Significance and applications of nanoparticles in siRNA delivery for cancer therapy

A pan-cancer multi-omics analysis of lactylation genes associated with tumor microenvironment and cancer development

Background

Lactylation is a significant post-translational modification bridging the gap between cancer epigenetics and metabolic reprogramming. However, the association between lactylation and prognosis, tumor microenvironment (TME), and response to drug therapy in various cancers remains unclear.

Methods

First, the expression, prognostic value, and genetic and epigenetic alterations of lactylation genes were systematically explored in a pan-cancer manner. Lactylation scores were derived for each tumor using the single-sample gene set enrichment analysis (ssGSEA) algorithm. The correlation of lactylation scores with clinical features, prognosis, and TME was assessed by integrating multiple computational methods. In addition, GSE135222 data was used to assess the efficacy of lactylation scores in predicting immunotherapy outcomes. The expression of lactylation genes in breast cancers and gliomas were verified by RNA-sequencing.

Results

Lactylation genes were significantly upregulated in most cancer types. CREBBP and EP300 exhibited high mutation rates in pan-cancer analysis. The prognostic impact of the lactylation score varied by tumor type, and lactylation score was a protective factor for KIRC, ACC, READ, LGG, and UVM, and a risk factor for CHOL, DLBC, LAML, and OV. In addition, a high lactylation score was associated with cold TME. The infiltration levels of CD8+ T, γδT, natural killer T cell (NKT), and NK cells were lower in tumors with higher lactylation scores. Finally, immunotherapy efficacy was worse in patients with high lactylation scores than other types.

Conclusion

Lactylation genes are involved in malignancy formation. Lactylation score serves as a promising biomarker for predicting patient prognosis and immunotherapy efficacy.

Targeting DEP domain containing 1 in anaplastic thyroid carcinoma: Implications for stemness regulation and malignant phenotype suppression

Background

Anaplastic thyroid carcinoma (ATC), a rare but highly aggressive endocrine malignancy, is characterized by a significant presence of cancer stem-like cells (CSCs). These CSCs, known for their self-renewal and differentiation capacities, contribute to various aggressive tumor properties, including recurrence, metastasis, heterogeneity, multidrug resistance, and radiation resistance. Despite their critical role, the regulatory mechanisms of CSCs in ATC remain poorly elucidated, posing challenges in effectively targeting these cells for treatment.

Methods

To delve into this, we employed the single sample gene set enrichment analysis (ssGSEA) algorithm to evaluate the stemness of samples in combined datasets. Samples were then classified into high and low stemness subgroups based on their average stemness scores. Differential gene expression between these subgroups was analyzed. We further explored the association of candidate genes with patient prognosis. Additionally, we conducted gene set enrichment analysis (GSEA) and a series of cell biology experiments to validate the role of DEP domain-containing protein 1 (DEPDC1) in fostering CSC-like traits and regulating the malignant phenotypes of ATC.

Results

Our investigation demonstrated that DEPDC1 was significantly upregulated in CSCs and is abundantly expressed in ATC tissues. In vitro assays revealed that knockdown of DEPDC1 markedly inhibited tumor sphere formation and attenuated the proliferation, invasion, and migration of ATC cells. This silencing also resulted in reduced expression of stemness markers associated with CSCs. Furthermore, our GSEA findings linked high DEPDC1 expression to cell cycle progression and the maintenance of tumor cell stemness, with DEPDC1 knockdown disrupting these signaling pathways. Collectively, our results position DEPDC1 as a pivotal regulator of CSC-like characteristics in ATC, where aberrant DEPDC1 expression amplifies stemness properties and fuels the cancer's aggressive behavior. Consequently, DEPDC1 emerges as a promising therapeutic target for ATC management. In summary, this study underscores the pivotal role of DEPDC1 in modulating CSC-like features in ATC, offering new avenues for targeted therapy in this challenging malignancy.

Insights on prospects of nano-siRNA based approaches in treatment of Cancer

siRNA interference, commonly referred to as gene silence, is a biological mechanism that inhibits gene expression in disorders such as cancer. It may enhance the precision, efficacy, and stability of medicines, especially genetic therapies to some extent. However, obstacles such as the delivery of oligonucleotide drugs to inaccessible areas of the body and the prevalence of severe side effects must be overcome. To maximize their potential, it is thus essential to optimize their distribution to target locations and limit their toxicity to healthy cells. The action of siRNA may be harnessed to delete a similar segment of mRNA that encodes a protein that causes sickness. The absence of an efficient delivery mechanism that shields siRNA from nuclease degradation, delivers it to cancer cells and releases it into the cytoplasm of specific cancer cells without causing side effects is currently the greatest obstacle to the practical implementation of siRNA therapy. This article focuses on combinations of siRNA with chemotherapeutic drug delivery systems for the treatment of cancer and gives an overview of several nanocarrier formulations in both research and clinical applications.

Supramolecular organization and biological interaction of squalenoyl siRNA nanoparticles

Small interfering RNAs (siRNA) are attractive and powerful tools to inhibit the expression of a targeted gene. However, their extreme hydrophilicities combined with a negative charge and short plasma half-life counteract their use as therapeutics. Previously, we chemically linked siRNA to squalene (SQ) which self-assembled as nanoparticles (NPs) with pharmacological efficiency in cancers and recently in a hereditary neuropathy. In order to understand the siRNA-SQ NP assembly and fate once intravenously injected, the present study detailed characterization of siRNA-SQ NP structure and its interaction with serum components. From SAXS and SANS analysis, we propose that the siRNA-SQ bioconjugate self-assembled as 11-nm diameter supramolecular assemblies, which are connected one to another to form spherical nanoparticles of around 130-nm diameter. The siRNA-SQ NPs were stable in biological media and interacted with serum components, notably with albumin and LDL. The high specificity of siRNA to decrease or normalize gene expression and the high colloidal stability when encapsulated into squalene nanoparticles offer promising targeted therapy with wide applications for pathologies with gene expression dysregulation.

Systemic siRNA delivery to tumors by cell-penetrating α-helical polypeptide-based metastable nanoparticles

Systemic, non-viral siRNA delivery for cancer treatment is mainly achieved via condensation by cationic materials (e.g., lipids and cationic polymers), which nevertheless, suffers from poor serum stability, non-specific tissue interaction, and unsatisfactory membrane activity against efficient in vivo gene knockdown. Here, we report the design of a metastable, cancer-targeting siRNA delivery system based on two functional polymers, PVBLG-8, a cationic, helical cell-penetrating polypeptide, and poly(l-glutamic acid) (PLG), an anionic random-coiled polypeptide. PVBLG-8 with rigid, linear structure showed weak siRNA condensation capability, and PLG with flexible chains was incorporated as a stabilizer which provided sufficient molecular entanglement with PVBLG-8 to encapsulate the siRNA within the polymeric network. The obtained PVBLG-8/siRNA/PLG nanoparticles (PSP NPs) with positive charges were sequentially coated with additional amount of PLG, which reversed the surface charge from positive to negative to yield the metastable PVBLG-8/siRNA/PLG@PLG (PSPP) NPs. The PSPP NPs featured desired serum stability during circulation to enhance tumor accumulation via the enhanced permeability and retention (EPR) effect. Upon acidification in the tumor extracellular microenvironment and intracellular endosomes, the partial protonation of PLG on PSPP NPs surface would lead to dissociation of PLG coating from NPs, exposure of the highly membrane-active PVBLG-8, and surface charge reversal from negative to positive, which subsequently promoted tumor penetration, selective cancer cell internalization, and efficient endolysosomal escape. When siRNA against epidermal growth factor receptor (EGFR) was encapsulated, the PSPP NPs showed excellent tumor penetration capability, tumor cell uptake level, EGFR silencing efficiency, and tumor growth inhibition efficacy in U-87 MG glioblastoma tumor spheroids in vitro and in xenograft tumor-bearing mice in vivo, outperforming the PSP NPs and several commercial reagents such as Lipofectamine 2000 and poly(l-lysine) (PLL). This study therefore demonstrates a facile and unique design approach of metastable and charge reversal NPs, which overcomes multiple biological barriers against systemic siRNA delivery toward anti-cancer treatment.

New Formulation for the Delivery of Oligonucleotides Using "Clickable" siRNA-Polyisoprenoid-Conjugated Nanoparticles: Application to Cancers Harboring Fusion Oncogenes

The aim of the present study is to take advantage of the unique property of polyisoprenoid chains to adopt a compact molecular conformation and to use these natural and biocompatible lipids as nanocarriers of drugs to deliver siRNA. A new chemical strategy is applied here to conjugate squalene (SQ) and solanesol (SOLA) to siRNA consisting of an activated variant of the azide-alkyne Huisgen cycloaddition also known as copper-free (Cu-free) click chemistry. We conjugated siRNA against TMPRSS2-ERG, a fusion oncogene found in more than 50% of prostate cancers to SQ or SOLA. First, several parameters such as molar ratio, solvents, temperature, incubation time, and the annealing schedule between both siRNA strands were investigated to bioconjugate the SQ or SOLA via Cu-free click chemistry. The best parameters of the new bioconjugation approach allowed us to (i) increase the synthesis yield up to 95%, (ii) avoid the formation of byproducts during the synthesis, and (iii) improve the reproducibility of the bioconjugation. Then, the biological activity of the resulting nanoparticles was assessed. In vitro, all four formulations were able to decrease the corresponding oncogene and oncoprotein expression. In vivo, only two of the four nanoformulations showed anti-neoplastic activity that seems to be tightly related to their dissimilar biodistribution behavior. In conclusion, we performed a new approach easily transposable for pharmaceutical development to synthesize siRNA-SQ and siRNA-SOLA and to obtain efficient siRNA-nanoparticles. The robustness of the process could be extended to several other polyterpenes and likely applied to other siRNA targeting genes whose overexpression results in the development of cancers or other genetic diseases.

Knocking Down TMPRSS2-ERG Fusion Oncogene by siRNA Could be an Alternative Treatment to Flutamide

Our purpose was to develop a new pharmacological approach for the treatment of prostate cancer (PCa), the most common neoplasia in men. Recently, we developed siRNA against the fusion oncogene TMPRSS2-ERG found in 50% of patients and showed an antitumoral activity in animal model. Herein, we want to compare or combine the developed siRNA to flutamide (FLU), one of the gold-standard treatment of PCa. Therefore, concomitant or subsequent association of FLU to siRNA TMPRSS2-ERG was performed in VCaP cells and in SCID mice bearing xenografted VCaP tumors. ERG, androgen receptor, cleaved-caspase-3 as well as phase 1 and 2 drug-metabolizing enzymes were investigated within tumors. We observed similar results in terms of TMPRSS2-ERG knock-down and cell viability impairment for all distinct schedules of administration. The association of siRNA TMPRSS2-ERG-squalene nanoparticles with flutamide displayed similar tumor growth inhibition as mice treated with siRNA TMPRSS2-ERG-squalene nanoparticles alone and was paralleled with modification of expression of ERG, androgen receptor, and cleaved-caspase-3. Phase 1 and 2 enzymes were essentially affected by FLU and reverted when combined with squalenoylated siRNA. In conclusion, these results confirm the therapeutic effectiveness of squalenoyl siRNA nanomedicine for PCa based on siRNA TMPRSS2-ERG.

Knockdown of RhoA expression alters ovarian cancer biological behavior in vitro and in nude mice

RhoA regulates cell proliferation, migration, angiogenesis and gene expression. Altered RhoA activity contributes to cancer progression. The present study investigated the effects of RhoA knockdown on the regulation of ovarian cancer biological behavior in vitro and in nude mice. The expression of RhoA was knocked down using a lentivirus carrying RhoA short hairpin RNA (shRNA) in ovarian cancer cells and was confirmed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. The altered ovarian cancer biological behaviors were assayed by cell viability, terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling (TUNEL), migration, invasion, and nude mice tumorigenicity assays, while the altered gene expression was detected by RT-qPCR and western blot analysis. The results showed that lentivirus-carrying RhoA shRNA significantly suppressed RhoA expression in ovarian cancer cells, which suppressed tumor cell viability, migration, invasion and adhesion in vitro. RhoA silencing also inhibited the tumorigenicity of ovarian cancer cells in nude mice, which was characterized by the suppression of tumor xenograft formation and growth and induction of tumor cell apoptosis. The results of the present study demonstrated that knockdown of RhoA expression had a significant antitumor effect on ovarian cancer cells in vitro and in nude mice, suggesting that RhoA may be a target for the development of a novel therapeutic strategy in the control of ovarian cancer.

Antineoplastic Effects of siRNA against TMPRSS2-ERG Junction Oncogene in Prostate Cancer

TMPRSS2-ERG junction oncogene is present in more than 50% of patients with prostate cancer and its expression is frequently associated with poor prognosis. Our aim is to achieve gene knockdown by siRNA TMPRSS2-ERG and then to assess the biological consequences of this inhibition. First, we designed siRNAs against the two TMPRSS2-ERG fusion variants (III and IV), most frequently identified in patients’ biopsies. Two of the five siRNAs tested were found to efficiently inhibit mRNA of both TMPRSS2-ERG variants and to decrease ERG protein expression. Microarray analysis further confirmed ERG inhibition by both siRNAs TMPRSS2-ERG and revealed one common down-regulated gene, ADRA2A, involved in cell proliferation and migration. The siRNA against TMPRSS2-ERG fusion variant IV showed the highest anti-proliferative effects: Significantly decreased cell viability, increased cleaved caspase-3 and inhibited a cluster of anti-apoptotic proteins. To propose a concrete therapeutic approach, siRNA TMPRSS2-ERG IV was conjugated to squalene, which can self-organize as nanoparticles in water. The nanoparticles of siRNA TMPRSS2-ERG-squalene injected intravenously in SCID mice reduced growth of VCaP xenografted tumours, inhibited oncoprotein expression and partially restored differentiation (decrease in Ki67). In conclusion, this study offers a new prospect of treatment for prostate cancer based on siRNA-squalene nanoparticles targeting TMPRSS2-ERG junction oncogene.

Targeted activation of melanoma differentiation-associated protein 5 (MDA5) for immunotherapy of pancreatic carcinoma

The RIG-I-like helicase melanoma differentiation-associated protein 5 (MDA5) is an innate immune receptor for double-stranded viral RNA (dsRNA) that, upon activation, induces a Type I interferon (IFN)-driven immune response. In the present study, we demonstrate that human und murine pancreatic cancer cells express functional MDA5 and are highly sensitive to MDA5-induced cell death. Activation of MDA5 by cytosolic delivery of the synthetic dsRNA analog poly(I:C) led to phosphorylation of the transcription factor IRF3, IFNβ production and upregulation of MHC-I expression. MDA5 signaling also induced tumor cell apoptosis via the intrinsic pathway and sensitized tumor cells toward extrinsic, Fas-mediated apoptosis. Systemic treatment of orthotopic pancreatic cancer-bearing mice with the MDA5 ligand resulted in activated CD8⁺ T cell tumor infiltration, an increased frequency of tumor antigen-specific CD8⁺ T cells and an immunogenic cytokine milieu in the tumor microenvironment. These effects were paralleled by MDA5-induced pronounced tumor cell death in situ and significantly prolonged survival in two different mouse models for pancreatic cancer, an immunotherapeutic response dependent on CD8⁺ T cells. Treated mice were further protected from subsequent tumor challenge. In summary, we identified MDA5 as a novel therapeutic target for overcoming apoptosis resistance and tumor-mediated immunosuppression in pancreatic cancer. MDA5 ligands link innate with adaptive immune mechanisms for effective tumor control.

Spatial control of cell gene expression by siRNA gradients in biodegradable hydrogels

The extracellular environment exposes cells to numerous biochemical and physical signals that regulate their behavior. Strategies for generating continuous gradients of signals in biomaterials may allow for spatial control and patterning of cell behavior, and ultimately aid in the engineering of complex tissues. Short interfering RNA (siRNA) can regulate gene expression by silencing specific mRNA molecules post-transcriptionally, which may be valuable when presented in a continuous gradient for regenerative or therapeutic applications. Here, a biodegradable hydrogel system containing a gradient of siRNA is presented, and its capacity to regulate protein expression of encapsulated cells in a spatially continuous manner is demonstrated. Photocross-linkable dextran hydrogels containing a gradient of siRNA have been successfully fabricated using a dual-programmable syringe pump system, and differential gene silencing in incorporated cells that is sustained over time has been shown using green fluorescent protein as a reporter. This platform technology may be applied in tissue engineering to spatially control biologically relevant cellular processes.

Effects of siRNA on RET/PTC3 junction oncogene in papillary thyroid carcinoma: from molecular and cellular studies to preclinical investigations

RET/PTC3 junction oncogene is typical of radiation-induced childhood papillary thyroid carcinoma (PTC) with a short latency period. Since, RET/PTC3 is only present in the tumour cells, thus represents an interesting target for specific therapy by small interfering RNA (siRNA). Our aim is to demonstrate in vitro and in vivo molecular and cellular effects of siRNA on RET/PTC3 knockdown for therapeutic application.First, we established a novel cell line stably expressing RET/PTC3 junction oncogene, named RP3 which was found tumorigenic in nude mice compared to NIH/3T3 mouse fibroblasts. Among four siRNAs and five concentrations tested against RET/PTC3, an efficient siRNA RET/PTC3 and an appropriate dose (50 nM) were selected which showed significant inhibition (p<0.001) of gene (RT-qPCR) and protein (Western blot) expressions. This siRNA was found efficient in RP3 cells (harbouring RET/PTC3) but non-efficient in BHP10-3 SCmice cell line (harbouring RET/PTC1) showing that a specific siRNA against fusion sequence is required to target the junction oncogene. In vitro siRNA RET/PTC3 showed significant (p<0.001) inhibitory effects on RP3 cell viability (MTT assay) and on invasion/migration (IncuCyte scratch test) with blockage of cell cycle at G0/G1 phase (flow cytometry) and induced apoptosis by caspase-3 and PARP1 cleavage (WB). After intravenous injection in nude mice, respective squalene (SQ) nanoparticles (NPs) of siRNA RET/PTC3 significantly (p<0.001) reduced RP3 tumour growth, oncogene and oncoprotein expressions, induced apoptosis and partially restored differentiation (decrease in Ki67). Hence, our findings highly support the use of siRNA RET/PTC3-SQ NPs as a new promising treatment for patients affected by PTC expressing RET/PTC3.

Introduction of mismatches in a random shRNA-encoding library improves potency for phenotypic selection

RNA interference (RNAi) is a mechanism for interfering with gene expression through the action of small, non-coding RNAs. We previously constructed a short-hairpin-loop RNA (shRNA) encoding library that is random at the nucleotide level [1]. In this library, the stems of the hairpin are completely complementary. To improve the potency of initial hits, and therefore signal-to-noise ratios in library screening, as well as to simplify hit-sequence retrieval by PCR, we constructed a second-generation library in which we introduced random mismatches between the two halves of the stem of each hairpin, on a random template background. In a screen for shRNAs that protect an interleukin-3 (IL3) dependent cell line from IL3 withdrawal, our second-generation library yielded hit sequences with significantly higher potencies than those from the first-generation library in the same screen. Our method of random mutagenesis was effective for a random template and is likely suitable, therefore, for any DNA template of interest. The improved potency of our second-generation library expands the range of possible unbiased screens for small-RNA therapeutics and biologic tools.

Effects of silencing the RET/PTC1 oncogene in papillary thyroid carcinoma by siRNA-squalene nanoparticles with and without fusogenic companion GALA-cholesterol

BACKGROUND

RET/PTC1 is the most prevalent type of gene rearrangement found in papillary thyroid carcinoma (PTC). Previously, we introduced a new noncationic nanosystem for targeted RET/PTC1 silencing by efficient delivery of small interfering RNA (siRNA) using the "squalenoylation" approach. With the aim of improving these results further, we designed new squalenoyl nanostructures consisting of the fusogenic peptide GALA-cholesterol (GALA-Chol) and squalene (SQ) nanoparticles (NPs) of siRNA RET/PTC1.

METHODS

The siRNA RET/PTC1-SQ bioconjugate was synthesized. The corresponding NPs were prepared with or without GALA-Chol by nanoprecipitation and then characterized for their size and zeta potential. The effects of NPs on BHP 10-3 SCmice and TPC-1 cell viability (MTT assay), gene and protein silencing (reverse transcription-quantitative polymerase chain reaction [rt-qPCR], Western blot), and cellular uptake (fluorescent microscopy) were studied. In vivo gene silencing efficiency of siRNA RET/PTC1-SQ NPs was assessed by administration in nude mice via either intratumoral (i.t.) or intravenous (i.v.) routes. Tumor growth was followed for 19 days. Tumors were then collected, and RET/PTC1 gene and protein inhibitions were assessed by RT-qPCR and Western blot.

RESULTS

The combination of siRNA RET/PTC1-SQ bioconjugate and GALA-Chol leads to stable NPs of ∼200 nm diameter. In vitro, the results revealed that combining GALA-Chol with siRNA RET/PTC1-SQ NPs decreased cell viability, enhanced cellular internalization, and induced gene silencing efficiency in both human PTC (BHP 10-3 SCmice and TPC-1) cell lines. On the contrary, in vivo, the siRNA RET/PTC1-SQ GALA-Chol NPs were not found to be efficient either in gene silencing or in tumor growth inhibition, compared to siRNA RET/PTC1-SQ NPs both via i.t. and i.v. routes (p<0.001).

CONCLUSIONS

Conversely to siRNA RET/PTC1-SQ NPs, the siRNA RET/PTC1-SQ GALA-Chol NPs are efficient in vitro but not in vivo. Finally, NPs of siRNA RET/PTC1-SQ were found to be efficient silencers of the RET/PTC1 fusion oncogene in in vivo applications even at a concentration lower than used in a previously published study.

Novel delivery system for T-oligo using a nanocomplex formed with an alpha helical peptide for melanoma therapy

Oligonucleotides homologous to 3′-telomere overhang (T-oligos) trigger inherent telomere-based DNA damage responses mediated by p53 and/or ATM and induce senescence or apoptosis in various cancerous cells. However, T-oligo has limited stability in vivo due to serum and intracellular nucleases. To develop T-oligo as an innovative, effective therapeutic drug and to understand its mechanism of action, we investigated the antitumor effects of T-oligo or T-oligo complexed with a novel cationic alpha helical peptide, PVBLG-8 (PVBLG), in a p53 null melanoma cell line both in vitro and in vivo. The uptake of T-oligo by MM-AN cells was confirmed by immunofluorescence, and fluorescence-activated cell sorting analysis indicated that the T-oligo-PVBLG nanocomplex increased uptake by 15-fold. In vitro results showed a 3-fold increase in MM-AN cell growth inhibition by the T-oligo-PVBLG nanocomplex compared with T-oligo alone. Treatment of preformed tumors in immunodeficient mice with the T-oligo-PVBLG nanocomplex resulted in a 3-fold reduction in tumor volume compared with T-oligo alone. This reduction in tumor volume was associated with decreased vascular endothelial growth factor expression and induction of thrombospondin-1 expression and apoptosis. Moreover, T-oligo treatment downregulated procaspase-3 and procaspase-7 and increased catalytic activity of caspase-3 by 4-fold in MM-AN cells. Furthermore, T-oligo induced a 10-fold increase of senescence and upregulated the melanoma tumor-associated antigens MART-1, tyrosinase, and thrombospondin-1 in MM-AN cells, which are currently being targeted for melanoma immunotherapy. Interestingly, siRNA-mediated knockdown of p73 (4–10-fold) abolished this upregulation of tumor-associated antigens. In summary, we suggest a key role of p73 in mediating the anticancer effects of T-oligo and introduce a novel nanoparticle, the T-oligo-PVBLG nanocomplex, as an effective anticancer therapeutic.

Bioengineering strategies for designing targeted cancer therapies

The goals of bioengineering strategies for targeted cancer therapies are (1) to deliver a high dose of an anticancer drug directly to a cancer tumor, (2) to enhance drug uptake by malignant cells, and (3) to minimize drug uptake by nonmalignant cells. Effective cancer-targeting therapies will require both passive- and active-targeting strategies and a thorough understanding of physiologic barriers to targeted drug delivery. Designing a targeted therapy includes the selection and optimization of a nanoparticle delivery vehicle for passive accumulation in tumors, a targeting moiety for active receptor-mediated uptake, and stimuli-responsive polymers for control of drug release. The future direction of cancer targeting is a combinatorial approach, in which targeting therapies are designed to use multiple-targeting strategies. The combinatorial approach will enable combination therapy for delivery of multiple drugs and dual ligand targeting to improve targeting specificity. Targeted cancer treatments in development and the new combinatorial approaches show promise for improving targeted anticancer drug delivery and improving treatment outcomes.

STAT6 siRNA matrix-loaded gelatin nanocarriers: formulation, characterization, and ex vivo proof of concept using adenocarcinoma cells

The clinical utility of siRNA therapy has been hampered due to poor cell penetration, nonspecific effects, rapid degradation, and short half-life. We herewith proposed the formulation development of STAT6 siRNA (S6S) nanotherapeutic agent by encapsulating them within gelatin nanocarriers (GNC). The prepared nanoformulation was characterized for size, charge, loading efficiency, release kinetics, stability, cytotoxicity, and gene silencing assay. The stability of S6S-GNC was also assessed under conditions of varying pH, serum level, and using electrophoretic assays. In vitro cytotoxicity performance was evaluated in human adenocarcinoma A549 cells following MTT assay. The developed formulation resulted in an average particle size, surface charge, and encapsulation efficiency as 70 ± 6.5 nm, +10 ± 1.5 mV, and 85 ± 4.0%, respectively. S6S-GNC showed an insignificant (P < 0.05) change in the size and charge in the presence of buffer solutions (pH 6.4 to 8.4) and FBS (10% v/v). A549 cells were treated with native S6S, S6S-lipofectamine, placebo-GNC, and S6S-GNC using untreated cells as a control. It was observed that cell viability was decreased significantly with S6S-GNC by 55 ± 4.1% (P < 0.001) compared to native S6S (2.0 ± 0.55%) and S6S-lipofectamine complex (40 ± 3.1%). This investigation infers that gelatin polymer-based nanocarriers are a robust, stable, and biocompatible strategy for the delivery of siRNA.

The role of gene therapy in regenerative surgery: updated insights

BACKGROUND

In the past two decades, regenerative surgeons have focused increasing attention on the potential of gene therapy for treatment of local disorders and injuries. Gene transfer techniques may provide an effective local and short-term induction of growth factors without the limits of other topical therapies. In 2002, Tepper and Mehrara accurately reviewed the topic: given the substantial advancement of research on this issue, an updated review is provided.

METHODS

Literature indexed in the National Center for Biotechnology Information database (PubMed) has been reviewed using variable combinations of keywords ("gene therapy," "regenerative medicine," "tissue regeneration," and "gene medicine"). Articles investigating the association between gene therapies and local pathologic conditions have been considered. Attention has been focused on articles published after 2002. Further literature has been obtained by analysis of references listed in reviewed articles.

RESULTS

Gene therapy approaches have been successfully adopted in preclinical models for treatment of a large variety of local diseases affecting almost every type of tissue. Experiences in abnormalities involving skin (e.g., chronic wounds, burn injuries, pathologic scars), bone, cartilage, endothelia, and nerves have been reviewed. In addition, the supporting role of gene therapies to other tissue-engineering approaches has been discussed. Despite initial reports, clinical evidence has been provided only for treatment of diabetic ulcers, rheumatoid arthritis, and osteoarthritis.

CONCLUSIONS

Translation of gene therapy strategies into human clinical trials is still a lengthy, difficult, and expensive process. Even so, cutting-edge gene therapy-based strategies in reconstructive procedures could soon set valuable milestones for development of efficient treatments in a growing number of local diseases and injuries.

Bimodal gold nanoparticle therapeutics for manipulating exogenous and endogenous protein levels in mammalian cells

A new advance in cell transfection protocol using a bimodal nanoparticle agent to selectively manipulate protein expression levels within mammalian cells is demonstrated. The nanoparticle based transfection approach functions by controlled release of gene regulatory elements from a 6 nm AuNP (gold nanoparticle) surface. The endosomal release of the regulatory elements from the nanoparticle surface results in endogenous protein knockdown simultaneously with exogenous protein expression for the first 48 h. The use of fluorescent proteins as the endogenous and exogenous signals for protein expression enables the efficiency of codelivery of siRNA (small interfering RNA) for GFP (green fluorescent protein) knockdown and a dsRed-express linearized plasmid for induction to be optically analyzed in CRL-2794, a human kidney cell line expressing an unstable green fluorescent protein. Delivery of the bimodal nanoparticle in cationic liposomes results in 20% GFP knockdown within 24 h of delivery and continues exhibiting knockdown for up to 48 h for the bimodal agent. Simultaneous dsRed expression is observed to initiate within the same time frame with expression levels reaching 34% after 25 days although cells have divided approximately 20 times, implying daughter cell transfection has occurred. Fluorescence cell sorting results in a stable colony, as demonstrated by Western blot analysis. The simultaneous delivery of siRNA and linearized plasmid DNA on the surface of a single nanocrystal provides a unique method for definitive genetic control within a single cell and leads to a very efficient cell transfection protocol.