A cost-effective tool to standardize the scratch assay for cell migration.

BACKGROUND: The scratch assay is commonly used in cell biology to evaluate cell migration; however, it is not a standardized method; it produces highly variable gap dimensions. We design a printable device, comprising a single wounding tool and a guide, and compared the gap produced by our device and the traditional method. The deviceis printable in a standard 3D printer. Cells were seeded on a 24-well plate. After reaching full confluency, a gap was created using the traditional method (scratch assay with a pipette tip), a pipette tip and the guide of the device, or the single wounding tool and the guide. The gaps were observed for up to 48 h under a light microscope and analyzed. RESULTS: The results show that the traditional method produces irregular and not straight gaps, and had the worst cell migration rates compared to the other groups. The wounding tool produced scrape signs at the well surface. CONCLUSION: The guide and pipette tip delivered the best results for the scratch assay. SIGNIFICANCE: The use of the guide and the pipette tip for the scratch assay allows allows to perform reproducible cell migration experiments.

Physiological responses of Holothuria grisea during a wound healing event: An integrated approach combining tissue, cellular and humoral evidence.

Due to their tissue structure similar to mammalian skin and their close evolutionary relationship with chordates, holothurians (Echinodermata: Holothuroidea) are particularly interesting for studies on wound healing. However, previous studies dealing with holothuroid wound healing have had limited approaches, being restricted to tissue repair or perivisceral immune response. In this study, we combined tissue, cellular and humoral parameters to study the wound healing process of Holothuria grisea. The immune responses of the perivisceral coelom were assessed by analyzing the number, proportion and viability of coelomocytes and the volume and protein concentration of the coelomic fluid. Additionally, the morphology of the healing tissue and number of coelomocytes in the connective tissue of different body wall layers were examined over 30 days. Our results showed that perivisceral reactions started 3 h after injury and decreased to baseline levels within 24 h. In contrast, tissue responses were delayed, beginning after 12 h and returning to baseline levels only after day 10. The number of coelomocytes in the connective tissue suggests a potential cooperation between these cells during wound healing: phagocytes and acidophilic spherulocytes act together in tissue clearance/homeostasis, whereas fibroblast-like and morula cells cooperate in tissue remodeling. Finally, our results indicate that the major phases observed in mammalian wound healing are also observed in H. grisea, despite occurring at a different timing, which might provide insights for future studies. Based on these data, we propose a model that explains the entire healing process in H. grisea.

Spheroid Model of Mammary Tumor Cells: Epithelial-Mesenchymal Transition and Doxorubicin Response.

Breast cancer is the most prevalent cancer among women worldwide. Therapeutic strategies to control tumors and metastasis are still challenging. Three-dimensional (3D) spheroid-type systems more accurately replicate the features of tumors in vivo, working as a better platform for performing therapeutic response analysis. This work aimed to characterize the epithelial-mesenchymal transition and doxorubicin (dox) response in a mammary tumor spheroid (MTS) model. We evaluated the doxorubicin treatment effect on MCF-7 spheroid diameter, cell viability, death, migration and proteins involved in the epithelial-mesenchymal transition (EMT) process. Spheroids were also produced from tumors formed from 4T1 and 67NR cell lines. MTSs mimicked avascular tumor characteristics, exhibited adherens junction proteins and independently produced their own extracellular matrix. Our spheroid model supports the 3D culturing of cells isolated from mice mammary tumors. Through the migration assay, we verified a reduction in E-cadherin expression and an increase in vimentin expression as the cells became more distant from spheroids. Dox promoted cytotoxicity in MTSs and inhibited cell migration and the EMT process. These results suggest, for the first time, that this model reproduces aspects of the EMT process and describes the potential of dox in inhibiting the metastatic process, which can be further explored.

Tumor-derived hypoxic small extracellular vesicles promote endothelial cell migration and tube formation via ALS2/Rab5/ß-catenin signaling.

Tumor hypoxia has been associated with cancer progression, angiogenesis, and metastasis via modifications in the release and cargo composition of extracellular vesicles secreted by tumor cells. Indeed, hypoxic extracellular vesicles are known to trigger a variety of angiogenic responses via different mechanisms. We recently showed that hypoxia promotes endosomal signaling in tumor cells via HIF-1α-dependent induction of the guanine exchange factor ALS2, which activates Rab5, leading to downstream events involved in cell migration and invasion. Since Rab5-dependent signaling is required for endothelial cell migration and angiogenesis, we explored the possibility that hypoxia promotes the release of small extracellular vesicles containing ALS2, which in turn activate Rab5 in recipient endothelial cells leading to pro-angiogenic properties. In doing so, we found that hypoxia promoted ALS2 expression and incorporation as cargo within small extracellular vesicles, leading to subsequent transfer to recipient endothelial cells and promoting cell migration, tube formation, and downstream Rab5 activation. Consequently, ALS2-containing small extracellular vesicles increased early endosome size and number in recipient endothelial cells, which was followed by subsequent sequestration of components of the ß-catenin destruction complex within endosomal compartments, leading to stabilization and nuclear localization of ß-catenin. These events converged in the expression of ß-catenin target genes involved in angiogenesis. Knockdown of ALS2 in donor tumor cells precluded its incorporation into small extracellular vesicles, preventing Rab5-downstream events and endothelial cell responses, which depended on Rab5 activity and guanine exchange factor activity of ALS2. These findings indicate that vesicular ALS2, secreted in hypoxia, promotes endothelial cell events leading to angiogenesis. Finally, these events might explain how tumor angiogenesis proceeds in hypoxic conditions.

Bayesian inverse problem for a fractional diffusion model of cell migration.

In the present work, both direct and inverse problems are considered for a Fisher-type fractional diffusion equation, which is proposed to describe the phenomenon of cell migration. For the direct problem, a solution is given via the Fourier method and the Laplace transform. On the other hand, we solved the inverse problem from a Bayesian statistical framework using a set of data that are the result of a cell migration experiment on a wound closure assay. We estimated the parameters of the mathematical model via Markov Chain Monte Carlo methods.

Elevated glycolytic metabolism of monocytes limits the generation of HIF1A-driven migratory dendritic cells in tuberculosis.

During tuberculosis (TB), migration of dendritic cells (DCs) from the site of infection to the draining lymph nodes is known to be impaired, hindering the rapid development of protective T-cell-mediated immunity. However, the mechanisms involved in the delayed migration of DCs during TB are still poorly defined. Here, we found that infection of DCs with Mycobacterium tuberculosis (Mtb) triggers HIF1A-mediated aerobic glycolysis in a TLR2-dependent manner, and that this metabolic profile is essential for DC migration. In particular, the lactate dehydrogenase inhibitor oxamate and the HIF1A inhibitor PX-478 abrogated Mtb-induced DC migration in vitro to the lymphoid tissue-specific chemokine CCL21, and in vivo to lymph nodes in mice. Strikingly, we found that although monocytes from TB patients are inherently biased toward glycolysis metabolism, they differentiate into poorly glycolytic and poorly migratory DCs compared with healthy subjects. Taken together, these data suggest that because of their preexisting glycolytic state, circulating monocytes from TB patients are refractory to differentiation into migratory DCs, which may explain the delayed migration of these cells during the disease and opens avenues for host-directed therapies for TB.

Betaglycan sustains HGF/Met signaling in lung cancer and endothelial cells promoting cell migration and tumor growth.

Persistent HGF/Met signaling drives tumor growth and dissemination. Proteoglycans within the tumor microenvironment might control HGF availability and signaling by affecting its accessibility to Met (HGF receptor), likely defining whether acute or sustained HGF/Met signaling cues take place. Given that betaglycan (BG, also known as type III TGFß receptor or TGFBR3), a multi-faceted proteoglycan TGFß co-receptor, can be found within the tumor microenvironment, we addressed its hypothetical role in oncogenic HGF signaling. We found that HGF/Met promotes lung cancer and endothelial cells migration via PI3K and mTOR. This effect was enhanced by recombinant soluble betaglycan (solBG) via a mechanism attributable to its glycosaminoglycan chains, as a mutant without them did not modulate HGF effects. Moreover, soluble betaglycan extended the effect of HGF-induced phosphorylation of Met, Akt, and Erk, and membrane recruitment of the RhoGEF P-Rex1. Data-mining analysis of lung cancer patient datasets revealed a significant correlation between high MET receptor, HGF, and PREX1 expression and reduced patient survival. Soluble betaglycan showed biochemical interaction with HGF and, together, they increased tumor growth in immunocompetent mice. In conclusion, the oncogenic properties of the HGF/Met pathway are enhanced and sustained by GAG-containing soluble betaglycan.

Lack of mTORC2 signaling in CD11c+ myeloid cells inhibits their migration and ameliorates experimental colitis.

The mammalian target of rapamycin (mTOR) pathway plays a key role in determining immune cells function through modulation of their metabolic status. By specific deletion of Rictor in CD11c+ myeloid cells (referred to here as CD11cRicΔ/Δ), we investigated the role of mTOR complex 2 (mTORC2) signaling in dendritic cells (DCs) function in mice. We showed that upon dextran sulfate sodium-induced colitis, the lack of mTORC2 signaling CD11c+ cells diminishes the colitis score and abrogates DC migration to the mesenteric lymph nodes, thereby diminishing the infiltration of T helper 17 cells in the lamina propria and subsequent inflammation. These findings corroborate with the abrogation of cytoskeleton organization and the decreased activation of Rac1 and Cdc42 GTPases observed in CD11c+-mTORC2-deficient cells. Meta-analysis on colonic samples from ulcerative colitis patients revealed increased gene expression of proinflammatory cytokines, which coincided with augmented expression of the mTOR pathway, a positive correlation between the DC marker ITGAX and interleukin-6, the expression of RICTOR, and CDC42. Together, this work proposes that targeting mTORC2 on DCs offers a key to hamper inflammatory responses, and this way, ameliorates the progression and severity of intestinal inflammatory diseases.

Blockage of αvß3 integrin in 3D culture of triple-negative breast cancer and endothelial cells inhibits migration and discourages endothelial-to-mesenchymal plasticity.

Breast cancer is a relevant cause of mortality in women and its triple-negative subtype (TNBC) is usually associated with poor prognosis. During tumor progression to metastasis, angiogenesis is triggered by the sprouting of endothelial cells from pre-existing vessels by a dynamic chain of events including VE-cadherin downregulation, actin protrusion, and integrin-mediated adhesion, allowing for migration and proliferation. The binding of tumoral and tumor-associated stromal cells with the extracellular matrix through integrins mediates angiogenic processes and certain integrin subtypes, such as the αvß3 integrin, are upregulated in hypoxic TNBC models. Integrin αvß3 inhibition by the high-affinity binding disintegrin DisBa-01 was previously demonstrated to induce anti-tumoral and anti-angiogenic responses in traditional 2D cell assays. Here, we investigate the effects of integrin αvß3 blockage in endothelial and TNBC cells by DisBa-01 in 3D cultures under two oxygen conditions (1% and 20%). 3D cultures created using non-adhesive micromolds with Matrigel were submitted to migration assay in Boyden chambers and fluorescence analysis. DisBa-01 inhibited cell migration in normoxia and hypoxia in both MDA-MB-231 and HUVEC spheroids. Protein levels of integrin αvß3 were overexpressed in HUVEC spheroids compared to MDA-MB-231 spheroids. In HUVEC 3D cultures, sprouting assays in collagen type I were decreased in normoxia upon DisBa-01 treatment, and VE-cadherin levels were diminished in HUVEC spheroids in hypoxia and upon DisBa-01 treatment. In conclusion, the blockage of integrin αvß3 by DisBa-01 inhibits cell migration in 3D culture and interferes with tumor-derived responses in different oxygen settings, implicating its crucial role in angiogenesis and tumor progression.

Development of a Resveratrol Nanoformulation for the Treatment of Diabetic Retinopathy.

Diabetic retinopathy (RD) is a microvascular disease that can cause the formation of fragile neovessels, increasing the risk of hemorrhages and leading to vision loss. Current therapies are based on the intravitreal injection of anti-VEGF (vascular endothelial growth factor), which is invasive and can cause secondary effects. The development of new treatments that complement the current therapies is necessary to improve the patient's outcomes. Nanostructured formulations offer several advantages regarding drug delivery and penetration. In this research, a resveratrol nanosuspension (RSV-NS) was prepared and characterized using dynamic light scattering, field emission scanning electron microscopy, and infrared spectroscopy. The RSV-NS had an average particle size of 304.0 ± 81.21 nm with a PDI of 0.225 ± 0.036, and a spherical-like morphology and uniform particle distribution. Cell viability, proliferation, and migration were tested on endothelial cells (HMRECs). RSV-NS in a concentration of less than 18.75 µM did not have a cytotoxic effect on HMRECs. Likewise, proliferation and migration were significantly reduced compared to the unstimulated control at 37.5 µM. The RSV-NS did not present cytotoxic effects but decreased cell proliferation and migration, indicating that it could provide an important contribution to future medical implementations and could have a high potential to treat this disease.

Laherradurin Inhibits Tumor Growth in an Azoxymethane/Dextran Sulfate Sodium Colorectal Cancer Model In Vivo.

Colorectal cancer (CRC) is the third most common neoplasia in the world. Its mortality rate is high due to the lack of specific and effective treatments, metastasis, and resistance to chemotherapy, among other factors. The natural products in cancer are a primary source of bioactive molecules. In this research, we evaluated the antitumor activity of an acetogenin (ACG), laherradurin (LH), isolated from the Mexican medicinal plant Annona macroprophyllata Donn.Sm. in a CRC murine model. The CRC was induced by azoxymethane-dextran sulfate sodium (AOM/DSS) in Balb/c mice and treated for 21 days with LH or cisplatin. This study shows for the first time the antitumor activity of LH in an AOM/DSS CRC model. The acetogenin diminished the number and size of tumors compared with cisplatin; the histologic studies revealed a recovery of the colon tissue, and the blood toxicity data pointed to less damage in animals treated with LH. The TUNEL assay indicated cell death by apoptosis, and the in vitro studies exhibited that LH inhibited cell migration in HCT116 cells. Our study provides strong evidence of a possible anticancer agent for CRC.

Antiproliferative and Antimigratory Activity of Poly-gallic Acid in Cancer Cell Lines.

BACKGROUND/AIM: Enzyme-mediated grafting of poly (gallic acid) (PGAL) and L-arginine and a-L-lysine onto PGAL produces reactive oxygen species (ROS)-suppressor multiradical molecules with low cytotoxicity, high thermostability and water solubility with cancer treatment potential. This study examined the anticancer effects of these molecules in hepatic (HepG2, ATCC HB-8065), breast (MCF7, ATCC HTB-22), and prostate (PC-3, ATCC CRL-1435 and DU 145, ATCC HTB-81) cancer cell lines, as well as in fibroblasts from healthy human skin as control cells. MATERIALS AND METHODS: PGAL was synthesized by the oxidative polymerization of the naturally abundant GA using laccase from Trametes versicolor. Insertions of amino acids L-arginine and α-L-lysine on the PGAL chain were carried out by microwave. The cells of dermal fibroblast (Fb) were obtained from primary skin cultures and isolated from skin biopsies. The cancer cells lines of hepatic (HepG2), breast (MCF7), and prostate (PC-3, DU 145) were obtained from ATCC. The viability of the cancer cells and the primary culture was obtained by the MTT assay. Proliferation was demonstrated by crystal violet assay. Cell migration was determined by Wound healing assay. Finally, cell cycle analysis was carried out with cells. RESULTS: The results show that 200 µg/ml of PGAL cultured in vitro with prostate cancer cells decreased viability, proliferation, and migration, as well as arrested cells in the G1 and S phases of the cell cycle. In contrast, the dermal fibroblasts and the hepatic line remained unaffected. The random grafting of L-Arg and a-L-Lys onto the PGAL chain also decreased the viability of prostate cancer cells. CONCLUSION: PGAL and PGAL-grafted amino acids are potential adjuvants for prostate cancer treatment, with improved physicochemical characteristics compared to GA.

Soluble guanylyl cyclase beta1 subunit targets epithelial-to-mesenchymal transition and downregulates Akt pathway in human endometrial and cervical cancer cells.

Endometrial and cervical cancer are among the most frequently diagnosed malignancies globally. Nitric oxide receptor-soluble guanylyl cyclase (sGC) is a heterodimeric enzyme composed of two subunits, α1 and ß1. Previously we showed that sGCα1 subunit promotes cell survival, proliferation, and migration, but the role of sGCß1 subunit has not been addressed. The aim of the present work was to study the impact of sGCß1 restoration in proliferation, survival, migration, and cell signaling in endometrial and cervical cancer cells. We found that sGCß1 transcript levels are reduced in endometrial and cervical tumors vs normal tissues. We confirmed nuclear enrichment of sGCß1, unlike sGCα1. Overexpression of sGCß1 reduced cell viability and augmented apoptotic index. Cell migration and invasion were also negatively affected. All these sGCß1-driven effects were independent of sGC enzymatic activity. sGCß1 reduced the expression of epithelial-to-mesenchymal transition factors such as N-cadherin and ß-catenin and increased the expression of E-cadherin. sGCß1 impacted signaling in endometrial and cervical cancer cells through significant downregulation of Akt pathway affecting some of its main targets such as GSK-3ß and c-Raf. Our results show for the first time that sGCß1 exerts several antiproliferative actions in ECC-1 and HeLa cell lines by targeting key regulatory pathways.

Caveolae-mediated endocytosis of extracellular QSOX1b modulates the migration of fibroblasts.

Quiescin/sulfhydryl oxidase (QSOX1) is a secreted flavoprotein that modulates cellular proliferation, migration and adhesion, roles attributed to its ability to organize the extracellular matrix. We previously showed that exogenously added QSOX1b induces smooth muscle cells migration in a process that depends on its enzymatic activity and that is mediated by hydrogen peroxide derived from Nox1, a catalytic subunit of NAD(P)H oxidases. Here, we report that exogenous QSOX1b also stimulates the migration of L929 fibroblasts and that this effect is regulated by its endocytosis. The use of endocytosis inhibitors and caveolin 1-knockdown demonstrated that this endocytic pathway is caveola-mediated. QSOX1b colocalized with Nox1 in intracellular vesicles, as detected by confocal fluorescence, suggesting that extracellular QSOX1b is endocytosed with the transmembrane Nox1. These results reveal that endosomal QSOX1b is a novel intracellular redox regulator of cell migration.

Thymus-Brain Connections in T-Cell Acute Lymphoblastic Leukemia.

BACKGROUND: T-cell acute lymphoblastic leukemia (T-ALL) is a malignant hematologic disease caused by the transformation and uncontrolled proliferation of T-cell precursors. T-ALL is generally thought to originate in the thymus since lymphoblasts express phenotypic markers comparable to those described in thymocytes in distinct stages of development. Although around 50% of T-ALL patients present a thymic mass, T-ALL is characterized by peripheral blood and bone marrow involvement, and central nervous system (CNS) infiltration is one of the most severe complications of the disease. SUMMARY: The CNS invasion is related to the expression of specific adhesion molecules and receptors commonly expressed in developing T cells, such as L-selectin, CD44, integrins, and chemokine receptors. Furthermore, T-ALL blasts also express neurotransmitters, neuropeptides, and cognate receptors that are usually present in the CNS and can affect both the brain and thymus, participating in the crosstalk between the organs. KEY MESSAGES: This review discusses how the thymus-brain connections, mediated by innervation and common molecules and receptors, can impact the development and migration of T-ALL blasts, including CNS infiltration.

Synthesis of the scFv fragment of anti-Frizzled-7 antibody and evaluation of its effects on triple-negative breast cancer in vitro study.

OBJECTIVES: Among the most promising antibody formats in terms of inhibiting carcinogenesis are single-stranded variable fragments, whose targeted binding to the Fzd7 receptor has been proven effective at suppressing tumorigenesis. In this study, we investigated the effectiveness of an anti-Fzd7 antibody fragment against both tumor growth and metastasis of breast cancer cells. METHODS: To develop anti-Fzd7 antibodies, bioinformatics approaches were used and the antibodies were expressed recombinantly in E. coli BL21 (DE3). The expression of anti-Fzd7 fragments was verified by Western blotting. Analysis of the antibody's binding capacity to Fzd7 was conducted by flow cytometry. Cell death and apoptosis were assessed by MTT and Annexin V/PI assays. The transwell migration and invasion assays, as well as the scratch method, were used to evaluate cell motility and invasiveness. RESULTS: The anti-Fzd7 antibody was expressed successfully as a single band of 31 kDa. It could bind to 21.5% of MDA-MB-231 cells, as opposed to only 0.54% of SKBR-3 cells as negative control. According to MTT assay, induced apoptosis was 73.7% in MDA-MB-231 cells, compared with 29.5% in SKBR-3 cells. Also, the antibody exerted a significant inhibitory effect of 76% and 58% on migration and invasion of MDA-MB-231 cells, respectively. CONCLUSION: The recombinantly developed anti-Fzd7 scFv of this study could exhibit significant antiproliferative and antimigratory properties, along with a high apoptosis-inducing potential, making it suitable for the immunotherapy of triple negative breast cancer.

Astaxanthin induces autophagy and apoptosis in murine melanoma B16F10-Nex2 cells and exhibits antitumor activity in vivo.

Countless efforts have been made to prevent and suppress the formation and spread of melanoma. Natural astaxanthin (AST; extracted from the alga Haematococcus pluvialis) showed an antitumor effect on various cancer cell lines due to its interaction with the cell membrane. This study aimed to characterize the antitumor effect of AST against B16F10-Nex2 murine melanoma cells using cell viability assay and evaluate its mechanism of action using electron microscopy, western blotting analysis, terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) assay, and mitochondrial membrane potential determination. Astaxanthin exhibited a significant cytotoxic effect in murine melanoma cells with features of apoptosis and autophagy. Astaxanthin also decreased cell migration and invasion in vitro assays at subtoxic concentrations. In addition, assays were conducted in metastatic cancer models in mice where AST significantly decreased the development of pulmonary nodules. In conclusion, AST has cytotoxic effect in melanoma cells and inhibits cell migration and invasion, indicating a promising use in cancer treatment.

Nordihydroguaiaretic Acid Affects Undifferentiated and Differentiated Neuroblastoma Cells Differently through Mechanisms that Impact on Cell Viability.

AIM: We aimed to investigate the mechanisms involved in the neurotoxic effects of NDGA on differentiated and undifferentiated human neuroblastoma cells (MSN), assessing cell viability, changes in the actin cytoskeleton, cell migration and the expression of the 5-LOX enzyme and the inhibitor of cell cycle progression p21WAF1/CIP1. BACKGROUND: High expression and activity of the lipoxygenase enzyme (LOX) have been detected in several tumors, including neuroblastoma samples, suggesting the use of LOX inhibitors as potential therapy molecules. Among these, the natural compound nordihydroguaiaretic acid (NDGA) has been extensively tested as an antiproliferative drug against diverse types of cancer cells. OBJECTIVE: In this study, we analyzed the toxic effect of NDGA on neuroblastoma cells at a dose that did not affect cell survival when they differentiated to a neuron-like phenotype and the potential mechanisms involved in the anticancer properties. METHODS: We exposed human neuroblastoma cells (MSN) to different concentrations of NDGA before and after a differentiation protocol with retinoic acid and nerve growth factor and analyzed cell viability, cell migration, actin cytoskeleton morphology and the levels of the cell cycle inhibitor p21WAF1/CIP1 and 5-LOX. RESULTS: We found that differentiated human neuroblastoma cells are more resistant to NDGA than undifferentiated cells. The toxic effects of NDGA were accompanied by reduced cell migration, changes in actin cytoskeleton morphology, induction of p21WAF1/CIP1 and decreased levels of the 5-LOX enzyme. CONCLUSION: This study provides new evidence regarding the potential use of NDGA to induce cell death in human neuroblastoma.

8-Methoxy-α-lapachone and lawsone: antiproliferative effects on bladder tumour cells.

Quinones are chemical compounds produced from the oxidation of phenols. Among the quinones, naphthoquinones stand out as potential antitumor agents. Bladder tumour is the tenth most diagnosed in the world. Based on this, using a urothelial carcinoma cell line (T24), two naphthoquinones had their cytotoxicity tested by the MTT colorimetric method and were submitted to assays of clonogenic survival, morphology, cell cycle, cell migration and species reactive oxygen. The results showed 8-methoxy-α-lapachone and lausone presented selectivity indexes (19.5 and 28.0, respectively) for T24 cells. Moreover, the two naphthoquinones reduced the cell viability, interfered with the process of cell migration, changed the cell cycle kinectics and induced the production of species reactive oxygen (ROS). Additionaly, 8-methoxy-α-lapachone altered the morphology of the cells. In conclusion, the studied naphthoquinones showed potential antiproliferative effects in bladder cancer cells, interfering in cellular processes, possibly through oxidative stress.

Tarin-Loaded Nanoliposomes Activate Apoptosis and Autophagy and Inhibit the Migration of Human Mammary Adenocarcinoma Cells.

Background: Tarin, a lectin purified from Colocasia esculenta, promotes in vitro and in vivo immunomodulatory effects allied to promising anticancer and antimetastatic effects against human adenocarcinoma mammary cells. This makes this 47 kDa-protein a natural candidate against human breast cancer, a leading cause of death among women. Tarin encapsulated in pegylated nanoliposomes displays increased effectiveness in controlling the proliferation of a mammary adenocarcinoma lineage comprising MDA-MB-231 cells. Methods: The mechanisms enrolled in anticancer and antimetastatic responses were investigated by treating MDA-MB-231 cells with nano-encapsulated tarin at 72 µg/mL for up to 48h through flow cytometry and transmission electron microscopy (TEM). The safety of nano-encapsulated tarin towards healthy tissue was also assessed by the resazurin viability assay, and the effect of nanoencapsulated tarin on cell migration was evaluated by scratch assays. Results: Ultrastructural analyses of MDA-MB-231 cells exposed to nanoencapsulated tarin revealed the accumulation of autophagosomes and damaged organelles, compatible with autophagy-dependent cell death. On the other hand, the flow cytometry investigation detected the increased occurrence of acidic vacuolar organelles, a late autophagosome trait, along with the enhanced presence of apoptotic cells, activated caspase-3/7, and cell cycle arrest at G0/G1. No deleterious effects were observed in healthy fibroblast cells following tarin nanoencapsulated exposition, in contrast to reduced viability in cells exposed to free tarin. The migration of MDA-MB-231 cells was inhibited by nano-encapsulated tarin, with delayed movement by 24 h compared to free tarin. Conclusion: The nanoliposome formulation delivers tarin in a delayed and sustained manner, as evidenced by the belated and potent antitumoral and anti-migration effects on adenocarcinoma cells, with no toxicity to healthy cells. Although further investigations are required to fully understand antitumorigenic tarin mechanisms, the activation of both apoptotic and autophagic machineries along with the caspase-3/7 pathway, and cell cycle arrest may comprise a part of these mechanisms.