Synergistic combination of small molecule inhibitor and RNA interference against antiapoptotic Bcl-2 protein in head and neck cancer cells

Targeting the lactic acid metabolic pathway for antitumor therapy

Lactic acid is one of the most abundant products of cellular metabolism and has historically been considered a cell-damaging metabolic product. However, as research has deepened, the beneficial effects of lactic acid on tumor cells and the tumor microenvironment have received increasing attention from the oncology community. Lactic acid can not only provide tumor cells with energy but also act as a messenger molecule that promotes tumor growth and progression and protects tumor cells from immune cells and killing by radiation and chemotherapy. Thus, the inhibition of tumor cell lactic acid metabolism has emerged as a novel antitumor treatment strategy that can also effectively enhance the efficacy of conventional antitumor therapies. In this review, we classify the currently available therapies targeting lactic acid metabolism and examine their prospects for clinical application.

Anticancer effects of putative and validated BH3-mimetic drugs in head and neck squamous cell carcinomas: An overview of current knowledge

The purpose of this review was to summarise available literature concerning the anticancer effects of both putative and validated BH3-mimetics in head and neck squamous cell carcinomas. A literature search was performed and studies assessing malignant cell lines, xenograft models, and/or humans were considered eligible. A total of 501 studies were identified, of which 40 were included. One phase-II clinical trial assessing gossypol (combined with docetaxel) was found. The remaining 39 preclinical studies investigated cell lines and/or xenograft models involving the use of six validated BH3-mimetics (A-1210477, A-1331852, ABT-737, navitoclax, S63845, venetoclax) and six putative BH3-mimetics (ApoG2, gossypol, obatoclax, sabutoclax, TW-37, and YC137). In preclinical settings, most validated BH3-mimetics were capable of inducing apoptosis (in-vitro) and tumour growth inhibition (in-vivo). The majority of putative BH3-mimetics were also capable of inducing cell death, although important off-target effects, such as autophagy induction, were also described. Combinations with conventional anticancer drugs, ionising radiation, or multiple BH3-mimetics generally resulted in enhanced anticancer effects, such as increased sensitivity to apoptotic stimuli, especially considering some cell lines that showed resistance to either treatment alone. In conclusion, although clinical data are still insufficient to evaluate the anticancer effects of BH3-mimetics in head and neck squamous cell carcinomas, promising results in preclinical settings were observed concerning induction of cell death and inhibition of tumour growth. Therefore, further clinical trials are highly encouraged.

Non-Viral Vectors for Delivery of Nucleic Acid Therapies for Cancer

The research and development of non-viral gene therapy has been extensive over the past decade and has received a big push thanks to the recent successful approval of non-viral nucleic acid therapy products. Despite these developments, nucleic acid therapy applications in cancer have been limited. One of the main causes of this has been the imbalance in development of delivery vectors as compared with sophisticated nucleic acid payloads, such as siRNA, mRNA, etc. This paper reviews non-viral vectors that can be used to deliver nucleic acids for cancer treatment. It discusses various types of vectors and highlights their current applications. Additionally, it discusses a perspective on the current regulatory landscape to facilitate the commercial translation of gene therapy.

MicroRNA-206 suppresses mesothelioma progression via the Ras signaling axis

Malignant pleural mesothelioma (MPM) is an incurable surface neoplasm with peculiar pathobiology. MPM proliferates by using the tyrosine-kinase-Ras pathway. Despite representing an attractive therapeutic target, there are no standard agent(s) specifically inhibiting Ras signaling adopted in clinical settings. We posited that biologic effects of microRNA (miRNA) can disrupt this molecular network. Using patient samples, cell lines, and murine tumor xenograft models, we confirmed specific genes in the Ras pathway are targeted by an MPM-associated miRNA and then examined its therapeutic effects. We verified significant and consistent downregulation of miR-206 in MPM tissues. When miR-206 is ectopically re-expressed in MPM cells and delivered to tumor xenografts in mice, it exerted significant cell killing by suppressing multiple components of the receptor-tyrosine-kinase-Ras-cell-cycle-signaling network; some of which were prognostic when overexpressed and/or have not been druggable. Of note, we validated CDK6 as a novel target of miR-206. Overall, this miR-206-targeting mechanism manifested as induced G1/S cell cycle arrest. In addition, we identified a novel MPM therapeutic combination by adding systemic-route abemaciclib with local-route miR-206, which showed additive efficacy translating to improved survival. Our pre-clinical study suggests a potential pathophysiologic role for, and therapeutic relevance of, miR-206 in MPM.

Droplet microarrays for cell culture: effect of surface properties and nanoliter culture volume on global transcriptomic landscape

The development of novel chemically developed and physically defined surfaces and environments for cell culture and screening is important for various biological applications. The Droplet microarray (DMA) platform based on hydrophilic-superhydrophobic patterning enables high-throughput cellular screening in nanoliter volumes and on various biocompatible surfaces. Here we performed phenotypic and transcriptomic analysis of HeLa-CCL2 cells cultured on DMA, with a goal to analyze cellular response on different surfaces and culture volumes down to 3 nL, compared with conventional cell culture platforms. Our results indicate that cells cultured on four tested substrates: nanostructured nonpolymer, rough and smooth variants of poly(2-hydroxyethyl methacrylate-co-ethylene dimethacrylate) polymer and poly(thioether) dendrimer are compatible with cells grown in Petri dish. Cells cultured on nanostructured nonpolymer coating exhibited the closet transcriptomic resemblance to that of cells grown in Petri dish. Analysis of cells cultured in 100, 9, and 3 nL media droplets on DMA indicated that all but cells grown in 3 nL volumes had unperturbed viability with minimal alterations in the transcriptome compared with 96-well plate. Our findings demonstrate the applicability of DMA for cell-based assays and highlight the possibility of establishing regular cell culture on various biomaterial-coated substrates and in nanoliter volumes, along with routinely used cell culture platforms.

Effect of photodynamic therapy on expression of HRAS, NRAS and caspase 3 genes at mRNA levels, apoptosis of head and neck squamous cell carcinoma cell line

OBJECTIVES

This study aimed to assess the effect of photodynamic therapy (PDT) on expression of CASP3, NRAS and HRAS genes at mRNA levels, and apoptosis of head and neck squamous cell carcinoma (HNSCC) cell line.

MATERIALS AND METHODS

In order to complete the present in vitro study, HNSCC cell line (NCBI C196 HN5) purchased from Pasteur Institute. Cells were divided into four groups; Group 1: photodynamic treatment (laser + methylene blue (MB) as photosensitizer), group 2: MB, group 3: laser (with 660 nm wavelength), and group 4: control (without any treatment). To determine the optimal concentration of MB, in a pilot study, toxicity of MB in different concentration was assessed using MTT assay. Cells in group 1, 2 and 3 was treated at optimal concentration of MB (1.6 μg/mL). Gene expression at mRNA levels was assessed after 24 h incubation, using real-time (qRT)-PCR. The expression of BAX and BCL2 genes at the mRNA levels was analyzed to evaluate apoptosis. 2^-ΔΔCt values of BCL2, BAX, CASP3, NRAS, and HRAS in groups was analyzed using ANOVA. Tukey's HSD and Games Howell test was used to compare between two groups.

RESULTS

Over-expression of BAX (p < 0.001), CASP3 (p < 0.001) and down-regulation of BCL2 (p = 0.004), HRAS (p = 0.023) and NRAS (p = 0.045) were noted in group 1 (PDT), compared with the control group. Treatment by laser alone induce down-regulation of CASP3 (p < 0.05), BAX (p < 0.05), BCL2 (p > 0.05), HRAS (p > 0.05) and NRAS (p > 0.05).

CONCLUSION

PDT caused down-regulation of NRAS, HRAS and BCL2 and over-expression of CASP3 and BAX genes at mRNA levels in HNSCC cell line. The present study raises the possibility that the role of MB on BCL2 down-regulation and BAX and CASP3 over-expression was higher than laser alone while it seems that laser alone was more effective than MB in HRAS and NRAS down-regulation.

Pre-clinical characterization of PKC412, a multi-kinase inhibitor, against colorectal cancer cells

The potential effect of PKC412, a small molecular multi-kinase inhibitor, in colorectal cancer (CRC) cells was evaluated here. We showed that PKC412 was cytotoxic and anti-proliferative against CRC cell lines (HT-29, HCT-116, HT-15 and DLD-1) and primary CRC cells. PKC412 provoked caspase-dependent apoptotic death, and induced G2-M arrest in the CRC cells. AKT activation was inhibited by PKC412 in CRC cells. Reversely, expression of constitutively-active AKT1 (CA-AKT1) decreased the PKC412's cytotoxicity against HT-29 cells. We propose that Bcl-2 could be a primary resistance factor of PKC412. ABT-737, a Bcl-2 inhibitor, or Bcl-2 siRNA knockdown, dramatically potentiated PKC412's lethality against CRC cells. Forced Bcl-2 over-expression, on the other hand, attenuated PKC412's cytotoxicity. Significantly, PKC412 oral administration suppressed AKT activation and inhibited HT-29 tumor growth in nude mice. Mice survival was also improved with PKC412 administration. These results indicate that PKC412 may have potential value for CRC treatment.

(±)-Gossypol induces apoptosis and autophagy in head and neck carcinoma cell lines and inhibits the growth of transplanted salivary gland cancer cells in BALB/c mice

Racemic Gossypol [(±)-GOS], composed of both (-)-GOS and (+)-GOS, is a small BH3-mimetic polyphenol derived from cotton seeds. (±)-GOS has been employed and well tolerated by cancer patients. Head and neck carcinoma (HNC) represents one of the most fatal cancers worldwide, and a significant proportion of HNC expresses high levels of antiapoptotic Bcl-2 proteins. In this study, we demonstrate that (±)-GOS inhibits cell proliferation and induces apoptosis and autophagy of human pharynx, tongue, and salivary gland cancer cell lines and of mouse salivary gland cancer cells (SALTO). (±)-GOS was able to: (a) decrease the ErbB2 protein expression; (b) inhibit the phosphorylation of ERK1/2 and AKT; (c) stimulate p38 and JNK1/2 protein phosphorylation. (±)-GOS administration was safe in BALB/c mice and it reduced the growth of transplanted SALTO cells in vivo and prolonged mice median survival. Our results suggest the potential role of (±)-GOS as an antitumor agent in HNC patients.

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.

"Smart" Nanoparticles Enhance the Cytoplasmic Delivery of Anti-RhoC Silencing RNA and Inhibit the Migration and Invasion of Aggressive Breast Cancer Cells

Rho-GTPases are small GTP-binding proteins that contribute to the epithelial-to-mesenchymal transition by regulating several cellular processes including organization of the actin cytoskeleton, cell motility, transcription, and cell proliferation. Overexpression of RhoC-GTPases (RhoC) in breast cancer has been implicated in poor disease prognosis due to increased cancer cells invasion, migration, and motility, which warranted its consideration as a therapeutic target for inhibiting breast cancer metastasis. Using silencing RNA (siRNA) molecules to knockdown RhoC expression is a promising approach to inhibit breast cancer metastases. However, transforming anti-RhoC siRNA molecules into a viable therapy remains a challenge due to the lack of a biocompatible carrier that can selectively deliver the RNA cargo into breast cancer cells. We report the use of a degradable, pH-sensitive, β-cyclodextrin (βCD)-based polymeric carrier that condenses anti-RhoC siRNA forming "smart" particles. These smart anti-RhoC particles were efficiently internalized, successfully escaped the endosome, and delivered the RNA cargo into the cytoplasm of SUM149 and MDA-MB-231 breast cancer cells. Our results show that anti-RhoC particles used at a low N/P ratio of 2.5/1 suppressed RhoC protein levels by 100% and 90% in SUM149 and MDA-MB-231 cells, respectively. Further, anti-RhoC particles inhibited the invasion, motility, and migration of SUM149 and MDA-MB-231 cells by 40-47%, 57-60%, and 61.5-73%, respectively. Smart particles encapsulating the scrambled siRNA sequence did not affect RhoC protein expression or the invasion, motility, and migration of SUM149 and MDA-MB-231 cells, which indicate the biocompatibility of the polymeric carrier and selectivity of the observed RhoC knockdown. These results collectively indicate the therapeutic potential of smart anti-RhoC particles in arresting the metastatic spread of breast cancer cells.

Oligospermines and Nucleic Acid Interaction: A Structure Property Relationship Study

A variety of delivery vehicles use spermine as a polycationic component to form complexes with nucleic acids. Thus, we investigated the influence of molecular architecture, amine density, and molecular weight of oligospermines on its binding to nucleic acids. We report the synthesis of mono, bis, and tetraspermines with linear, cyclic, dendritic, and quatrefoil architecture. The effect of molecular weight was more pronounced in linear oligospermines than their cyclic counterparts. Oligospermines with similar amine density but different molecular architectures exhibited different binding profiles. Among all oligospermines evaluated, dendritic tetraspermine exhibited the highest binding affinity. Atomistic molecular dynamics simulations also indicated higher affinity for dendritic tetraspermine to siRNA than its linear counterpart suggesting the importance of spermine geometry in binding to nucleic acids. Importantly, dendritic tetraspermine was less toxic than linear tetraspermine, suggesting its potential in nucleic acid delivery.

Simultaneous inhibition of tumor growth and angiogenesis for resistant hepatocellular carcinoma by co-delivery of sorafenib and survivin small hairpin RNA

The development of multidrug resistance (MDR) in human hepatocellular carcinoma (HCC) is one of the major obstacles for successful chemotherapy of HCC. Co-delivery of sorafenib (SF) and survivin shRNA (shSur) was postulated to achieve synergistic effects in reversing MDR, suppressing tumor growth and angiogenesis. For this purpose, in this work, SF and shSur co-loaded pluronic P85-polyethyleneimine/d-α-tocopheryl polyethylene glycol 1000 succinate nanocomplexes (SSNs) were first designed and developed for the treatment of drug resistant HCC. The experimental results showed that SSNs could achieve effective cellular internalization and shSur transfection efficiency, induce significant downregulation of the survivin protein, and cause remarkable cell arrest and cell apoptosis. The tube formulation assay demonstrated that SSNs completely disrupted the enclosed capillary networks formed by human microvascular endothelial cells. The in vivo antitumor efficacy showed that SSNs were superior to that of other treatments on drug resistant hepatocellular tumor models. Therefore, it could be an efficient strategy to co-deliver SF and shSur for therapy of drug resistant HCC.

LRIG1 dictates the chemo-sensitivity of temozolomide (TMZ) in U251 glioblastoma cells via down-regulation of EGFR/topoisomerase-2/Bcl-2

In the current study, we aimed to understand the potential role of leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1) in TMZ-resistance of U251 glioma cells. We established TMZ-resistant U251 clones (U251/TMZ cells), which expressed low level of LRIG1, but high levels of epidermal growth factor receptor (EGFR), topoisomerase-2 (Topo-2) and Bcl-2. Depletion of LRIG1 by the targeted RNA interference (RNAi) upregulated EGFR/Topo-2/Bcl-2 in U251 cells, and the cells were resistant to TMZ. Reversely, over-expression of LRIG1 in U251 cells downregulated EGFR/Topo-2/Bcl-2 expressions, and cells were hyper-sensitive to TMZ. Our data suggested EGFR-dependent mammalian target of rapamycin (mTOR) activation was important for Topo-2 and Bcl-2 expressions in U251/TMZ cells. The EGFR inhibitor and the mTOR inhibitor downregulated Topo-2/Bcl-2 expressions, both inhibitors also restored TMZ sensitivity in U251/TMZ cells. Finally, inhibition of Topo-2 or Bcl-2 by targeted RNAi(s) knockdown or by the corresponding inhibitor re-sensitized U251/TMZ cells to TMZ, indicating that both Topo-2 and Bcl-2 were important for TMZ resistance in the resistant U251 cells. Based on these results, we concluded that LRIG1 inhibits EGFR expression and the downstream signaling activation, interferes with Bcl-2/Topo-2 expressions and eventually sensitizes glioma cells to TMZ.