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© 2021 by the authors., Conjugated polymer nanoparticles (CPNs) have emerged as advanced polymeric nanoplatforms in biomedical applications by virtue of extraordinary properties including high fluorescence brightness, large absorption coefficients of one and two-photons, and excellent photostability and colloidal stability in water and physiological medium. In addition, low cytotoxicity, easy functionalization, and the ability to modify CPN photochemical properties by the incorporation of dopants, convert them into excellent theranostic agents with multifunctionality for imaging and treatment. In this work, CPNs were designed and synthesized by incorporating a metal oxide magnetic core (Fe3O4 and NiFe2O4 nanoparticles, 5 nm) into their matrix during the nanoprecipitation method. This modification allowed the in vivo monitoring of nanoparticles in animal models using magnetic resonance imaging (MRI) and intravital fluorescence, techniques widely used for intracranial tumors evaluation. The modified CPNs were assessed in vivo in glioblastoma (GBM) bearing mice, both heterotopic and orthotopic developed models. Biodistribution studies were performed with MRI acquisitions and fluorescence images up to 24 h after the i.v. nanoparticles administration. The resulting IONP-doped CPNs were biocompatible in GBM tumor cells in vitro with an excellent cell incorporation depending on nanoparticle concentration exposure. IONP-doped CPNs were detected in tumor and excretory organs of the heterotopic GBM model after i.v. and i.t. injection. However, in the orthotopic GBM model, the size of the nanoparticles is probably hindering a higher effect on intratumorally T2-weighted images (T2WI) signals and T2 values. The photodynamic therapy (PDT)—cytotoxicity of CPNs was not either affected by the IONPs incorporation into the nanoparticles., This research was funded by grants from Ministerio de Economía y Competitividad (SAF2017-83043-R, MINECO/AEI/FEDER, UE), Comunidad de Madrid (S2017/BMD-3688, CM/FEDER/FSE, UE), Agencia Nacional de Promoción Científica y Tecnológica (PICT) (2676/18, 3577/18), and Secretaría de Ciencia y Técnica Universidad Nacional de Río Cuarto (PPI-SECyT UNRC).

[Aim]: To assess monocyte-based delivery of conjugated polymer nanoparticles (CPNs) for improved photodynamic therapy (PDT) in glioblastoma (GBM)., [Materials and methods]: Human monocyte cells (THP-1) and murine monocytes isolated from bone marrow (mBMDMs) were employed as stealth CPN carriers to penetrate into GBM spheroids and an orthotopic model of the tumor. The success of PDT, using this cell-mediated targeting strategy, was determined by its effect on the spheroids., [Results]: CPNs did not affect monocyte viability in the absence of light and did not show nonspecific release after cell loading. Activated monocytes incorporated CPNs in a higher proportion than monocytes in their naive state, without a loss of cellular functionality. In vitro PDT efficacy using cell-mediated delivery was superior to that using non vehiculized CPNs., [Conclusion]: CPN-loaded monocytes could efficiently deliver CPNs into GBM spheroids and the orthotopic model. Improved PDT in spheroids was confirmed using this delivery strategy.

© 2019 by the authors., Despite important advances in multimodal therapeutic options, glioblastoma (GBM), the most frequent and aggressive form of all astrocytomas, remains with a median overall survival period of 15 months. A direct correlation between GBM hypoxia and higher aggressiveness, poor prognosis and greater resistance to different treatments has been established. However, because of intratumoral and interindividual heterogeneity, it has not been possible to assess accurately the hypoxia degree from physiopathological parameters or neuroimaging methods. This study aims to develop and evaluate a magnetic resonance imaging (MRI) approach to identify more precisely those tumors that could improve the outcome through an oxygen targeted therapy. Methods: To assess the efficacy of radiotherapy in animals irradiated under air and oxygen breathing, we implemented a GBM animal model obtained by intracranial injection of glioma C6 cells in rats. MRI studies, based on the oxygen-induced contrast in blood (BOLD) and tissues (TOLD), were carried out to evaluate the effect of the modulation in oxygen breathing conditions on the tumors in vivo. The efficacy of the oxygen breathing therapies was determined by the relative tumor volume at the end of the experiment, compared to its size on the day before the treatment. Results: Our results categorized the tumors in responding, non-responding and intermediate behaviors. While BOLD analysis did not show any statistical difference between animals, either breathing air or oxygen, TOLD parameters allowed for the identification of the tumors with higher responses to hyperoxygenic radiotherapy. Conclusions: The non-invasive oxygen enhanced MRI acquisitions proposed here show promising potential to identify those tumors that would generally improve their response to a hypoxia targeted treatment., This work was supported by grants from the Ministry of Economy, Industry and Competitiveness (SAF2017-83043-R), and by the Program MULTITARGET&VIEW-CM from the Community of Madrid (S-BIO-0170-2006), involving contributions from FEDER and FSE funds.

The pharmacological action of the V(IV) compound VO(dmpp)2 was previously evaluated in vivo using obese pre-diabetic Zucker rats treated with this compound for four weeks. Besides the promising results regarding biological parameters indicative of insulin-mimetism, a specific biological activity in mitigating impaired lipid metabolism was observed. This work aims at complementing and reinforcing data formerly attained and it represents an attempt to unveil the effect of this compound at the molecular level, particularly on the metabolic profile of different organs. Ex vivo experiments with tissue samples of the brain, liver and skeletal muscle from treated and non-treated obese Zucker rats, using lean Zucker rats as a control, were carried out by using 1H-HRMAS. The results obtained showed that the lipid liver content, a characteristic of obese rats, significantly decreased after 4 weeks of VO(dmpp)2 treatment, as demonstrated by the quantification of the respective signals in the 1H-HRMAS NMR spectra. In the other analyzed tissues, the differences were not statistically significant, but a trend of a decrease of the abnormal metabolite content in treated obese rats was observed. Importantly, the therapeutic dose used showed no renal toxicity. VO(dmpp)2 was demonstrated to be able to revert the impaired lipid metabolism in vivo and 1H-HRMAS NMR was revealed to be a good tool to simultaneously assess the effects of a drug on the metabolic profile of different organs and tissues., This work was supported by grants from the Ministry of Economy, Industry and Competitivity (SAF2017-83043-R), and by the Program MULTITARGET&VIEW-CM from Community of Madrid, Spain (S-BIO-0170-2006), involving contributions from FEDER and FSE. A. M. M. and M. M. C. A. C. acknowledge Fundação para a Ciência e Tecnologia (FCT), Portugal, for the financial support to the CQC research unit through the project 007630 UID/QUI/00313/2013, co-funded by COMPETE2020-EU.

In the last years, extensive attention has been paid on designing and developing functional imaging contrast agents for providing accurate noninvasive evaluation of pathology in vivo. However, the issue of false-positives or ambiguous imaging and the lack of a robust strategy for simultaneous dual-mode imaging remain to be fully addressed. One effective strategy for improving it is to rationally design magnetic resonance imaging (MRI) contrast agents (CAs) with intrinsic T1/ T2 dual-mode imaging features. In this work, the development and characterization of one-pot synthesized nanostructured coordination polymers (NCPs) which exhibit dual mode T1/ T2 MRI contrast behavior is described. The resulting material comprises the combination of different paramagnetic ions (Fe3+, Gd3+, Mn2+) with selected organic ligands able to induce the polymerization process and nanostructure stabilization. Among them, the Fe-based NCPs showed the best features in terms of colloidal stability, low toxicity, and dual T1/ T2 MRI contrast performance overcoming the main drawbacks of reported CAs. The dual-mode CA capability was evaluated by different means: in vitro phantoms, ex vivo and in vivo MRI, using a preclinical model of murine glioblastoma. Interestingly, the in vivo MRI of Fe-NCPs show T1 and T2 high contrast potential, allowing simultaneous recording of positive and negative contrast images in a very short period of time while being safer for the mouse. Moreover, the biodistribution assays reveals the persistence of the nanoparticles in the tumor and subsequent gradual clearance denoting their biodegradability. After a comparative study with commercial CAs, the results suggest these nanoplatforms as promising candidates for the development of dual-mode MRI CAs with clear advantages., This work was supported by the project MAT2015-70615-R and BIO2016-78057-R from the Spanish Government and by FEDER − European Commission funds. ICN2 acknowledges support from the Severo Ochoa Program of the Spanish Ministry of Economy, Industry and Competitiveness (MINECO, Grant SEV-2013-0295).

Oxygen monitoring is a topic of exhaustive research due to its central role in many biological processes, from energy metabolism to gene regulation. The ability to monitor in vivo the physiological distribution and the dynamics of oxygen from subcellular to macroscopic levels is a prerequisite to better understand the mechanisms associated with both normal and disease states (cancer, neurodegeneration, stroke, etc.). This chapter focuses on magnetic resonance imaging (MRI) based techniques to assess oxygenation in vivo. The first methodology uses injected fluorinated agents to provide quantitative pO2 measurements with high precision and suitable spatial and temporal resolution for many applications. The second method exploits changes in endogenous contrasts, i.e., deoxyhemoglobin and oxygen molecules through measurements of T2* and T1, in response to an intervention to qualitatively evaluate hypoxia and its potential modulation., Method development and application supported in part by CPRIT RP140399, RP120670-03, P30 CA142543, and P41 EB015908.

Glioblastoma (GBM) is the most common aggressive primary brain tumor in adults, with a short survival time even after aggressive therapy. Non-invasive surrogate biomarkers of therapy response may be relevant for improving patient survival. Previous work produced such biomarkers in preclinical GBM using semi-supervised source extraction and single-slice Magnetic Resonance Spectroscopic Imaging (MRSI). Nevertheless, GBMs are heterogeneous and single-slice studies could prevent obtaining relevant information. The purpose of this work was to evaluate whether a multi-slice MRSI approach, acquiring consecutive grids across the tumor, is feasible for preclinical models and may produce additional insight into therapy response. Nosological images were analyzed pixel-by-pixel and a relative responding volume, the Tumor Responding Index (TRI), was defined to quantify response. Heterogeneous response levels were observed and treated animals were ascribed to three arbitrary predefined groups: high response (HR, n = 2), TRI = 68.2 ± 2.8%, intermediate response (IR, n = 6), TRI = 41.1 ± 4.2% and low response (LR, n = 2), TRI = 13.4 ± 14.3%, producing therapy response categorization which had not been fully registered in single-slice studies. Results agreed with the multi-slice approach being feasible and producing an inverse correlation between TRI and Ki67 immunostaining. Additionally, ca. 7-day oscillations of TRI were observed, suggesting that host immune system activation in response to treatment could contribute to the responding patterns detected.

Glioblastoma (GBM) causes poor survival in patients even with aggressive treatment. Temozolomide (TMZ) is the standard chemotherapeutic choice for GBM treatment but resistance always ensues. Protein kinase CK2 (CK2) contributes to tumour development and proliferation in cancer, and it is overexpressed in human GBM. Accordingly, targeting CK2 in GBM may benefit patients. Our goal has been to evaluate whether CK2 inhibitors (iCK2s) could increase survival in an immunocompetent preclinical GBM model. Cultured GL261 cells were treated with different iCK2s including CX-4945, and target effects evaluated in vitro. CX-4945 was found to decrease CK2 activity and Akt(S129) phosphorylation in GL261 cells. Longitudinal in vivo studies with CX-4945 alone or in combination with TMZ were performed in tumour-bearing mice. Increase in survival (p < 0.05) was found with combined CX-4945 and TMZ metronomic treatment (54.7 ± 11.9 days, n = 6) when compared to individual metronomic treatments (CX-4945: 24.5 ± 2.0 and TMZ: 38.7 ± 2.7, n = 6) and controls (22.5 ± 1.2, n = 6). Despite this, CX-4945 did not improve mice outcome when administered on every/alternate days, either alone or in combination with 3-cycle TMZ. The highest survival rate was obtained with the metronomic combined TMZ+CX-4945 every 6 days, pointing to the participation of the immune system or other ancillary mechanism in therapy response.

Glioblastoma (GBM) causes poor survival in patients even when applying aggressive treatment. Temozolomide (TMZ) is the standard chemotherapeutic choice for GBM treatment, but resistance always ensues. In previous years, efforts have focused on new therapeutic regimens with conventional drugs to activate immune responses that may enhance tumor regression and prevent regrowth, for example the “metronomic” approaches. In metronomic scheduling studies, cyclophosphamide (CPA) in GL261 GBM growing subcutaneously in C57BL/6 mice was shown not only to activate antitumor CD8+ T-cell response, but also to induce long-term specific T-cell tumor memory. Accordingly, we have evaluated whether metronomic CPA or TMZ administration could increase survival in orthotopic GL261 in C57BL/6 mice, an immunocompetent model. Longitudinal in vivo studies with CPA (140 mg/kg) or TMZ (range 140–240 mg/kg) metronomic administration (every 6 days) were performed in tumor-bearing mice. Tumor evolution was monitored at 7 T with MRI (T2-weighted, diffusion-weighted imaging) and MRSI-based nosological images of response to therapy. Obtained results demonstrated that both treatments resulted in increased survival (38.6 ± 21.0 days, n = 30) compared with control (19.4 ± 2.4 days, n = 18). Best results were obtained with 140 mg/kg TMZ (treated, 44.9 ± 29.0 days, n = 12, versus control, 19.3 ± 2.3 days, n = 12), achieving a longer survival rate than previous group work using three cycles of TMZ therapy at 60 mg/kg (33.9 ± 11.7 days, n = 38). Additional interesting findings were, first, clear edema appearance during chemotherapeutic treatment, second, the ability to apply the semi-supervised source analysis previously developed in our group for non-invasive TMZ therapy response monitoring to detect CPA-induced response, and third, the necropsy findings in mice cured from GBM after high TMZ cumulative dosage (980–1400 mg/kg), which demonstrated lymphoma incidence. In summary, every 6 day administration schedule of TMZ or CPA improves survival in orthotopic GL261 GBM with respect to controls or non-metronomic therapy, in partial agreement with previous work on subcutaneous GL261.