Ladislau Albert

New York Medical College, New York, New York, United States

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Publications (7)12.08 Total impact

  • Michael Karsy · Ladislau Albert · Raj Murali · Meena Jhanwar-Uniyal
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    ABSTRACT: Glioblastoma (GBM) is the most common primary brain tumor in adults and demonstrates a 1-year median survival time. Codon-specific hotspot mutations of p53 result in constitutively active mutant p53, which promotes aberrant proliferation, anti-apoptosis, and cell cycle checkpoint failure in GBM. Recently identified CD133(+) cancer stem cell populations (CSC) within GBM also confer therapeutic resistance. We studied targeted therapy in a codon-specific p53 mutant (R273H) created by site-directed mutagenesis in U87MG. The effects of arsenic trioxide (ATO, 1 μM) and all-trans retinoic acid (ATRA, 10 μM), possible targeted treatments of CSCs, were investigated in U87MG neurospheres. The results showed that U87-p53(R273H) cells generated more rapid neurosphere growth than U87-p53(wt) but inhibition of neurosphere proliferation was seen with both ATO and ATRA. U87-p53(R273H) neurospheres showed resistance to differentiation into glial cells and neuronal cells with ATO and ATRA exposure. ATO was able to generate apoptosis at high doses and proliferation of U87-p53(wt) and U87-p53(R273H) cells was reduced with ATO and ATRA in a dose-dependent manner. Elevated pERK1/2 and p53 expression was seen in U87-p53(R273H) neurospheres, which could be reduced with ATO and ATRA treatment. Additionally, differential responses in pERK1/2 were seen with ATO treatment in neurospheres and non-neurosphere cells. In conclusion, codon-specific mutant p53 conferred a more aggressive phenotype to our CSC model. However, ATO and ATRA could potently suppress CSC properties in vitro and may support further clinical investigation of these agents.
    No preview · Article · Jan 2014 · Tumor Biology
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    ABSTRACT: Atypical serine-threonine kinase, mTOR (mechanistic target of Rapamycin; originally coined "mammalian TOR"), exists in two distinct multi-protein complexes termed mTOR complex 1 (mTORC1) and 2 (mTORC2), that senses and integrates a variety of environmental signals to control organism growth and homeostasis via non-overlapping signaling pathways. mTOR belongs to the phosphoinositide 3-kinase (PI3-K)-related kinase family, and an aberrant activation of mTORC1 is a potential contributing factor in uncontrolled cell growth, proliferation, and survival of tumor cells via specific effects on cap-dependent translation initiation, as well as in a more sustained manner via advancing ribosome biogenesis. It is thereby shown to be deregulated in numerous pathological conditions including cancer, obesity, type 2 diabetes, and neurodegeneration. Notably, mTOR itself, or through its substrates, regulates stem cell differentiation and maintenance of plueropotency. mTORC2 has been linked to cytoskeletal reorganization and cell survival through Akt, and is crucial to many divergent physiological functions, which may include stem cell regulation.
    No preview · Article · Oct 2012
  • Ladislau Albert · Joseph A DeMattia
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    ABSTRACT: The abuse of cocaine can lead to significant destruction of midline craniofacial structures. This process occurs secondary to myriad mechanisms, including ischemic necrosis, irritation by chemical adulterants, and direct trauma during its administration. Coupled with a prolonged chronic infection of intranasal and anterior skull base regions, an encephalocele can be formed. We report a case of an encephalocele secondary to cocaine use and its associated complications. A 56-year-old man presented with altered mental status and cerebritis secondary to the presence of an intranasal encephalocele. On computed tomography, extensive destruction of the anterior cranial fossa was observed. The patient had a 30-year history of intranasal cocaine abuse, and his urine tested positive for the presence of cocaine on admission. The patient was treated with intravenous antibiotics and underwent a repair of his cranial defect and resection of the encephalocele. The patient made a good recovery after treatment. Alternative causes of an encephalocele, including trauma, surgery, and congenital malformation, were ruled out in this patient. Histopathological analysis of the necrotic tissue and the absence of renal or pulmonary disease also indicated that the patient did not suffer from Wegener granulomatosis, a known cause of spontaneous intranasal lesions. To the best of our knowledge, this is the first report of an encephalocele likely induced solely by cocaine abuse.
    No preview · Article · Jan 2011 · Neurosurgery
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    ABSTRACT: Glioblastoma multiforme (GBM), a grade IV glioma, appears to harbor therapy-resistant cancer stem cells (CSCs) that are the major cause of recurrence. All-trans retinoic acid (ATRA), a derivative of retinoid, is capable of differentiating a variety of stem cells, as well as normal neural progenitor cells, and down-regulates expression of the stem cell marker nestin. This study investigated the effects of ATRA on differentiation, proliferation, self-renewal, and signaling pathways of CSCs in GBM. CSCs differentiated into glial and neuronal lineages at low concentrations of ATRA (10 μM). Proliferation and self renewal of neurospheres were reduced following ATRA, although ATRA induced apopotsis at higher (40 μM) concentrations. Analysis of mitogen-activated protein kinase signaling pathways, specifically extracellular signal-regulated kinases (ERK1/2), showed that ATRA-induced alterations in ERK1/2 were associated with regulation of differentiation, proliferation and apoptosis. These results emphasize that low doses of ATRA may have therapeutic potential by differentiating GBM CSCs and rendering them sensitive to targeted therapy.
    No preview · Article · Dec 2010 · Anticancer research
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    ABSTRACT: These findings emphasize that the mTOR pathway may contribute to maintenance of quiescence of CSCs, and provide a basis for manipulating CSCs in the treatment of GBM. Future research should focus on further defining the PI3K/Akt/mTOR molecular network in the regulation of stem cell quiescence and provide rationale for targeting the cancer-initiating cells of GBM.
    No preview · Article · Oct 2010 · Advances in enzyme regulation
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    ABSTRACT: The AKT/mammalian target of rapamycin (mTOR) signaling pathway plays a critical role in glioblastoma multiforme (GBM) oncogenesis due to activation of AKT. We studied two distinct complexes, mTOR complex 1 (mTORC1) and mTOR complex 2 (mTORC2), through which mTOR controls cell survival, growth and motility. Inhibition of mTOR by rapamycin (RAPA) resulted in time-dependent suppression of S6 ribosomal protein (pS6KSer235/236; mTORC1 substrate) and caused transient suppression of pAKTSer473 (mTORC2 substrate) at 1 to 3 h followed by a consistent increase from 6 to 24 h. Inhibition of mTOR or phosphoinositide 3-kinase (PI3K) suppressed platelet-derived growth factor (PDGF)- or fibronectin (FN)-induced activation of p70S6KThr389. Combined inhibition of mTOR and PI3K abolished PDGF- or FN-induced activation of STAT3Ser727. Expression of pAKT was suppressed by siRNA silencing of mTORC2 co-protein rictor, but not by mTORC1 co-protein raptor. GBM cell proliferation and motility paralleled the activation of mTORC2. Combined inhibition of mTOR and PI3K had an additive effect on suppressing cell growth and motility. PDGF-induced nuclear localization of mTOR was blocked by pre-treatment with RAPA. The results demonstrated that an activation of mTORC2 occurs when mTORC1 is inhibited by RAPA. Therefore, simultaneous suppression of mTORC1 and mTORC2 may provide novel therapy for GBM.
    No preview · Article · Nov 2009 · International Journal of Oncology
  • Ladislau Albert · Michael Karsy · Raj Murali · Meena Jhanwar-Uniyal
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    ABSTRACT: Tumorigenesis of glioblastoma multiforme (GBM), the most aggressive primary intracranial neoplasm, is associated with aberrant PI3K/AKT/mTOR signaling. Inhibitors of mTOR, such as rapamycin (RAPA) or its analogs, have provided limited benefit. Here, we aim to decipher the signaling pathways involved in RAPA resistance. We found that RAPA induced a time-dependent activation of MAPK (pERK1/2) and MEK1/2. Inhibition of upstream kinase MEK1/2 by U0126 partially suppressed RAPA-induced ERK1/2 activation. Small interfering RNA suppression of mTOR resulted in higher pERK1/2 levels and pre-treatment with RAPA potentiated PDGF-induced activation of ERK1/2. Furthermore, nuclear localization of pERK1/2 was evident following RAPA, which was MEK1/2-dependent. Cell proliferation was significantly suppressed by combined MEK1/2 and mTOR inhibition compared to mTOR inhibition alone. These results demonstrate activation of a mitogenic pathway involving a feedback mechanism between mTOR and PI3K/ERK1/2 and support the basis for combined inhibitors in GBM treatment.
    No preview · Article · Jan 2009