Photodynamic Therapy (PDT) relies on the use of non-toxic photosensitizers that are locally and selectively activated by light to induce cell death or apoptosis through reactive oxygen species ...generation. The conjugation of porphyrinoids with sugars that target cancer is increasingly viewed as an effective way to increase the selectivity of PDT. To date, in vitro PDT efficacy is mostly screened using two-dimensional monolayer cultures. Compared to monolayer cultures, three-dimensional spheroid cultures have unique spatial distributions of nutrients, metabolites, oxygen and signalling molecules; therefore better mimic in vivo conditions. We obtained 0.05 mm3 spheroids with four different human tumor cell lines (HCT-116, MCF-7, UM-UC-3 and HeLa) with appropriate sizes for screening PDT agents. We observed that detachment from monolayer culture and growth as tumor spheroids was accompanied by changes in glucose metabolism, endogenous ROS levels, galectin-1 and glucose transporter GLUT1 protein levels. We compared the phototoxic responses of a porphyrin conjugated with four glucose molecules (PorGlu4) in monolayer and spheroid cultures. The uptake and phototoxicity of PorGlu4 is highly dependent on the monolayer versus spheroid model used and on the different levels of GLUT1 protein expressed by these in vitro platforms. This study demonstrates that HCT-116, MCF-7, UM-UC-3 and HeLa spheroids afford a more rational platform for the screening of new glycosylated-photosensitizers compared to monolayer cultures of these cancer cells.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Human epidermal growth factor receptor 2 (HER2) gene amplification and/or protein overexpression in tumors is a prerequisite for initiation of trastuzumab therapy. Although HER2 is a cell membrane ...receptor, differential rates of endocytosis and recycling engender a dynamic surface pool of HER2. Since trastuzumab must bind to the extracellular domain of HER2, a depressed HER2 surface pool hinders binding. Using in vivo biological models and cultures of fresh human tumors, we find that the caveolin-1 (CAV1) protein is involved in HER2 cell membrane dynamics within the context of receptor endocytosis. The translational significance of this finding is highlighted by our observation that temporal CAV1 depletion with lovastatin increases HER2 half-life and availability at the cell membrane resulting in improved trastuzumab binding and therapy against HER2-positive tumors. These data show the important role that CAV1 plays in the effectiveness of trastuzumab to target HER2-positive tumors.
•Brazilian berries and cherries characteristics are in agreement with literature.•All fruits analyzed showed levels of ascorbic acid well above those found in the literature.•Blackberry – highest ...antioxidant activity and richest source of bioactive compounds.•Antioxidant activity was correlated with the phenolics, ascorbic acid, flavonoid and anthocyanin.
This study aimed to evaluate the chemical composition, identify the bioactive compounds and measure the antioxidant activity present in blackberry, red raspberry, strawberry, sweet cherry and blueberry fruits produced in the subtropical areas of Brazil and to verify that the chemical properties of these fruit are similar when compared to the temperate production zones. Compared with berries and cherries grown in temperate climates, the centesimal composition and physical chemical characteristics found in the Brazilian berries and cherries are in agreement with data from the literature. For the mineral composition, the analyzed fruits presented lower concentrations of P, K, Ca, Mg and Zn and higher levels of Fe. The values found for the bioactive compounds generally fit the ranges reported in the literature with minor differences. The greatest difference was found in relation to ascorbic acid, as all fruits analyzed showed levels well above those found in the literature.
Photodynamic therapy (PDT) combines a photosensitizer (PS) with the physical energy of non-ionizing light to trigger cell death pathways. PDT has potential as a therapeutic modality to be used in ...alternative or in combination with other conventional cancer treatment protocols (
e.g.
surgery, chemotherapy and radiotherapy). Still, due to the lack of specificity of the current PSs to target the tumor cells, several studies have exploited their conjugation with targeting moieties. PSs conjugated with antibodies (Abs) or their fragments, able to bind antigens overexpressed in the tumors, have demonstrated potential in PDT of tumors. This review provides an overview of the most recent advances on photoimmunoconjugates (PICs) for cancer PDT, which involve the first and second-generation PSs conjugated to Abs. This is an update of our previous review "Antibodies armed with photosensitizers: from chemical synthesis to photobiological applications", published in 2015 in
Org. Biomol. Chem.
The most recent advances in targeted PDT are revised, presenting novel photoimmunoconjugates and their biological results.
Resistance mechanisms and heterogeneity in HER2-positive gastric cancers (GC) limit Trastuzumab benefit in 32% of patients, and other targeted therapies have failed in clinical trials. Using patient ...samples, patient-derived xenografts (PDXs), partially humanized biological models, and HER2-targeted imaging technologies we demonstrate the role of caveolin-1 (CAV1) as a complementary biomarker in GC selection for Trastuzumab therapy. In retrospective analyses of samples from patients enrolled on Trastuzumab trials, the CAV1-high profile associates with low membrane HER2 density and low patient survival. We show a negative correlation between CAV1 tumoral protein levels - a major protein of cholesterol-rich membrane domains - and Trastuzumab-drug conjugate TDM1 tumor uptake. Finally, CAV1 depletion using knockdown or pharmacologic approaches (statins) increases antibody drug efficacy in tumors with incomplete HER2 membranous reactivity. In support of these findings, background statin use in patients associates with enhanced antibody efficacy. Together, this work provides preclinical justification and clinical evidence that require prospective investigation of antibody drugs combined with statins to delay drug resistance in tumors.
Statins are cholesterol-depleting drugs used to treat patients with hypercholesterolemia. Preclinically, statins disrupt trafficking of receptors present at the cell membrane. Membrane receptors, ...defined as tumor biomarkers and therapeutic targets, are often internalized by an endocytic pathway. Indeed, receptor endocytosis and recycling are dynamic mechanisms that often affect receptor density at the cell surface. In therapies using monoclonal antibodies (mAb), a downregulation in receptor density at the cell surface decreases antibody binding to the extracellular domain of the membrane receptor. Here, we determined the potential of lovastatin, simvastatin, and rosuvastatin in preclinically modulating epidermal growth factor receptor (EGFR) and prostate-specific membrane antigen (PSMA) receptor density at the tumor cell surface.
Small-animal PET was used to study the binding of
Zr-labeled antibodies in ectopic xenografts.
analyses were performed to determine changes in endocytic proteins, EGFR, and PSMA surface levels.
Acute statin treatment using lovastatin, simvastatin, or rosuvastatin enhanced tumors' avidity for the mAbs panitumumab, cetuximab, and huJ591. Statins temporarily modulated caveolin-1, cavin-1, endophilin, clathrin, and dynamin proteins in EGFR- and PSMA-overexpressing xenografts.
These data show the potential of statins as pharmacologic modulators of endocytic proteins for improved tumors' accumulation of mAbs. The translational significance of these findings lies in the potential of statins to temporarily modulate the heterogeneous presence of receptors at the cell membrane, a characteristic often associated with poor response in tumors to therapeutic antibodies.
Spheroids recapitulate the organization, heterogeneity and microenvironment of solid tumors. Herein, we targeted spatiotemporally the accelerated metabolism of proliferative cells located on the ...spheroid surface that ensure structure maintenance and/or growth. We demonstrate that phosphorylated carbohydrate amphiphile acts as a potent antimetabolite due to glycolysis inhibition and to
in situ
formation of supramolecular net around spheroid surface where alkaline phosphatase is overexpressed. The efficiency of the treatment is higher in spheroids as compared to the conventional 2D cultures because of the 2-fold higher expression of glucose transporter 1 (GLUT1). Moreover, treated spheroids do not undergo following relapse.
Phosphorylated carbohydrate amphiphile acts as a potent antimetabolite due to glycolysis inhibition and
in situ
formation of supramolecular net. Its efficiency is higher in spheroids as compared to the conventional 2D cultures.
Photosensitizers (PSs) are of crucial importance in the effectiveness of photodynamic therapy (PDT) for cancer. Due to their high reactive oxygen species production and strong absorption in the ...wavelength range between 650 and 850 nm, where tissue light penetration is rather high, phthalocyanines (Pcs) have been studied as PSs of excellence. In this work, we report the evaluation of a phthalocyanine surrounded by a carbohydrate shell of sixteen galactose units distributed in a dendritic manner (PcGal16) as a new and efficient third generation PSs for PDT against two bladder cancer cell lines, HT-1376 and UM-UC-3. Here, we define the role of galacto-dendritic units in promoting the uptake of a Pc through interaction with GLUT1 and galectin-1. The photoactivation of PcGal16 induces cell death by generating oxidative stress. Although PDT with PcGal16 induces an increase on the activity of antioxidant enzymes immediately after PDT, bladder cancer cells are unable to recover from the PDT-induced damage effects for at least 72 h after treatment. PcGal16 co-localization with galectin-1 and GLUT1 and/or generation of oxidative stress after PcGal16 photoactivation induces changes in the levels of these proteins. Knockdown of galectin-1 and GLUT1, via small interfering RNA (siRNA), in bladder cancer cells decreases intracellular uptake and phototoxicity of PcGal16. The results reported herein show PcGal16 as a promising therapeutic agent for the treatment of bladder cancer, which is the fifth most common type of cancer with the highest rate of recurrence of any cancer.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Legumes have the unique ability to host nitrogen-fixing Rhizobium bacteria as symbiosomes inside root nodule cells. To get insight into this key process, which forms the heart of the endosymbiosis, ...we isolated specific cells/tissues at different stages of symbiosome formation from nodules of the model legume Medicago truncatula using laser-capture microdissection. Next, we determined their associated expression profiles using Affymetrix Medicago GeneChips. Cells were collected from the nodule infection zone divided into a distal (where symbiosome formation and division occur) and proximal region (where symbiosomes are mainly differentiating), as well as infected cells from the fixation zone containing mature nitrogen fixing symbiosomes. As non-infected cells/tissue we included nodule meristem cells and uninfected cells from the fixation zone. Here, we present a comprehensive gene expression map of an indeterminate Medicago nodule and selected genes that show specific enriched expression in the different cells or tissues. Validation of the obtained expression profiles, by comparison to published gene expression profiles and experimental verification, indicates that the data can be used as digital "in situ". This digital "in situ" offers a genome-wide insight into genes specifically associated with subsequent stages of symbiosome and nodule cell development, and can serve to guide future functional studies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Here, we report the rational design of a new third-generation photosensitizer (PS), a chlorin conjugated with galactodendritic units, ChlGal8, to improve the effectiveness of bladder cancer ...treatment. ChlGal8 shows better photochemical and photophysical properties than a recently reported homologous porphyrin, PorGal8. In addition to inheriting excellent photostability, the ability to generate singlet oxygen, and the ability to interact with the proteins galectin-1 and human serum albumin (HSA), ChlGal8 exhibits high absorption in the red region of the electromagnetic spectrum. In vitro studies of anticancer activity of ChlGal8 revealed that once this PS is taken up by UM-UC-3 bladder cancer cells, it induces high cytotoxicity after a single dose of light irradiation. In HT-1376 bladder cancer cells resistant to therapy, a second light irradiation treatment enhanced in vitro and in vivo photodynamic efficacy. The enhanced phototoxicity in HT-1376 cancer cells seems to be due to the ability of ChlGal8 to accumulate in the mitochondria, via facilitative glucose transporter 1 (GLUT1), in the period between single and repeated irradiation. A photodynamic therapy (PDT) regimen using an extra dose of light irradiation and ChlGal8 as PS represents a promising strategy in treating resistant cancers in a clinical setting.
PDF
