Epithelial-to-mesenchymal transition in pancreatic ductal adenocarcinoma: Characterization in a 3D-cell culture model

AIM: To analyze the effect of three-dimensional (3D)-arrangement on the expression of epithelial-to-mesenchymal transition markers in pancreatic adenocarcinoma (PDAC) cells.METHODS: HPAF-II, HPAC, and PL45 PDAC cells were cultured in either 2D-monolayers or 3D-spheroids. Ultrastructure was analyzed by transmission electron microscopy. The expression of E-cadherin, β-catenin, N-cadherin, collagen type I (COL-I), vimentin, α-smooth muscle actin (αSMA), and podoplanin was assayed by confocal microscopy in cells cultured on 12-mm diameter round coverslips and in 3D-spheroids. Gene expression for E-cadherin, Snail, Slug, Twist, Zeb1, and Zeb2 was quantified by real-time PCR. E-cadherin protein level and its electrophoretic pattern were studied by Western blot in cell lysates obtained from cells grown in 2D-monolayers and 3D-spheroids.RESULTS: The E-cadherin/β-catenin complex was expressed in a similar way in plasma membrane cell boundaries in both 2D-monolayers and 3D-spheroids. E-cadherin increased in lysates obtained from 3D-spheroids, while cleavage fragments were more evident in 2D-monolayers. N-cadherin expression was observed in very few PDAC cells grown in 2D-monolayers, but was more evident in 3D-spheroids. Some cells expressing COL-I were observed in 3D-spheroids. Podoplanin, expressed in collectively migrating cells, and αSMA were similarly expressed in both experimental conditions. The concomitant maintenance of the E-cadherin/β-catenin complex at cell boundaries supports the hypothesis of a collective migration for these cells, which is consistent with podoplanin expression.CONCLUSION: We show that a 3D-cell culture model could provide deeper insight into understanding the biology of PDAC and allow for the detection of marked differences in the phenotype of PDAC cells grown in 3D-spheroids.

Neural grafting for Parkinson's disease:challenges and prospects

Parkinson＇s disease（PD） is a neurodegenerative condition which causes a characteristic movement disorder secondary to loss of dopaminergic neurons in the substanitia nigra.The motor disorder responds well to dopamine-replacement therapies,though these result in significant adverse effects due to non-physiological release of dopamine in the striatum,and off-target effects.Cell-based regenerative treatments offer a potential means for targeted replacement of dopamine,in a physiological manner.Dopaminergic neurons for cell-based therapies can be obtained from several sources.Fetal ventral mesencephalon tissue contains dopaminergic neuron progenitors,and has been transplanted into the striatum of PD patients with good results in a number of cases.However,the ethical implications and logistical challenges of using fetal tissue mean that fetal ventral mesencephalon is unlikely to be used in a widespread clinical setting.Induced pluripotent stem cells can be used to generate dopaminergic neurons for transplantation,providing a source of autologous tissue for grafting.This approach means that challenges associated with allografts,such as the potential for immune rejection,can be circumvented.However,the associated cost and difficulty in producing a standardized product from different cell lines means that,at present,this approach is not commercially viable as a cell-based therapy.Dopaminergic neurons derived from embryonic stem cells offer the most promising basis for a cell-based therapy for Parkinson＇s disease,with trials due to commence in the next few years.Though there are ethical considerations to take into account when using embryonic tissue,the possibility of producing a standardized,optimized cell product means that this approach can be both effective,and commercially viable.

Drugging SUMOylation for neuroprotection and oncotherapy

Recently there have been exciting research advances in neuroprotective therapies for ischemic stroke. In the past, the search for neu- roprotective agents has been fraught with failure at the clinical trials stage due to numerous factors, including subject heterogeneity and improper therapeutic windows （Tymianski, 2017）. Moreover, it is becoming clearer that the complex and evolving pathobiology of stroke requires multimodal therapeutic approaches capable of modulating the numerous axes that contribute to ischemia/reperfusion damage, rather than targeting a single axis （Bernstock et al., 2018a）. With the success of recent endovascular thrombectomy （EVT） trials, it has been suggested that clinical trials of EVT with adjunct neuroprotection can overcome past difficulties and maximize the effect size by using imaging to reduce patient heterogeneity （i. e., selecting those with large vessel occlusions, small ischemic cores, and good collateral circulation）, restoring perfusion using better EVT devices, and enrolling patients in the correct therapeutic window （i.e., when they still have salvageable brain tissue） （Tymianski, 2017）. Considering the opportunity that this represents for new, better clinical trials of neuroprotective agents, the search is on for high-potential compounds that may be investigated in these future studies.