The initiation of androgen-deprivation therapy (ADT) induces susceptibilities in prostate cancer cells that make them vulnerable to synergistic treatment and enhanced cell death. Senescence results in cell-cycle arrest, but cells remain viable. In this study, we investigated the mechanisms by which prostate cancer cells undergo senescence in response to ADT, and determined whether an FDA-approved antidiabetic drug metformin has a synergistic effect with ADT in prostate cancer both in vitro and in vivo. Our results show that longer term exposure to ADT induced senescence associated with p16INK4a and/or p27kip2 induction. The activation of PI3K/AKT and inactivation of AMPK in senescent cells resulted in mTORC1 activation. In addition, the antiapoptotic protein XIAP expression was increased in response to ADT. The addition of metformin following ADT induced apoptosis, attenuated mTOR activation, reduced senescent cell number in vitro, and inhibited tumor growth in prostate cancer patient-derived xenograft models. This study suggests that combining ADT and metformin may be a feasible therapeutic approach to remove persistent prostate cancer cells after ADT.
Androgen deprivation therapy (ADT) has been the standard of care for the last 75 years in metastatic hormone sensitive prostate cancer (PCa). However, this approach is rarely curative. Recent clinical trials have demonstrated that ADT combined with other agents, notably docetaxel and abiraterone, lead to improved survival. The mechanisms surrounding this improved cancer outcomes are incompletely defined. The response of cancer cells to ADT includes apoptosis and cell death, but a significant fraction remains viable. Our laboratory has demonstrated both in vitro and in vivo that cellular senescence occurs in a subset of these cells. Cellular senescence is a phenotype characterized by cell cycle arrest, senescence-associated β-galactosidase (SA-β-gal), and a hypermetabolic state. Positive features of cellular senescence include growth arrest and immune stimulation, although persistence may release cytokines and growth factors that are detrimental. Senescent tumor cells generate a catabolic state with increased glycolysis, protein turnover and other metabolic changes that represent targets for drugs, like metformin, to be applied in a synthetic lethal approach. This review examines the response to ADT and the putative role of cellular senescence as a biomarker and therapeutic target in this context.
Purpose To evaluate the association between ellipsoid zone (EZ) on spectral domain optical coherence tomography (SD-OCT) and visual acuity letter score (VALS) in participants with retinal vein occlusion in the Study of Comparative Treatments for Retinal Vein Occlusion 2. Methods SD-OCT scans of 362 participants were qualitatively assessed at baseline and months 1, 6, 12, and 24 for EZ status as normal, patchy, or absent. The thickness of EZ layer in the central subfield was also obtained using machine learning. Results EZ assessments were not possible at baseline due to signal blockage in >75% of eyes. At month 1, EZ was normal in 37.6%, patchy in 48.1%, and absent in 14.3%. EZ was measurable in 48.7% with a mean area of 0.07 ± 0.16 mm 2 . Mean VALS was better in eyes without an EZ defect compared to eyes with an EZ defect ( P < 0.0001 at all visits). EZ defect at month 1 was associated with poorer VALS at all follow-up visits ( P < 0.0001). Conclusions Both qualitative and quantitative assessments of EZ status strongly correlated with VALS. Absence of EZ was associated with poorer VALS at both corresponding and future visits, with larger areas of EZ loss associated with worse VALS. Translational Relevance Assessment of EZ can be used to identify patients with potentially poor response in eyes with retinal vein occlusion.
Purpose We present 3 cases of Alström syndrome (ALMS) that highlight the importance of the ophthalmic exam, as well as the diagnostic challenges and management considerations of this ultra-rare disease. Observations The first case is of a 2-year-old boy with history of spasmus nutans who presented with head bobbing and nystagmus. The second patient is a 5-year-old boy with history of infantile dilated cardiomyopathy status post heart transplant, Burkitt lymphoma status post chemotherapy, obesity, global developmental delay, and high hyperopia previously thought to have cortical visual impairment secondary to heart surgery/possible ischemic event. This patient presented with nystagmus, photophobia, and reduced vision. The third case involves a 8-year-old boy with history of obesity, bilateral optic nerve atrophy, hyperopic astigmatism, exotropia, and nystagmus. Upon presentation to the consulting pediatric ophthalmologist, none of the patients had yet been diagnosed with ALMS. All 3 cases were subsequently found to have an electroretinogram (ERG) that exhibited severe global depression and to carry ALMS1 pathogenic variants. Conclusions and Importance ALMS is an autosomal recessive disease caused by ALMS1 variations, characterized by cone-rod dystrophy, obesity, progressive sensorineural hearing loss, cardiomyopathy, insulin resistance, and multiorgan dysfunction. Retinal dystrophy diagnosis is critical given clinical criteria and detection rates of genetic testing. Early diagnosis is extremely important because progression to flat ERG leads to the inability to differentiate between rod-cone or cone-rod involvement, either of which have their own differential diagnoses. In our series, the ophthalmic exam and abnormal ERG prompted further genetic testing and the subsequent diagnosis of ALMS. Multidisciplinary care ensures the best possible outcome with the ophthalmologist playing a key role.
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