Nanospermidine in Combination with Nanofenretinide Induces Cell Death in Neuroblastoma Cell Lines

Antiproliferative and Morphological Effects of Fenretinide Lipid Nanosystems in Colon Adenocarcinoma Cells

Objective: Colon adenocarcinoma is characterized by the downregulation of the retinoic acid receptor, making natural retinoids such as all-trans retinoic acid, 9-cis retinoic acid and 13-cis retinoic acid effective in treatment and chemoprevention due to their ability to increase RARβ expression. However, major limitations to their use include tolerability and acquired resistance. In this study, we evaluated fenretinide, a semisynthetic derivative of all-trans retinoic acid, in an HT-29 cell line. Fenretinide was evaluated both as a free drug and encapsulated in self-assembling phosphatidylcholine nanosystems with the aim of increasing the aqueous solubility and cell availability of the drug. Methods: Fenretinide was encapsulated in lipid nanosystems obtained in water by the dispersion of an amphiphilic mixture of phospholipids, glyceryl tributyrate and polysorbate 80. The physico-chemical characterization of the nanosystems was carried out by dynamic light scattering and spectrophotometry. The biological activity was evaluated by quantitative phase imaging microscopy, MTT assay, flow cytometry and confocal laser-scanning fluorescence microscopy. Results: Fenretinide in phosphatidylcholine nanosystems was more active than free fenretinide in inhibiting HT-29 cells' proliferation, as indicated by quantitative phase imaging data. Indeed, encapsulated fenretinide increased duplication time, decreased dry mass and decreased the rate of cell growth more efficiently than fenretinide. Moreover, encapsulated fenretinide effectively decreased the motility of the cells that survived the treatment. Conclusions: The results indicate that the proposed nanosystems can be considered a valuable alternative to natural retinoids in the chemoprevention and treatment of colorectal cancer. This is due to the favorable pharmacologic characteristics of fenretinide in colorectal cancer and the improved drug activity provided by nanoencapsulation.

Involvement of mammalian SoLute Carriers (SLC) in the traffic of polyamines

Polyamines interact with different molecular targets to regulate a vast range of cellular processes. A network of enzymes and transport systems is crucial for the maintenance of polyamine homeostasis. Indeed, polyamines after synthesis must be distributed to the various tissues and some intracellular organelles. Differently from the well characterized enzymes devoted to polyamine synthesis, the transport systems are not unequivocally identified or characterized. Besides some ATPases which have been identified as polyamine transporters, much less is known about solute carriers (SLC) involved in the transport of these compounds. Only two SLCs have been unequivocally identified as polyamine transporters: SLC18B1 (VPAT) and SLC22A4 (OCTN1). Transport studies have been performed with cells transfected with the cDNAs encoding the two and other SLCs or, in the case of OCTN1, also by in vitro assay using proteoliposomes harboring the recombinant human protein. According to the role proposed for OCTN1, polyamines have been associated with prolonged and quality of life. This review provides an update on the most recent findings concerning the polyamine transporters or the prediction of the putative ones.

Neuroblastoma-A Review of Combination Immunotherapy

Neuroblastoma is the most common extracranial solid tumor found in childhood and is responsible for 15% of deaths among children with cancer. Although multimodal therapies focused on surgery, chemotherapy, radiotherapy, and stem cell transplants have favorable results in many cases, the use of conventional therapies has probably reached the limit their possibility. Almost half of the patients with neuroblastoma belong to the high-risk group. Patients in this group require a combination of several therapeutic approaches. It has been shown that various immunotherapies combined with conventional methods can work synergistically. Due to the development of such therapeutic methods, we present combinations and forms of combining immunotherapy, focusing on their mechanisms and benefits but also their limitations and potential side effects.

Nano-fenretinide demonstrates remarkable activity in acute promyeloid leukemia cells

Acute promyelocytic leukemia (APL) is characterized by rearrangements of the retinoic acid receptor, RARα, which makes all-trans retinoic acid (ATRA) highly effective in the treatment of this disease, inducing promyelocytes differentiation. Current therapy, based on ATRA in combination with arsenic trioxide, with or without chemotherapy, provides high rates of event-free survival and overall survival. However, a decline in the drug activity, due to increased ATRA metabolism and RARα mutations, is often observed over long-term treatments. Furthermore, dedifferentiation can occur providing relapse of the disease. In this study we evaluated fenretinide, a semisynthetic ATRA derivative, encapsulated in nanomicelles (nano-fenretinide) as an alternative treatment to ATRA in APL. Nano-fenretinide was prepared by fenretinide encapsulation in a self-assembling phospholipid mixture. Physico-chemical characterization was carried out by dinamic light scattering and spectrophotometry. The biological activity was evaluated by MTT assay, flow cytometry and confocal laser-scanning fluorescence microscopy. Nano-fenretinide induced apoptosis in acute promyelocytic leukemia cells (HL60) by an early increase of reactive oxygen species and a mitochondrial potential decrease. The fenretinide concentration that induced 90-100% decrease in cell viability was about 2.0 µM at 24 h, a concentration easily achievable in vivo when nano-fenretinide is administered by oral or intravenous route, as demonstrated in previous studies. Nano-fenretinide was effective, albeit at slightly higher concentrations, also in doxorubicin-resistant HL60 cells, while a comparison with TK6 lymphoblasts indicated a lack of toxicity on normal cells. The results indicate that nano-fenretinide can be considered an alternative therapy to ATRA in acute promyelocytic leukemia when decreased efficacy, resistance or recurrence of disease emerge after protracted treatments with ATRA.

Pholiotic acid promotes apoptosis in human metastatic melanoma cells

Mushrooms produce a great variety of secondary metabolites that can be successful in both prevention and treatment of various cancers. In particular, higher Basidiomycete mushrooms contain various types of biologically active low-molecular compounds in fruiting bodies with suggested anticarcinogenic effects. The polyamine analogue {(2R)-2-[(S)-3-hydroxy-3-methylglutaryloxy] putrescine dicinnamamide} indicated with the name pholiotic acid, isolated for the first time by us from the fruiting bodies of the Basidiomycete Pholiota spumosa (Fr.) Sing. (Strophariaceae), inhibited the viability of human prostate cancer cells, such as other polyamine synthetic analogues that have shown antitumor activity in several types of cancer, including melanoma. Melanoma is an aggressive skin cancer that can metastasize to other organs and presents a high resistance to conventional therapies. In light of these considerations, the present study was therefore designed to assess whether this putrescine derivative could inhibit the growth of human metastatic melanoma cell lines, M14 and A2058. The results obtained demonstrate that this natural compound, at 12.5-50 μM concentration, was able to reduce cell viability of both cancer cells inducing cell death by intrinsic apoptotic pathway that probably involves PTEN activity, inhibition of Hsp70 expression and reactive oxygen species production. On the other hand, the increased expression of enzymes involved in polyamine catabolism trigger apoptotic cell death leading to polyamine depletion and generation of reactive oxygen species as by-products. In conclusion, these findings, starting point for further investigation, implement available our data to support pholiotic acid as an attractive potential chemopreventive agent, and provide a basis for further research into the use of this polyamine derivative as potential anticancer agent for melanoma in combination with existing therapies to improve treatment efficacy and overcome the obstacle of drug resistance.

Polyamines: their significance for maintaining health and contributing to diseases

Polyamines are essential for the growth and proliferation of mammalian cells and are intimately involved in biological mechanisms such as DNA replication, RNA transcription, protein synthesis, and post-translational modification. These mechanisms regulate cellular proliferation, differentiation, programmed cell death, and the formation of tumors. Several studies have confirmed the positive effect of polyamines on the maintenance of health, while others have demonstrated that their activity may promote the occurrence and progression of diseases. This review examines a variety of topics, such as polyamine source and metabolism, including metabolism, transport, and the potential impact of polyamines on health and disease. In addition, a brief summary of the effects of oncogenes and signaling pathways on tumor polyamine metabolism is provided. Video Abstract.

Application of Nanomedicine in Immunotherapy: Recent Advances and Prospects

Nanomedicine is a special medical field focused on the application of nanotechnology to provide innovations for healthcare in different areas, including the treatment of a wide variety of diseases, including cancer [...].

Naxitamab Activity in Neuroblastoma Cells Is Enhanced by Nanofenretinide and Nanospermidine

Neuroblastoma cells highly express the disialoganglioside GD2, a tumor-associated carbohydrate antigen, which is also expressed in neurons, skin melanocytes, and peripheral nerve fibers. Immunotherapy with monoclonal anti-GD2 antibodies has a proven efficacy in clinical trials and is included in the standard treatment for children with high-risk neuroblastoma. However, the strong neuro-toxicity associated with anti-GD2 antibodies administration has hindered, until now, the possibility for dose-escalation and protracted use, thus restraining their therapeutic potential. Strategies to increase the efficacy of anti-GD2 antibodies are actively sought, with the aim to enable chronic treatments that could eradicate minimal residual disease and subsequent relapses, often occurring after treatment. Here, we report that Nanofenretinide and Nanospermidine improved the expression of GD2 in neuroblastoma cells (CHP-134) and provided different effects in combination with the anti-GD2 antibody naxitamab. In particular, Nanofenretinide significantly increased the cytotoxic effect of naxitamab while Nanospermidine inhibited cell motility at extents proportional to naxitamab concentration. In neuroblastoma cells characterized by a low and heterogeneous basal expression of GD2, such as SH-SY5Y, which may represent the cell heterogeneity in tumors after chemotherapy, both Nanofenretinide and Nanospermidine increased GD2 expression in approximately 50% of cells, thus shifting the tumor population towards improved sensitivity to anti-GD2 antibodies.

Spermine oxidase induces DNA damage and sensitizes fusion negative rhabdomyosarcoma cells to irradiation

Rhabdomyosarcoma (RMS) is a pediatric myogenic soft tissue sarcoma that includes fusion-positive (FP) and fusion-negative (FN) molecular subtypes. FP-RMS expresses PAX3-FOXO1 fusion protein and often shows dismal prognosis. FN-RMS shows cytogenetic abnormalities and frequently harbors RAS pathway mutations. Despite the multimodal heavy chemo and radiation therapeutic regimens, high risk metastatic/recurrent FN-RMS shows a 5-year survival less than 30% due to poor sensitivity to chemo-radiotherapy. Therefore, the identification of novel targets is needed. Polyamines (PAs) such as putrescine (PUT), spermidine (SPD) and spermine (SPM) are low-molecular-mass highly charged molecules whose intracellular levels are strictly modulated by specific enzymes. Among the latter, spermine oxidase (SMOX) regulates polyamine catabolism oxidizing SPM to SPD, which impacts cellular processes such as apoptosis and DNA damage response. Here we report that low SMOX levels are associated with a worse outcome in FN-RMS, but not in FP-RMS, patients. Consistently, SMOX expression is downregulated in FN-RMS cell lines as compared to normal myoblasts. Moreover, SMOX transcript levels are reduced FN-RMS cells differentiation, being indirectly downregulated by the muscle transcription factor MYOD. Noteworthy, forced expression of SMOX in two cell lines derived from high-risk FN-RMS: 1) reduces SPM and upregulates SPD levels; 2) induces G0/G1 cell cycle arrest followed by apoptosis; 3) impairs anchorage-independent and tumor spheroids growth; 4) inhibits cell migration; 5) increases γH2AX levels and foci formation indicative of DNA damage. In addition, forced expression of SMOX and irradiation synergize at activating ATM and DNA-PKCs, and at inducing γH2AX expression and foci formation, which suggests an enhancement in DNA damage response. Irradiated SMOX-overexpressing FN-RMS cells also show significant decrease in both colony formation capacity and spheroids growth with respect to single approaches. Thus, our results unveil a role for SMOX as inhibitor of tumorigenicity of FN-RMS cells in vitro. In conclusion, our in vitro results suggest that SMOX induction could be a potential combinatorial approach to sensitize FN-RMS to ionizing radiation and deserve further in-depth studies.

Chlorotoxin and Lung Cancer: A Targeting Perspective for Drug Delivery

In the generational evolution of nano-based drug delivery carriers, active targeting has been a major milestone for improved and selective drug accumulation in tissues and cell types beyond the existing passive targeting capabilities. Among the various active targeting moieties, chlorotoxin, a peptide extracted from scorpions, demonstrated promising tumor cell accumulation and selection. With lung cancer being among the leading diagnoses of cancer-related deaths in both men and women, novel therapeutic methodologies utilizing nanotechnology for drug delivery emerged. Given chlorotoxin's promising biological activity, we explore its potential against lung cancer and its utilization for active targeting against this cancer's tumor cells. Our analysis indicates that despite the extensive chlorotoxin's research against glioblastoma, lung cancer research with the molecule has been limited, despite some promising early results.