Photoacoustic Probes for Molecular Detection: Recent Advances and Perspectives

Photoacoustic (PA) imaging (PAI) is a noninvasive and nonionizing biomedical imaging modality that combines the advantages of optical imaging and ultrasound imaging. Based on PAI, photoacoustic detection (PAD) is an emerging approach that is involved with the interaction between PA probes and analytes resulting in the changes of photoacoustic signals for molecular detection with rich contrast, high resolution, and deep tissue penetration. This Review focuses on the recent development of PA probes in PAD. The following contents will be discussed in detail: 1) the construction of PA probes; 2) the applications and mechanisms of PAD to different types of analytes, including microenvironments, small biomolecules, or metal ions; 3) the challenges and perspectives of PA probes in PAD.

Dopamine D1-Like Receptor Agonist and D2-Like Receptor Antagonist (-)-Stepholidine Reduces Reinstatement of Drug-Seeking Behavior for 3,4-Methylenedioxypyrovalerone (MDPV) in Rats

Psychostimulant reinforcement is mediated by stimulation of both dopamine (DA) D1-like and D2-like receptors, suggesting that pharmacotherapy agents with a dual DA receptor mechanism may be useful for managing psychostimulant abuse. (-)-Stepholidine (L-SPD) is a Chinese herbal extract that functions as a D1-like receptor agonist and D2-like receptor antagonist. L-SPD has been shown to attenuate the reinforcing effects of heroin; however, its effects on the synthetic cathinone 3,4-methylenedioxypyrovalerone (MDPV) have not been examined. The current study determined the effects of L-SPD on reinstatement of MDPV-seeking behavior in the drug intravenous self-administration (IVSA) and conditioned place preference (CPP) paradigms. To determine whether the effects of L-SPD were specific to psychostimulant reinforcement, we also examined its effects on sucrose-seeking behavior. Using a locomotor activity assay, we tested the locomotor effects of L-SPD, as well as its effects on MDPV-induced hyperactivity. The results of a battery of in vitro binding and functional assays confirmed that L-SPD functioned as a D1-like receptor agonist and D2-like receptor antagonist. In behavioral experiments, L-SPD dose-dependently attenuated cue plus MDPV-primed reinstatement of MDPV-seeking behavior in the IVSA model. The highest dose of L-SPD also attenuated MDPV-primed reinstatement of MDPV CPP, as well as cue-induced reinstatement of sucrose-seeking. L-SPD had no significant locomotor effects, and did not modulate the robust hyperactivity induced by MDPV. The current findings show for the first time a robust reinstatement effect with MDPV, which can be reduced by L-SPD. These results establish a role for DA receptors in drug-seeking behavior for MDPV.

Identification of cisplatin sensitizers through high-throughput combinatorial screening

cis-Diamminedichloroplatinum/cisplatin (CDDP) is a major drug used in cancer chemotherapy; however, the toxic side-effects and development of drug resistance represent major challenges to the clinical use of CDDP. The aim of the present study was to identify effective drug combination regimens through high-throughput drug screening that can enhance the efficacy of CDDP, and to investigate the underlying mechanisms. A cell-based high-throughput screening methodology was implemented, using a library of 1,280 Food and Drug Administration (FDA)-approved drugs, to identify clinical compounds that act synergistically with CDDP. Our study identified two compounds, namely potassium antimony tartrate and topotecan, that significantly enhanced the sensitivity of colorectal and non-small cell lung cancer cells to CDDP. The synergistic action of both compounds with CDDP was confirmed by further quantitative analyses. Topotecan is a topoisomerase-1 inhibitor that has previously been shown to enhance the clinical response and overall patient survival when combined with CDDP by a yet unclear mechanism. We demonstrated that the combination of topotecan with CDDP significantly inhibited colony formation ability and increased the apoptosis of several cancer cell lines. Mechanistic analyses revealed that topotecan enhanced CDDP-induced DNA damage and inhibited the repair of DNA strand breaks, without affecting the cellular platinum content. Overall, the findings of this study demonstrated that the use of the FDA-approved drug panel in high-throughput screening is an effective method for identifying effective therapeutic regimens that are clinically relevant, and may have high feasibility for translation into clinical practice.

Aberrant FGFR Tyrosine Kinase Signaling Enhances the Warburg Effect by Reprogramming LDH Isoform Expression and Activity in Prostate Cancer

The acquisition of ectopic fibroblast growthfactor receptor 1 (FGFR1) expression is well documented in prostate cancer progression. How it contributes to prostate cancer progression is not fully understood, although it is known to confer a growth advantage and promote cell survival. Here, we report that FGFR1 tyrosine kinase reprograms the energy metabolism of prostate cancer cells by regulating the expression of lactate dehydrogenase (LDH) isozymes. FGFR1 increased LDHA stability through tyrosine phosphorylation and reduced LDHB expression by promoting its promoter methylation, thereby shifting cell metabolism from oxidative phosphorylation to aerobic glycolysis. LDHA depletion compromised, whereas LDHB depletion enhanced the tumorigenicity of prostate cancer cells. Furthermore, FGFR1 overexpression and aberrant LDH isozyme expression were associated with short overall survival and biochemical recurrence times in patients with prostate cancer. Our results indicate that ectopic FGFR1 expression reprograms the energy metabolism of prostate cancer cells, representing a hallmark change in prostate cancer progression.Significance: FGF signaling drives the Warburg effect through differential regulation of LDHA and LDHB, thereby promoting the progression of prostate cancer.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/16/4459/F1.large.jpg Cancer Res; 78(16); 4459-70. ©2018 AACR.

Association of CXCR2 genotype variations with HCV clearance in a Chinese population

Chemokines are known to play a vital role in guiding and regulating the immune response to viral infections. The chemokine CXC subfamily is a major subfamily in the chemokine family. Outcomes of hepatitis C virus (HCV) infection, as well as the response to treatment, depend on virus and host factors. Here we recruited chronic hepatitis C (CHC) patients to perform an association study between three single nucleotide polymorphisms (SNPs) (CXCR2 rs1126579, CXCL10 rs8878 and CXCL10 rs3921) and HCV infection outcomes and treatment responses among a Chinese population, using primarily a TaqMan assay. Multivariate logistic regression analysis was performed to identify the influencing factors on HCV infection outcome and treatment response. The results showed that subjects with the CXCR2 rs1126579 TT genotype had a significantly increased possibility of HCV spontaneous clearance (Dominant model: adjusted OR = 1.32, 95% CI = 1.06-1.64; P = 0.013). Additionally, CHC patients carrying the CXCR2 rs1126579 TT genotype were also more likely to achieve a sustained virological response (SVR) (Dominant model: adjusted OR = 0.49, 95% CI = 0.29-0.84; P = 0.010). We also established a predictive model for HCV treatment response including the CXCR2 rs1126579 SNP status, albumin (ALB) levels and baseline HCV RNA levels, which produced an area under the curve (AUC) of about 0.660. These findings highlight that variant CXCR2 rs1126579 genotypes are associated with HCV clearance within the Chinese population.

Calcified inferior vena cava and right atrial myxoma in an 18-month-old male: A case report

INTRODUCTION

Cardiac myxomas are the most frequent primary cardiac tumor in adults. The incidence in pediatric patients is extremely low. Heavy calcification of an atrial myxoma is uncommon in children.

CASE PRESENTATION

An 18-month-old boy was admitted for a significant precordial systolic murmur. Transthoracic echocardiography revealed a cardiac mass extending from the inferior vena cava across the right atrium and tricuspid valve into the right ventricle with severe tricuspid regurgitation. According to the echocardiography result, the patient was diagnosed with an inferior vena cava and right atrial tumor with tricuspid regurgitation. After the diagnosis, the patient underwent removal of the tumor via median sternotomy. The mass was removed under cardiopulmonary bypass with deep hypothermia circulatory arrest. The tricuspid valve was repaired by valvuloplasty and annuloplasty. The postoperative recovery was unremarkable. Follow-up echocardiogram at 1 month revealed moderate tricuspid regurgitation without myxoma recurrence.

CONCLUSION

Heavy calcification of an atrial myxoma is uncommon especially in children. Definitive therapy for myxomas requires prompt surgical excision and long-term follow-up is recommended in children although recurrence after excision is rare.

Multi-layered tumor-targeting photothermal-doxorubicin releasing nanotubes eradicate tumors in vivo with negligible systemic toxicity

Multi-layered single-walled carbon nanotubes, termed SWNT@BSA@Au-S-PEG-FA@DOX, which integrate photothermal therapy with small molecule drug delivery, were prepared using a facile layer-by-layer assembly process. Oxidized and cut single-walled carbon nanotubes (SWNTs) were coated with bovine serum albumin (BSA) to provide abundant active sites for the nucleation of Au seeds, which are subsequently converted into gold nanoparticles (Au NPs) by in situ reduction. The resulting SWNT@BSA@Au material exhibits ideal photothermal properties. Further modification of the nanomaterial with folic acid terminated-polyglycol (FA-PEG-SH) and subsequent loading with doxorubicin (DOX) afford the SWNT@BSA@Au-S-PEG-FA@DOX. The FA terminated PEG endows the material with high water-dispersibility, biocompatibility and cancer cell selectivity. A high drug loading ratio for DOX of up to 590% was achieved, with the drug release being pH and temperature dependent, adding to the selectivity of the system. High efficacy of the SWNT@BSA@Au-S-PEG-FA@DOX material, when combined with photothermal therapy (irradiation of the tumor with an 808 nm laser, 1 W cm-2 for 5 min, 24 h after systemic injection of the nanomedicine), was demonstrated in vivo, resulting in complete tumor eradication. Remarkably, the side effects are negligible with only minor damage to normal tissues including the liver and kidneys being observed.

Cd/In-Codoped TiO2 nanochips for high-efficiency photocatalytic dye degradation

Titanium dioxide has been widely investigated in the field of photocatalysis research. However, the wide bandgap (3.2 eV) greatly limits its practical applications because only ultraviolet light can be absorbed by bare TiO2. Herein, we report a facile approach to prepare Cd/In-codoped TiO2 nanochips with the capability of visible light absorption. Such bimetallic-doped TiO2 was synthesized through a two-step process: Cd/In/S-TiO2 gels were first synthesized by mixing the preformed Cd-In-S supertetrahedral nanoclusters with a titanium source, and the subsequent pyrolytic process effectively converted the gels into Cd/In-TiO2 nanochips with a thickness of ∼2.19 nm and a uniform diameter of ∼10.60 nm. Interestingly, the absorption band of Cd/In-TiO2 nanochips was adjusted by pyrolysis temperature, which further regulated the photocatalytic efficiency of dye degradation under visible light. Current research demonstrates that doping TiO2 by multimetallic sulfide nanoclusters opens up a new door to further enrich the dopants in TiO2 and broaden their potential applications.

Changes in the bilateral pulse transit time difference with a moving arm

BACKGROUND:

Changes of pulse transit time (PTT) induced by arm position were studied for unilateral arm. However, consistency of the PTT changes was not validated for both arm sides.

OBJECTIVE:

We aimed to quantify the PTT changes between horizontal and non-horizontal positions from right arm and left arm in order to explore the consistency of both arms.

METHODS:

Twenty-four normal subjects aged between 21 and 50 (14 male and 10 female) years were enrolled. Left and right radial artery pulses were synchronously recorded from 24 healthy subjects with one arm (left or right) at five angles (90∘, 45∘, 0∘, -45∘ and -90∘) and the other arm at the horizontal level (0∘) for reference.

RESULTS:

The overall mean PTT changes at the five angles (from 90∘ to -90∘) in the left arm (right as reference) were 16.1, 12.3, -0.5, -2.5 and -2.6 ms, respectively, and in the right arm (left as reference) were 18.0, 12.6, 1.6, -1.6 and -2.0 ms, respectively.

CONCLUSIONS:

Obvious differences were not found in the PTT changes between the two arms (left arm moving or right arm moving) under each of the five different positions (all P> 0.05).

Optimized application of the secreted Nano-luciferase reporter system using an affinity purification strategy

Secreted Nano-luciferase (secNluc) is a newly engineered secreted luciferase that possesses advantages of high structural stability, long half-life, and glow-type kinetics together with high light emission intensity, and thus would become one of the most valuable tools for bioluminescence assays. However, like other secreted luciferases, secNluc has to mix with the components in the conditioned medium surrounding test cells, or in the biological samples such as blood or urine after being secreted. These components may interfere with secNluc-catalyzed bioluminescence reactions and thus limit the application of the secNluc reporter system. In this study, we first examined the effects of three factors, pH, serum and residual reagents, on secNluc-catalyzed bioluminescence reactions, finding that these factors could interfere with bioluminescence reactions and result in background signal. To resolve these problems, we applied a simple affinity purification strategy in which secNluc was fused with a FLAG-tag, and anti-FLAG magnetic beads were used to catch and transfer the fusion protein to PBST, an optimal buffer for secNluc-catalyzed bioluminescence reactions that was identified in this study. The results indicated that this strategy could not only negate the interferences from serum or residual reagents and enhance the stability of light emission but also greatly increase signal intensity through enzyme enrichment. This strategy may contribute to biomedical studies that utilize secNluc and other secreted luciferases, especially those requiring superior sensitivity, low background noise and high reproducibility.

Room-Temperature and Aqueous Solution-Processed Two-Dimensional TiS2 as an Electron Transport Layer for Highly Efficient and Stable Planar n-i-p Perovskite Solar Cells

In this study, a room-temperature and aqueous solution-processed two-dimensional (2D) transition-metal dichalcogenide TiS₂ was applied as an electron transport layer (ETL) in planar n-i-p perovskite solar cells (Pero-SCs). Upon insertion of the 2D TiS₂ ETL with UV-ozone (UVO) treatment, the power conversion efficiency (PCE) of the planar Pero-SCs was optimized to 18.79%. To the best of our knowledge, this value should be the highest efficiency to date among those PCEs of the n-i-p Pero-SCs with room-temperature-processed metal compound ETLs. More importantly, the n-i-p Pero-SCs with the UVO-treated 2D TiS₂ as an ETL also show extremely high stability, where the average PCE remained over 95% of its initial value after 816 h storage without encapsulation.

Identification of lncRNAs via microarray analysis for predicting HER2-negative breast cancer response to neoadjuvant chemotherapy

Mortality is high in patients with locally advanced HER2-negative breast cancer, especially those with residual tumor after neoadjuvant chemotherapy (NAC). Tissue-specific long non-coding RNAs (lncRNAs) are responsible for specific breast cancer subtypes. To identify the lncRNAs involved in residual cancer tissues (RCTs) and to evaluate their potential for predicting HER2-negative breast cancer response to NAC, we used three paired tissues to compare differences in gene expression between RCTs and remittent tissues (RTs) after NAC in human HER2-negative breast cancer. Subsequently, we detected expression of the top ten up-regulated and down-regulated lncRNAs in 11 paired tissues via quantitative RT-PCR analysis. Finally, we explored the potential function of these dysregulated lncRNAs through bioinformatics analysis. Our results indicate that 1348 mRNAs and 183 lncRNAs were differentially expressed in RCTs compared with RTs, and the expression levels of four novel lncRNAs (DSCAM-AS1, LINC01508, lnc-MGST1-2 and lnc-BTG2-2) were in agreement with the microarray analysis results. Furthermore, we found that the expression level of LINC01508 was significantly related to poor prognosis, suggesting that LINC01508 is a potential biomarker for predicting breast cancer response to NAC, which might be helpful in exploring potential diagnostic factors and therapeutic targets for chemo-resistant HER2-negative breast cancer.

Remote ischemic preconditioning upregulates microRNA-21 to protect the kidney in children with congenital heart disease undergoing cardiopulmonary bypass

BACKGROUND

Acute kidney injury (AKI) is one of the most common emergencies and severe diseases in the clinic. We sought to verify whether remote ischemic preconditioning (RIPC) has a protective effect on the kidney of child with congenital heart disease undergoing cardiopulmonary bypass (CPB) surgery. We hypothesized it may be related to the up-regulation of microRNA-21 (miR-21).

METHODS

We performed a prospective randomized clinical study among children with congenital heart disease undergoing CPB surgery between January and December 2016. Children were randomized to an RIPC or control group. Patients in each group were divided into an AKI and a non-AKI group according to the occurrence of AKI at 48 h after surgery. Remote ischemic preconditioning (RIPC) conducted by blood-pressure cuff was performed 12 h before surgery. Serum creatinine (S_Cr), tumor necrosis factor-α (TNF-α), and miR-21 expression in blood and urine were measured at different time points.

RESULTS

A total of 449 cases (200 RIPC; 249 controls) were enrolled. The male/female ratio was 1.18, with a mean age of 37.50 ± 25.31 months. The incidence of AKI in the RIPC group was significantly lower than that in the control group (19.0% vs. 46.2%, P<0.01). In further analysis, at 6 h, 24 h, and 48 h after CPB operation, blood TNF-α levels were significantly lower in the RIPC group than in the control group (P<0.01); at 24 h, 48 h, and 72 h, urine TNF-α levels were significantly lower in the RIPC group than in the control group (P<0.05). Urine and blood miR-21 expression in the RIPC group increased significantly, while there was no obvious change in the control group.

CONCLUSIONS

Remote ischemic preconditioning has a protective effect on the kidney in children with congenital heart disease, which may be related with the up-regulation of miR-21 and down-regulating the inflammatory mediator, such as TNF-α.

PD-1 Blockade Cellular Vesicles for Cancer Immunotherapy

Cancer cells resist to the host immune antitumor response via multiple suppressive mechanisms, including the overexpression of PD-L1 that exhausts antigen-specific CD8⁺ T cells through PD-1 receptors. Checkpoint blockade antibodies against PD-1 or PD-L1 have shown unprecedented clinical responses. However, limited host response rate underlines the need to develop alternative engineering approaches. Here, engineered cellular nanovesicles (NVs) presenting PD-1 receptors on their membranes, which enhance antitumor responses by disrupting the PD-1/PD-L1 immune inhibitory axis, are reported. PD-1 NVs exhibit a long circulation and can bind to the PD-L1 on melanoma cancer cells. Furthermore, 1-methyl-tryptophan, an inhibitor of indoleamine 2,3-dioxygenase can be loaded into the PD-1 NVs to synergistically disrupt another immune tolerance pathway in the tumor microenvironment. Additionally, PD-1 NVs remarkably increase the density of CD8⁺ tumor infiltrating lymphocytes in the tumor margin, which directly drive tumor regression.

Increased Tumor Glycolysis Characterizes Immune Resistance to Adoptive T Cell Therapy

Adoptive T cell therapy (ACT) produces durable responses in some cancer patients; however, most tumors are refractory to ACT and the molecular mechanisms underlying resistance are unclear. Using two independent approaches, we identified tumor glycolysis as a pathway associated with immune resistance in melanoma. Glycolysis-related genes were upregulated in melanoma and lung cancer patient samples poorly infiltrated by T cells. Overexpression of glycolysis-related molecules impaired T cell killing of tumor cells, whereas inhibition of glycolysis enhanced T cell-mediated antitumor immunity in vitro and in vivo. Moreover, glycolysis-related gene expression was higher in melanoma tissues from ACT-refractory patients, and tumor cells derived from these patients exhibited higher glycolytic activity. We identified reduced levels of IRF1 and CXCL10 immunostimulatory molecules in highly glycolytic melanoma cells. Our findings demonstrate that tumor glycolysis is associated with the efficacy of ACT and identify the glycolysis pathway as a candidate target for combinatorial therapeutic intervention.

Down-Regulated miR-125a-5p Promotes the Reprogramming of Glucose Metabolism and Cell Malignancy by Increasing Levels of CD147 in Thyroid Cancer

BACKGROUND

CD147 contributes to increased aerobic glycolysis through which it promotes tumor growth. Accumulating evidence suggests that CD147 exerts a variety of functions in thyroid cancer (TC) progression but the molecular mechanisms and therapeutic value of CD147 remain unclear.

METHODS

CD147 levels in TC tissues were analyzed to assess its relationship with prognosis and disease progression. A microRNA (miRNA) microarray and bioinformatics approach were used to identify microRNA regulators of CD147 through measurement of the expression and functions of these miRNAs in TC tissues and cell lines. Precursor miRNA-transfected cells were used to assess regulation of CD147 by miRNA. The effect of miRNA on TC cells via inhibition of glycolysis through CD147 targeting was also evaluated.

RESULTS

We found that miR-125a-5p regulates CD147 and is negatively correlated with its expression and function. Moreover, CD147 knockdown or increased miR-125a-5p expression significantly reduced the viability, migration, and invasion of TC cells. Our mechanistic studies demonstrate that, through directly repressing the expression of the CD147 protein, miR-125a-5p suppresses aerobic glycolysis and lactate production and subsequently reduces TC cell viability, migration, and invasion, thereby exerting tumor suppressor functions.

CONCLUSIONS

The novel connection identified between miR-125a-5p and CD147 suggests a new diagnostic and prognostic role for miR-125a-5p and that CD147 inhibition may be a candidate therapeutic target in the therapy of for TC.

The association of CCL3 and CCL4 polymorphisms with HCV clearance in Chinese Han population

AIM

To explore the association of CCL3 (rs1063340) and CCL4 (rs1049807) polymorphisms with hepatitis C virus (HCV) clearance and sustained virologic response (SVR).

METHODS

Two populations were enrolled in the current study; one was a general population including 1585 untreated individuals, with HCV infection and the other was a treatment population comprising 353 HCV-infected patients treated with pegylated interferon-α and ribavirin (pegIFN-α/RBV). Two single nucleotide polymorphisms (SNPs) were genotyped, and the relationship between HCV clearance and treatment outcome was analysed.

RESULTS

The general population comprised 995 persistent HCV cases (both HCV RNA and anti-HCV were positive) and 590 spontaneous clearance cases (HCV RNA was negative, but anti-HCV was positive). An association between the SNPs and HCV clearance was not found in our study. The treatment population consisted of 235 patients who achieved SVR and 118 non-responders. Variants of both SNPs (rs1063340-C and rs1049807-G) were associated with a reduction in SVR following IFN treatment (dominant model: P = 0.026 for rs1063340 and P = 0.048 for rs1049807). In addition, the ancestral alleles of rs1063340 and rs1049807 increased the likelihood of virus clearance by 62% compared to both the derived and minor alleles of the two SNPs (P = 0.040).The interaction analysis showed that the level of glucose interacted with the association of rs1063340 and SVR.

CONCLUSIONS

Our results suggested that genetic variants at the CCL3 and CCL4 loci may be marker SNPs for risk of HCV treatment outcome.

Identifying first-episode drug naïve patients with schizophrenia with or without auditory verbal hallucinations using whole-brain functional connectivity: A pattern analysis study

Many studies have focused on patients with schizophrenia with or without auditory verbal hallucinations (AVHs), but due to the complexity of schizophrenia, biologically based diagnosis of patients with schizophrenia remains unsolved. The objectives of this study are to classify between first-episode drug-naïve patients with schizophrenia and healthy controls, and to classify between patients with and without AVHs. Resting state fMRI data from 41 patients with schizophrenia (22 with and 19 without AVHs) and 23 normal controls (NC) were included to compute functional connectivity between brain regions. Classifiers based on support vector machine (SVM) were developed to classify patients with schizophrenia from NC, as well as between the two subgroups of patients. The classification accuracy was evaluated with a leave-one-out cross-validation (LOOCV) strategy. The accuracy in discriminating both subgroups of patients from NC was 81.3%, with 92.0% (sensitivity) and 65.2% (specificity) for the patients and NC, respectively. The classification accuracy in discriminating patients with and without AVHs was 75.6%, with 77.3% (sensitivity) and 73.9% (specificity) for patients with and without AVHs, respectively. The results suggest that functional connectivity provided good discriminative power not only for identifying patients with schizophrenia among NC, but also in discriminating patients with schizophrenia with and without AVHs.

3D Bioprinting of Artificial Tissues: Construction of Biomimetic Microstructures

It is promising that artificial tissues/organs for clinical application can be produced via 3D bioprinting of living cells and biomaterials. The construction of microstructures biomimicking native tissues is crucially important to create artificial tissues with biological functions. For instance, the fabrication of vessel-like networks to supply cells with initial nutrient and oxygen, and the arrangement of multiple types of cells for creating lamellar/complex tissues through 3D bioprinting are widely reported. The current advances in 3D bioprinting of artificial tissues from the view of construction of biomimetic microstructures, especially the fabrication of lamellar, vascular, and complex structures are summarized. In the end, the conclusion and perspective of 3D bioprinting for clinical applications are elaborated.