Androgen receptor (AR) signaling reprograms cellular metabolism to support prostate cancer (PCa) growth and survival. Another key regulator of cellular metabolism is mTOR, a kinase found in diverse protein complexes and cellular localizations, including the nucleus. However, whether nuclear mTOR plays a role in PCa progression and participates in direct transcriptional cross-talk with the AR is unknown. Here, via the intersection of gene expression, genomic, and metabolic studies, we reveal the existence of a nuclear mTOR-AR transcriptional axis integral to the metabolic rewiring of PCa cells. Androgens reprogram mTOR-chromatin associations in an AR-dependent manner in which activation of mTOR-dependent metabolic gene networks is essential for androgeninduced aerobic glycolysis and mitochondrial respiration. In models of castration-resistant PCa cells, mTOR was capable of transcriptionally regulating metabolic gene programs in the absence of androgens, highlighting a potential novel castration resistance mechanism to sustain cell metabolism even without a functional AR. Remarkably, we demonstrate that increased mTOR nuclear localization is indicative of poor prognosis in patients, with the highest levels detected in castration-resistant PCa tumors and metastases. Identification of a functional mTOR targeted multigene signature robustly discriminates between normal prostate tissues, primary tumors, and hormone refractory metastatic samples but is also predictive of cancer recurrence. This study thus underscores a paradigm shift from AR to nuclear mTOR as being the master transcriptional regulator of metabolism in PCa.

Reprogramming of cellular metabolism plays a central role in fueling malignant transformation, and AMPK and the PGC-1α/ERRα axis are key regulators of this process. The intersection of gene-expression and binding-event datasets for breast cancer cells shows that activation of AMPK significantly increases the expression of PGC-1α/ERRα and promotes the binding of ERRα to its cognate sites. Unexpectedly, the data also reveal that ERRα, in concert with PGC-1α, negatively regulates the expression of several one-carbon metabolism genes, resulting in substantial perturbations in purine biosynthesis. This PGC-1α/ERRα-mediated repression of one-carbon metabolism promotes the sensitivity of breast cancer cells and tumors to the anti-folate drug methotrexate. These data implicate the PGC-1α/ERRα axis as a core regulatory node of folate cycle metabolism and further suggest that activators of AMPK could be used to modulate this pathway in cancer.

How androgen signaling contributes to the oncometabolic state of prostate cancer remains unclear. Here, we show how the estrogen-related receptor γ (ERRγ) negatively controls mitochondrial respiration in prostate cancer cells. Sustained treatment of prostate cancer cells with androgens increased the activity of several metabolic pathways, including aerobic glycolysis, mitochondrial respiration, and lipid synthesis. An analysis of the intersection of gene expression, binding events, and motif analyses after androgen exposure identified a metabolic gene expression signature associated with the action of ERRγ. This metabolic state paralleled the loss of ERRγ expression. It occurred in both androgen-dependent and castration-resistant prostate cancer and was associated with cell proliferation. Clinically, we observed an inverse relationship between ERRγ expression and disease severity. These results illuminate a mechanism in which androgen-dependent repression of ERRγ reprograms prostate cancer cell metabolism to favor mitochondrial activity and cell proliferation. Furthermore, they rationalize strategies to reactivate ERRγ signaling as a generalized therapeutic approach to manage prostate cancer. Cancer Res; 77(2); 378-89. ©2016 AACR.

Reprogramming of cellular metabolism is an important feature of prostate cancer, including altered lipid metabolism. Recently, it was observed that the nuclear fraction of mTOR is essential for the androgen-mediated metabolic reprogramming of prostate cancer cells. Herein, it is demonstrated that the androgen receptor (AR) and mTOR bind to regulatory regions of sterol regulatory element-binding transcription factor 1 (SREBF1) to control its expression, whereas dual activation of these signaling pathways also promotes SREBF1 cleavage and its translocation to the nucleus. Consequently, SREBF1 recruitment to regulatory regions of its target genes is induced upon treatment with the synthetic androgen R1881, an effect abrogated upon inhibition of the mTOR signaling pathway. In turn, pharmacologic and genetic inhibition of SREBF1 activity impairs the androgen-mediated induction of the key lipogenic genes fatty acid synthase () and stearoyl-CoA desaturase (). Consistent with these observations, the expression of the and genes is significantly correlated in human prostate cancer tumor clinical specimens. Functionally, blockade of SREBF1 activity reduces the androgen-driven lipid accumulation. Interestingly, decreased triglyceride accumulation observed upon SREBF1 inhibition is paralleled by an increase in mitochondrial respiration, indicating a potential rewiring of citrate metabolism in prostate cancer cells. Altogether, these data define an AR/mTOR nuclear axis, in the context of prostate cancer, as a novel pathway regulating SREBF1 activity and citrate metabolism. The finding that an AR/mTOR complex promotes SREBF1 expression and activity enhances our understanding of the metabolic adaptation necessary for prostate cancer cell growth and suggests novel therapeutic approaches to target metabolic vulnerabilities in tumors. .

The accuracy and cost savings of pooling specimens prior to testing for Chlamydia trachomatis by PCR were evaluated with genital and urine specimens (n ‫؍‬ 2,600). There was a 60% reduction in tests without significant loss of accuracy. The efficiency of pooling vaginal swabs is demonstrated for the first time.Nucleic acid amplification tests, although sensitive and specific, are expensive. Acceptable accuracy and cost savings have been demonstrated by pooling urine and pooling endocervical specimens to detect Chlamydia trachomatis (1-9), but we are not aware of any studies testing pooled vaginal swabs. The aim of this study was to determine the accuracy and cost savings associated with pooling vaginal swabs as well as endocervical swabs and urine specimens for the detection of C. trachomatis by PCR.All genital swabs and urine specimens sent to a large hospital-based laboratory over a 3-month period were tested individually and in pools of five. This pool size is consistent with other studies and was considered likely to maximize savings without significantly compromising sensitivity in our population. On receipt in the laboratory, individual specimens were processed and tested the following working day in accordance with the manufacturer's instructions (Roche Diagnostics Systems). Sixty percent of urine specimens and a small percentage of genital swabs were stored at Ϫ20°C for 1 to 4 weeks prior to pooling. Frozen specimens were thawed, pooled, and tested on the same day. One-hundred-microliter aliquots from each processed swab were combined to create pools of five, and 50 l of this was amplified. One-hundred-microliter aliquots from each unprocessed urine specimen were combined in pools of five and processed, and 50 l of the processed pool sample was amplified.Specimens were considered positive if the absorbance at 660 nm was Ն0.8 and the absorbance for the internal control was Ն2. All pools and 50% of the individually tested specimens included internal controls. When a pool was positive, all individual samples were retested the next working day to identify the positive specimen(s). Specimens testing negative in the pool were deemed negative in the presence of a positive internal control. Specimens from pools presumed to be inhibited (i.e., a negative internal control) were retested individually. Inhibited individual specimens were diluted 1:10 and retested the next working day. All individual and pooled specimens were retested if the results were discrepant.We compared the accuracy of the PCR test with the pooled and individually tested specimens and calculated 95% confidence intervals (Stata Statistical Software, Release 7; Stat Corporation, College Station, Tex.). We compared inhibition rates for pooled specimens with present laboratory inhibition rates, as internal controls are now included in all tests.Cost savings attributable to pooling were calculated by using normal laboratory procedures (individual testing plus reflex testing of positive, inhibited, and equivocal tests) as the baseline. Analyzed elem...

5α-Reductase types 1 and 2, encoded by SRD5A1 and SRD5A2, are the two enzymes that can catalyze the conversion of testosterone to dihydrotestosterone, the most potent androgen receptor (AR) agonist in prostate cells. 5α-Reductase type 2 is the predominant isoform expressed in the normal prostate. However, its expression decreases during prostate cancer (PCa) progression, whereas SRD5A1 increases, and the mechanism underlying this transcriptional regulatory switch is still unknown. Interrogation of SRD5A messenger RNA expression in three publicly available data sets confirmed that SRD5A1 is increased in primary and metastatic PCa compared with nontumoral prostate tissues, whereas SRD5A2 is decreased. Activation of AR, a major oncogenic driver of PCa, induced the expression of SRD5A1 from twofold to fourfold in three androgen-responsive PCa cell lines. In contrast, AR repressed SRD5A2 expression in this context. Chromatin-immunoprecipitation studies established that AR is recruited to both SRD5A1 and SRD5A2 genes following androgen stimulation but initiates transcriptional activation only at SRD5A1 as monitored by recruitment of RNA polymerase II and the presence of the H3K27Ac histone mark. Furthermore, we showed that the antiandrogens bicalutamide and enzalutamide block the AR-mediated regulation of both SRD5A1 and SRD5A2, highlighting an additional mechanism explaining their beneficial effects in patients. In summary, we identified an AR-dependent transcriptional regulation that explains the differential expression of 5α-reductase types 1 and 2 during PCa progression. Our work thus defines a mechanism by which androgens control their own synthesis via differential regulatory control of the expression of SRD5A1 and SRD5A2.

<p>The files contains extended Materials and Methods, Supplementary Table 1 and 2 contains primer sequences, Supplementary Table 3 contains Cox Regression Analysis, Figure S1 presents ChIP-sequencing data, Figure S2 show regulation of expression of ERRg by the androgen receptor, Figure S3 shows ERRg control of metabolic gene expression, Figure S4 and S5 ERRg control of prostate cancer cell metabolism, Figure S6 shows ERRa expression in relation to prostate cancer recurrence.</p>

<div>Abstract<p>Reprogramming of cellular metabolism is an important feature of prostate cancer, including altered lipid metabolism. Recently, it was observed that the nuclear fraction of mTOR is essential for the androgen-mediated metabolic reprogramming of prostate cancer cells. Herein, it is demonstrated that the androgen receptor (AR) and mTOR bind to regulatory regions of sterol regulatory element-binding transcription factor 1 (SREBF1) to control its expression, whereas dual activation of these signaling pathways also promotes SREBF1 cleavage and its translocation to the nucleus. Consequently, SREBF1 recruitment to regulatory regions of its target genes is induced upon treatment with the synthetic androgen R1881, an effect abrogated upon inhibition of the mTOR signaling pathway. In turn, pharmacologic and genetic inhibition of SREBF1 activity impairs the androgen-mediated induction of the key lipogenic genes fatty acid synthase (<i>FASN</i>) and stearoyl-CoA desaturase (<i>SCD1</i>). Consistent with these observations, the expression of the <i>SREBF1, FASN,</i> and <i>SCD1</i> genes is significantly correlated in human prostate cancer tumor clinical specimens. Functionally, blockade of SREBF1 activity reduces the androgen-driven lipid accumulation. Interestingly, decreased triglyceride accumulation observed upon SREBF1 inhibition is paralleled by an increase in mitochondrial respiration, indicating a potential rewiring of citrate metabolism in prostate cancer cells. Altogether, these data define an AR/mTOR nuclear axis, in the context of prostate cancer, as a novel pathway regulating SREBF1 activity and citrate metabolism.</p><p><b>Implications:</b> The finding that an AR/mTOR complex promotes SREBF1 expression and activity enhances our understanding of the metabolic adaptation necessary for prostate cancer cell growth and suggests novel therapeutic approaches to target metabolic vulnerabilities in tumors. <i>Mol Cancer Res; 16(9); 1396–405. ©2018 AACR</i>.</p></div>