uPAR-controlled oncolytic adenoviruses eliminate cancer stem cells in human pancreatic tumors

Hyaluronidase and pH Dual-Responsive Nanoparticles for Targeted Breast Cancer Stem Cells

pH-responsive and CD44 receptor-mediated targeted nanoparticles for eliminating cancer stem cells (CSCs) were developed based on complexes of PEG-poly(β-amino ester) (PEG-PBAE) micelles (PPM) coated with hyaluronic acid (HA) (HA-coated PPM complex, or HPPMc). Thioridazine (Thz) was loaded into HPPMc with a decent drug loading content. The release results of the drug in vitro showed that Thz was released from the HPPMc, which was stimulated by both the acidic pH and specific enzymes. Cytotoxicity studies on mammospheres (MS) revealed that the toxicity potential of Thz-loaded HPPMc (Thz–HPPMc) at pH 5.5 was better than drug solutions. Compared with that at pH 7.4, a higher cellular uptake of a coumarin-6 (C6)-labeled complex at pH 5.5 was observed, which demonstrated that complexes were efficiently taken up in MS. Meanwhile, free HA competitively inhibited the cellular uptake of HPPMc, which revealed that the uptake mechanism was CD44 receptor-mediated endocytosis. Within the acidic endolysosomal environment, the protonation of PBAE facilitated the escape of the complex from the lysosome and releases the drug. The results of in vivo distribution studies and tumor suppression experiments showed that HPMMc could stay in the tumor site of BALB/c nude mice for a longer period of time, and Thz–HPPMc could significantly improve the tumor-suppressing effect. All these results demonstrated the great potential of the multifunctional nanoparticle system for eliminating CSCs.

The Development of Oncolytic Adenovirus Therapy in the Past and Future - For the Case of Pancreatic Cancer

Pancreatic cancer is an aggressive malignant disease and the efficacy of current treatments for unresectable diseases is quite limited despite recent advances. Gene therapy /virotherapy strategies may provide new options for the treatment of various cancers including pancreatic cancer. Oncolytic adenovirus shows an antitumoral effect via its intratumoral amplification and strong cytocidal effect in a variety of cancers and it has been employed for the development of potent oncolytic virotherapy agents for pancreatic cancer. Our ultimate goal is to develop an oncolytic adenovirus enabling the treatment of patients with advanced or spread diseases by systemic injection. Systemic application of oncolytic therapy mandates more efficient and selective gene delivery and needs to embody sufficient antitumor effect even with limited initial delivery to the tumor location. In this review, the current status of oncolytic adenoviruses from the viewpoints of vector design and potential strategies to overcome current obstacles for its clinical application will be described. We will also discuss the efforts to improve the antitumor activity of oncolytic adenovirus, in in vivo animal models, and the combination therapy of oncolytic adenovirus with radiation and chemotherapy.

Role of Gene Therapy in Pancreatic Cancer-A Review

Mortality from pancreatic ductal adenocarcinoma (PDAC) has remained essentially unchanged for decades and its relative contribution to overall cancer death is projected to only increase in the coming years. Current treatment for PDAC includes aggressive chemotherapy and surgical resection in a limited number of patients, with median survival of optimal treatment rather dismal. Recent advances in gene therapies offer novel opportunities for treatment, even in those with locally advanced disease. In this review, we summarize emerging techniques to the design and administration of virotherapy, synthetic vectors, and gene-editing technology. Despite these promising advances, shortcomings continue to exist and here will also be highlighted those approaches to overcoming obstacles in current laboratory and clinical research.

A NOTCH-sensitive uPAR-regulated oncolytic adenovirus effectively suppresses pancreatic tumor growth and triggers synergistic anticancer effects with gemcitabine and nab-paclitaxel

Notch signaling pathway is an embryonic program that becomes reactivated in pancreatic cancer and contributes to cancer stem cell (CSC) maintenance. We explored the concept of oncolytic adenoviral activity in response to Notch activation signaling, in the context of a chimeric promoter with uPAR regulatory sequences, as a strategy to drive its activity in neoplastic and CSC. We explored the advantages of a chemo-virotherapy approach based on synergistic combinations. Regulatory sequences recognized by the transcriptional factor CSL upstream a minimal uPAR promoter were engineered in adenoviral vectors and in the oncolytic adenovirus AdNuPARmE1A. Viral response to Notch signaling, and viral potency in cell lines and pancreatic cancer stem cells (PCSC) was tested. Preclinical toxicity and antitumor efficacy in xenografts and Patient-derived xenografts (PDX) mouse models was evaluated, as unimodal or in combination with gemcitabine+nab-paclitaxel. Mechanistic studies were conducted to explore the synergism of combined therapies.

We demonstrate that CSL-binding site optimized-engineered sequences respond to Notch activation in AdNuPARmLuc and AdNuPARmE1A. AdNuPARmE1A showed strong lytic effects in pancreatic cancer cell lines and PCSC. AdNuPARmE1A displayed attenuated activity in normal tissues, but robust antitumor effects in xenograft and PDX models, leading to a reduced capacity of treated tumors to form tumorspheres. Chemo-virotherapy treatment enlarged therapeutic response in both tumor models. Synergistic effects of the combination resulted from viral sensitization of apoptotic cell death triggered by chemotherapy.

In summary we present a novel effective oncolytic adenovirus, AdNuPARmE1A that reduces PCSC and presents synergistic effects with gemcitabine and nab-paclitaxel, supporting further clinical development.

A view on clinical genetics and genomics in Spain: of challenges and opportunities

A view on clinical genetics and genomics in Spain: of challenges and opportunities.

Late-phase miRNA-controlled oncolytic adenovirus for selective killing of cancer cells

Tissue-specific detargeting by miRNAs has been demonstrated to be a potent strategy to restrict adenoviral replication to cancer cells. These studies have generated adenoviruses with miRNA target sites placed in the 3′UTR of early gene products. In this work, we have studied the feasibility of providing tissue-specific selectivity to replication-competent adenoviruses through the regulation of the late structural protein fiber (L5 gene). We have engineered a 3′UTR containing eight miR-148a binding sites downstream the L5 coding sequence (Ad-L5-8miR148aT). We present in vitro and in vivo evidences of Ad-L5-8miR148aT miRNA-dependent regulation. In vitro data show that at 72 hours post-infection miR-148a-regulation impaired fiber expression leading to a 70% reduction of viral release. The application of seven consecutive rounds of infection in miR-148a cells resulted in 10.000-fold reduction of viral genomes released. In vivo, liver production of infective viral particles was highly impaired, similarly to that triggered by an adenovirus with miRNA target sites regulating the early E1A gene. Noticeably, mice treated with Ad-L5-8miR148aT showed an attenuation of adenoviral-induced hepatotoxicity but retained full lytic activity in cancer cells and exhibited robust antitumoral responses in patient-derived xenografts. Thus, miRNA-control of late proteins constitutes a novel strategy to provide selectivity to adenoviruses.

AduPARE1A and gemcitabine combined treatment trigger synergistic antitumor effects in pancreatic cancer through NF-κB mediated uPAR activation

BACKGROUND

Combined treatment of oncolytic adenoviruses with chemotherapeutic agents is foreseen as a therapeutic option for cancer. Here we have investigated the potential to use gemcitabine in combination with the oncolytic adenovirus AduPARE1A to treat pancreatic cancer and evaluate the underlying mechanism.

METHODS

We treated pancreatic cancer cell lines BxPC-3 and PANC-1 with AduPARE1A and gemcitabine individually or in combination and analyzed cell viability, combination index, apoptosis and viral production. We also investigated the effects of the combination on tumor growth and mice survival in two xenograft models. Furthermore, we analyzed uPAR promoter activity from different uPAR-controlled adenovirus and studied NF-κB mediated effects.

RESULTS

Synergistic cell killing from the combination AduPARE1A/Gemcitabine was observed in BxPC-3 and PANC-1 cells. Moreover, the combination treatment produced therapeutic benefits over either individual modality in two mouse models bearing orthotopic tumors, showing reduced tumor progression and significant prolonged mouse survival. Mechanistic studies showed that the synergistic cell death was not due to an increase in viral replication but occurred through an enhancement of apoptotic cell death. Gemcitabine stimulation increased the transcription of uPAR-controlled transgenes through the induction of NF-κB acting on the uPAR promoter. Interestingly, NF-κB gemcitabine-mediated induction of AduPAR adenoviruses interfered with the activation of NF-κB regulated genes, probably as a result of an intracellular competition for NF-κB DNA binding. Consequently, AduPARE1A infection sensitized cells to gemcitabine-induced apoptosis in the combined treatment.

CONCLUSIONS

These data highlights the potential of the combination as a treatment modality for pancreatic cancer patients.