ASF, and ASF did not affect the capacity of O. formigenes to degrade dietary oxalate in the cecum. Twentyfour-hour collections of urine and feces in metabolic cages in semirigid isolators demonstrated that the introduction of ASF into germfree mice significantly reduced urinary oxalate excretion. These experiments also showed that O. formigenes-monocolonized mice excreted significantly more urinary calcium than did germfree mice, which may be due to degradation of calcium oxalate crystals by O. formigenes and subsequent intestinal absorption of free calcium. In conclusion, the successful establishment of mouse models with defined flora and O. formigenes should improve our understanding of O. formigenes-host and O. formigenes-microbe interactions. These data support the use of O. formigenes as a probiotic that has limited impact on the composition of the resident microbiota but provides an efficient oxalate-degrading function. Oxalobacter formigenes is part of the bacterial flora in the large intestine of many humans and other mammalian species and is unique in that it is the only bacterium yet identified in the intestines of mammals that requires oxalate as both an energy source and a carbon source. Recent evidence suggests that a lack of colonization with this oxalate-degrading specialist is a risk factor for idiopathic recurrent calcium oxalate stone disease (1, 2). A review of worldwide data indicated that 38% to 77% of a normal population and only 17% of stone formers were colonized with O. formigenes (1). The ability to recolonize individuals lacking O. formigenes was previously addressed in a study in which two healthy adults not colonized with O. formigenes became colonized following the ingestion of cultured O. formigenes (3) and remained colonized for 9 months. However, studies in which O. formigenes was provided in either a lyophilized form in enteric coated capsules or as a frozen paste to patients suffering from primary hyperoxaluria resulted in only a minority of the patients remaining colonized posttreatment (4, 5). Therefore, although it seems quite possible that O. formigenes colonization of noncolonized stone formers may be an effective way to minimize the risk of recurrent calcium oxalate stone disease, a better understanding o...

Oxalobacter formigenes (O. formigenes) is a nonpathogenic, Gram-negative, obligate anaerobic bacterium that commonly inhabits the human gut and degrades oxalate as its major energy and carbon source. Results from a case-controlled study suggested that lack of O. formigenes colonization is a risk factor for recurrent calcium oxalate stone formation. Hence, O. formigenes colonization may prove to be an efficacious method for limiting calcium oxalate stone risk. However, challenges exist in the preparation of O. formigenes as a successful probiotic due to it being an anaerobe with fastidious growth requirements. Here we examine in vitro properties expected of a successful probiotic strain. The data show that the Group 1 O. formigenes strain OxCC13 is sensitive to pH < 5.0, persists in the absence of oxalate, is aerotolerant, and survives for long periods when freeze-dried or mixed with yogurt. These findings highlight the resilience of this O. formigenes strain to some processes and conditions associated with the manufacture, storage and distribution of probiotic strains.

Morbidity and mortality of breast cancer patients are drastically increased when primary tumor cells are able to spread to distant sites and proliferate to become secondary lesions. Effective treatment of metastatic disease has been limited; therefore, an increased molecular understanding to identify biomarkers and therapeutic targets is needed. Breast cancer metastasis suppressor 1 (BRMS1) suppresses development of pulmonary metastases when expressed in a variety of cancer types, including metastatic mammary carcinoma. Little is known of Brms1 function throughout the initiation and progression of mammary carcinoma. The goal of this study was to investigate mechanisms of Brms1-mediated metastasis suppression in transgenic mice that express Brms1 using polyoma middle T oncogene-induced models. Brms1 expression did not significantly alter growth of the primary tumors. When expressed ubiquitously using a β-actin promoter, Brms1 suppressed pulmonary metastasis and promoted apoptosis of tumor cells located in the lungs but not in the mammary glands. Surprisingly, selective expression of Brms1 in the mammary gland using the MMTV promoter did not significantly block metastasis nor did it promote apoptosis in the mammary glands or lung, despite MMTV-induced expression within the lungs. These results strongly suggest that cell type-specific over-expression of Brms1 is important for Brms1-mediated metastasis suppression.

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Morbidity and mortality in breast cancer patients are drastically increased when primary tumor cells are able to spread to distant sites and proliferate to become secondary lesions. Effective treatment of metastatic disease has been limited; therefore, increased molecular understanding to identify biomarkers and targets is needed. We have previously shown that breast cancer metastasis suppressor 1 (Brms1) can suppress development of pulmonary metastases when expressed in a variety of cancer types, including metastatic mammary carcinoma. Our lab has developed two transgenic Brms1 mouse models, one which expresses murine Brms1 cDNA specifically in mammary tissue (expression by the mouse mammary tumor virus (MMTV) promoter) and a ubiquitous Brms1 expression model (expression by the chicken beta actin promoter). The goal of this study was to investigate mechanisms of Brms1-mediated metastasis suppression in transgenic mice that express Brms1 using a polyoma middle T (PyMT) oncogene-induced model. Brms1 expression, either ubiquitously or predominantly in the mammary gland, did not significantly alter growth of the primary tumor, confirming earlier studies. When expressed ubiquitously, Brms1 suppressed pulmonary metastasis and promoted tumor cell apoptosis in the lung but not in the mammary gland. However, selective expression of Brms1 in the mammary gland using the MMTV promoter did not significantly block metastasis nor did it promote apoptosis in mammary glands or lungs despite increased expression within primary tumors and the lungs. These results suggest tissue- or cell-type specific expression of Brms1 is a critical determinant for Brms1-mediated metastasis suppression. 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 3416. doi:1538-7445.AM2012-3416

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