A novel RNA aptamer identifies plasma membrane ATP synthase beta subunit as an early marker and therapeutic target in aggressive cancer

Recent advancements in aptamers as promising nanotool for therapeutic and diagnostic applications

Aptamers are single-strand oligonucleotide molecules having certain structural interactions which allow them to bind to specific targets. Modified nucleotides are added during or after a selection procedure like Systematic Evolution of Ligands by Exponential Enrichment i.e., SELEX to enhance the characteristics and functionality of aptamers. Aptamers are extensible molecular tools with several uses such as in drug administration, biosensing, bioimaging, drug therapies and diagnostics. The ability to detect is improved by using aptamer-based sensors in conjunction with biological molecules among other sensing techniques. Chemical modification, and strong resistance to denaturation, aptamers are appropriate biological recognizing agents for developing sensitive and repeatable aptasensors. This review discusses the most current developments in the aptamers, SELEX method, applications of aptamers as innovative diagnostic, therapeutic & theragnostic tool along with major limitations & prospective directions in the future.

The VDAC1 oligomerization regulated by ATP5B leads to the NLRP3 inflammasome activation in the liver cells under PFOS exposure

As a persistent organic pollutant, perfluorooctane sulfonate (PFOS) has a serious detrimental impact on human health. It has been suggested that PFOS is associated with liver inflammation. However, the underlying mechanisms are still unclear. Here, PFOS was found to elevate the oligomerization tendency of voltage-dependent anion channel 1 (VDAC1) in the mice liver and human normal liver cells L-02. Inhibition of VDAC1 oligomerization alleviated PFOS-induced nucleotide-binding domain and leucine-rich repeat protein-3 (NLRP3) inflammasome activation. Cytoplasmic membrane VDAC1 translocated to mitochondria was also observed in response to PFOS. Therefore, the oligomerization of VDAC1 occurred mainly in the mitochondria. VDAC1 was found to interact with the ATP synthase beta subunit (ATP5B) under PFOS treatment. Knockdown of ATP5B or immobilization of ATP5B to the cytoplasmic membrane alleviated the increased VDAC1 oligomerization and NLRP3 inflammasome activation. Therefore, our results suggested that PFOS induced NLRP3 inflammasome activation through VDAC1 oligomerization, a process dependent on ATP5B to transfer VDAC1 from the plasma membrane to the mitochondria. The findings offer novel perspectives on the activation of the NLRP3 inflammasome, the regulatory mode on VDAC1 oligomerization, and the mechanism of PFOS toxicity.

Autophagy-dependent lysosomal calcium overload and the ATP5B-regulated lysosomes-mitochondria calcium transmission induce liver insulin resistance under perfluorooctane sulfonate exposure

Perfluorooctane sulfonate (PFOS), an officially listed persistent organic pollutant, is a widely distributed perfluoroalkyl substance. Epidemiological studies have shown that PFOS is intimately linked to the occurrence of insulin resistance (IR). However, the detailed mechanism remains obscure. In previous studies, we found that mitochondrial calcium overload was concerned with hepatic IR induced by PFOS. In this study, we found that PFOS exposure noticeably raised lysosomal calcium in L-02 hepatocytes from 0.5 h. In the PFOS-cultured L-02 cells, inhibiting autophagy alleviated lysosomal calcium overload. Inhibition of mitochondrial calcium uptake aggravated the accumulation of lysosomal calcium, while inhibition of lysosomal calcium outflowing reversed PFOS-induced mitochondrial calcium overload and IR. Transient receptor potential mucolipin 1 (TRPML1), the calcium output channel of lysosomes, interacted with voltage-dependent anion channel 1 (VDAC1), the calcium intake channel of mitochondria, in the PFOS-cultured cells. Moreover, we found that ATP synthase F1 subunit beta (ATP5B) interacted with TRPML1 and VDAC1 in the L-02 cells and the liver of mice under PFOS exposure. Inhibiting ATP5B expression or restraining the ATP5B on the plasma membrane reduced the interplay between TRPML1 and VDAC1, reversed the mitochondrial calcium overload and deteriorated the lysosomal calcium accumulation in the PFOS-cultured cells. Our research unveils the molecular regulation of the calcium crosstalk between lysosomes and mitochondria, and explains PFOS-induced IR in the context of activated autophagy.

Advances of aptamer-based small-molecules sensors in body fluids detection

The field of aptamer-based sensing has evolved considerably over the past three decades. The aptamer sensor-based detection of small-molecule targets in body fluids is designed for real-time or rapid, low-cost, non- or minimally invasive tracking and diagnosis of human health status. It can be achieved by specifically monitoring biomarkers or metabolites excreted from various body fluids, including blood, urine, cerebrospinal fluid, saliva, ect. This article reviews a comprehensive collection of aptamer-based sensors for detecting small-molecule in various body fluids. A comparative analysis of aptamer features, emerging chemistry, advanced sensing materials, transduction techniques, and detection performance is conducted, and the strengths and pitfalls of each approach are discussed. Finally, the development process and application challenges of aptamer-based sensors in the detection of small-molecule in body fluids are presented and discussed.

RNA therapeutics in cancer treatment

RNA therapeutics are a class of drugs that use RNA molecules to treat diseases, including cancer. RNA therapeutics work by targeting specific genes or proteins involved in the disease process, with the aim of blocking or altering their activity to ultimately halt or reverse the disease progression. The use of RNA therapeutics in cancer treatment has shown great potential, as they offer the ability to specifically target cancer cells while leaving healthy cells intact. This is in contrast to traditional chemotherapy and radiation treatments, which can damage healthy cells and cause unpleasant side effects. The field of RNA therapeutics is rapidly advancing, with several types of RNA molecules being developed for cancer treatment, including small interfering RNA, microRNA, mRNA, and RNA aptamers. Each type of RNA molecule has unique properties and mechanisms of action, allowing for targeted and personalized cancer treatments. In this chapter, we will explore the different types of RNA therapeutics used in cancer treatment, their mechanisms of action, and their potential applications in treating different types of cancer. We will also discuss the challenges and opportunities in the development and research of RNA therapeutics for cancer, as well as the future outlook for this promising field.

Targeted Delivery of Potent Chemical Drugs and RNAi to Drug-Resistant Breast Cancer Using RNA-Nanotechnology and RNA-Ligand Displaying Extracellular vesicles

This review describes a new technology to treat breast-cancer-drug-resistance by targeting the ABC as the multi-homo-subunit ATPase, enlightening by the Christmas-lighting budge with serial circuit and the asymmetrical homo-hexamer of the phi29 DNA packaging motor with sequential revolving mechanism. Chemotherapeutics has been widely used in breast cancer treatments, but drug resistance has raised a serious concern. RNA therapeutics has emerged as the third milestone in pharmaceutical drug development. RNA nanoparticles are dynamic, mild, and deformative, resulting in spontaneous, rapid, and efficient accumulation in tumor vasculature after IV injection. Their negative charge and favorable size bypass the nonspecific targeting of vital organs and normal cells. This motile and deformable nature also led to the fast passing of glomerular filters and their movement into the urine for rapid body clearance for those non-tumor-accumulated nanoparticles, resulting in undetectable toxicity. Extracellular vesicles have shown potential as a delivery system for RNAi and chemotherapeutic drugs in vivo, contributing to the efficacy of cancer remission. However, the lack of cell-targeting ligands on extracellular vesicles and the nonspecific entry into healthy cells has led to safety concerns. This review addresses how to apply RNA nanotechnology and RNA-ligand displaying extracellular vesicles for specific delivery to breast cancer. The particular focus is on using and combining the RNA and extracellular vesicle technology to deal with breast cancer drug resistance. The targeting capabilities and drug safety can be improved through extracellular vesicle engineering techniques, such as affixing ligands on the extracellular vesicle surface utilizing arrow-tail RNA nanoparticles, ultimately addressing off-target effects and toxicity. Using RNA ligands for specific targeting and the efficient membrane fusion of extracellular vesicles has enabled the development of ligand-displayed extracellular vesicles capable of delivering both RNAi and chemical drugs to cells with precision, effectively inhibiting tumor growth. The negative charge inherent in the vesicles results in electrostatic repulsion, reducing non-specific binding to healthy cells that contain negatively charged lipid membranes. By leveraging the principles of RNA nanotechnology, the engineering of extracellular vesicles offers a promising avenue for addressing breast cancer drug resistance. This review also discusses applying the series of circuit mechanisms in Christmas-decorating-lighting to develop effective therapeutics to combat breast cancer chemoresistance by targeting the ABC drug transporter and breast cancer surface receptors.

Molecular targets, therapeutic agents and multitasking nanoparticles to deal with cancer stem cells: A narrative review

There is increasing evidence that malignant tumors are initiated and maintained by a sub-population of tumor cells that have similar biological properties to normal adult stem cells. This very small population of Cancer Stem Cells (CSC) comprises tumor initiating cells responsible for cancer recurrence, drug resistance and metastasis. Conventional treatments such as chemotherapy, radiotherapy and surgery, in addition to being potentially toxic and non-specific, may paradoxically increase the population, spread and survival of CSCs. Next-generation sequencing and omics technologies are increasing our understanding of the pathways and factors involved in the development of CSCs, and can help to discover new therapeutic targets against CSCs. In addition, recent advances in nanomedicine have provided hope for the development of optimal specific therapies to eradicate CSCs. Moreover, the use of artificial intelligence and nano-informatics can elucidate new drug targets, and help to design drugs and nanoparticles (NPs) to deal with CSCs. In this review, we first summarize the properties of CSCs and describe the signaling pathways and molecular characteristics responsible for the emergence and survival of CSCs. Also, the location of CSCs within the tumor and the effect of host factors on the creation and maintenance of CSCs are discussed. Newly discovered molecular targets involved in cancer stemness and some novel therapeutic compounds to combat CSCs are highlighted. The optimum properties of anti-CSC NPs, including blood circulation and stability, tumor accumulation and penetration, cellular internalization, drug release, endosomal escape, and aptamers designed for specific targeting of CSCs are covered. Finally, some recent smart NPs designed for therapeutic and theranostic purposes to overcome CSCs are discussed.

Proteomics Investigation of the Impact of the Enterococcus faecalis Secretome on MCF-7 Tumor Cells

Breast cancer is the most prevalent form of cancer among women. The microenvironment of a cancer tumor is surrounded by various cells, including the microbiota. An imbalance between microbes and their host may contribute to the development and spread of breast cancer. Therefore, the objective of this study is to investigate the influence of Enterococcus faecalis on a breast cancer cell line (MCF-7) to mimic the luminal A subtype of breast cancer, using an untargeted proteomics approach to analyze the proteomic profiles of breast cancer cells after their treatment with E. faecalis in order to understand the microbiome and its role in the development of cancer. The breast cancer cell line MCF-7 was cultured and then treated with a 10% bacterial supernatant at two time points (24 h and 48 h) at 37 °C in a humidified incubator with 5% CO2. Proteins were then extracted and separated using two-dimensional difference (2D-DIGE) gel electrophoresis, and the statistically significant proteins (p-value < 0.05, fold change > 1.5) were identified via matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS). The protein fingerprints showed a differential protein expression pattern in the cells treated with E. faecalis for 24 and 48 h compared with the control. We found 58 statistically significant proteins changes in the MCF-7 breast cancer cells affected by E. faecalis. Kilin and transgelin were upregulated after 24 h of treatment and could be used as diagnostic and prognostic markers for breast cancer. In addition, another protein involved in the inhibition of cell proliferation was coiled-coil domain-containing protein 154. The protein markers identified in this study may serve as possible biomarkers for breast cancer progression. This promotes their future uses as important therapeutic goals in the treatment and diagnosis of cancer and increases our understanding of the breast microbiome and its role in the development of cancer.

MTA1, a Novel ATP Synthase Complex Modulator, Enhances Colon Cancer Liver Metastasis by Driving Mitochondrial Metabolism Reprogramming

Liver metastasis is the most fatal event of colon cancer patients. Warburg effect has been long challenged by the fact of upregulated oxidative phosphorylation (OXPHOS), while its mechanism remains unclear. Here, metastasis-associated antigen 1 (MTA1) is identified as a newly identified adenosine triphosphate (ATP) synthase modulator by interacting with ATP synthase F1 subunit alpha (ATP5A), facilitates colon cancer liver metastasis by driving mitochondrial bioenergetic metabolism reprogramming, enhancing OXPHOS; therefore, modulating ATP synthase activity and downstream mTOR pathways. High-throughput screening of an anticancer drug shows MTA1 knockout increases the sensitivity of colon cancer to mitochondrial bioenergetic metabolism-targeted drugs and mTOR inhibitors. Inhibiting ATP5A enhances the sensitivity of liver-metastasized colon cancer to sirolimus in an MTA1-dependent manner. The therapeutic effects are verified in xenograft models and clinical cases. This research identifies a new modulator of mitochondrial bioenergetic reprogramming in cancer metastasis and reveals a new mechanism on upregulating mitochondrial OXPHOS as the reversal of Warburg effect in cancer metastasis is orchestrated.

Impact of Opioids on Cellular Metabolism: Implications for Metabolic Pathways Involved in Cancer

Opioid utilization for pain management is prevalent among cancer patients. There is significant evidence describing the many effects of opioids on cancer development. Despite the pivotal role of metabolic reprogramming in facilitating cancer growth and metastasis, the specific impact of opioids on crucial oncogenic metabolic pathways remains inadequately investigated. This review provides an understanding of the current research on opioid-mediated changes to cellular metabolic pathways crucial for oncogenesis, including glycolysis, the tricarboxylic acid cycle, glutaminolysis, and oxidative phosphorylation (OXPHOS). The existing literature suggests that opioids affect energy production pathways via increasing intracellular glucose levels, increasing the production of lactic acid, and reducing ATP levels through impediment of OXPHOS. Opioids modulate pathways involved in redox balance which may allow cancer cells to overcome ROS-mediated apoptotic signaling. The majority of studies have been conducted in healthy tissue with a predominant focus on neuronal cells. To comprehensively understand the impact of opioids on metabolic pathways critical to cancer progression, research must extend beyond healthy tissue and encompass patient-derived cancer tissue, allowing for a better understanding in the context of the metabolic reprogramming already undergone by cancer cells. The current literature is limited by a lack of direct experimentation exploring opioid-induced changes to cancer metabolism as they relate to tumor growth and patient outcome.

Spatial and temporal dynamics of ATP synthase from mitochondria toward the cell surface

Ectopic ATP synthase complex (eATP synthase), located on cancer cell surface, has been reported to possess catalytic activity that facilitates the generation of ATP in the extracellular environment to establish a suitable microenvironment and to be a potential target for cancer therapy. However, the mechanism of intracellular ATP synthase complex transport remains unclear. Using a combination of spatial proteomics, interaction proteomics, and transcriptomics analyses, we find ATP synthase complex is first assembled in the mitochondria and subsequently delivered to the cell surface along the microtubule via the interplay of dynamin-related protein 1 (DRP1) and kinesin family member 5B (KIF5B). We further demonstrate that the mitochondrial membrane fuses to the plasma membrane in turn to anchor ATP syntheses on the cell surface using super-resolution imaging and real-time fusion assay in live cells. Our results provide a blueprint of eATP synthase trafficking and contribute to the understanding of the dynamics of tumor progression.

Current Methods for Identifying Plasma Membrane Proteins as Cancer Biomarkers

Plasma membrane proteins are a special class of biomolecules present on the cellular membrane. They provide the transport of ions, small molecules, and water in response to internal and external signals, define a cell's immunological identity, and facilitate intra- and intercellular communication. Since they are vital to almost all cellular functions, their mutants, or aberrant expression is linked to many diseases, including cancer, where they are a part of cancer cell-specific molecular signatures and phenotypes. In addition, their surface-exposed domains make them exciting biomarkers for targeting by imaging agents and drugs. This review looks at the challenges in identifying cancer-related cell membrane proteins and the current methodologies that solve most of the challenges. We classified the methodologies as biased, i.e., search cells for the presence of already known membrane proteins. Second, we discuss the unbiased methods that can identify proteins without prior knowledge of what they are. Finally, we discuss the potential impact of membrane proteins on the early detection and treatment of cancer.

Targeted delivery of RNAi to cancer cells using RNA-ligand displaying exosome

Exosome is an excellent vesicle for in vivo delivery of therapeutics, including RNAi and chemical drugs. The extremely high efficiency in cancer regression can partly be attributed to its fusion mechanism in delivering therapeutics to cytosol without endosome trapping. However, being composed of a lipid-bilayer membrane without specific recognition capacity for aimed-cells, the entry into nonspecific cells can lead to potential side-effects and toxicity. Applying engineering approaches for targeting-capacity to deliver therapeutics to specific cells is desirable. Techniques with chemical modification in vitro and genetic engineering in cells have been reported to decorate exosomes with targeting ligands. RNA nanoparticles have been used to harbor tumor-specific ligands displayed on exosome surface. The negative charge reduces nonspecific binding to vital cells with negatively charged lipid-membrane due to the electrostatic repulsion, thus lowering the side-effect and toxicity. In this review, we focus on the uniqueness of RNA nanoparticles for exosome surface display of chemical ligands, small peptides or RNA aptamers, for specific cancer targeting to deliver anticancer therapeutics, highlighting recent advances in targeted delivery of siRNA and miRNA that overcomes the previous RNAi delivery roadblocks. Proper understanding of exosome engineering with RNA nanotechnology promises efficient therapies for a wide range of cancer subtypes.

Mitochondrial iron overload mediated by cooperative transfer of plasma membrane ATP5B and TFR2 to mitochondria triggers hepatic insulin resistance under PFOS exposure

In general populations, insulin resistance (IR) is related to perfluorooctane sulfonate (PFOS), a persistent organic pollutant. However, the underlying mechanism remains unclear. In this study, PFOS induced mitochondrial iron accumulation in the liver of mice and human hepatocytes L-O2. In the PFOS-treated L-O2 cells, mitochondrial iron overload preceded the occurrence of IR, and pharmacological inhibition of mitochondrial iron relieved PFOS-caused IR. Both transferrin receptor 2 (TFR2) and ATP synthase β subunit (ATP5B) were redistributed from the plasma membrane to mitochondria with PFOS treatment. Inhibiting the translocation of TFR2 to mitochondria reversed PFOS-induced mitochondrial iron overload and IR. In the PFOS-treated cells, ATP5B interacted with TFR2. Stabilizing ATP5B on the plasma membrane or knockdown of ATP5B disturbed the translocation of TFR2. PFOS inhibited the activity of plasma-membrane ATP synthase (ectopic ATP synthase, e-ATPS), and activating e-ATPS prevented the translocation of ATP5B and TFR2. Consistently, PFOS induced ATP5B/TFR2 interaction and redistribution of ATP5B and TFR2 to mitochondria in the liver of mice. Thus, our results indicated that mitochondrial iron overload induced by collaborative translocation of ATP5B and TFR2 was an up-stream and initiating event for PFOS-related hepatic IR, providing novel understandings of the biological function of e-ATPS, the regulatory mechanism for mitochondrial iron and the mechanism underlying PFOS toxicity.

Aptamer-Based Tumor-Targeted Diagnosis and Drug Delivery

Early cancer identification is crucial for providing patients with safe and timely therapy. Highly dependable and adaptive technologies will be required to detect the presence of biological markers for cancer at very low levels in the early stages of tumor formation. These techniques have been shown to be beneficial in encouraging patients to develop early intervention plans, which could lead to an increase in the overall survival rate of cancer patients. Targeted drug delivery (TDD) using aptamer is promising due to its favorable properties. Aptamer is suitable for superior TDD system candidates due to its desirable properties including a high binding affinity and specificity, a low immunogenicity, and a chemical composition that can be simply changed.Due to these properties, aptamer-based TDD application has limited drug side effect along with organ damages. The development of aptasensor has been promising in TDD for cancer cell treatment. There are biomarkers and expressed molecules during cancer cell development; however, only few are addressed in aptamer detection study of those molecules. Its great potential of attachment of binding to specific target molecule made aptamer a reliable recognition element. Because of their unique physical, chemical, and biological features, aptamers have a lot of potential in cancer precision medicine.In this review, we summarized aptamer technology and its application in cancer. This includes advantages properties of aptamer technology over other molecules were thoroughly discussed. In addition, we have also elaborated the application of aptamer as a direct therapeutic function and as a targeted drug delivery molecule (aptasensor) in cancer cells with several examples in preclinical and clinical trials.

The SKBR3 cell-membrane proteome reveals telltales of aberrant cancer cell proliferation and targets for precision medicine applications

The plasma membrane proteome resides at the interface between the extra- and intra-cellular environment and through its various roles in signal transduction, immune recognition, nutrient transport, and cell-cell/cell-matrix interactions plays an absolutely critical role in determining the fate of a cell. Our work was aimed at exploring the cell-membrane proteome of a HER2+ breast-cancer cell line (SKBR3) to identify triggers responsible for uncontrolled cell proliferation and intrinsic resources that enable detection and therapeutic interventions. To mimic environmental conditions that enable cancer cells to evolve adaptation/survival traits, cell culture was performed under serum-rich and serum-deprived conditions. Proteomic analysis enabled the identification of ~ 2000 cell-membrane proteins. Classification into proteins with receptor/enzymatic activity, CD antigens, transporters, and cell adhesion/junction proteins uncovered overlapping roles in processes that drive cell growth, apoptosis, differentiation, immune response, adhesion and migration, as well as alternate pathways for proliferation. The large number of tumor markers (> 50) and putative drug targets (> 100) exposed a vast potential for yet unexplored detection and targeting opportunities, whereas the presence of 15 antigen immunological markers enabled an assessment of epithelial, mesenchymal or stemness characteristics. Serum-starved cells displayed altered processes related to mitochondrial OXPHOS/ATP synthesis, protein folding and localization, while serum-treated cells exhibited attributes that support tissue invasion and metastasis. Altogether, our findings advance the understanding of the biological triggers that sustain aberrant cancer cell proliferation, survival and development of resistance to therapeutic drugs, and reveal vast innate opportunities for guiding immunological profiling and precision medicine applications aimed at target selection or drug discovery.

Targeting of Ubiquitin E3 Ligase RNF5 as a Novel Therapeutic Strategy in Neuroectodermal Tumors

RNF5, an endoplasmic reticulum (ER) E3 ubiquitin ligase, participates to the ER-associated protein degradation guaranteeing the protein homeostasis. Depending on tumor model tested, RNF5 exerts pro- or anti-tumor activity. The aim of this study was to elucidate the controversial role of RNF5 in neuroblastoma and melanoma, two neuroectodermal tumors of infancy and adulthood, respectively. RNF5 gene levels are evaluated in publicly available datasets reporting the gene expression profile of melanoma and neuroblastoma primary tumors at diagnosis. The therapeutic effect of Analog-1, an RNF5 pharmacological activator, was investigated on in vitro and in vivo neuroblastoma and melanoma models. In both neuroblastoma and melanoma patients the high expression of RNF5 correlated with a better prognostic outcome. Treatment of neuroblastoma and melanoma cell lines with Analog-1 reduced cell viability by impairing the glutamine availability and energy metabolism through inhibition of F1Fo ATP-synthase activity. This latter event led to a marked increase in oxidative stress, which, in turn, caused cell death. Similarly, neuroblastoma- and melanoma-bearing mice treated with Analog-1 showed a significant delay of tumor growth in comparison to those treated with vehicle only. These findings validate RNF5 as an innovative drug target and support the development of Analog-1 in early phase clinical trials for neuroblastoma and melanoma patients.

Profiling Cancer Cells by Cell-SELEX: Use of Aptamers for Discovery of Actionable Biomarkers and Therapeutic Applications Thereof

The identification of tumor cell-specific surface markers is a key step towards personalized cancer medicine, allowing early assessment and accurate diagnosis, and development of efficacious targeted therapies. Despite significant efforts, currently the spectrum of cell membrane targets associated with approved treatments is still limited, causing an inability to treat a large number of cancers. What mainly limits the number of ideal clinical biomarkers is the high complexity and heterogeneity of several human cancers and still-limited methods for molecular profiling of specific cancer types. Thanks to the simplicity, versatility and effectiveness of its application, cell-SELEX (Systematic Evolution of Ligands by Exponential Enrichment) technology is a valid complement to the present strategies for biomarkers' discovery. We and other researchers worldwide are attempting to apply cell-SELEX to the generation of oligonucleotide aptamers as tools for both identifying new cancer biomarkers and targeting them by innovative therapeutic strategies. In this review, we discuss the potential of cell-SELEX for increasing the currently limited repertoire of actionable cancer cell-surface biomarkers and focus on the use of the selected aptamers as components of innovative conjugates and nano-formulations for cancer therapy.

Defueling the cancer: ATP synthase as an emerging target in cancer therapy

Reprogramming of cellular metabolism is a hallmark of cancer. Mitochondrial ATP synthase (MAS) produces most of the ATP that drives the cell. High expression of the MAS-composing proteins is found during cancer and is linked to a poor prognosis in glioblastoma, ovarian cancer, prostate cancer, breast cancer, and clear cell renal cell carcinoma. Cell surface-expressed ATP synthase, translocated from mitochondrion to cell membrane, involves the angiogenesis, tumorigenesis, and metastasis of cancer. ATP synthase has therefore been considered a therapeutic target. We review recent various ATP synthase inhibitors that suppress tumor growth and are being tested for the clinic.

Advances in Screening and Development of Therapeutic Aptamers Against Cancer Cells

Cancer has become the leading cause of death in recent years. As great advances in medical treatment, emerging therapies of various cancers have been developed. Current treatments include surgery, radiotherapy, chemotherapy, immunotherapy, and targeted therapy. Aptamers are synthetic ssDNA or RNA. They can bind tightly to target molecules due to their unique tertiary structure. It is easy for aptamers to be screened, synthesized, programmed, and chemically modified. Aptamers are emerging targeted drugs that hold great potentials, called therapeutic aptamers. There are few types of therapeutic aptamers that have already been approved by the US Food and Drug Administration (FDA) for disease treatment. Now more and more therapeutic aptamers are in the stage of preclinical research or clinical trials. This review summarized the screening and development of therapeutic aptamers against different types of cancer cells.

Comparative Proteomic Study Shows the Expression of Hint-1 in Pituitary Adenomas

Pituitary adenomas (PAs) can be unpredictable and aggressive tumors. No reliable markers of their biological behavior have been found. Here, a proteomic analysis was applied to identify proteins in the expression profile between invasive and non-invasive PAs to search for possible biomarkers. A histopathological and immunohistochemical (adenohypophyseal hormones, Ki-67, p53, CD34, VEGF, Flk1 antibodies) analysis was done; a proteomic map was evaluated in 64 out of 128 tumors. There were 107 (84%) invasive and 21 (16%) non-invasive PAs; 80.5% belonged to III and IV grades of the Hardy–Vezina classification. Invasive PAs (n = 56) showed 105 ± 43 spots; 86 ± 32 spots in non-invasive PAs (n = 8) were observed. The 13 most prominent spots were selected and 11 proteins related to neoplastic process in different types of tumors were identified. Hint1 (Histidine triad nucleotide-binding protein 1) high expression in invasive PA was found (11.8 ± 1.4, p = 0.005), especially at high index (>10; p = 0.0002). High Hint1 expression was found in invasive VEGF positive PA (13.8 ± 2.3, p = 0.005) and in Flk1 positive PA (14.04 ± 2.28, p = 0.006). Hint1 is related to human tumorigenesis by its interaction with signaling pathways and transcription factors. It could be related to invasive behavior in PAs. This is the first report on Hint expression in PAs. More analysis is needed to find out the possible role of Hint in these tumors.

APTANI2: update of aptamer selection through sequence-structure analysis

SUMMARY

Here we present APTANI2, an expanded and optimized version of APTANI, a computational tool for selecting target-specific aptamers from high-throughput-Systematic Evolution of Ligands by Exponential Enrichment data through sequence-structure analysis. As compared to its original implementation, APTANI2 ranks aptamers and identifies relevant structural motifs through the calculation of a score that combines frequency and structural stability of each secondary structure predicted in any aptamer sequence. In addition, APTANI2 comprises modules for a deeper investigation of sequence motifs and secondary structures, a graphical user interface that enhances its usability, and coding solutions that improve performances.

AVAILABILITY AND IMPLEMENTATION

Source code, documentation and example command lines can be downloaded from http://aptani.unimore.it. APTANI2 is implemented in Python 3.4, released under the GNU GPL3.0 License, and compatible with Linux, Mac OS and the MS Windows subsystem for Linux.

SUPPLEMENTARY INFORMATION

Supplementary information is available at Bioinformatics online.

Natural products and other inhibitors of F1FO ATP synthase

F₁F_O ATP synthase is responsible for the production of >95% of all ATP synthesis within the cell. Dysregulation of its expression, activity or localization is linked to various human diseases including cancer, diabetes, and Alzheimer's and Parkinson's disease. In addition, ATP synthase is a novel and viable drug target for the development of antimicrobials as evidenced by bedaquiline, which was approved in 2012 for the treatment of tuberculosis. Historically, natural products have been a rich source of ATP synthase inhibitors that help unravel the role of F₁F_O ATP synthase in cellular bioenergetics. During the last decade, new modulators of ATP synthase have been discovered through the isolation of novel natural products as well as through a ligand-based drug design process. In addition, new data has been obtained with regards to the structure and function of ATP synthase under physiological and pathological conditions. Crystal structure studies have provided a significant insight into the rotary function of the enzyme and may provide additional opportunities to design a new generation of inhibitors. This review provides an update on recently discovered ATP synthase modulators as well as an update on existing scaffolds.

Cellular Mechanisms of Circulating Tumor Cells During Breast Cancer Metastasis

Circulating tumor cells (CTCs) are cancer cells that detach from the primary site and travel in the blood stream. A higher number of CTCs increases the risk of breast cancer metastasis, and it is inversely associated with the survival rates of patients with breast cancer. Although the numbers of CTCs are generally low and the majority of CTCs die in circulation, the survival of a few CTCs can seed the development of a tumor at a secondary location. An increasing number of studies demonstrate that CTCs undergo modification in response to the dynamic biophysical environment in the blood due in part to fluid shear stress. Fluid shear stress generates reactive oxygen species (ROS), triggers redox-sensitive cell signaling, and alters the function of intracellular organelles. In particular, the mitochondrion is an important target organelle in determining the metastatic phenotype of CTCs. In healthy cells, mitochondria produce adenosine triphosphate (ATP) via oxidative phosphorylation in the electron transport chain, and during oxidative phosphorylation, they produce physiological levels of ROS. Mitochondria also govern death mechanisms such as apoptosis and mitochondrial permeability transition pore opening to, in order eliminate unwanted or damaged cells. However, in cancer cells, mitochondria are dysregulated, causing aberrant energy metabolism, redox homeostasis, and cell death pathways that may favor cancer invasiveness. In this review, we discuss the influence of fluid shear stress on CTCs with an emphasis on breast cancer pathology, then discuss alterations of cellular mechanisms that may increase the metastatic potentials of CTCs.

Advances of aptamers screened by Cell-SELEX in selection procedure, cancer diagnostics and therapeutics

Aptamers are a class of short artificial single-stranded oligo(deoxy) nucleotides that can bind to different targets, which generated by Systematic Evolution of Ligands by Exponential Enrichment (SELEX). Due to excellent selectivity and high affinity to targets, aptamers hold considerable potential as molecular probe in diverse applications ranging from ensuring food safety, monitoring environment, disease diagnosis to therapy. This review highlights recent development and challenges about aptamers screened by Cell-SELEX, and its application about cancer diagnostics and therapeutics. Advances about some operation methods such as seperation method and culture method in aptamers selection procedure were summarized in this paper. Some common challenges and technological difficulties such as nonspecific binding and biostability were discussed. Up to now, the recent endeavors about cancer diagnostic and therapeutic applications of aptamers are summarized and expatiated. Most of aptamers screened by Cell-SELEX took tumor cells as target cells, and such aptamers have been assembled to various aptasensor for cancer diagnosis. Aptamers conjugated various drugs or nanomaterials are functioned for cancer target therapy to improve drugs delivery efficiency and reduce side effects. Furthermore, the duplexed aptamer is discussed to be applied for cancer cells detection and some conflicts of theories about duplexed aptamer designs are analyzed.