NRF2 interacts with distal enhancer and inhibits nitric oxide synthase 2 expression in KRAS-driven pancreatic cancer cells.

Nitric oxide is a pleiotropic free radical produced by three nitric oxide synthases (NOS1-3), of which inducible NOS2 is involved in tumor initiation and progression. In this study, RNA-seq, ChIP-seq and qRT-PCR experiments combined with bioinformatic analyses showed that NRF2 is a repressor of NOS2 gene by maintaining a distal enhancer located 22 kb downstream of TSS in an inactive state. Deletion of NRF2 leads to activation of the enhancer, which exerts a pioneering function before it is fully activated. Specifically, NRF2 controls the expression of NOS2 in response to intracellular oxidative stress and extracellular oxygen pressure. We found that abrogation of NOS2 expression by siRNAs partially reduced the ability of WT Panc-1 cells to form 3D spheroids, but strongly reduced the formation of 3D spheroids by NRF2-depleted Panc-1 cells. Mechanistically, this effect correlates with the finding that NOS2 and nitric oxide stimulate epithelial-to-mesenchymal transition in NRF2-depleted Panc-1 and MIA PaCa-2 cells. We also found that knockdown of NOS2 leads to blockade of 3D matrigel invasion of NRF2-depleted PDAC cells, demonstrating that a short-circuit in the reciprocal regulation of NOS2 and NRF2 attenuates the malignancy of PDAC cells. In summary, we show for the first time that: (i) NRF2 is a suppressor of NOS2 in pancreatic cancer cells; (ii) NRF2 binds to and inactivates an enhancer located 22 kb downstream of TSS of the NOS2 gene; (iii) activation of NOS2 requires suppression of NRF2; (iv) NOS2 is required for NRF2-depleted Panc-1 cells to maintain their malignancy and invasiveness.

Suppression of the KRAS-NRF2 axis shifts arginine into the phosphocreatine energy system in pancreatic cancer cells.

In pancreatic ductal adenocarcinomas (PDAC), the KRASG12D-NRF2 axis controls cellular functions such as redox homeostasis and metabolism. Disruption of this axis through suppression of NRF2 leads to profound reprogramming of metabolism. Unbiased transcriptome and metabolome analyses showed that PDAC cells with disrupted KRASG12D-NRF2 signaling (NRF2-/- cells) shift from aerobic glycolysis to metabolic pathways fed by amino acids. Metabolome, RNA-seq and qRT-PCR analyses revealed a blockade of the urea cycle, making NRF2-/- cells dependent on exogenous arginine for survival. Arginine is channeled into anabolic pathways, including the synthesis of phosphocreatine, which generates an energy buffer essential for cell growth. A similar switch was observed in tumor clones that had survived FOLFIRINOX therapy or blockade of KRAS signaling. Inhibition of the creatine pathway with cyclocreatine reduced both ATP and invasion rate in 3D spheroids from NRF2-deficient PDAC cells. Our study provides basis for the rational development of combination therapies for pancreatic cancer.

Super-enhancer landscape rewiring in cancer: The epigenetic control at distal sites.

Super-enhancers evolve as elements at the top of the hierarchical control of gene expression. They are important end-gatherers of signaling pathways that control stemness, differentiation or adaptive responses. Many epigenetic regulations focus on these regions, and not surprisingly, during the process of tumorigenesis, various alterations can account for their dysfunction. Super-enhancers are emerging as key drivers of the aberrant gene expression landscape that sustain the aggressiveness of cancer cells. In this review, we will describe and discuss about the structure of super-enhancers, their epigenetic regulation, and the major changes affecting their functionality in cancer.

Dual-targeting peptides@PMO, a mimetic to the pro-apoptotic protein Smac/DIABLO for selective activation of apoptosis in cancer cells.

The refractoriness of tumor cells to apoptosis represents the main mechanism of resistance to chemotherapy. Smac/DIABLO mimetics proved to be effective in overcoming cancer-acquired resistance to apoptosis as a consequence of overexpression of the anti-apoptotic proteins XIAP, cIAP1, and cIAP2. In this work, we describe a dual-targeting peptide capable of selectively activating apoptosis in cancer cells. The complex consists of a fluorescent periodic mesoporous organosilica nanoparticle that carries the short sequences of Smac/DIABLO bound to the αvß3-integrin ligand. The dual-targeting peptide @PMO shows significantly higher toxicity in αvß3-positive HeLa cells with respect to αvß3-negative Ht29 cells. @PMO exhibited synergistic effects in combination with oxaliplatin in a panel of αvß3-positive cancer cells, while its toxicity is overcome by XIAP overexpression or integrin ß3 silencing. The successful uptake of the molecule by αvß3-positive cells makes @PMO promising for the re-sensitization to apoptosis of many cancer types.

Fetal growth at term and placental oxidative stress in a tissue micro-array model: a histological and immunohistochemistry study.

This study examines 8-hydroxyguanine (8-oxo-Gua) staining in placental tissue samples based on fetal size at birth as well as its relationships with placental histology and other pregnancy variables. This prospective cohort study included women > 18 years with a singleton pregnancy, a live fetus, fluency in Italian, and delivery at term. A total of 165 pregnancies were included in the study. The nuclear syncytiotrophoblast 8-oxo-Gua staining score in LGA was substantially greater than in late FGR (p < 0.05), although the cytoplasm score was lower in SGA and LGA than in AGA (p < 0.05). Furthermore, a sex-specific pattern of 8-oxo-Gua staining was discovered in single-term placentas, with more oxidative damage found in the nuclei of syncytiotrophoblast cells and stromal and endothelial cells in AGA males compared to AGA females (p < 0.05). Second, the histological pattern of late FGR placentae differed by gender. Finally, a significant correlation (p < 0.05) was found between high-intensity 8-oxo-Gua staining in the cytoplasm of syncytiotrophoblast cells and thrombi in the chorionic plate or villi in males. On the other hand, female fetuses demonstrated a significant connection (p < 0.05) between high-intensity 8-oxo-Gua staining in endothelial and stromal cells and high birthweight MoM values. Our findings indicated a significant variation in the oxidative stress pattern between male and female placentae, implying that fetal growth is regulated differently in the two sexes.

Bystander effect in photosensitized prostate cancer cells with a different grade of malignancy: The role of nitric oxide.

Photodynamic therapy (PDT) is a therapeutic modality based on the simultaneous action of three elements: photosensitizer, light and oxygen. This triad generates singlet oxygen and reactive oxygen species that can reduce the mass of a tumor. PDT is also able to stimulate iNOS, the enzyme that generates nitric oxide (NO). The role of NO in PDT-treated cancer cells has been investigated in several studies. They showed that low iNOS/NO levels stimulate signaling pathways that promote tumor survival, while high iNOS/NO levels arrest tumor growth. There is increasing evidence that ROS/RNS control both proliferation and migration of cells in the vicinity of PDT-treated tumor cells (so-called bystander cells). In this work, we addressed the question of how NO, which is generated by weak PDT, affects bystander cells. We used a conditioned medium: medium of PDT-treated tumor cells containing the stressors produced by the cells was added to untreated cells mimicking the neighboring bystander cells to investigate whether the conditioned medium affects cell proliferation. We found that low-level NO in prostate cancer cells affects the bystander tumor cells in a manner that depends on their malignancy grade.

Endogenous Retroviruses (ERVs): Does RLR (RIG-I-Like Receptors)-MAVS Pathway Directly Control Senescence and Aging as a Consequence of ERV De-Repression?

Bi-directional transcription of Human Endogenous Retroviruses (hERVs) is a common feature of autoimmunity, neurodegeneration and cancer. Higher rates of cancer incidence, neurodegeneration and autoimmunity but a lower prevalence of autoimmune diseases characterize elderly people. Although the re-expression of hERVs is commonly observed in different cellular models of senescence as a result of the loss of their epigenetic transcriptional silencing, the hERVs modulation during aging is more complex, with a peak of activation in the sixties and a decline in the nineties. What is clearly accepted, instead, is the impact of the re-activation of dormant hERV on the maintenance of stemness and tissue self-renewing properties. An innate cellular immunity system, based on the RLR-MAVS circuit, controls the degradation of dsRNAs arising from the transcription of hERV elements, similarly to what happens for the accumulation of cytoplasmic DNA leading to the activation of cGAS/STING pathway. While agonists and inhibitors of the cGAS-STING pathway are considered promising immunomodulatory molecules, the effect of the RLR-MAVS pathway on innate immunity is still largely based on correlations and not on causality. Here we review the most recent evidence regarding the activation of MDA5-RIG1-MAVS pathway as a result of hERV de-repression during aging, immunosenescence, cancer and autoimmunity. We will also deal with the epigenetic mechanisms controlling hERV repression and with the strategies that can be adopted to modulate hERV expression in a therapeutic perspective. Finally, we will discuss if the RLR-MAVS signalling pathway actively modulates physiological and pathological conditions or if it is passively activated by them.

Photosensitization of pancreatic cancer cells by cationic alkyl-porphyrins in free form or engrafted into POPC liposomes: The relationship between delivery mode and mechanism of cell death.

Cationic porphyrins bearing an alkyl side chain of 14 (2b) or 18 (2d) carbons dramatically inhibit proliferation of pancreatic cancer cells following treatment with light. We have compared two different ways of delivering porphyrin 2d: either in free form or engrafted into palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine liposomes (L-2d). Cell cytometry shows that while free 2d is taken up by pancreatic cancer cells by active (endocytosis) and passive (membrane fusion) transports, L-2d is internalized solely by endocytosis. Confocal microscopy showed that free 2d co-localizes with the cell membrane and lysosomes, whereas L-2d partly co-localizes with lysosomes and ER. It is found that free 2d inhibits the KRAS-Nrf2-GPX4 axis and strongly triggers lipid peroxidation, resulting in cell death by ferroptosis. By contrast, L-2d does not affect the KRAS-Nrf2-GPX4 axis and activates cell death mainly through apoptosis. Overall, our study demonstrates for the first time that cationic alkyl porphyrins, which have a IC50 ~ 23 nM, activate a dual mechanism of cell death, ferroptosis and apoptosis, where the predominant form depends on the delivery mode.

hnRNPA1/UP1 Unfolds KRAS G-Quadruplexes and Feeds a Regulatory Axis Controlling Gene Expression.

Recent studies have proven that the genetic landscape of pancreatic cancer is dominated by the KRAS oncogene. Its transcription is controlled by a G-rich motif (called 32R) located immediately upstream of the TSS. 32R may fold into a G-quadruplex (G4) in equilibrium between two G4 conformers: G9T (T M = 61.2 °C) and G25T (T M = 54.7 °C). We found that both G4s bind to hnRNPA1 and its proteolytic fragment UP1, promoting several contacts with the RRM protein domains. 1D NMR analysis of DNA imino protons shows that, upon binding to UP1, G25T is readily unfolded at both 5' and 3' tetrads, while G9T is only partially unfolded. The impact of hnRNPA1 on KRAS expression was determined by comparing Panc-1 cells with two Panc-1 knockout cell lines in which hnRNPA1 was deleted by the CRISPR/Cas9 technology. The results showed that the expression of KRAS is inhibited in the knockout cell lines, indicating that hnRNPA1 is essential for the transcription of KRAS. In addition, the knockout cell lines, compared to normal Panc-1 cells, show a dramatic decrease in cell growth and capacity of colony formation. Pull-down and Western blot experiments indicate that conformer G25T is a better platform than conformer G9T for the assembly of the transcription preinitiation complex with PARP1, Ku70, MAZ, and hnRNPA1. Together, our data prove that hnRNPA1, being a key transcription factor for the activation of KRAS, can be a new therapeutic target for the rational design of anticancer strategies.

Does Delayed Cord Clamping Improve Long-Term (≥4 Months) Neurodevelopment in Term Babies? A Systematic Review and a Meta-Analysis of Randomized Clinical Trials.

Background: Recently, the literature suggested that placental transfusion facilitated by delayed cord clamping (DCC), besides having benefits on hematological parameters, might improve the infants' brain development. Objective: The present review primarily evaluates the Ages and Stages Questionnaire (ASQ) total score mean difference (MD) at long-term follow-up (≥4 months) comparing DCC (>90 or >180 s) to early cord clamping (ECC). Secondary aims consisted of evaluating the ASQ domains' MD and the results obtained from other methods adopted to evaluate the infants' neurodevelopment. Methods: MEDLINE, Scopus, Cochrane, and ClinicalTrials.gov databases were searched (up to 2nd November 2020) for systematic review and meta-analysis. All randomized controlled trials (RCTs) of term singleton gestations received DCC or ECC. Multiple pregnancies, pre-term delivery, non-randomized studies, and articles in languages other than English were excluded. The included studies were assessed for bias and quality. ASQ data were pooled stratified by time to follow up. Results: This meta-analysis of 4 articles from 3 RCTs includes 765 infants with four-month follow-up and 672 with 12 months follow-up. Primary aim (ASQ total score) pooled analysis was possible only for 12 months follow-up, and no differences were found between DCC and ECC (MD 1.1; CI 95: -5.1; 7.3). DCC approach significantly improves infants' communication domains (MD 0.6; CI 95: 0.1; 1.1) and personal-social assessed (MD 1.0; CI 95: 0.3; 1.6) through ASQ at 12 months follow-up. Surprisingly, the four-month ASQ personal social domain (MD -1.6; CI 95: -2.8; -0.4) seems to be significantly lower in the DCC group than in the ECC group. Conclusions: DCC, a simple, non-interventional, and cost-effective approach, might improve the long-term infants' neurological outcome. Single-blinding and limited studies number were the main limitations. Further research should be performed to confirm these observations, ideally with RCTs adopting standard methods to assess infants' neurodevelopment. Trial registration: NCT01245296, NCT01581489, NCT02222805, NCT01620008, IRCT201702066807N19, and NCT02727517.

Antiviral Activity of the G-Quadruplex Ligand TMPyP4 against Herpes Simplex Virus-1.

The herpes simplex virus 1 (HSV-1) genome is extremely rich in guanine tracts that fold into G-quadruplexes (G4s), nucleic acid secondary structures implicated in key biological functions. Viral G4s were visualized in HSV-1 infected cells, with massive virus cycle-dependent G4-formation peaking during viral DNA replication. Small molecules that specifically interact with G4s have been shown to inhibit HSV-1 DNA replication. We here investigated the antiviral activity of TMPyP4, a porphyrin known to interact with G4s. The analogue TMPyP2, with lower G4 affinity, was used as control. We showed by biophysical analysis that TMPyP4 interacts with HSV-1 G4s, and inhibits polymerase progression in vitro; in infected cells, it displayed good antiviral activity which, however, was independent of inhibition of virus DNA replication or entry. At low TMPyP4 concentration, the virus released by the cells was almost null, while inside the cell virus amounts were at control levels. TEM analysis showed that virus particles were trapped inside cytoplasmatic vesicles, which could not be ascribed to autophagy, as proven by RT-qPCR, western blot, and immunofluorescence analysis. Our data indicate a unique mechanism of action of TMPyP4 against HSV-1, and suggest the unprecedented involvement of currently unknown G4s in viral or antiviral cellular defense pathways.

Effect of DNA Glycosylases OGG1 and Neil1 on Oxidized G-Rich Motif in the KRAS Promoter.

The promoter of the Kirsten ras (KRAS) proto-oncogene contains, upstream of the transcription start site, a quadruplex-forming motif called 32R with regulatory functions. As guanine under oxidative stress can be oxidized to 8-oxoguanine (8OG), we investigated the capacity of glycosylases 8-oxoguanine glycosylase (OGG1) and endonuclease VIII-like 1 (Neil1) to excise 8OG from 32R, either in duplex or G-quadruplex (G4) conformation. We found that OGG1 efficiently excised 8OG from oxidized 32R in duplex but not in G4 conformation. By contrast, glycosylase Neil1 showed more activity on the G4 than the duplex conformation. We also found that the excising activity of Neil1 on folded 32R depended on G4 topology. Our data suggest that Neil1, besides being involved in base excision repair pathway (BER), could play a role on KRAS transcription.

Role of Poly [ADP-ribose] Polymerase 1 in Activating the Kirsten ras (KRAS) Gene in Response to Oxidative Stress.

In pancreatic Panc-1 cancer cells, an increase of oxidative stress enhances the level of 7,8-dihydro-8-oxoguanine (8OG) more in the KRAS promoter region containing G4 motifs than in non-G4 motif G-rich genomic regions. We found that H2O2 stimulates the recruitment to the KRAS promoter of poly [ADP-ribose] polymerase 1 (PARP-1), which efficiently binds to local G4 structures. Upon binding to G4 DNA, PARP-1 undergoes auto PARylation and thus becomes negatively charged. In our view this should favor the recruitment to the KRAS promoter of MAZ and hnRNP A1, as these two nuclear factors, because of their isoelectric points >7, are cationic in nature under physiological conditions. This is indeed supported by pulldown assays which showed that PARP-1, MAZ, and hnRNP A1 form a multiprotein complex with an oligonucleotide mimicking the KRAS G4 structure. Our data suggest that an increase of oxidative stress in Panc-1 cells activates a ROS-G4-PARP-1 axis that stimulates the transcription of KRAS. This mechanism is confirmed by the finding that when PARP-1 is silenced by siRNA or auto PARylation is inhibited by Veliparib, the expression of KRAS is downregulated. When Panc-1 cells are treated with H2O2 instead, a strong up-regulation of KRAS transcription is observed.

Role of nitric oxide in the response to photooxidative stress in prostate cancer cells.

A continuous state of oxidative stress during inflammation contributes to the development of 25% of human cancers. Epithelial and inflammatory cells release reactive oxygen species (ROS) and reactive nitrogen species (RNS) that can damage DNA. ROS/RNS have biological implications in both chemoresistance and tumor recurrence. As several clinically employed anticancer drugs can generate ROS/RNS, we have addressed herein how inducible nitric oxide synthase and nitric oxide (iNOS/•NO) affect the molecular pathways implicated in the tumor response to oxidative stress. To mimic the oxidative stress associated with chemotherapy, we used a photosensitizer (pheophorbide a) that can generate ROS/RNS in a controlled manner. We investigated how iNOS/•NO modulates the tumor response to oxidative stress by involving the NF-κB and Nrf2 molecular pathways. We found that low levels of iNOS induce the development of a more aggressive tumor population, leading to survival, recurrence and resistance. By contrast, high levels of iNOS/•NO sensitize tumor cells to oxidative treatment, causing cell growth arrest. Our analysis showed that NF-κB and Nrf2, which are activated in response to oxidative stress, communicate with each other through RKIP. For this critical role, RKIP could be an interesting target for anticancer drugs. Our study provides insight into the complex signaling response of cancer cells to oxidative treatments as well as new possibilities for the rational design of new therapeutic strategies.

Structure of two G-quadruplexes in equilibrium in the KRAS promoter.

KRAS is one of the most mutated oncogenes and still considered an undruggable target. An alternative strategy would consist in targeting its gene rather than the protein, specifically the formation of G-quadruplexes (G4) in its promoter. G4 are secondary structures implicated in biological processes, which can be formed among G-rich DNA (or RNA) sequences. Here we have studied the major conformations of the commonly known KRAS 32R, or simply 32R, a 32 residue sequence within the KRAS Nuclease Hypersensitive Element (NHE) region. We have determined the structure of the two major stable conformers that 32R can adopt and which display slow equilibrium (>ms) with each other. By using different biophysical methods, we found that the nucleotides G9, G25, G28 and G32 are particularly implicated in the exchange between these two conformations. We also showed that a triad at the 3' end further stabilizes one of the G4 conformations, while the second conformer remains more flexible and less stable.

Photodynamic Therapy for ras-Driven Cancers: Targeting G-Quadruplex RNA Structures with Bifunctional Alkyl-Modified Porphyrins.

Designing small molecules able to break down G4 structures in mRNA (RG4s) offers an interesting approach to cancer therapy. Here, we have studied cationic porphyrins (CPs) bearing an alkyl chain up to 12 carbons, as they bind to RG4s while generating reactive oxygen species upon photoirradiation. Fluorescence-activated cell sorting (FACS) and confocal microscopy showed that the designed alkyl CPs strongly penetrate cell membranes, binding to KRAS and NRAS mRNAs under low-abundance cell conditions. In Panc-1 cells, alkyl CPs at nanomolar concentrations promote a dramatic downregulation of KRAS and NRAS expression, but only if photoactivated. Alkyl CPs also reduce the metabolic activity of pancreatic cancer cells and the growth of a Panc-1 xenograft in SCID mice. Propidium iodide/annexin assays and caspase 3, caspase 7, and PARP-1 analyses show that these compounds activate apoptosis. All these data demonstrate that the designed alkyl CPs are efficient photosensitizers for the photodynamic therapy of ras-driven cancers.

The ROS-KRAS-Nrf2 axis in the control of the redox homeostasis and the intersection with survival-apoptosis pathways: Implications for photodynamic therapy.

In highly proliferating cancer cells oncogenic mutations reprogram the metabolism and increase the production of reactive oxygen species (ROS). Cancer cells prevent ROS accumulation by upregulating antioxidant systems. Here we show that an increase of oxidative stress (ROS and singlet oxygen), generated by photoactivated TMPyP4, results in the upregulation of KRAS and Nrf2, the major regulator of the redox homeostasis. In agreement with a previous observation, the ectopic expression of KRAS G12D or G12 V is found to stimulate Nrf2. This suggests that ROS, KRAS and Nrf2 establish a molecular axis controlling the redox homeostasis in cancer cells. We found that this axis also modulates the function of the NF-kB/Snail/RKIP circuitry, regulating the survival and apoptosis pathways. Our data show that low ROS levels, obtained when Nrf2 is activated by KRAS, results in the upregulation of prosurvival Snail and simultaneous downregulation of proapoptotic RKIP: an expression pattern favouring cell proliferation. By contrast, high ROS levels, obtained when Nrf2 is inhibited by a small molecule (luteolin), favour apoptosis by upregulating proapoptotic RKIP and downregulating prosurvival Snail. The results of this study are useful to design efficient photodynamic therapy (PDT) against cancer. We hypothesize that cancer cells can be sensitized to PDT when the photosensitizer is used in the presence of an inhibitor of Nrf2 (adjuvant). To test this hypothesis, we used luteolin (3',4',5,7-tetrahydroflavone) as Nrf2 inhibitor, since it reduces the expression of Nrf2 and increases intracellular ROS. By means of colony formation and viability assays we found that when Nrf2 is inhibited, PDT shows an increase of efficiency up to 45%.

Interleukin 1 receptor antagonist gene variable number of tandem repeats polymorphism and cutaneous melanoma.

Immunity and cytokines serve crucial roles in cutaneous melanoma. The present study investigated whether a variable number tandem repeat (VNTR) polymorphism of interleukin-1 receptor antagonist (IL-1RA) gene (IL-1RN) located in intron 2 (rs2234663) is associated with cutaneous melanoma. A total of 515 subjects were studied, 133 of which were cutaneous melanoma cases (72 stage I+II non-metastatic melanoma cases and 61 stage III+IV metastatic melanoma cases), and 382 subjects were matching healthy controls from the Friuli-Venezia-Giulia Region located in Northeast Italy, an area with a high melanoma incidence. The IL-1RN-VNTR polymorphism was determined by DNA fragment length analysis following PCR amplification. According to the number of 86-bp repeats, five different IL-1RN alleles were identified: Allele 1 (4-repeats), allele 2 (2-repeats, short allele), allele 3 (5-repeats), allele 4 (3-repeats) and allele 5 (6-repeats). Alleles with three or more 86-bp repeats, i.e. allele 1, 3, 4 and 5 were collectively denoted as long (L) repeats. The present study revealed that IL-1RN-VNTR 1/2 and 2/L genotypes were more frequent among patients with cutaneous melanoma (43.6 and 45.1%, respectively) compared with healthy controls [29.6 and 30.6%, respectively; odds ratio (OR), 1.84; CI, 1.22-2.77; P=0.003; and OR, 1.66; CI, 1.24-2.79; P=0.002, respectively]. Conversely, the IL-1RN-VNTR 1/1 genotype was less frequent among melanoma cases (45.9%) compared with healthy controls (57.9%; OR, 0.62; CI, 0.41-0.92; P=0.017). Comparison of metastatic vs. non-metastatic melanoma cases identified no significant differences. The present study first demonstrated that carriage of the 1/1 IL-1RN-VNTR genotype was protective, whereas 1/2 and 2/L was a risk factor for patients with cutaneous melanoma vs. healthy controls. The short allele 2 was associated with higher expression levels of IL-1RA, a potent competitive inhibitor of the proinflammatory cytokines IL-1α and IL-1ß. VNTR-IL-1RN polymorphism may affect susceptibility to melanoma and, thus, it is a potential novel diagnostic biomarker for melanoma. The present study increased the understanding of genetic melanoma susceptibility/carcinogenesis, and may indicate novel strategies in the personalized prevention of cutaneous melanoma.

Folate-Decorated Amphiphilic Cyclodextrins as Cell-Targeted Nanophototherapeutics.

Nowadays, active targeting of nanotherapeutics is a challenging issue. Here, we propose a rational design of a ternary nanoassembly (SAP) composed of nonionic amphiphilic ß-cyclodextrins (amphiphilic CD) incorporating pheophorbide (Pheo) as a phototherapeutic and an adamantanyl-folic acid conjugate (Ada-FA) to target tumor cells overexpressing α-folate receptor (FR-α(+)). Dynamic light scattering and ζ-potential pointed out the presence of nanoassemblies bearing a negative surface charge (ζ = -51 mV). Morphology of SAP was investigated by atomic force microscopy and microphotoluminescence, indicating the presence of highly emissive near-spherical assemblies of about 280 nm in size. Complementary spectroscopic techniques such as ROESY-NMR, UV/vis and steady-state fluorescence revealed that the folic acid protrudes out of amphiphilic CD rims, prone for recognition with FR-α. Pheo was strongly loaded in the nanoassembly mostly in monomeric form, thus generating singlet oxygen (1O2) and consequentely showing phototherapeutic action. SAP remained stable until 2 weeks in aqueous solutions. Stability studies in biologically relevant media pointed out the ability of SAP to interact with serum proteins by means of the oligoethylenglycole fringe, without destabilization. Release experiments demonstrated the sustained release of Pheo from SAP in environments mimiking physiological conditions (∼20% within 1 week), plausibly suggesting low Pheo leaking and high integrity of the assembly within 24 h, time spent on average to reach the target sites. Cellular uptake of SAP was confirmed by confocal microscopy, pointing out that SAP was internalized into the tumoral cells expressing FR-α more efficiently than SP. SAP showed improved phototoxicity in human breast MCF-7 cancer cells FR-α(+) (IC50 = 270 nM) with respect to human prostate carcinoma PC3 cells (IC50 = 700 nM) that express a low level of that receptor (FR-α(-)). Finally, an improved phototoxicity in FR-α(+) MCF-7 cells (IC50 = 270 nM) was assessed after treatment with SAP vs SP (IC50 = 600 nM) which was designed without Ada-FA as a targeting unit.

MicroRNA therapeutics: design of single-stranded miR-216b mimics to target KRAS in pancreatic cancer cells.

Datasets reporting microRNA expression profiles in normal and cancer cells show that miR-216b is aberrantly downregulated in pancreatic ductal adenocarcinoma (PDAC). We found that KRAS, whose mutant G12D allele drives the pathogenesis of PDAC, is a target of miR-216b. To suppress oncogenic KRAS in PDAC cells, we designed single-stranded (ss) miR-216b mimics with unlocked nucleic acid (UNA) modifications to enhance their nuclease resistance. We prepared variants of ss-miR-216b mimics with and without a 5' phosphate group. Both variants strongly suppressed oncogenic KRAS in PDAC cells and inhibited colony formation in pancreatic cancer cells. We observed that the designed ss-miR-216b mimics engaged AGO2 to promote the silencing of KRAS. We also tested a new delivery strategy based on the use of palmityl-oleyl-phosphatidylcholine (POPC) liposomes functionalized with ss-miR-216b conjugated with two palmityl chains and a lipid-modified cell penetrating peptide (TAT). These versatile nanoparticles suppressed oncogenic KRAS in PDAC cells.