Enhanced Anticancer Activity of PF-04691502, a Dual PI3K/mTOR Inhibitor, in Combination With VEGF siRNA Against Non-small-cell Lung Cancer

Ionizable Drugs Enable Intracellular Delivery of Co-Formulated siRNA

Targeting complementary pathways in diseases such as cancer can be achieved with co-delivery of small interfering ribonucleic acid (siRNA) and small molecule drugs; however, current formulation strategies are typically limited to one, but not both. Here, ionizable small molecule drugs and siRNA are co-formulated in drug-rich nanoparticles. Ionizable analogs of the selective estrogen receptor degrader fulvestrant self-assemble into colloidal drug aggregates and cause endosomal disruption, allowing co-delivery of siRNA against a non-druggable target. siRNA is encapsulated in lipid-stabilized, drug-rich colloidal nanoparticles where the ionizable lipid used in conventional lipid nanoparticles is replaced with an ionizable fulvestrant analog. The selection of an appropriate phospholipid and formulation buffer enables endocytosis and potent reporter gene knockdown in cancer cells. Importantly, siRNA targeting cyclin E1 is effectively delivered to drug-resistant breast cancer cells, demonstrating the utility of this approach. This strategy opens the possibility of using ionizable drugs to co-deliver RNA and ultimately improve therapeutic outcomes.

A patent perspective of antiangiogenic agents

INTRODUCTION

Angiogenesis plays a crucial role in the development of numerous vascular structures and is involved in a variety of physiologic and pathologic processes, including psoriasis, diabetic retinopathy, and especially cancer. By obstructing the process of angiogenesis, these therapies effectively inhibit the progression of the disease. Consequently, anti-angiogenic agents were subsequently developed.

AREAS COVERED

This review provides a comprehensive summary of the anti-angiogenic inhibitors developed in the past five years in terms of chemical structure, biochemical/pharmacological activity and potential clinical applications. A literature search was conducted using utilizing the databases Web of Science, SciFinder and PubMed with the key word 'anti-angiogenic agents' and 'angiogenesis inhibitor.'

EXPERT OPINION

This is despite the fact that the concept of antiangiogenesis has been proposed for more than 50 years and angiogenesis inhibitors are extensively employed in clinical practice. However, significant challenges continue to confront them. In recent years, there has been a significant increase in the number of patents focusing on angiogenesis inhibitors. These patents aim to enhance the selectivity of drugs against VEGF/VEGFR, explore new targets to overcome drug resistance, and explore potential drug combinations, thereby expanding the therapeutic possibilities in this field.

Quinacrine enhances the efficacy of cisplatin by increasing apoptosis and modulating cancer survival proteins in a colorectal cancer cell line

BACKGROUND

Cisplatin and platinum-based compounds have been used successfully to treat various cancers. However, their use is often restricted due to the acquired resistance by cancer cells. Over-expression of p53 and inhibition of NF-kB sensitize several cancer cells towards cisplatin-induced apoptosis. Quinacrine, a cytotoxic drug with predictable safety revealed to concurrently suppress NF-kB and activate p53, which may be an attractive adjuvant in cisplatin chemotherapy. Therefore, the objective of the present study was to establish the role of quinacrine as an adjuvant in lowering the dose of cisplatin during cancer therapy to circumvent its toxic effects.

MATERIALS AND METHODS

The colon cancer (HCT-8) cells were cultured and cell survival assays were performed using standard procedures. Cell cycle arrest and the extent of apoptosis were determined using a muse cell analyzer. Cancer survival proteins were analyzed using western blotting techniques.

RESULTS AND CONCLUSION

We demonstrated that concomitant use of quinacrine with cisplatin increased cell apoptosis, suppressed cell proliferation and inhibited colony formation in a colorectal cancer cell line. Moreover, cell cycle arrest in the G0/G1 and G2/M phases and upregulation of p53 expression were observed. There was also downregulation of NF-kB and Bcl-xL protein expressions, both of which are associated with enhanced cell apoptosis and an increase in the sensitivity of cancer cells to cisplatin, overcoming its chemoresistance. Overall, the results of the present study and available literature clearly indicate that the use of quinacrine as an adjuvant with cisplatin may enhance its anti-cancer activity and reduce chemoresistance.

Evaluation of a Dual PI3K/mTOR Inhibitor PF-04691502 against Bladder Cancer Cells

Targeting the phosphatidylinositol-3 kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) signalling pathway is a promising strategy for the treatment of various cancers, including bladder cancer (BC). PF-04691502 is a relatively novel dual PI3K/mTOR inhibitor that exerts inhibitory effects against various cancer cells. However, the effects of PF-04691502 in BC cells have not been clarified thus far. This study aimed to evaluate the antitumour effects of PF-04691502 and the mechanisms underlying these antitumour effects in BC cells. The effects of PF-04691502 on the viabilities of BC cells were examined using the cell counting kit 8 (CCK-8) assay. Cell migration and invasion were measured using the wound healing assay and transwell assay, respectively. Cellular apoptosis was determined using flow cytometry. The change in the cellular protein levels was measured using western blotting. siRNA was used to study the role of PTEN in the antitumour effects of PF-04691502. PF-04691502 inhibited the proliferation, migration, and invasion of BC cells. Additionally, PF-04691502 induced apoptosis of BC cells via the intrinsic pathway. PF-04691502 inhibited the expression of Mcl-1 and the PI3K/Akt/mTOR pathway in BC cells. In addition, PF-04691502 increased the apoptosis induced by various chemotherapeutic agents in BC cells. Taken together, PF-04691502 could be used alone or in combination with other chemotherapeutic agents in the treatment of BC.

How can we turn the PI3K/AKT/mTOR pathway down? Insights into inhibition and treatment of cancer

Introduction: The phosphatidylinositol 3-kinase/protein kinase-B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway is a fundamental regulator of cell proliferation and survival. Dysregulation in this pathway leads to the development of cancer. Accumulating evidence indicates that dysregulation in this pathway is involved in cancer initiation, progression, and recurrence. However, the pathway consists of various signal transducing factors related with cellular events, such as transformation, tumorigenesis, cancer progression, and drug resistance. Therefore, it is very important to determine the targets in this pathway for cancer therapy. Although many drugs inhibiting this signaling pathway are in clinical trials or have been approved for treating solid tumors and hematologic malignancies, further understanding of the signaling mechanism is required to achieve better therapeutic efficacy.Areas covered: In this review, we have describe the PI3K/AKT/mTOR pathway in detail, along with its critical role in cancer stem cells, for identifying potential therapeutic targets. We also summarize the recent developments in different types of signaling inhibitors.Expert opinion: Downregulation of the PI3K/AKT/mTOR pathway is very important for treating all types of cancers. Thus, further studies are required to establish novel prognostic factors to support the current progress in cancer treatment with emphasis on this pathway.

3D Microfluidic Platform and Tumor Vascular Mapping for Evaluating Anti-Angiogenic RNAi-Based Nanomedicine

Three-dimensional (3D) visualization of tumor vasculature is a key factor in accurate evaluation of RNA interference (RNAi)-based antiangiogenic nanomedicine, a promising approach for cancer therapeutics. However, this remains challenging because there is not a physiologically relevant in vitro model or precise analytic methodology. To address this limitation, a strategy based on 3D microfluidic angiogenesis-on-a-chip and 3D tumor vascular mapping was developed for evaluating RNAi-based antiangiogenic nanomedicine. We developed a microfluidic model to recapitulate functional 3D angiogenic sprouting when co-cultured with various cancer cell types. This model enabled efficient and rapid assessment of antiangiogenic nanomedicine in treatment of hyper-angiogenic cancer. In addition, tissue-clearing-based whole vascular mapping of tumor xenograft allowed extraction of complex 3D morphological information in diverse quantitative parameters. Using this 3D imaging-based analysis, we observed tumor sub-regional differences in the antiangiogenic effect. Our systematic strategy can help in narrowing down the promising targets of antiangiogenic nanomedicine and then enables deep analysis of complex morphological changes in tumor vasculature, providing a powerful platform for the development of safe and effective nanomedicine for cancer therapeutics.

An in vitro Assessment of Thermo-Reversible Gel Formulation Containing Sunitinib Nanoparticles for Neovascular Age-Related Macular Degeneration

Anti-vascular endothelial growth factor agents have been widely used to treat several eye diseases including age-related macular degeneration (AMD). An approach to maximize the local concentration of drug at the target site and minimize systemic exposure is to be sought. Sunitinib malate, a multiple receptor tyrosine kinase inhibitor was encapsulated in poly(lactic-co-glycolic acid) nanoparticles to impart sustained release. The residence time in vitreal fluid was further increased by incorporating nanoparticles in thermo-reversible gel. Nanoparticles were characterized using TEM, DSC, FTIR, and in vitro drug release profile. The cytotoxicity of the formulation was assessed on ARPE-19 cells using the MTT assay. The cellular uptake, wound scratch assay, and VEGF expression levels were determined in in vitro settings. The optimized formulation had a particle size of 164.5 nm and zeta potential of - 18.27 mV. The entrapment efficiency of 72.0% ± 3.5% and percent drug loading of 9.1 ± 0.7% were achieved. The viability of ARPE-19 cells was greater than 90% for gel loaded, as such and blank nanoparticles at 10 μM and 20 μM concentration tested, whereas for drug solution viability was found to be 83% and 71% respectively at above concentration. The cell viability results suggest the compatibility of the developed formulation. Evaluation of cellular uptake, wound scratch assay, and VEGF expression levels for the developed formulations indicated that the formulation had higher uptake, superior anti-angiogenic potential, and prolonged inhibition of VEGF activity compared with drug solution. The results showed successful development of sunitinib-loaded nanoparticle-based thermo-reversible gel which may be used for the treatment of neovascular AMD.

Design of Oligonucleotide Carriers: Importance of Polyamine Chain Length

Amine containing polymers are extensively studied as special carriers for short-chain RNA (13⁻25 nucleotides), which are applied as gene silencing agents in gene therapy of various diseases including cancer. Elaboration of the oligonucleotide carriers requires knowledge about peculiarities of the oligonucleotide⁻polymeric amine interaction. The critical length of the interacting chains is an important parameter which allows us to design sophisticated constructions containing oligonucleotide binding segments, solubilizing, protective and aiming parts. We studied interactions of (TCAG)n, n = 1⁻6 DNA oligonucleotides with polyethylenimine and poly(N-(3-((3-(dimethylamino)propyl)(methyl)amino)propyl)-N-methylacrylamide). The critical length for oligonucleotides in interaction with polymeric amines is 8⁻12 units and complexation at these length can be accompanied by "all-or-nothing" effects. New dimethylacrylamide based polymers with grafted polyamine chains were obtained and studied in complexation with DNA and RNA oligonucleotides. The most effective interaction and transfection activity into A549 cancer cells and silencing efficiency against vascular endothelial growth factor (VEGF) was found for a sample with average number of nitrogens in polyamine chain equal to 27, i.e., for a sample in which all grafted chains are longer than the critical length for polymeric amine⁻oligonucleotide complexation.

Mechanistic/mammalian target of rapamycin: Recent pathological aspects and inhibitors

The mechanistic/mammalian target of rapamycin (mTOR), also known as the mechanistic target of rapamycin, regulates many normal cell processes such as transcription, cell growth, and autophagy. Overstimulation of mTOR by its ligands, amino acids, sugars, and/or growth factors leads to physiological disorders, including cancer and neurodegenerative diseases. In this study, we reviewed the recent advances regarding the mechanism that involves mTOR in cancer, aging, and neurodegenerative diseases. The chemical and biological properties of recently reported small molecules that function as mTOR kinase inhibitors, including adenosine triphosphate-competitive inhibitors and dual mTOR/PI3K inhibitors, have also been reviewed. We focused on the reports published in the literature from 2012 to 2017.

miR-409 Inhibits Human Non-Small-Cell Lung Cancer Progression by Directly Targeting SPIN1

Lung cancers, the leading cause of cancer mortality worldwide, are characterized by a high metastatic potential. Growing evidence reveals that Spindlin 1 (SPIN1) is involved in tumor progression and carcinogenesis. However, the role of SPIN1 in non-small-cell lung cancer (NSCLC) and the molecular mechanisms underlying SPIN1 in human NSCLC remain undetermined. Here we examined the function of SPIN1 in human NSCLC and found that the expression of SPIN1 was closely correlated with the overall survival and poor prognosis of NSCLC patients. Aberrant regulation of microRNAs (miRNAs) has an important role in cancer progression. We revealed that miR-409 inhibits the expression of SPIN1 by binding directly to the 3′ UTR of SPIN1 using dual-luciferase reporter assays. Overexpression of miR-409 significantly suppressed cell migration, growth, and proliferation by inhibiting SPIN1 in vitro and in vivo. SPIN1 overexpression in miR-409-transfected NSCLC cells effectively rescued the suppression of cell migration, growth, and proliferation regulated by miR-409. miR-409 regulates the PI3K/AKT (protein kinase B) pathway in NSCLC. Moreover, clinical data showed that NSCLC patients with high levels of miR-409 experienced significantly better survival. miR-409 expression was also negatively associated with SPIN1 expression. Taken together, these findings highlight that the miR-409/SPIN1 axis is a useful pleiotropic regulatory network and could predict the metastatic potential in NSCLC patients early, indicating the possibility that miR-409 and SPIN1 might be attractive prognostic markers for treating NSCLC patients.

Reverse of non-small cell lung cancer drug resistance induced by cancer-associated fibroblasts via a paracrine pathway

The tumor microenvironment orchestrates the sustained growth, metastasis and recurrence of cancer. As an indispensable component of the tumor microenvironment, cancer-associated fibroblasts (CAF) are considered as an essential synthetic machine producing various tumor components, leading to cancer sustained stemness, drug resistance and tumor recurrence. Here, we developed a sustainable primary culture of lung cancer cells fed with lung cancer-associated fibroblasts, resulting in enrichment and acquisition of drug resistance in cancer cells. Moreover, IGF2/AKT/Sox2/ABCB1 signaling activation in cancer cells was observed in the presence of CAF, which induces upregulation of P-glycoprotein expression and the drug resistance of non-small cell lung cancer cells. Our results demonstrated that CAF cells constitute a mechanism for cancer drug resistance. Thus, traditional chemotherapy combined with insulin-like growth factor 2 (IGF2) signaling inhibitor may present an innovative therapeutic strategy for non-small cell lung cancer therapy.

Highly Selective, Potent, and Oral mTOR Inhibitor for Treatment of Cancer as Autophagy Inducer

On the basis of novel pyrazino[2,3-c]quinolin-2(1H)-one scaffold, we designed and identified a highly selective, potent and oral mTOR inhibitor, 9m. Compound 9m showed low nanomolar activity against mTOR (IC₅₀ = 7 nM) and greater selectivity over the related PIKK family kinases, which demonstrated only modest activity against 3 out of the 409 protein kinases. In vitro assays, compound 9m exhibited high potency against human breast and cervical cancer cells and induced tumor cell cycle arrest and autophagy. 9m inhibited cellular phosphorylation of mTORC1 (pS6 and p4E-BP1) and mTORC2 (pAKT (S473)) substrates. In T-47D xenograft mouse model, oral administration of compound 9m led to significant tumor regression without obvious toxicity. In addition, this compound showed good pharmacokinetics. Collectively, due to its high potency and selectivity, compound 9m could be used as a mTOR drug candidate.

LncRNA-DANCR contributes to lung adenocarcinoma progression by sponging miR-496 to modulate mTOR expression

Long non‐coding RNAs (lncRNAs) have emerged as new and important regulators of pathological processes including tumour development. In this study, we demonstrated that differentiation antagonizing non‐protein coding RNA (DANCR) was up‐regulated in lung adenocarcinoma (ADC) and that the knockdown of DANCR inhibited tumour cell proliferation, migration and invasion and restored cell apoptosis rescued; cotransfection with a miR‐496 inhibitor reversed these effects. Luciferase reporter assays showed that miR‐496 directly modulated DANCR; additionally, we used RNA‐binding protein immunoprecipitation (RIP) and RNA pull‐down assays to further confirm that the suppression of DANCR by miR‐496 was RISC‐dependent. Our study also indicated that mTOR was a target of miR‐496 and that DANCR could modulate the expression levels of mTOR by working as a competing endogenous RNA (ceRNA). Furthermore, the knockdown of DANCR reduced tumour volumes in vivo compared with those of the control group. In conclusion, this study showed that DANCR might be an oncogenic lncRNA that regulates mTOR expression through directly binding to miR‐496. DANCR may be regarded as a biomarker or therapeutic target for ADC.

miR-206/133b Cluster: A Weapon against Lung Cancer?

Lung cancer is a deadly disease that ends numerous lives around the world. MicroRNAs (miRNAs) are a group of non-coding RNAs involved in a variety of biological processes, such as cell growth, organ development, and tumorigenesis. The miR-206/133b cluster is located on the human chromosome 6p12.2, which is essential for growth and rebuilding of skeletal muscle. The miR-206/133b cluster has been verified to be dysregulated and plays a crucial role in lung cancer. miR-206 and miR-133b participate in lung tumor cell apoptosis, proliferation, migration, invasion, angiogenesis, drug resistance, and cancer treatment. The mechanisms are sophisticated, involving various target genes and molecular pathways, such as MET, EGFR, and the STAT3/HIF-1α/VEGF signal pathway. Hence, in this review, we summarize the role and potential mechanisms of the miR-206/133b cluster in lung cancer.

Therapeutic potentials of short interfering RNAs

Short interfering RNA (siRNA) is one of the members of the family of RNA interference (RNAi). Coupled with the RNA-induced silencing complex (RISC), siRNA is able to trigger the cleavage of target RNAs which serve as a defensive system against pathogens. Meanwhile, siRNA in gene silencing opens a new avenue for the treatment of various diseases. SiRNA can effectively inhibit viral infection and replication and suppress tumorigenesis and various inflammation-associated diseases and cardiovascular diseases by inactivation of viral genes and downregulation of oncogene expression. Recently, endogenous siRNAs (endo-siRNAs) were discovered in the reproductive cells of animals which may be associated with regulation of cell division. Structural modification of siRNA enhances the delivery, specificity and efficacy and bioavailability to the target cells. There are at least five categories of siRNA delivery systems including viral vectors, lipid-based nanoparticles, peptide-based nanoparticles, polymer-based nanoparticles and inorganic small molecules like metal ions, silica and carbon. Sufficient preclinical and clinical studies supported that siRNA may be a potential medicine for targeted therapy of various diseases in the near future.

Targeted Expression of miR-7 Operated by TTF-1 Promoter Inhibited the Growth of Human Lung Cancer through the NDUFA4 Pathway

Targeted expression of gene technique is an important therapeutic strategy for lung cancer. MicroRNA-7 has been well documented as a promising tumor suppressor but never been test in specific gene-promoter-targeted expression in cancer gene therapy. Here, we first evaluated the efficacy of miR-7 expression operated by the promoter of TTF-1, a lineage-specific oncogene in lung cancer, in vitro using an eukaryotic vector of TTF-1-promoter-operated expression of miR-7 (termed as p-T-miR-7). Interestingly, using a nude mice model, the growth and metastasis of human lung cancer cells in vivo were significantly reduced in remote hypodermic injection of the p-T-miR-7 group, accompanied by increased expression of miR-7 and reduced transduction of the Akt and Erk pathway in situ. Mechanism aspect, global gene expression analysis showed that downregulation of NDUFA4, a novel target of miR-7, contributed to the effects of miR-7 expression operated by TTF-1 promoter on the growth and metastasis of human lung cancer cells, as well as altered transduction of the Akt and Erk pathway. Finally, there was no significant difference in weight or histopathology of other organs. These data provided a basis for development of novel modality of miRNA-based targeted expression therapy against clinical lung cancer.