The molecular pathomechanisms of major depressive disorder (MDD) are still not completely understood. Here, we follow the hypothesis, that mitochondria dysfunction which is inevitably associated with bioenergetic disbalance is a risk factor that contributes to the susceptibility of an individual to develop MDD. Thus, we investigated molecular mechanisms related to mitochondrial function in induced neuronal progenitor cells (NPCs) which were reprogrammed from fibroblasts of eight MDD patients and eight non-depressed controls. We found significantly lower maximal respiration rates, altered cytosolic basal calcium levels, and smaller soma size in NPCs derived from MDD patients. These findings are partially consistent with our earlier observations in MDD patient-derived fibroblasts. Furthermore, we differentiated MDD and control NPCs into iPS-neurons and analyzed their passive biophysical and active electrophysiological properties to investigate whether neuronal function can be related to altered mitochondrial activity and bioenergetics. Interestingly, MDD patient-derived iPS-neurons showed significantly lower membrane capacitance, a less hyperpolarized membrane potential, increased Na+ current density and increased spontaneous electrical activity. Our findings indicate that functional differences evident in fibroblasts derived from MDD patients are partially present after reprogramming to induced-NPCs, could relate to altered function of iPS-neurons and thus might be associated with the aetiology of major depressive disorder.
We show that quantification of an oligonucleotide and multiple metabolites, including isobaric 3´ and 5´ metabolites, is achievable in a single assay through good sample clean-up and careful optimization of the LC-MS/MS parameters. The strategy presented here can be applied elsewhere and may be useful for other oligonucleotides and their metabolites.
4034 Background: TGF-β2 overexpression in solid tumors triggers key cancer pathomechanisms, i.e. suppression of antitumor immune responses system and metastasis. Trabedersen specifically inhibits TGF-β2 expression. In the clinical Phase I/II study we evaluate MTD, safety, pharmakokinetics (PK), and efficacy of i.v. trabedersen in patients with advanced tumors. Methods: A total of 61 patients with pancreatic cancer (PancCa, n=37), malignant melanoma (MM, n=19), or colorectal carcinoma (n=5) were treated with i.v. trabedersen as 2nd to 4th-line therapy with escalating doses in 2 treatment schedules. (1st schedule: 7d on, 7d off; 2nd schedule: 4d on, 10d off; up to 10 cycles). Within the 1st schedule, the MTD was established at 160 mg/m2/d. In the 2nd schedule dose-escalation was stopped before reaching MTD. In the Phase II-part of the study further PancCa and MM patients were treated with 140 mg/m2/d. For assessment of PK parameters, plasma time profiles were analyzed for trabedersen and its n-1 to n-5 metabolites by non-compartimental analysis. Results: Trabedersen was safe and well-tolerated. The only expected adverse reaction identified is non-serious and transient thrombocytopenia. Only 2 SAEs (gastrointestinal hemorrhage und pyrexia) were considered as possibly related to study medication. Further clinical development will focus on PancCa patients receiving 140 mg/m2/d trabedersen as 2nd-line treatment. Survival analysis of these patients revealed a mOS of 13.4 months (n=9; 95% CI: 2.2, 39.7). One PanCa patient had a complete response of liver metastases and is still alive after 75 months. Promising efficacy data were also seen in MM patients enrolled into the last cohort (140 mg/m2/day) with a current mOS of 9.3 months (n=14; 95% CI: 6.5, 12.2). PK analyses showed for both treatment schedules that exposure to trabedersen was in the expected range for all doses and half-life of trabedersen (1.12 to 2.08 hrs) as well as clearance (2.22-4.37 L/h*m2) were independent of dose. Conclusions: Trabedersen showed excellent safety and encouraging survival results in the Phase I/II clinical study. A randomized, active-controlled study in 2nd line stage IV PanCa patients is in preparation.
Brain-tumor-initiating cells (BTICs) of proneural and mesenchymal origin contribute to the highly malignant phenotype of glioblastoma (GB) and resistance to current therapies. BTICs of different subtypes were challenged with oxidative phosphorylation (OXPHOS) inhibition with metformin to assess the differential effects of metabolic intervention on key resistance features. Whereas mesenchymal BTICs varied according to their invasiveness, they were in general more glycolytic and less responsive to metformin. Proneural BTICs were less invasive, catabolized glucose more via the pentose phosphate pathway, and responded better to metformin. Targeting glycolysis may be a promising approach to inhibit tumor cells of mesenchymal origin, whereas proneural cells are more responsive to OXPHOS inhibition. Future clinical trials exploring metabolic interventions should account for metabolic heterogeneity of brain tumors.
BackgroundThe phosphatase chronophin (CIN/PDXP) has been shown to be an important regulator of glioma cell migration and invasion. It has two known substrates: p-Ser3-cofilin, the phosphorylated form of the actin binding protein cofilin, and pyridoxal 5′-phosphate, the active form of vitamin B6. Phosphoregulation of cofilin, among other functions, plays an important role in cell migration, whereas active vitamin B6 is a cofactor for more than one hundred enzymatic reactions. The role of CIN has yet only been examined in glioblastoma cell line models derived under serum culture conditions.ResultsWe found that CIN is highly expressed in cells cultured under non-adherent, serum-free conditions that are thought to better mimic the in vivo situation. Furthermore, the substrates of CIN, p-Ser3-cofilin and active vitamin B6, were significantly reduced as compared to cell lines cultured in serum-containing medium. To further examine its molecular role we stably knocked down the CIN protein with two different shRNA hairpins in the glioblastoma cell lines NCH421k and NCH644. Both cell lines did not show any significant alterations in proliferation but expression of differentiation markers (such as GFAP or TUBB3) was increased in the knockdown cell lines. In addition, colony formation was significantly impaired in NCH644. Of note, in both cell lines CIN knockdown increased active vitamin B6 levels with vitamin B6 being known to be important for S-adenosylmethionine biosynthesis. Nevertheless, global histone and DNA methylation remained unaltered as was chemoresistance towards temozolomide. To further elucidate the role of phosphocofilin in glioblastoma cells we applied inhibitors for ROCK1/2 and LIMK1/2 to our model. LIMK- and ROCK-inhibitor treatment alone was not toxic for glioblastoma cells. However, it had profound, but antagonistic effects in NCH421k and NCH644 under chemotherapy.ConclusionIn non-adherent glioblastoma cell lines cultured in serum-free medium, chronophin knockdown induces phenotypic changes, e.g. in colony formation and transcription, but these are highly dependent on the cellular background. The same is true for phenotypes observed after treatment with inhibitors for kinases regulating cofilin phosphorylation (ROCKs and LIMKs). Targeting the cofilin phosphorylation pathway might therefore not be a straightforward therapeutic option in glioblastoma.Electronic supplementary materialThe online version of this article (10.1186/s12885-018-4440-4) contains supplementary material, which is available to authorized users.
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