Mahboubeh Papari-Zareei

Dihydrotestosterone synthesis bypasses testosterone to drive castration-resistant prostate cancer

In the majority of cases, advanced prostate cancer responds initially to androgen deprivation therapy by depletion of gonadal testosterone. The response is usually transient, and metastatic tumors almost invariably eventually progress as castration-resistant prostate cancer (CRPC). The development of CRPC is dependent upon the intratumoral generation of the potent androgen, dihydrotestosterone (DHT), from adrenal precursor steroids. Progression to CRPC is accompanied by increased expression of steroid-5α-reductase isoenzyme-1 (SRD5A1) over SRD5A2, which is otherwise the dominant isoenzyme expressed in the prostate. DHT synthesis in CRPC is widely assumed to require 5α-reduction of testosterone as the obligate precursor, and the increased expression of SRD5A1 is thought to reflect its role in converting testosterone to DHT. Here, we show that the dominant route of DHT synthesis in CRPC bypasses testosterone, and instead requires 5α-reduction of androstenedione by SRD5A1 to 5α-androstanedione, which is then converted to DHT. This alternative pathway is operational and dominant in both human CRPC cell lines and fresh tissue obtained from human tumor metastases. Moreover, CRPC growth in mouse xenograft models is dependent upon this pathway, as well as expression of SRD5A1. These findings reframe the fundamental metabolic pathway that drives CRPC progression, and shed light on the development of new therapeutic strategies.

3β-hydroxysteroid dehydrogenase is a possible pharmacological target in the treatment of castration-resistant prostate cancer

Prostate cancer usually responds to androgen deprivation therapy, although the response in metastatic disease is almost always transient and tumors eventually progress as castration-resistant prostate cancer (CRPC). CRPC continues to be driven by testosterone or dihydrotestosterone from intratumoral metabolism of 19-carbon adrenal steroids from circulation, and/or de novo intratumoral steroidogenesis. Both mechanisms require 3beta-hydroxysteroid dehydrogenase (3betaHSD) metabolism of Delta(5)-steroids, including dehydroepiandrosterone (DHEA) and Delta(5)-androstenediol (A5diol), to testosterone. In contrast, reports that DHEA and A5diol directly activate the androgen receptor (AR) suggest that 3betaHSD metabolism is not required and that 3betaHSD inhibitors would be ineffective in the treatment of CRPC. We hypothesized that activation of AR in prostate cancer by DHEA and A5diol requires their conversion via 3betaHSD to androstenedione and testosterone, respectively. Here, we show that DHEA and A5diol induce AR chromatin occupancy and AR-regulated genes. Furthermore, we show that Delta(5)-androgens undergo 3beta-dehydrogenation in prostate cancer and that induction of AR nuclear translocation, AR chromatin occupancy, transcription of PSA, TMPRSS2, and FKBP5, as well as cell proliferation by DHEA and A5diol, are all blocked by inhibitors of 3betaHSD. These findings demonstrate that DHEA and A5diol must be metabolized by 3betaHSD to activate AR in these models of CRPC. Furthermore, this work suggests that 3betaHSD may be exploited as a pharmacologic target in the treatment of CRPC.

Puberty in a case with novel 17-hydroxylase mutation and the putative role of estrogen in development of pubic hair

OBJECTIVE 17-Hydroxylase/17,20-lyase deficiency (17OHD) results from mutations in the CYP17A1 gene, leading to failure to synthesize cortisol, adrenal androgens, and gonadal steroids. Adrenarche is a consequence of the increased production of adrenal androgens. Here, we report a case carrying novel R239Q mutation causing complete functional loss of CYP17A1, and thus absence of adrenal and gonadal sex hormone production. The patient has had unexpected pubic hair development and insufficient breast development with estrogen replacement therapy. Possible mechanisms leading to pubic hair development and breast underdevelopment are discussed. PATIENT AND METHODS A 15-year-old female born to consanguineous parents presented with the lack of full breast development and irregular menses after the age of 14 years. She had Tanner III breast development on one side, Tanner I on the other side and Tanner I pubic hair and, no axillary hair development. The serum levels of FSH, LH, and progesterone were high and, estradiol was low. The measurement of basal and ACTH-stimulated steroids was consistent with the diagnosis of 17OHD. Genetic analysis revealed novel homozygous mutation R239Q in CYP17A1 gene. Therapy with hydrocortisone was initiated and followed by the addition of conjugated estrogen. Her breast development did not improve considerably, however, pubic hair development started after estrogen treatment in spite of undetectable serum levels of androgens. CONCLUSION This case study suggests that estrogen exerts a permissive effect on pubic hair development in girls, even in the presence of very low-circulating androgens, and impaired breast development might be due to estrogen/progesterone imbalance in breast tissue.

Phenotypic variation in a Chinese family with 46,XY and 46,XX 17α-hydroxylase deficiency

Background: 17α-hydroxylase deficiency is a rare autosomal recessive disorder characterized by sexual infantilism, amenorrhea, hypertension and hypokalemia, which is caused by mutations in the CYP17A1 gene. To date, more than 50 mutations in this gene have been described. Methods: The clinical features and biochemical data of a pair of 46,XY and 46,XX Chinese siblings with 17α-hydroxylase deficiency from Singapore were studied. Direct DNA sequence analysis of the CYP17A1 gene was performed. Results: There was significant phenotypic variation between the siblings. The proband (46,XY) presented classically with sexual infantilism, amenorrhea and hypertension. The younger sibling (46,XX) also presented with amenorrhea, but she had breast development and absence of hypokalemic hypertension. The same compound heterozygous mutations in CYP17A1 gene were identified in both patients. A missense mutation (P409R) was detected in exon 7, and a 9-bp deletion (D487-S488-F489del) was detected in exon 8. Conclusion: We confirmed the diagnosis of 17α-hydroxylase deficiency in these two patients. Both P409R and D487-S488-F489del have been described previously and are widely propagated in the Chinese population in East and Southeast Asia. We propose that the phenotypic expression of affected individuals with 17α-hydroxylase deficiency is karyotype-dependent, with individuals having the 46,XX karyotype having less pronounced clinical symptoms.

Combined 17α-hydroxylase/17,20-lyase deficiency due to p.R96W mutation in the CYP17 gene in a Brazilian patient

Congenital adrenal hyperplasia (CAH) resulting from 17α-hydroxylase/17,20-lyase deficiency is a rare autosomal recessive disease and the second most common form of CAH in Brazil. We describe the case of a Brazilian patient with CYP17 deficiency (17α-hydroxylase/17,20-lyase deficiency) caused by a homozygous p.R96W mutation on exon 1 of the CYP17 gene, an unusual genotype in Brazilian patients with this form of CAH. The patient, raised as a normal female, sought medical care for lack of pubertal signs and primary amenorrhea at the age of 16 years. At evaluation, the presence of a 46,XY karyotype, hypertension and hypokalemia were observed. We emphasize the recognition of CYP17 deficiency in the differential diagnosis of cases of hypergonadotrophic hypogonadism and hypertension in young patients who need specific treatment for both situations.

A comprehensively characterized cell line panel highly representative of clinical ovarian high-grade serous carcinomas

Recent literature suggests that most widely used ovarian cancer (OVCA) cell models do not recapitulate the molecular features of clinical tumors. To address this limitation, we generated 18 cell lines and 3 corresponding patient-derived xenografts predominantly from high-grade serous carcinoma (HGSOC) peritoneal effusions. Comprehensive genomic characterization and comparison of each model to its parental tumor demonstrated a high degree of molecular similarity. Our characterization included whole exome-sequencing and copy number profiling for cell lines, xenografts, and matched non-malignant tissues, and DNA methylation, gene expression, and spectral karyotyping for a subset of specimens. Compared to the Cancer Genome Atlas (TCGA), our models more closely resembled HGSOC than any other tumor type, justifying their validity as OVCA models. Our meticulously characterized models provide a crucial resource for the OVCA research community that will advance translational findings and ultimately lead to clinical applications.Recent literature suggests that most widely used ovarian cancer (OVCA) cell models do not recapitulate the molecular features of clinical tumors. To address this limitation, we generated 18 cell lines and 3 corresponding patient-derived xenografts predominantly from high-grade serous carcinoma (HGSOC) peritoneal effusions. Comprehensive genomic characterization and comparison of each model to its parental tumor demonstrated a high degree of molecular similarity. Our characterization included whole exome-sequencing and copy number profiling for cell lines, xenografts, and matched non-malignant tissues, and DNA methylation, gene expression, and spectral karyotyping for a subset of specimens. Compared to the Cancer Genome Atlas (TCGA), our models more closely resembled HGSOC than any other tumor type, justifying their validity as OVCA models. Our meticulously characterized models provide a crucial resource for the OVCA research community that will advance translational findings and ultimately lead to clinical applications.

Abstract 5605: Spectral karyotyping characterization of ovarian adenocarcinomas and corresponding cell lines and xenografts

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Ovarian cancer is the 9th leading cancer and the 5th cause of cancer deaths in women in the USA. To understand tumor biology, identify oncogenic driver pathways and verify response to drugs, numerous in vitro (cell lines) and in vivo (xenograft in mouse) models have been developed and extensively used. In this study, we aimed to cytogenetically characterize ovarian carcinomas and their respective in vitro and in vivo models to investigate how representative the models are of their originating source. Ascitic fluid was collected from 10 women with previously untreated high grade serous papillary adenocarcinomas of the ovary that presented with malignant ascites (stage 3). Ascitic fluid was subjected to differential centrifugation and plating to enrich for the tumor cell population (TCP). The TCP cells were cultured and considered permanent cell lines (CLP) when grew continuously without evidence of a non-malignant component and could be recovered from cryopreservation. TCP cells were also inoculated intraperitoneally into athymic nude mice and tumors harvested and cryopreserved (XCP). Eight pairs of TCP and CLP and two triplets of TCP, CLP and XCP specimens were characterized by spectral karyotyping (SKY), for a total of 22 specimens. Highly rearranged karyotypes were detected in all specimens. All matched pairs and triplets were obviously related, sharing most of the structural (SA) and numerical (NA) abnormalities identified. Numerous examples of evolution from simple to complex chromosomal rearrangements and of multiple rearrangements originating from a single breakpoint were detected. For 9 patients, TCP and CLP specimens had the same ploidy level (near-2n in 4, near-3n in 3 and near 4n in 2); for one patient, the ploidy changed from near-2n (TCP) to near-4n (CLP). The 2 xenografts had same ploidy as their matched TCP and CLP specimens. In individual analyses, specific SA accounted for 30% in 6. Specific NA accounted for 30% in 3. In the TCP-CLP analyses, 3 pairs were very similar, differing by 30%. Higher frequency of abnormalities was detected in the TCP specimen for 4 pairs, and in the CLP for 3 pairs. One xenograft was very similar to both TCP and CLP, while the other was closer to the CLP. In conclusion, the ovarian adenocarcinomas were highly rearranged chromosomally and highly heterogeneous. In vitro (CLP) and in vivo (XCP) models maintained a core of the TCPs SA and NA but also displayed unique events, quantitatively and qualitatively variable in distinct tumors, indicating evidence of ex vivo tumor cell selection or progression events. These findings have implications for using established tumor models in research, as well as for potentially identifying the driver rearrangements in specific tumors. Citation Format: Marileila Varella-Garcia, Isabel M. Bernal, Sakshi Mahale, Evelyn M. Musselwhite, Victor Stastny, Mahboubeh Papari-Zareei, Jayanthi Lea, Tito Woodburn, Patrick Reynolds, Adi F. Gazdar. Spectral karyotyping characterization of ovarian adenocarcinomas and corresponding cell lines and xenografts. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5605. doi:10.1158/1538-7445.AM2014-5605