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.

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.

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.

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.

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.

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.

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.

Different RET gene mutation-induced multiple endocrine neoplasia type 2A in 3 Chinese families

BACKGROUD

Multiple endocrine neoplasia type 2A (MEN2A) is a condition with inherited autosomal dominant mutations in RET (rearranged during transfection) gene that predisposes the carrier to extremely high risk of medullary thyroid cancer (MTC) and other MEN2A-associated tumors such as parathyroid cancer and/or pheochromocytoma. Little is reported about MEN2A syndrome in the Chinese population.

METHODS

All members of the 3 families along with specific probands of MEN2A were analyzed for their clinical, laboratory, and genetic characteristics. Exome sequencing was performed on the 3 probands, and specific mutation in RET was further screened on each of the family members.

RESULTS

Different mutations in the RET gene were identified: C634S in Family 1, C611Y in Family 2, and C634Y in Family 3. Proband 1 mainly showed pheochromocytoma with MTC, both medullary thyroid carcinoma and pheochromocytoma were seen in proband 2, and proband 3 showed medullary thyroid carcinoma.

CONCLUSION

The genetic evaluation is strongly recommended for patients with a positive family history, early onset of age, or multiple sites of masses. If the results verified the mutations of RET gene, thyroidectomy should be undertaken as the guide for better prognosis.

Identification of novel somatic fusions of ERG-VEGFA, TMPRSS2-ERG, and VEGFA-TMPRSS2 in prostate cancer treated with anlotinib and androgen deprivation therapy: A case report

The TMPRSS2-ERG fusion gene has frequently been found in prostate cancer and is associated with malignancy. Identifying novel fusions will help to stratify patients and establish patient-tailored therapies. A 78-year-old man presented to our hospital with severe symptoms of urinary urgency and frequency for 2 years, as well as severe bone pain for 1 year. He was diagnosed with metastatic prostate cancer with a Gleason score of 5 + 5. Three gene fusions, ERG_VEGFA, TMPRSS2_ERG, and VEGFA_TMPRSS2, were identified in the patient's prostate cancer tissue. Notably, administration of the tyrosine kinase inhibitor, anlotinib, in combination with a gonadotropin-releasing hormone agonist (GnRHa) and abiraterone, reduced the patient's bone pain and also stabilized his prostate cancer for more than 2 years. This is the first report of somatic fusions among the VEGFA, ERG, and TMPRSS2 genes in cancer tissues from a patient with prostate cancer who responded well to antiangiogenic treatment combined with a GnRHa and abiraterone.