SETD2 Restricts Prostate Cancer Metastasis by Integrating EZH2 and AMPK Signaling Pathways

The level of SETD2-mediated H3K36me3 is inversely correlated with that of EZH2-catalyzed H3K27me3. Nevertheless, it remains unclear whether these two enzymatic activities are molecularly intertwined. Here, we report that SETD2 delays prostate cancer (PCa) metastasis via its substrate EZH2. We show that SETD2 methylates EZH2 which promotes EZH2 degradation. SETD2 deficiency induces a Polycomb-repressive chromatin state that enables cells to acquire metastatic traits. Conversely, mice harboring nonmethylated EZH2 mutant or SETD2 mutant defective in binding to EZH2 develop metastatic PCa. Furthermore, we identify that metformin-stimulated AMPK signaling converges at FOXO3 to stimulate SETD2 expression. Together, our results demonstrate that the SETD2-EZH2 axis integrates metabolic and epigenetic signaling to restrict PCa metastasis.

Metformin inhibits castration-induced EMT in prostate cancer by repressing COX2/PGE2/STAT3 axis

Castration is the standard therapeutic treatment for advanced prostate cancer but with limited benefit due to the profound relapse and metastasis. Activation of inflammatory signaling pathway and initiation of epithelial-mesenchymal transition (EMT) are closely related to drug resistance, tumor relapseas well as metastasis. In this study, we demonstrated that metformin is capable of inhibiting prostate cancer cell migration and invasion by repressing EMT evidenced by downregulating the mesenchymal markers N-cadherin, Vimentin, and Twist and upregulating the epithelium E-cadherin. These effects have also been observed in our animal model as well as prostate cancer patients. In addition, we showed the effects of metformin on the expression of genes involved in EMT through repressing the levels of COX2, PGE2 and phosphorylated STAT3. Furthermore, inactivating COX2 abolishes metformin's regulatory effects and exogenously administered PGE2 is capable of enhancing STAT3 phosphorylation and expression of EMT biomarker. We propose that metformin represses prostate cancer EMT and metastasis through targeting the COX2/PGE2/STAT3 axis. These findings suggest that metformin by itself or in combination with other anticancer drugs could be used as an anti-metastasis therapy.

Metformin reverses prostate cancer resistance to enzalutamide by targeting TGF-β1/STAT3 axis-regulated EMT

Although the newly developed second-generation anti-androgen drug enzalutamide can repress prostate cancer progression significantly, it only extends the survival of prostate cancer patients by 4-6 months mainly due to the occurrence of enzalutamide resistance. Most of the previous studies on AR antagonist resistance have been focused on AR signaling. Therefore, the non-AR pathways on enzalutamide resistance remain largely unknown. By using C4-2, CWR22Rv1 and LNCaP cell lines, as well as mice bearing CWR22Rv1 xenografts treated with either enzalutamide or metformin alone or in combination, we demonstrated that metformin is capable of reversing enzalutamide resistance and restores sensitivity of CWR22Rv1 xenografts to enzalutamide. We showed that metformin alleviated resistance to enzalutamide by inhibiting EMT. Furthermore, based on the effect of metformin on the activation of STAT3 and expression of TGF-β1, we propose that metformin exerts its effects by targeting the TGF-β1/STAT3 axis. These findings suggest that combination of metformin with enzalutamide could be a more efficacious therapeutic strategy for the treatment of castration-resistant prostate cancer.

Metformin Inhibits Prostate Cancer Progression by Targeting Tumor-Associated Inflammatory Infiltration

Purpose: Inflammatory infiltration plays important roles in both carcinogenesis and metastasis. We are interested in understanding the inhibitory mechanism of metformin on tumor-associated inflammation in prostate cancer.Experimental Design: By using a transgenic adenocarcinoma of the mouse prostate (TRAMP) mouse model, in vitro macrophage migration assays, and patient samples, we examined the effect of metformin on tumor-associated inflammation during the initiation and after androgen deprivation therapy of prostate cancer.Results: Treating TRAMP mice with metformin delays prostate cancer progression from low-grade prostatic intraepithelial neoplasia to high-grade PIN, undifferentiated to well-differentiated, and PIN to adenocarcinoma with concurrent inhibition of inflammatory infiltration evidenced by reduced recruitment of macrophages. Furthermore, metformin is capable of inhibiting the following processes: inflammatory infiltration after androgen deprivation therapy (ADT) induced by surgically castration in mice, bicalutamide treatment in patients, and hormone deprivation in LNCaP cells. Mechanistically, metformin represses inflammatory infiltration by downregulating both COX2 and PGE2 in tumor cells.Conclusions: Metformin is capable of repressing prostate cancer progression by inhibiting infiltration of tumor-associated macrophages, especially those induced by ADT, by inhibiting the COX2/PGE2 axis, suggesting that a combination of ADT with metformin could be a more efficient therapeutic strategy for prostate cancer treatment. Clin Cancer Res; 24(22); 5622-34. ©2018 AACR.

The roles of the COX2/PGE2/EP axis in therapeutic resistance

Therapeutic resistance has been and remains to be the major challenge in developing successful treatments for different cancers and therefore, understanding the underlying mechanisms in the development of therapeutic resistance is crucial in combating cancers. Multiple mechanisms underlie the development of therapeutic resistance, and the signaling pathways involved in cancer stem cell repopulation, enhanced epithelial-mesenchymal transition (EMT), inflammatory infiltration, and immunosuppression play pivotal roles in this process. Accumulating evidence indicates that the COX2/PGE2/EP axis plays crucial roles not only in tumor development including initiation and progression but also in the development of therapeutic resistance. In this review, we will first dissect the relationship between the COX2/PGE2/EP axis and therapeutic resistance by focusing on the roles of the COX2/PGE2/EP axis in cancer stem cell repopulation, EMT, and anti-cancer immunity. Then, we will summarize the currently available compounds/drugs targeting each component of this axis as well as some of the underlying mechanisms. We hope that better understanding the underlying mechanisms of the functional compounds will be helpful in seeking additive and/or synergistic effects against therapeutic resistance without or with minimal adverse consequence.

Antiandrogen treatment induces stromal cell reprogramming to promote castration resistance in prostate cancer

Lineage plasticity causes therapeutic resistance; however, it remains unclear how the fate conversion and phenotype switching of cancer-associated fibroblasts (CAFs) are implicated in disease relapse. Here, we show that androgen deprivation therapy (ADT)-induced SPP1+ myofibroblastic CAFs (myCAFs) are critical stromal constituents that drive the development of castration-resistant prostate cancer (CRPC). Our results reveal that SPP1+ myCAFs arise from the inflammatory CAFs in hormone-sensitive PCa; therefore, they represent two functional states of an otherwise ontogenically identical cell type. Antiandrogen treatment unleashes TGF-β signaling, resulting in SOX4-SWI/SNF-dependent CAF phenotype switching. SPP1+ myCAFs in turn render PCa refractory to ADT via an SPP1-ERK paracrine mechanism. Importantly, these sub-myCAFs are associated with inferior therapeutic outcomes, providing the rationale for inhibiting polarization or paracrine mechanisms to circumvent castration resistance. Collectively, our results highlight that therapy-induced phenotypic switching of CAFs is coupled with disease progression and that targeting this stromal component may restrain CRPC.

ARID1A loss induces polymorphonuclear myeloid-derived suppressor cell chemotaxis and promotes prostate cancer progression

Chronic inflammation and an immunosuppressive microenvironment promote prostate cancer (PCa) progression and diminish the response to immune checkpoint blockade (ICB) therapies. However, it remains unclear how and to what extent these two events are coordinated. Here, we show that ARID1A, a subunit of the SWI/SNF chromatin remodeling complex, functions downstream of inflammation-induced IKKβ activation to shape the immunosuppressive tumor microenvironment (TME). Prostate-specific deletion of Arid1a cooperates with Pten loss to accelerate prostate tumorigenesis. We identify polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) as the major infiltrating immune cell type that causes immune evasion and reveal that neutralization of PMN-MDSCs restricts the progression of Arid1a-deficient tumors. Mechanistically, inflammatory cues activate IKKβ to phosphorylate ARID1A, leading to its degradation via β-TRCP. ARID1A downregulation in turn silences the enhancer of A20 deubiquitinase, a critical negative regulator of NF-κB signaling, and thereby unleashes CXCR2 ligand-mediated MDSC chemotaxis. Importantly, our results support the therapeutic strategy of anti-NF-κB antibody or targeting CXCR2 combined with ICB for advanced PCa. Together, our findings highlight that the IKKβ/ARID1A/NF-κB feedback axis integrates inflammation and immunosuppression to promote PCa progression.

Metformin represses bladder cancer progression by inhibiting stem cell repopulation via COX2/PGE2/STAT3 axis

Cancer stem cells (CSCs) are a sub-population of tumor cells playing essential roles in initiation, differentiation, recurrence, metastasis and development of drug resistance of various cancers, including bladder cancer. Although multiple lines of evidence suggest that metformin is capable of repressing CSC repopulation in different cancers, the effect of metformin on bladder cancer CSCs remains largely unknown. Using the N-methyl-N-nitrosourea (MNU)-induced rat orthotropic bladder cancer model, we demonstrated that metformin is capable of repressing bladder cancer progression from both mild to moderate/severe dysplasia lesions and from carcinoma in situ (CIS) to invasive lesions. Metformin also can arrest bladder cancer cells in G1/S phases, which subsequently leads to apoptosis. And also metformin represses bladder cancer CSC repopulation evidenced by reducing cytokeratin 14 (CK14+) and octamer-binding transcription factor 3/4 (OCT3/4+) cells in both animal and cellular models. More importantly, we found that metformin exerts these anticancer effects by inhibiting COX2, subsequently PGE2 as well as the activation of STAT3. In conclusion, we are the first to systemically demonstrate in both animal and cell models that metformin inhibits bladder cancer progression by inhibiting stem cell repopulation through the COX2/PGE2/STAT3 axis.

The HIF/PHF8/AR axis promotes prostate cancer progression

Recent studies provide strong evidence that the androgen receptor (AR) signaling pathway remains active in castration-resistant prostate cancer (CRPC). However, the underlying mechanisms are not well understood. In this study, we demonstrate that plant homeo domain finger protein 8 (PHF8 )interacts with and functions as an essential histone demethylase activity-dependent AR coactivator. Furthermore, we demonstrate that the expression of PHF8 is induced by hypoxia in various prostate cancer cell lines. Knockdown of either hypoxia-inducible factor HIF2α or HIF1α almost completely abolished hypoxia-induced PHF8 expression. Importantly, we observed that PHF8 is highly expressed in clinical androgen deprived prostate cancer samples and expression of PHF8 correlates with increased levels of HIF1α and HIF2α. Moreover, elevated PHF8 is associated with higher grade prostate cancers and unfavorable outcomes. Our findings support a working model in which hypoxia in castrated prostate cancer activates HIF transcription factors which then induces PHF8 expression. The elevated PHF8 in turn promotes the AR signaling pathway and prostate cancer progression. Therefore, the HIF/PHF8/AR axis could serve as a potential biomarker for CRPC and is also a promising therapeutic target in combating CRPC.

Histone demethylase PHF8 drives neuroendocrine prostate cancer progression by epigenetically upregulating FOXA2

Neuroendocrine prostate cancer (NEPC) is a more aggressive subtype of castration-resistant prostate cancer (CRPC). Although it is well established that PHF8 can enhance prostate cancer cell proliferation, whether PHF8 is involved in prostate cancer initiation and progression is relatively unclear. By comparing the transgenic adenocarcinoma of the mouse prostate (TRAMP) mice with or without Phf8 knockout, we systemically examined the role of PHF8 in prostate cancer development. We found that PHF8 plays a minimum role in initiation and progression of adenocarcinoma. However, PHF8 is essential for NEPC because not only is PHF8 highly expressed in NEPC but also animals without Phf8 failed to develop NEPC. Mechanistically, PHF8 transcriptionally upregulates FOXA2 by demethylating and removing the repressive histone markers on the promoter region of the FOXA2 gene, and the upregulated FOXA2 subsequently regulates the expression of genes involved in NEPC development. Since both PHF8 and FOXA2 are highly expressed in NEPC tissues from patients or patient-derived xenografts, the levels of PHF8 and FOXA2 can either individually or in combination serve as NEPC biomarkers and targeting either PHF8 or FOXA2 could be potential therapeutic strategies for NEPC treatment. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Histone methyltransferase WHSC1 loss dampens MHC-I antigen presentation pathway to impair IFN-γ-stimulated anti-tumor immunity

IFN-γ–stimulated MHC class I (MHC-I) antigen presentation underlies the core of antitumor immunity. However, sustained IFN-γ signaling also enhances the programmed death ligand 1 (PD-L1) checkpoint pathway to dampen antitumor immunity. It remains unclear how these opposing effects of IFN-γ are regulated. Here, we report that loss of the histone dimethyltransferase WHSC1 impaired the antitumor effect of IFN-γ signaling by transcriptional downregulation of the MHC-I machinery without affecting PD-L1 expression in colorectal cancer (CRC) cells. Whsc1 loss promoted tumorigenesis via a non-cell-autonomous mechanism in an Apc^min/+ mouse model, CRC organoids, and xenografts. Mechanistically, we found that the IFN-γ/STAT1 signaling axis stimulated WHSC1 expression and, in turn, that WHSC1 directly interacted with NLRC5 to promote MHC-I gene expression, but not that of PD-L1. Concordantly, silencing Whsc1 diminished MHC-I levels, impaired antitumor immunity, and blunted the effect of immune checkpoint blockade. Patient cohort analysis revealed that WHSC1 expression positively correlated with enhanced MHC-I expression, tumor-infiltrating T cells, and favorable disease outcomes. Together, our findings establish a tumor-suppressive function of WHSC1 that relays IFN-γ signaling to promote antigen presentation on CRC cells and provide a rationale for boosting WHSC1 activity in immunotherapy.

The ZMYND8-regulated mevalonate pathway endows YAP-high intestinal cancer with metabolic vulnerability

Cholesterol metabolism is tightly associated with colorectal cancer (CRC). Nevertheless, the clinical benefit of statins, the inhibitor of cholesterol biogenesis mevalonate (MVA) pathway, is inconclusive, possibly because of a lack of patient stratification criteria. Here, we describe that YAP-mediated zinc finger MYND-type containing 8 (ZMYND8) expression sensitizes intestinal tumors to the inhibition of the MVA pathway. We show that the oncogenic activity of YAP relies largely on ZMYND8 to enhance intracellular de novo cholesterol biogenesis. Disruption of the ZMYND8-dependent MVA pathway greatly restricts the self-renewal capacity of Lgr5⁺ intestinal stem cells (ISCs) and intestinal tumorigenesis. Mechanistically, ZMYND8 and SREBP2 drive the enhancer-promoter interaction to facilitate the recruitment of Mediator complex, thus upregulating MVA pathway genes. Together, our results establish that the epigenetic reader ZMYND8 endows YAP-high intestinal cancer with metabolic vulnerability.

The VHL/HIF Axis in the Development and Treatment of Pheochromocytoma/Paraganglioma

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors originating from chromaffin cells in the adrenal medulla (PCCs) or extra-adrenal sympathetic or parasympathetic paraganglia (PGLs). About 40% of PPGLs result from germline mutations and therefore they are highly inheritable. Although dysfunction of any one of a panel of more than 20 genes can lead to PPGLs, mutations in genes involved in the VHL/HIF axis including PHD, VHL, HIF-2A (EPAS1), and SDHx are more frequently found in PPGLs. Multiple lines of evidence indicate that pseudohypoxia plays a crucial role in the tumorigenesis of PPGLs, and therefore PPGLs are also known as metabolic diseases. However, the interplay between VHL/HIF-mediated pseudohypoxia and metabolic disorder in PPGLs cells is not well-defined. In this review, we will first discuss the VHL/HIF axis and genetic alterations in this axis. Then, we will dissect the underlying mechanisms in VHL/HIF axis-driven PPGL pathogenesis, with special attention paid to the interplay between the VHL/HIF axis and cancer cell metabolism. Finally, we will summarize the currently available compounds/drugs targeting this axis which could be potentially used as PPGLs treatment, as well as their underlying pharmacological mechanisms. The overall goal of this review is to better understand the role of VHL/HIF axis in PPGLs development, to establish more accurate tools in PPGLs diagnosis, and to pave the road toward efficacious therapeutics against metastatic PPGLs.

LSD1 Promotes Bladder Cancer Progression by Upregulating LEF1 and Enhancing EMT

Epithelial-to-mesenchymal transition (EMT) is one of the important underlying molecular mechanisms for most types of cancers including bladder cancer. The precise underlying molecular mechanism in EMT-mediated bladder cancer progression is far from completed. LSD1, a histone lysine-specific demethylase, is known to promote cancer cell proliferation, metastasis, and chemoresistance. We found in this study that LSD1 is highly upregulated in bladder cancer specimens, especially those underwent chemotherapy, and the elevated levels of LSD1 are highly associated with bladder cancer grades, metastasis status, and prognosis. Inhibiting or knockdown LSD1 repressed not only EMT process but also cancer progression. Mechanistically, LSD1 complexes with β-catenin to transcriptionally upregulate LEF1 and subsequently enhances EMT-mediated cancer progression. More importantly, LSD1 specific inhibitor GSK2879552 is capable of repressing tumor progression in patient-derived tumor xenograft. These findings altogether suggest that LSD1 can serve as not only a prognostic biomarker but also a promising therapeutic target in bladder cancer treatment.

G250 Antigen-Targeting Drug-Loaded Nanobubbles Combined with Ultrasound Targeted Nanobubble Destruction: A Potential Novel Treatment for Renal Cell Carcinoma

Purpose

We intended to design G250 antigen-targeting temsirolimus-loaded nanobubbles (G250-TNBs) based on the targeted drug delivery system and to combine G250-TNBs with ultrasound targeted nanobubble destruction (UTND) to achieve a synergistic treatment for renal cell carcinoma (RCC).

Methods

The filming-rehydration method was combined with mechanical shock and electrostatic interactions to prepare temsirolimus-loaded nanobubbles (TNBs). G250-TNBs were prepared by attaching anti-G250 nanobodies to the surface of TNBs using the biotin-streptavidin-bridge method. The ability of G250-TNBs to target the G250 antigen of RCC cells and the synergistic efficacy of G250-TNBs and UTND in the treatment of RCC were assessed.

Results

The average diameter of the prepared G250-TNBs was 368.7 ± 43.4 nm, the encapsulation efficiency was 68.59% ± 5.43%, and the loading efficiency was 5.23% ± 0.91%. In vitro experiments showed that the affinity of G250-TNBs to the human RCC 786-O cells was significantly higher than that of TNBs (P <0.05), and the inhibitory effect on 786-O cell proliferation and the induction of 786-O cell apoptosis was significantly enhanced in the group treated with G250-TNBs and UTND (G250-TNBs+ UTND group) compared with the other groups (P <0.05). In a nude mouse xenograft model, compared with TNBs, G250-TNBs could target the transplanted tumors and thus significantly enhance the ultrasound imaging of the tumors. Compared with all other groups, the G250-TNBs+UTND group exhibited a significantly lower tumor volume, a higher tumor growth inhibition rate, and a higher apoptosis index (P <0.05).

Conclusion

The combined G250-TNBs and UTND treatment can deliver anti-tumor drugs to local areas of RCC, increase the local effective drug concentration, and enhance anti-tumor efficacy, thus providing a potential novel method for targeted therapy of RCC.

Anti-G250 nanobody-functionalized nanobubbles targeting renal cell carcinoma cells for ultrasound molecular imaging

Traditional imaging examinations have difficulty in identifying benign and malignant changes in renal masses. This difficulty may be solved by ultrasound molecular imaging based on targeted nanobubbles, which could specifically enhance the ultrasound imaging of renal cell carcinomas (RCC) so as to discriminate benign and malignant renal masses. In this study, we aimed to prepare anti-G250 nanobody-functionalized targeted nanobubbles (anti-G250 NTNs) by coupling anti-G250 nanobodies to lipid nanobubbles and to verify their target specificity and binding ability to RCC cells that express G250 antigen and their capacity to enhance ultrasound imaging of RCC xenografts. Anti-G250 nanobodies were coupled to the lipid nanobubbles using the biotin-streptavidin bridge method. The average particle diameter of the prepared anti-G250 NTNs was 446 nm. Immunofluorescence confirmed that anti-G250 nanobodies were uniformly distributed on the surfaces of nanobubbles. In vitro experiments showed that the anti-G250 NTNs specifically bound to G250-positive 786-O cells and HeLa cells with affinities of 88.13% ± 4.37% and 71.8% ± 5.7%, respectively, and that they did not bind to G250-negative ACHN cells. The anti-G250 NTNs could significantly enhance the ultrasound imaging of xenograft tumors arising from 786-O cells and HeLa cells compared with blank nanobubbles, while the enhancement was not significant for xenograft tumors arising from ACHN cells. Immunofluorescence of tumor tissue slices confirmed that the anti-G250 NTNs could enter the tissue space through tumor blood vessels and bind to tumor cells specifically. In conclusion, anti-G250 nanobody-functionalized targeted nanobubbles could specifically bind to G250-positive RCC cells and enhance the ultrasound imaging of G250-positive RCC xenografts. This study has high-potential clinical application value for the diagnosis and differential diagnosis of renal tumors.

Resveratrol enhances polyubiquitination-mediated ARV7 degradation in prostate cancer cells

Although androgen deprivation therapy (ADT) serves as the primary treatment option for localized or metastatic prostate cancer, most cases eventually develop into castration-resistant prostate cancer (CRPC). However, androgen receptor (AR) continues to be functional in CRPC through various mechanisms, including the development of AR splicing variants, especially ARV7. Since it lacks the ligand binding domain but retains the intact DNA binding domain, ARV7 is constitutively active, which makes ARV7-positive prostate cancer responsive to neither abiraterone nor enzalutamide. In this study, we explored the effect of resveratrol on ARV7 transcriptional activity and the potential for development of resveratrol as a treatment for ARV7-positive prostate cancer. First, we ectopically expressed ARV7 in PC3 cells, an AR-negative prostate cancer cell line, and demonstrated that resveratrol is capable of inhibiting ARV7 transcriptional activity by downregulating ARV7 protein levels. Of note, resveratrol does not affect the mRNA levels of ARV7 nor its nuclear translocation. Next, we demonstrated that resveratrol is capable of downregulating the levels of the endogenously expressed ARV7 as well as AR target gene mRNAs in 22RV1 prostate cancer cells. Mechanistically, resveratrol downregulates ARV7 by enhancing ARV7 polyubiquitination and subsequent proteasome-mediated degradation. These findings suggest that resveratrol could be a potential treatment for ARV7-positive CPRC.

A Somatic HIF2α Mutation-Induced Multiple and Recurrent Pheochromocytoma/Paraganglioma with Polycythemia: Clinical Study with Literature Review

A syndrome known as pheochromocytomas (PCC)/paragangliomas (PGL) and polycythemia resulted from gain-of-function mutation of hypoxia-inducible factor 2α (HIF2α) has been reported recently. However, clinical features of this syndrome vary from patient to patient. In our study, we described the clinical features of the patient within 15-year follow-up with a literature review. The patient presented with "red face" since childhood and was diagnosed with polycythemia and pheochromocytoma in 2000, and then, tumor was removed at his age of 27 (year 2000). However, 13 years later (2013), he was diagnosed with multiple paragangliomas. Moreover, 2 years later (2015), another two paragangaliomas were also confirmed. Genetic analysis of hereditary PCC/PGL-related genes was conducted. A somatic heterozygous missense mutation of HIF2α (c.1589C>T) was identified at exon 12, which is responsible for the elevated levels of HIF2α and erythropoietin (EPO) and subsequent development of paragangaliomas. However, this mutation was only found in the tumors from three different areas, not in the blood. So far, 13 cases of PCC/PGL with polycythemia have been reported. Among them, somatic mutations of HIF2α at exon 12 are responsible for 12 cases, and only 1 case was caused by germline mutation of HIF2α at exon 9. The HIF2α mutation-induced polycythemia with PCC/PGL is a rare syndrome with no treatment for cure. Comprehensive therapies for this disease include removal of the tumors and intermittent phlebotomies; administration of medications to control blood pressure and to prevent complications or death resulted from high concentration of red blood cell (RBC). Genetic test is strongly recommended for patients with early onset of polycythemia and multiple/recurrent PCC/PGL.

A novel BRCA2 mutation in prostate cancer sensitive to combined radiotherapy and androgen deprivation therapy

Genetic factors contribute to more than 40% of prostate cancer risk, and mutations in BRCA1 and BRCA2 are well-established risk factors. By using target capture-based deep sequencing to identify potential pathogenic germline mutations, followed by Sanger sequencing to determine the loci of the mutations, we identified a novel pathogenic BRCA2 mutation caused by a cytosine-to-guanine base substitution at position 4211, resulting in protein truncation (p.Ser1404Ter), which was confirmed by immunohistochemistry. Analysis of peripheral blood also identified benign polymorphisms in BRCA2 (c.7397T>C, p.Val2466Ala) and SRD5A2 (c.87G>C, p.Lys29Asn). Analysis of tumor tissues revealed seven somatic mutations in prostate tumor tissue and nine somatic mutations in esophageal squamous carcinoma tissue (single nucleotide polymorphisms, insertions, and deletions). Five-year follow-up results indicate that ADT combined with radiotherapy successfully treated the prostate cancer. To our knowledge, we are the first to report the germline BRCA2 mutation c.4211C>G (p.Ser1404Ter) in prostate cancer. Combined ADT and radiotherapy may be effective in treating other patients with prostate cancer caused by this or similar mutations.

HIF2A germline-mutation-induced polycythemia in a patient with VHL-associated renal-cell carcinoma

In this study, we report here a rare case of polycythemia and cRCC in the same patient, which may be helpful in understanding clinical features and molecular mechanisms underlying VHL-mutation-associated cRCC and polycythemia induced by germline mutation of HIF2A. Firstly, we identified a rare but well studied germline mutation resulting in polycythemia in HIF2A (c.1609G>A, p.Gly537Arg) in the blood of the patient and his daughter. Meanwhile, we identified an inactivating VHL mutation (c.391A>T, p.N131Y), as well as TP53 mutation(c.977A>T, p.E326V) and mTOR mutation(c.7498A>T, p.I2500F) in renal cancer tissue. Moreover, protein levels of VHL, HIF1A, HIF2A, EPO, and VEGF estimated by immunohistochemical staining substantiated hyperactivation of the oxygen-sensing pathway. In addition, we identified 158 somatic SNP/indel mutations, including 90 missense/nonsense/splice/stop-loss mutations by whole-exome sequencing (WES) of the tumor specimen and matched normal DNA.

Carney complex with PRKAR1A gene mutation: A case report and literature review

RATIONALE

Carney complex (CNC) is a multiple neoplasia syndrome with autosomal dominant inheritance. CNC is characterized by the presence of myxomas, spotty skin pigmentation, and endocrine overactivity. No direct correlation has been established between disease-causing mutations and phenotype.

PATIENT CONCERNS

A 16-year-old boy was admitted because of excessive weight gain over 3 years and purple striae for 1 year. Physical examination revealed Cushingoid features and spotty skin pigmentation on his face, lip, and sclera.

DIAGNOSES

The patient was diagnosed as Carney complex.

INTERVENTIONS

the patient underwent right adrenalectomy and partial adrenalectomy of the left adrenal gland.

OUTCOME

Results of imaging showed bilateral adrenal nodular hyperplasia, multiple microcalcifications of the bilateral testes, and compression fracture of the thoracolumbar spine. Histopathological results confirmed multiple pigmented nodules in the adrenal glands. DNA sequencing revealed a nonsense mutation in the gene encoding regulatory subunit type 1-alpha of protein kinase A (PRKAR1A; c.205C > T). After the second adrenalectomy, the Cushingoid features disappeared, and cortisol levels returned to normal.

LESSONS

Carney complex is a rare disease that lacks consistent genotype-phenotype correlations. Our patient, who carried a germline PRKAR1A nonsense mutation (c.205C > T), clinical features included spotty skin pigmentation, osteoporosis, and primary pigmented nodular adrenal disease. Adrenalectomy is the preferred treatment for Cushing syndrome due to primary pigmented nodular adrenal disease.

A novel germline ARMC5 mutation in a patient with bilateral macronodular adrenal hyperplasia: a case report

BACKGROUND

Bilateral macronodular adrenal hyperplasia (BMAH) is a rare cause of Cushing's syndrome (CS). BMAH is predominantly believed to be caused by two mutations, a germline and somatic one, respectively, as described in the two-hit hypothesis. In many familial cases of BMAH, mutations in armadillo repeat containing 5 (ARMC5), a putative tumor suppressor gene, are thought to induce the disorder. The objective of this study was to report a case in which the patient presented with BMAH induced by a novel heterozygous germline ARMC5 mutation (c. 517C > T, p. Arg173*) alone rather than a two-hit mutation.

CASE PRESENTATION

A 51-year-old woman was identified with masses in the bilateral adrenals. Serum cortisol levels were increased significantly both in the morning (08:00 AM) and late at night (24:00 AM), while plasma adrenocorticotropic hormone was normal. The patient underwent a left adrenalectomy and histopathology substantiated the BMAH diagnosis. WES of the germline DNA discovered a novel heterozygous germline ARMC5 mutation (c. 517C > T, p. Arg173*) and in silico analysis predicted that the mutation significantly impaired protein function, resulting in inactivated ARMC5. Subsequently, WES of the tumor specimen identified 79 somatic single nucleotide polymorphisms (SNPs)/insertion-deletion (indel) mutations, including 32 missense/nonsense/splice/stop-loss mutations. None of these mutations were CS-related.

CONCLUSIONS

A novel germline ARMC5 mutation (c. 517C > T, p. Arg173*) was identified that induced BMAH alone without a second mutation. ARMC5 sequencing may improve the identification of clinical forms of BMAH and allow earlier diagnosis of this disease.

Giant bilateral adrenal myelolipomas in two Chinese families with congenital adrenal hyperplasia

Congenital adrenal hyperplasia (CAH) is one of the most prevalent, and potentially severe, genetic inborn errors of steroid synthesis directly affecting metabolism. Most patients are diagnosed and treated at an early age. There have been very limited reports of adults with CAH-associated adrenal myelolipomas. We aimed to analyze two families with CAH-associated giant adrenal myelolipomas caused by defects in CYP21A2 and CYP17A1 genes. A total of 14 individuals from two unrelated families were identified with either CYP21A2 or CYP17A1 mutations. Of note, five patients were found with adrenal myelolipomas. Total DNA isolated from the peripheral blood of the two probands was screened for potential mutations in the following susceptibility genes of CAH: CYP21A2, CYP11B1, CYP17A1, HSD17B3, HSD3B2, ARMC5, and STAR using target capture-based deep sequencing; and Sanger sequencing was conducted for the family members to detect the potential mutations. The following results were obtained. In family 1, molecular genetics sequencing revealed a compound heterozygous mutation (c.293-13C>G/c.518T>A, p.I173N) in CYP12A2 in the patient and his brother. In family 2, all three female patients with adrenal myelolipomas were found to have a compound heterozygous mutation (c.1118A>T, p.H373L/c.1459_1467del9, p.D487_F489del) in CYP17A1. To avoid giant CAH-associated adrenal myelolipomas in adults, it is important to identify CAH early so that appropriate treatment can be initiated to interrupt the chronic adrenal hyperstimulation resulting from increased ACTH. Genetic testing and counseling could be useful in CAH.

Novel genotype-phenotype correlations in five Chinese families with Von Hippel-Lindau disease

CONTEXT

Von Hippel-Lindau (VHL) disease manifests as a variety of benign and malignant neoplasms. Previous studies of VHL disease have documented several genotype-phenotype correlations; however, many such correlations are still unknown. Increased identification of new mutations and patients with previously described mutations will allow us to better understand how VHL mutations influence disease phenotypes.

PATIENTS AND DESIGN

A total of 45 individuals from five unrelated families were evaluated, of which 21 patients were either diagnosed with VHL disease or showed strong evidence related to this disease. We compared the patients' gene sequencing results with their medical records including CT or MRI scans, eye examinations and laboratory/pathological examinations. Patients were also interviewed to obtain information regarding their family history.

RESULTS

We identified four missense mutations: c.239G>T (p.Ser80Ile), linked with VHL Type 2B, was associated with renal cell carcinoma, pheochromocytoma and hemangioma in the cerebellum; c.232A>T (p.Asn78Tyr) manifested as RCC alone and likely caused VHL Type 1; c.500G>A (p.Arg167Gln) mutation was more likely to cause VHL Type 2 than Type 1 as it preferentially induced Pheo and HB in the retina, cerebellum and spinal cord; c.293A>G (p.Try98Cys) was associated with Pheo and thus likely induced VHL Type 2.

CONCLUSIONS

Characterizing VHL disease genotype-phenotype correlations can enhance the ability to predict the risk of individual patients developing different VHL-related phenotypes. Ultimately, such insight will improve the diagnostics, surveillance and treatment of VHL patients.

PRECIS

Four missense mutations in VHL have been identified in 21 individuals when five unrelated Chinese families with VHL disease were analyzed; VHL mutations are highly associated with unique disease phenotypes.