Targeting MTA1/HIF-1α signaling by pterostilbene in combination with histone deacetylase inhibitor attenuates prostate cancer progression.

The metastasis-associated protein 1(MTA1)/histone deacetylase (HDAC) unit is a cancer progression-related epigenetic regulator, which is overexpressed in hormone-refractory and metastatic prostate cancer (PCa). In our previous studies, we found a significantly increased MTA1 expression in a prostate-specific Pten-null mouse model. We also demonstrated that stilbenes, namely resveratrol and pterostilbene (Pter), affect MTA1/HDAC signaling, including deacetylation of tumor suppressors p53 and PTEN. In this study, we examined whether inhibition of MTA1/HDAC using combination of Pter and a clinically approved HDAC inhibitor, SAHA (suberoylanilide hydroxamic acid, vorinostat), which also downregulates MTA1, could block prostate tumor progression in vivo. We generated and utilized a luciferase reporter in a prostate-specific Pten-null mouse model (Pb-Cre+ ; Ptenf/f ; Rosa26Luc/+ ) to evaluate the anticancer efficacy of Pter/SAHA combinatorial approach. Our data showed that Pter sensitized tumor cells to SAHA treatment resulting in inhibiting tumor growth and additional decline of tumor progression. These effects were dependent on the reduction of MTA1-associated proangiogenic factors HIF-1α, VEGF, and IL-1ß leading to decreased angiogenesis. In addition, treatment of PCa cell lines in vitro with combined Pter and low dose SAHA resulted in more potent inhibition of MTA1/HIF-1α than by high dose SAHA alone. Our study provides preclinical evidence that Pter/SAHA combination treatment inhibits MTA1/HIF-1α tumor-promoting signaling in PCa. The beneficial outcome of combinatorial strategy using a natural agent and an approved drug for higher efficacy and less toxicity supports further development of MTA1-targeted therapies in PCa.

Acute oxalate nephropathy associated with orlistat.

BACKGROUND: Obesity is a major world-wide epidemic which has led to a surge of various weight loss-inducing medical or surgical treatments. Orlistat is a gastrointestinal lipase inhibitor used as an adjunct treatment of obesity and type 2 diabetes mellitus to induce clinically significant weight loss via fat malabsorption. CASE PRESENTATION: We describe a case of a 76-year-old female with past medical history of chronic kidney disease (baseline serum creatinine was 1.5-2.5 mg/dL), hypertension, gout and psoriatic arthritis, who was admitted for evaluation of elevated creatinine, peaking at 5.40 mg/dL. She was started on orlistat 120 mg three times a day six weeks earlier. Initial serologic work-up remained unremarkable. Percutaneous kidney biopsy revealed massive calcium oxalate crystal depositions with acute tubular necrosis and interstitial inflammation. Serum oxalate level returned elevated at 45 mm/l (normal <27). Timed 24-hour urine collection documented increased oxalate excretion repeatedly (54-96 mg/24 hour). After five renal dialysis sessions in eighth days she gradually regained her former baseline kidney function with creatinine around 2 mg/dL. Given coexisting proton-pump inhibitor therapy, only per os calcium-citrate provided effective intestinal oxalate chelation to control hyperoxaluria. CONCLUSIONS: Our case underscores the potential of medically induced fat malabsorption to lead to an excessive oxalate absorption and acute kidney injury (AKI), especially in subjects with pre-existing renal impairment. Further, it emphasizes the importance of kidney biopsy to facilitate early diagnosis and treatment.

Dietary pterostilbene is a novel MTA1-targeted chemopreventive and therapeutic agent in prostate cancer.

Overexpression of the epigenetic modifier metastasis-associated protein 1 (MTA1) is associated with aggressive human prostate cancer. The purpose of this study was to determine MTA1- targeted chemopreventive and therapeutic efficacy of pterostilbene, a natural potent analog of resveratrol, in pre-clinical models of prostate cancer. Here, we show that high levels of MTA1 expression in Pten-loss prostate cooperate with key oncogenes, including c-Myc and Akt among others, to promote prostate cancer progression. Loss-of-function studies using human prostate cancer cells indicated direct involvement of MTA1 in inducing inflammation and epithelial-to-mesenchymal transition. Importantly, pharmacological inhibition of MTA1 by pterostilbene resulted in decreased proliferation and angiogenesis and increased apoptosis. This restrained prostatic intraepithelial neoplasia (PIN) formation in prostate-specific Pten heterozygous mice and reduced tumor development and progression in prostate-specific Pten-null mice. Our findings highlight MTA1 as a key upstream regulator of prostate tumorigenesis and cancer progression. More significantly, it offers pre-clinical proof for pterostilbene as a promising lead natural agent for MTA1-targeted chemopreventive and therapeutic strategy to curb prostate cancer.

Allelic Variants in Arhgef11 via the Rho-Rock Pathway Are Linked to Epithelial-Mesenchymal Transition and Contributes to Kidney Injury in the Dahl Salt-Sensitive Rat.

Previously, genetic analyses identified that variants in Arhgef11 may influence kidney injury in the Dahl salt-sensitive (S) rat, a model of hypertensive chronic kidney disease. To understand the potential mechanism by which altered expression and/or protein differences in Arhgef11 could play a role in kidney injury, stably transduced Arhgef11 knockdown cell lines as well as primary cultures of proximal tubule cells were studied. Genetic knockdown of Arhgef11 in HEK293 and NRK resulted in reduced RhoA activity, decreased activation of Rho-ROCK pathway, and less stress fiber formation versus control, similar to what was observed by pharmacological inhibition (fasudil). Primary proximal tubule cells (PTC) cultured from the S exhibited increased expression of Arhgef11, increased RhoA activity, and up regulation of Rho-ROCK signaling compared to control (small congenic). The cells were also more prone (versus control) to TGFß-1 induced epithelial-mesenchymal transition (EMT), a hallmark feature of the development of renal interstitial fibrosis, and characterized by development of spindle shape morphology, gene expression changes in EMT markers (Col1a3, Mmp9, Bmp7, and Ocln) and increased expression of N-Cadherin and Vimentin. S derived PTC demonstrated a decreased ability to uptake FITC-albumin compared to the small congenic in vitro, which was confirmed by assessment of albumin re-uptake in vivo by infusion of FITC-albumin and immunofluorescence imaging. In summary, these studies suggest that genetic variants in the S form of Arhgef11 via increased expression and/or protein activity play a role in promoting kidney injury in the S rat through changes in cell morphology (Rho-Rock and/or EMT) that impact the function of tubule cells.

Epigenetic potential of resveratrol and analogs in preclinical models of prostate cancer.

Lifestyle, particularly diet, is a risk factor for prostate cancer. Dietary polyphenols such as resveratrol possess anticancer properties and therefore have chemopreventive and therapeutic potential. Resveratrol has pleiotropic effects, exerting its biological activity through multiple pathways and targets, including those associated with cancer. Numerous studies have demonstrated the anticancer effects of resveratrol and, to a lesser extent, its analogs, in tissue culture, while in vivo observations are limited. Here, we provide a concise summary of our results on epigenetic mechanisms of resveratrol and analogs mediated through regulation of chromatin modifier metastasis-associated protein 1 (MTA1) and microRNAs (miRNAs), and highlight the anticancer effects of these compounds in preclinical models of prostate cancer. We suggest that the identified stilbene responsive mechanism-based biomarkers, such as MTA1 and oncogenic miRNAs, may become indicative of treatment efficacy in prostate cancer. Resveratrol analogs with better bioavailability, conferring superior pharmacological potencies and greater anticancer effects, may become stronger candidates for clinical development.

Pigmented Epithelioid Angiomyolipoma of the Kidney.

Extensive melanin pigment in an epithelioid angiomyolipoma, a potentially malignant and locally aggressive renal tumor, has been rarely reported. A 53-year-old, asymptomatic man with no significant past medical history underwent partial nephrectomy for a right kidney mass discovered on CT scan. Grossly, the mass was 4 cm, well-circumscribed, dark, brown-black. Microscopically, nests of large, clear-to-eosinophilic cells with mildly atypical, vesicular nuclei and prominent nucleoli were separated by striking vascular network. Abundant, brown-black, coarsely granular pigment was noted. The tumor stained with HMB-45 and MART-1 and was negative for broad spectrum cytokeratin, CK-7, CD-10, RCC antigen, EMA, vimentin, SMA, desmin, synaptophysin, chromogranin, and S 100. Fontana-Masson stain confirmed presence of melanin. Thick-walled vessels, spindle cells, and fat were absent. The patient had no family history of tuberous sclerosis. Close follow-up was recommended. It is important to differentiate this entity from melanoma, pigmented renal cell carcinoma, and pigmented paraganglioma.

Resolution of C1q deposition but not of the clinical nephrotic syndrome after immunomodulating therapy in focal sclerosis.

BACKGROUND: The natural evolution of C1q nephropathy (C1qNP) during immunosuppressive treatment is relatively little studied or understood. CASE PRESENTATION: A 30 year-old Caucasian female was referred to us for further management of biopsy-proven C1qNP and severe nephrotic syndrome. Serologic work-up remained negative, including complement C3 and C4 levels and repeated testing for antinuclear antibodies. A renal biopsy revealed minimal change nephropathy vs. focal sclerosis on light microscopy and C1qNP on immunopathology. She has failed trials of high-dose oral prednisone, mycophenolate mofetil 1,500 mg twice a day and a subsequent regimen of monthly IV cyclophosphamide 750 mg × 9 cycles. She also received the maximum tolerated angiotensin-converting enzyme inhibitor and spironolactone therapy. Random urine protein-to-creatinine (UPC) ratio predicted proteinuria in the range between 5-35 gm/day, while serum creatinine rose progressively from 1.0 mg/dL to 1.4 mg/dL (to convert to µmol/L, multiply by 88.4). A decision was made to repeat renal biopsy to reassess the underlying histology. The biopsy revealed focal sclerosis but no C1q deposition. CONCLUSIONS: Our case illustrates at least two points: first, an established pathologic diagnosis does not obviate the need for repeated renal biopsy later on, should diagnostic uncertainty persist. Second, histological diagnoses may evolve over time, especially in a patient receiving active and powerful immune-modulating treatment. In our case, the clinical nephrosis did not change with immunosuppressive therapy while C1q deposition ceased, making this latter entity likely the immunologically mediated process.

Cytomegalovirus colitis in a critically ill, dialysis-dependent, acute kidney injury patient without immunosuppressive therapy.

BACKGROUND: Historically, cytomegalovirus (CMV) infection in immunocompetent patients has been considered to have a relatively indolent and self-limited course, not warranting specific treatment. CASE PRESENTATION: We are presenting a 72-year-old African-American male transferred to our intensive care unit (ICU) with methicillin-resistant Staphylococcus aureus bacteremia, respiratory failure, and dialysis-dependent acute kidney injury. While he recovered from bacteremia, he remained difficult to wean from respiratory support, had labile blood pressure, and manifested persistent diarrhea. Stool antigen testing for C. difficile colitis returned repeatedly negative. Flexible sigmoidoscopy described diffuse ulceration, attributed to ischemic colitis. The colon biopsy specimen, however, described tissue-invasive cytomegalovirus (CMV) infection. Polymerase chain reaction (PCR) testing confirmed viremia with 8,900 copies/mL viral DNA. Human immunodeficiency virus antibody and PCR testing were both negative. Absolute lymphocyte count varied between 80 and 450/mm3 during the admission. After IV ganciclovir initiation, diarrhea and respiratory failure resolved, while renal function recovered to the patient'€™s baseline. CONCLUSION: The combination of critical illness and recent bacteremia likely represented a state of profound immunosuppression in this formerly healthy patient. CMV colitis may be under-diagnosed in sick ICU patients with renal failure and otherwise unexplained diarrhea. Serum PCR testing may aid the diagnosis.

Primary renal sclerosing epithelioid fibrosarcoma: report of 2 cases with EWSR1-CREB3L1 gene fusion.

We report the first 2 genetically confirmed cases of primary renal sclerosing epithelioid fibrosarcoma (SEF), occurring in a 17-year-old boy and a 61-year-old woman. In both cases, the tumors demonstrated the typical epithelioid clear cell morphology associated with extensive hyalinizing fibrosis, raising the differential diagnosis of solitary fibrous tumor, metanephric stromal tumor, and the sclerosing variant of clear cell sarcoma of the kidney. Both neoplasms demonstrated diffuse immunoreactivity for MUC4, a highly specific marker for SEF, and both demonstrated evidence of rearrangement of both the EWSR1 and CREB3L1 genes, which have recently been shown to be fused in this entity. Both neoplasms presented with metastatic disease. Primary renal SEF represents yet another translocation-associated sarcoma now shown to arise primarily in the kidney.

Intracystic hemorrhage in a non-endometriotic mullerian vaginal cyst.

The commonest type of simple vaginal cyst is the Mullerian cyst. These are typically lined by columnar epithelium and contain serous or mucinous fluid. If blood is found in the cyst, the source is usually due to the presence of endometrial elements in the cyst wall. The cyst is then termed an endometriotic cyst. In this case report, we have described a woman with a symptomatic 3 cm upper vaginal cyst who underwent surgical excision of the cyst. The cyst cavity was found to be full of old dark blood and mucous, however the wall contained no endometrial tissue and was lined by columnar epithelium which stained positive for mucous with mucicarmine. No cause for the intracystic hemorrhage was identified. We conclude that intracystic hemorrhage can occur in a simple Mullerian vaginal cyst in the absence of endometrial components.

Vulvar granular cell tumor.

Granular cell tumors are rare, usually benign, soft tissue neoplasms of neural origin. They occur more often in females than males, the peak age incidence is in the fourth through fifth decades. They can occur anywhere in the body with up to 15% situated in the vulva. The commonest presentation is as an asymptomatic mass. Microscopic findings are usually sufficient, but immunohistochemistry can also be helpful in confirming the diagnosis. The vulvar tumors are benign in 98% of cases with 2% reported as malignant. In this case report we describe a woman with a granular cell tumor confirmed by biopsy who underwent excision of the mass but with focal extension to the resection margin on microscopy. Our recommendation of re-excision was declined. Since it is not uncommon with these tumors to find groups of tumor cells extending beyond the macroscopic limits of growth, we conclude that it is advisable to have margins assessed intraoperatively by frozen section such that further excision can be performed for positive margins. Our patient has been followed for 18 mo without recurrence, should the tumor recur, re-excision, with frozen section control, is indicated. Recurrence rates are reported as 2%-8% with clear margins and 20% with positive margins.

Residual renal function in peritoneal dialysis with failed allograft and minimum immunosuppression.

Immunosuppression (IS) is often withdrawn in patients with end stage renal disease secondary to a failed renal allograft, and this can lead to an accelerated loss of residual renal function (RRF). As maintenance of RRF appears to provide a survival benefit to peritoneal dialysis (PD) patients, it is not clear whether this benefit of maintaining RRF in failed allograft patients returning to PD outweigh the risks of maintaining IS. A 49 year-old Caucasian male developed progressive allograft failure nine years after living-donor renal transplantation. Hemodialysis was initiated via tunneled dialysis catheter (TDC) and IS was gradually withdrawn. Two weeks after IS withdrawal he developed a febrile illness, which necessitate removal of the TDC and conversion to PD. He was maintained on small dose of tacrolimus (1 mg/d) and prednisone (5 mg/d). Currently (1 year later) he is doing exceedingly well on cycler-assisted PD. Residual urine output ranges between 600-1200 mL/d. Total weekly Kt/V achieved 1.82. RRF remained well preserved in this patient with failed renal allograft with minimal immunosuppressive therapy. This strategy will need further study in well-defined cohorts of PD patients with failed allografts and residual RRF to determine efficacy and safety.

Pterostilbene acts through metastasis-associated protein 1 to inhibit tumor growth, progression and metastasis in prostate cancer.

The development of natural product agents with targeted strategies holds promise for enhanced anticancer therapy with reduced drug-associated side effects. Resveratrol found in red wine, has anticancer activity in various tumor types. We reported earlier on a new molecular target of resveratrol, the metastasis-associated protein 1 (MTA1), which is a part of nucleosome remodeling and deacetylation (NuRD) co-repressor complex that mediates gene silencing. We identified resveratrol as a regulator of MTA1/NuRD complex and re-activator of p53 acetylation in prostate cancer (PCa). In the current study, we addressed whether resveratrol analogues also possess the ability to inhibit MTA1 and to reverse p53 deacetylation. We demonstrated that pterostilbene (PTER), found in blueberries, had greater increase in MTA1-mediated p53 acetylation, confirming superior potency over resveratrol as dietary epigenetic agent. In orthotopic PCa xenografts, resveratrol and PTER significantly inhibited tumor growth, progression, local invasion and spontaneous metastasis. Furthermore, MTA1-knockdown sensitized cells to these agents resulting in additional reduction of tumor progression and metastasis. The reduction was dependent on MTA1 signaling showing increased p53 acetylation, higher apoptotic index and less angiogenesis in vivo in all xenografts treated with the compounds, and particularly with PTER. Altogether, our results indicate MTA1 as a major contributor in prostate tumor malignant progression, and support the use of strategies targeting MTA1. Our strong pre-clinical data indicate PTER as a potent, selective and pharmacologically safe natural product that may be tested in advanced PCa.