Verteporfin Inhibits Cell Proliferation and Induces Apoptosis in Human Leukemia NB4 Cells without Light Activation

Increasing cancer permeability by photodynamic priming: from microenvironment to mechanotransduction signaling

The dense cancer microenvironment is a significant barrier that limits the penetration of anticancer agents, thereby restraining the efficacy of molecular and nanoscale cancer therapeutics. Developing new strategies to enhance the permeability of cancer tissues is of major interest to overcome treatment resistance. Nonetheless, early strategies based on small molecule inhibitors or matrix-degrading enzymes have led to disappointing clinical outcomes by causing increased chemotherapy toxicity and promoting disease progression. In recent years, photodynamic therapy (PDT) has emerged as a novel approach to increase the permeability of cancer tissues. By producing excessive amounts of reactive oxygen species selectively in the cancer microenvironment, PDT increases the accumulation, penetration depth, and efficacy of chemotherapeutics. Importantly, the increased cancer permeability has not been associated to increased metastasis formation. In this review, we provide novel insights into the mechanisms by which this effect, called photodynamic priming, can increase cancer permeability without promoting cell migration and dissemination. This review demonstrates that PDT oxidizes and degrades extracellular matrix proteins, reduces the capacity of cancer cells to adhere to the altered matrix, and interferes with mechanotransduction pathways that promote cancer cell migration and differentiation. Significant knowledge gaps are identified regarding the involvement of critical signaling pathways, and to which extent these events are influenced by the complicated PDT dosimetry. Addressing these knowledge gaps will be vital to further develop PDT as an adjuvant approach to improve cancer permeability, demonstrate the safety and efficacy of this priming approach, and render more cancer patients eligible to receive life-extending treatments.

New Insights into the Clinical Implications of Yes-Associated Protein in Lung Cancer: Roles in Drug Resistance, Tumor Immunity, Autophagy, and Organoid Development

Simple Summary

Innovative advancements in lung cancer treatment have developed over the past decade with the advent of targeted and immune therapies. Yes-associated protein (YAP), an effector of the Hippo pathway, promotes the resistance of these targeted drugs and modulates tumor immunity in lung cancer. YAP is involved in autophagy in lung cancer and plays a prominent role in forming the tubular structure in lung organoids and alveolar differentiation. In this review, we discuss the central roles of YAP in lung cancer and present YAP as a novel target for treating resistance to targeted therapies and immunotherapies in lung cancer.

Abstract

Despite significant innovations in lung cancer treatment, such as targeted therapy and immunotherapy, lung cancer is still the principal cause of cancer-associated death. Novel strategies to overcome drug resistance and inhibit metastasis in cancer are urgently needed. The Hippo pathway and its effector, Yes-associated protein (YAP), play crucial roles in lung development and alveolar differentiation. YAP is known to mediate mechanotransduction, an important process in lung homeostasis and fibrosis. In lung cancer, YAP promotes metastasis and confers resistance against chemotherapeutic drugs and targeted agents. Recent studies revealed that YAP directly controls the expression of programmed death-ligand 1 (PD-L1) and modulates the tumor microenvironment (TME). YAP not only has a profound relationship with autophagy in lung cancer but also controls alveolar differentiation, and is responsible for tubular structure formation in lung organoids. In this review, we discuss the various roles and clinical implications of YAP in lung cancer and propose that targeting YAP can be a promising strategy for treating lung cancer.

New Insights into YES-Associated Protein Signaling Pathways in Hematological Malignancies: Diagnostic and Therapeutic Challenges

Simple Summary

YES-associated protein (YAP) is a co-transcriptional activator that binds to transcriptional factors to increase the rate of transcription of a set of genes, and it can intervene in the onset and progression of different tumors. Most of the data in the literature refer to the effects of the YAP system in solid neoplasms. In this review, we analyze the possibility that YAP can also intervene in hematological neoplasms such as lymphomas, multiple myeloma, and acute and chronic leukemias, modifying the phenomena of cell proliferation and cell death. The possibilities of pharmacological intervention related to the YAP system in an attempt to use its modulation therapeutically are also discussed.

Abstract

The Hippo/YES-associated protein (YAP) signaling pathway is a cell survival and proliferation-control system with its main activity that of regulating cell growth and organ volume. YAP operates as a transcriptional coactivator in regulating the onset, progression, and treatment response in numerous human tumors. Moreover, there is evidence suggesting the involvement of YAP in the control of the hematopoietic system, in physiological conditions rather than in hematological diseases. Nevertheless, several reports have proposed that the effects of YAP in tumor cells are cell-dependent and cell-type-determined, even if YAP usually interrelates with extracellular signaling to stimulate the onset and progression of tumors. In the present review, we report the most recent findings in the literature on the relationship between the YAP system and hematological neoplasms. Moreover, we evaluate the possible therapeutic use of the modulation of the YAP system in the treatment of malignancies. Given the effects of the YAP system in immunosurveillance, tumorigenesis, and chemoresistance, further studies on interactions between the YAP system and hematological malignancies will offer very relevant information for the targeting of these diseases employing YAP modifiers alone or in combination with chemotherapy drugs.

Verteporfin induces apoptosis and reduces the stem cell-like properties in Neuroblastoma tumour-initiating cells through inhibition of the YAP/TAZ pathway

Neuroblastoma is an embryonal malignancy of early childhood arising from the embryonic sympatho-adrenal lineage of the neural crest. About half of all cases are currently classified as high-risk of disease recurrence, with an overall survival rate of less than 40% at 5 years despite intensive therapy. Recent studies on matched primary tumours and at the relapse revealed downregulation of genes transcriptionally silenced by YAP as significant association with neuroblastoma relapse. Here, we evaluated the pharmacological targeting of YAP/TAZ with the YAP/TAZ-TEAD inhibitor Verteporfin (VP) in Tumour Initiating Cells (TICs) derived from High-Risk Neuroblastoma patients. VP treatment suppresses YAP/TAZ expression, induces apoptosis and causes the re-organization of the cytoskeleton reducing cells migration and clonogenic ability. Moreover, VP reduces the percentage of side population cells and ABC transporters involved in drug resistance, and the percentage of stem cell subpopulations CD133+ and CD44⁺ of TICs. Finally, we demonstrated that VP sensitizes TICs to the standard drugs used for neuroblastoma therapy etoposide and cis-platin opening the way to use VP as drug repositioning candidate for recurrent neuroblastoma.

Verteporfin Is a Promising Anti-Tumor Agent for Cervical Carcinoma by Targeting Endoplasmic Reticulum Stress Pathway

Accumulated evidence has shown that the photosensitizer Verteporfin (VP) may be an ideal agent for various cancer types. However, the effect and mechanism of VP on human cervical carcinoma remain rudimentary. The aim of this study was to investigate the effect of VP on human cervical carcinoma cells (HeLa and SiHa cells) and to elucidate the possible mechanism. CCK-8, wound healing assay, flow cytometry analysis, western blotting, TUNEL staining were performed to evaluate the effects of VP on HeLa and SiHa cells in vitro as well as in vivo on a xenograft model. In addition, the role of endoplasmic reticulum (ER) stress in VP-induced apoptosis was investigated using RT-qPCR and western blotting. The results showed that the viability of HeLa and SiHa cells was suppressed by VP in dose- and time-dependent manners. Compared with the control group, apoptosis rates were higher with stronger TUNEL fluorescence signals in the experimental group, which substantiated that VP induced apoptosis at both 2D and 3D cell levels. Besides, VP can squelch the growth of tumors in both sizes and weights on the xenograft models without impairing ovarian reserve. Mechanism studies demonstrated that VP activated ER stress by upregulating the expression of GRP78, CHOP, and Caspase-12, and VP-induced apoptosis can be alleviated when ER stress pathway was inhibited. Our results provided a foundation for repurposing VP as a promising agent for cervical cancer patients without obvious reproductive toxicity by targeting ER stress pathway, and more researches are required to support its application in clinical practice.

Theranostic verteporfin- loaded lipid-polymer liposome for photodynamic applications

In this study we report a novel theranostic lipid-polymer liposome, obtained from DPPC and the triblock copolymer F127 covalently modified with 5(6)-carboxyfluorescein (CF) for photodynamic applications. Due to the presence of F127, small unilamellar vesicle (SUV) liposomes were synthesized by a simple and fast thin-film hydration method without the need for an extrusion process. The vesicles have around 100 nm, low polydispersity and superb solution stability. The clinically used photosensitizer verteporfin (VP) was entrapped into the vesicles, mostly in monomeric form, with 90% loading efficiency. Stern-Volmer and fluorescence lifetime assays showed heterogeneous distribution of the VP and CF into the vesicles, ensuring the integrity of their individual photophysical properties. The theranostic properties were entirely photoactivatable and can be trigged by a unique wavelength (470 nm). The feasibility of the system was tested against the Glioblastoma multiforme cell line T98G. Cellular uptake by time-resolved fluorescence microscopy showed monomerized VP (monoexponential decay, 6.0 ns) at nucleus level, while CF was detected at the membrane by fluorescence microscopy. The strategy's success was supported by the reduction of 98% in the viability of T98G cells by the photoactivated lipid-polymer liposome with [VP] = 1.0 μmol L^-1. Therefore, the novel theranostic liposome is a potential system for use in cancer and ocular disease therapies.

ACADL plays a tumor-suppressor role by targeting Hippo/YAP signaling in hepatocellular carcinoma

Long-chain acyl-CoA dehydrogenase (ACADL) is a mitochondrial enzyme that catalyzes the initial step of fatty acid oxidation, but the role of ACADL in tumor biology remains largely unknown. Here, we found that ACADL was frequently downregulated in hepatocellular carcinoma (HCC), and its low expression was significantly correlated with poor clinical prognosis of HCC patients. Restoring the expression of ACADL in HCC cells resulted cell cycle arrest and growth suppression through suppressing Hippo/YAP signaling evidenced by decreased YAP nuclear accumulation and downstream target genes expression. Reactivation of YAP by XMU-MP-1 diminished the inhibitory effect of ACADL on HCC growth. More importantly, the nuclear accumulation of YAP was negatively correlated with ACADL expression levels in HCC specimens, and YAP inhibitor verteporfin effectively suppressed growth of HCC organoids with low ACADL expression. Together, our findings highlight a novel function of ACADL in regulating HCC growth and targeting ACADL/Yap may be a potential strategy for HCC precise treatment.

Harnessing the Potential Synergistic Interplay Between Photosensitizer Dark Toxicity and Chemotherapy

The combination of photodynamic therapy and taxol- or platinum-based chemotherapy (photochemotherapy) is an effective and promising cancer treatment. While the mechanisms of action of photochemotherapy are actively studied, relatively little is known about the cytotoxicity and molecular alterations induced by the combination of chemotherapy and photosensitizers without light activation in cancer cells. This study investigates the interplay between the photosensitizer benzoporphyrin derivative (BPD) without light activation and cisplatin or paclitaxel in two glioblastoma lines, U87 and U251. The combination effect of BPD and cisplatin in U87 cells is slightly synergistic (combination index, CI = 0.93), showing 1.8- to 2.6-fold lower half-maximal inhibitory concentrations (IC₅₀ ) compared to those of individual drugs. In contrast, combining BPD and paclitaxel is slightly antagonistic (CI = 1.14) in U87 cells. In U251 cells, the combinations of BPD and cisplatin or paclitaxel are both antagonistic (CI = 1.24 and 1.34, respectively). Western blotting was performed to investigate changes in the expression levels of YAP, TAZ, Bcl-2 and EGFR in U87 and U251 cells treated with BPD, cisplatin and paclitaxel, both as monotherapies and in combination. Our study provides insights into the molecular alterations in two glioma lines caused by each monotherapy and the combinations, in order to inform the design of effective treatments.

Verteporfin inhibits oxidative phosphorylation and induces cell death specifically in glioma stem cells

Glioblastoma multiforme (GBM) is the most malignant primary brain tumour in adults. Since glioma stem cells (GSCs) are associated with therapeutic resistance as well as the initiation and recurrence in GBM, therapies targeting GSCs are considered to be effective for long-term survival in GBM. Several reports suggested that oxidative phosphorylation (OXPHOS) of cancer stem cells is important for their survival; however, the requirement of OXPHOS in GSCs remains unclear. Few effective and safe agents that target GSC mitochondria are available in clinical settings. In this study, we demonstrated that GSCs had high OXPHOS activity compared with isogenic differentiated GSCs and that GSC survival depended on their OXPHOS activity. Remarkably, we showed that complexes III and IV had broad therapeutic windows and that the expression levels of mitochondrial DNA-coded components of complexes III and IV were elevated in GSCs compared with differentiated GSCs. Moreover, our search of the Food and Drug Administration-approved drugs for those targeting GSC mitochondria revealed that verteporfin (Visudyne^® ), a drug approved for macular degeneration, was a novel GSC-specific cytotoxic compound that reduced OXPHOS activity. Importantly, the cytotoxic effect of verteporfin was specific to GSCs without any toxicity to normal cells, and the IC₅₀ of approximately 200 nm was ten times less than its maximum blood concentration in humans. Overall, these findings indicated that high mitochondrial OXPHOS of GSCs is a potential GSC-specific vulnerability and that clinically available drugs, such as verteporfin, might become novel GSC-specific cytotoxic agents.

PLCε knockdown prevents serine/glycine metabolism and proliferation of prostate cancer by suppressing YAP

The metabolic reprogramming is an important basis for the development of many tumors, including prostate cancer (PCa). Metabolic changes in many amino acids consist of serine and glycine affect the biological behavior of them. Phospholipase C epsilon (PLCε) plays an important role as an oncogene. However, its role in regulating amino acid metabolism remains unclear. In this study, results found significantly positive correlation between PLCε and Yes-associated protein (YAP) in PCa tissues. LC-MS/MS and GC-MS results further displayed abnormally elevated levels of serine, glycine and its some downstream metabolites in the blood of PCa patients. Secondly, PLCε knockdown can inhibit serine/glycine producing and proliferation of PCa both in vivo and in vitro. Mechanistically, PLCε may affect the serine/glycine metabolism by regulating dephosphorylation and nuclear translocation of YAP. More interestingly, verteporfin (VP, a specific inhibitor of YAP) could effectively enhance the PLCε-depletion induced inhibition of serine/glycine secretion and growth. Overall, this research revealed the possibility of anomalous serine/glycine levels in the blood for the diagnosis of PCa, identified the important role of the PLCε/YAP axis in regulating serine/glycine metabolism, cell proliferation and tumor growth, and suggested the combination of VP with PLCε-depletion may provide a new idea for the treatment of PCa.

Mutations in TOP2B cause autosomal-dominant hereditary hearing loss via inhibition of the PI3K-Akt signalling pathway

Hereditary hearing impairment is a clinically and genetically heterogeneous disease. Whole-exome sequencing was performed on seven affected and six unaffected members in a large Chinese family with autosomal-dominant nonsyndromic hearing loss. The pathogenic variant of the gene encoding human topoisomerase IIβ TOP2B (c.G4837C:p.D1613H) was cosegregated with hearing loss in this pedigree and another two variants of TOP2B were detected in 66 sporadic patients with hearing loss. top2b knockdown led to significant defects in zebrafish inner ears and caused downregulation of akt which resulted in inactivation of PI3K-Akt signalling. As a result, supporting cell and hair cell numbers were reduced through inhibition of the PI3K-Akt pathway. Therefore, we hypothesized that mutations in TOP2B can cause autosomal-dominant nonsyndromic hearing impairment through inhibition of the PI3K-Akt signalling pathway. DATABASE: The whole-exome sequence data in the study are available at the Sequence Read Archive database (NCBI) under the accession numbers SRR9050868, SRR9050867, SRR90508676, SRR90508675, SRR90508674, SRR90508673, SRR90508672, SRR90508671, SRR90508679, SRR90508670, SRR9050859. SRR9050858 and SRR9050857, respectively.

WW-Domain Containing Protein Roles in Breast Tumorigenesis

Protein-protein interactions are key factors in executing protein function. These interactions are mediated through different protein domains or modules. An important domain found in many different types of proteins is WW domain. WW domain-containing proteins were shown to be involved in many human diseases including cancer. Some of these proteins function as either tumor suppressor genes or oncogenes, while others show dual identity. Some of these proteins act on their own and alter the function(s) of specific or multiple proteins implicated in cancer, others interact with their partners to compose WW domain modular pathway. In this review, we discuss the role of WW domain-containing proteins in breast tumorigenesis. We give examples of specific WW domain containing proteins that play roles in breast tumorigenesis and explain the mechanisms through which these proteins lead to breast cancer initiation and progression. We discuss also the possibility of using these proteins as biomarkers or therapeutic targets.

A drug screening assay on cancer cells chronically adapted to acidosis

Background

Drug screening for the identification of compounds with anticancer activity is commonly performed using cell lines cultured under normal oxygen pressure and physiological pH. However, solid tumors are characterized by a microenvironment with limited access to nutrients, reduced oxygen supply and acidosis. Tumor hypoxia and acidosis have been identified as important drivers of malignant progression and contribute to multicellular resistance to different forms of therapy. Tumor acidosis represents an important mechanism mediating drug resistance thus the identification of drugs active on acid-adapted cells may improve the efficacy of cancer therapy.

Methods

Here, we characterized human colon carcinoma cells (HCT116) chronically adapted to grow at pH 6.8 and used them to screen the Prestwick drug library for cytotoxic compounds. Analysis of gene expression profiles in parental and low pH-adapted cells showed several differences relating to cell cycle, metabolism and autophagy.

Results

The screen led to the identification of several compounds which were further selected for their preferential cytotoxicity towards acid-adapted cells. Amongst 11 confirmed hits, we primarily focused our investigation on the benzoporphyrin derivative Verteporfin (VP). VP significantly reduced viability in low pH-adapted HCT116 cells as compared to parental HCT116 cells and normal immortalized epithelial cells. The cytotoxic activity of VP was enhanced by light activation and acidic pH culture conditions, likely via increased acid-dependent drug uptake. VP displayed the unique property to cause light-dependent cross-linking of proteins and resulted in accumulation of polyubiquitinated proteins without inducing inhibition of the proteasome.

Conclusions

Our study provides an example and a tool to identify anticancer drugs targeting acid-adapted cancer cells.

Electronic supplementary material

The online version of this article (10.1186/s12935-018-0645-5) contains supplementary material, which is available to authorized users.

The role of YAP/TAZ activity in cancer metabolic reprogramming

In contrast to normal cells, which use the aerobic oxidation of glucose as their main energy production method, cancer cells prefer to use anaerobic glycolysis to maintain their growth and survival, even under normoxic conditions. Such tumor cell metabolic reprogramming is regulated by factors such as hypoxia and the tumor microenvironment. In addition, dysregulation of certain signaling pathways also contributes to cancer metabolic reprogramming. Among them, the Hippo signaling pathway is a highly conserved tumor suppressor pathway. The core oncosuppressive kinase cascade of Hippo pathway inhibits the nuclear transcriptional co-activators YAP and TAZ, which are the downstream effectors of Hippo pathway and oncogenic factors in many solid cancers. YAP/TAZ function as key nodes of multiple signaling pathways and play multiple regulatory roles in cancer cells. However, their roles in cancer metabolic reprograming are less clear. In the present review, we examine progress in research into the regulatory mechanisms of YAP/TAZ on glucose metabolism, fatty acid metabolism, mevalonate metabolism, and glutamine metabolism in cancer cells. Determining the roles of YAP/TAZ in tumor energy metabolism, particularly in relation to the tumor microenvironment, will provide new strategies and targets for the selective therapy of metabolism-related cancers.

Verteporfin inhibits YAP-induced bladder cancer cell growth and invasion via Hippo signaling pathway

The highly conserved Hippo signaling pathway is one of the most important pathways involved in tumorigenesis and progress. Previous studies show that YAP, the transcriptional coactivator of Hippo pathway, is expressed highly in many clinical bladder cancer tissues and plays crucial role on bladder cancer progress. To find the YAP-specific target drug and its molecular mechanism in bladder cancer, we apply Verteporfin (VP), a YAP specific inhibitor to function as anti-bladder cancer drug and discover that VP is able to inhibit bladder cancer cell growth and invasion in a dosage dependent manner. Moreover, we demonstrate that VP may inhibit bladder cancer cell growth and invasion via repressing target genes' expression of the Hippo signaling pathway. In further study, we provide evidence that VP is able to inhibit excessive YAP induced bladder cancer cell growth and invasion. To address the repressive function of VP against YAP in bladder cancer, we check the target genes' expression and find VP can dramatically repress YAP overexpression induced Hippo pathway target genes' expression. Taken together, we discover that VP inhibits YAP-induced bladder cancer cell growth and invasion via repressing the target genes' expression of Hippo signaling pathway.