Adenoviral gene therapy for non-small cell lung cancer

Adenoviral gene therapy is an experimental approach to cancer refractory to standard cancer therapies. Adenoviruses can be utilized as vectors to deliver therapeutic transgenes into cancer cells, while gene therapy with oncolytic adenoviruses exploits the lytic potential of viruses to kill tumor cells. Although adenoviruses demonstrate several advantages over other vectors - such as the unparalleled transduction efficacy and natural tropism to a wide range of tissues - the gene transfer efficacy to cancer cells has been limited, consequently restricting the therapeutic effect. There are, however, several approaches to circumvent this problem. We utilized different modified adenoviruses to obtain information on adenovirus tropism towards non-small cell lung cancer (NSCLC) cells. To enhance therapeutic outcome, oncolytic adenoviruses were evaluated. Further, to enhance gene delivery to tumors, we used mesenchymal stem cells (MSCs) as carriers. To improve adenovirus specificity, we investigated whether widely used cyclooxygenase 2 (Cox-2) promoter is induced by adenovirus infection in nontarget cells and whether selectivity can be retained by the 3 untranslated region (UTR) AU-rich elements. In addition, we investigated whether switching adenovirus fiber can retain gene delivery in the presence of neutralizing antibodies. Our results show that adenoviruses, whose capsids were modified with arginine-glycine-aspartatic acid (RGD-4C), the serotype 3 knob, or polylysins displayed enhanced gene transfer into NSCLC cell lines and fresh clinical specimens from patients. The therapeutic efficacy was further improved by using respective oncolytic adenoviruses with isogenic 24bp deletion in the E1A gene. Cox-2 promoter was also shown to be induced in normal and tumor cells following adenovirus infection, but utilization of 3 UTR elements can increase the tumor specificity of the promoter. Further, the results suggested that use of MSCs could enhance the bioavailability and delivery of adenoviruses into human tumors, although cells had no tumor tropism per se. Finally, we demonstrated that changing adenovirus fiber can allow virus to escape from existing neutralizing antibodies when delivered systemically. In conclusion, these results reveal that adenovirus gene transfer and specificity can be increased by using modified adenoviruses and MSCs as carriers, and fiber modifications simultaneously decrease the effect of neutralizing antibodies. This promising data suggest that these approaches could translate into clinical testing in patients with NSCLC refractory to current modalities.Adenovirus geeniterapia on yksi kehitteillä olevista syövän hoitomuodoista. Adenoviruksia voidaan käyttää joko kuljettimina, joiden avulla kohdekudokseen viedään hoitogeenejä tai syöpäsoluja voidaan tuhota hyödyntämällä adenoviruksien jakautumissykliä, minkä seurauksena infektoitu solu tuhoutuu. Vaikka adenoviruksilla on monia etuja verrattuna muihin viruksiin, niiden kyky infektoida syöpäsoluja on rajallinen. Tässä työssä olemme tutkineet eritavoin muokattujen adenoviruksien kykyä infektoida ei pieni soluisen keuhkosyövän solulinjoja ja lisääntyä niissä. Lisäksi olemme tutkineet mahdollisuutta käyttää mesenkymaalisia kantasoluja kuljettimina, jotta virus saataisiin paremmin kohdennettua tuumorikudokseen. Lisätäksemme adenoviruksien spesifisyyttä, olemme selvittäneet aktivoituuko paljon käytetty tuumorispesifinen promoottori, Cox-2 normaalisoluissa adenovirus infektion seurauksena ja voidaanko promoottorin tuumorispesifisyys palauttaa erillisellä 3'UTR säätelytekijällä. Lopuksi tutkimme, voidaanko adenoviruksen geeninsiirtotehokkuus säilyttää myös adenovirukselle spesifisen immuunivasteen vallitessa vaihtamalla toistamiseen injektoivan viruksen fiber erilaiseen kuin ensimmäisellä hoitokerralla annetulla viruksella. Saadut tulokset osoittavat, että muokatut adenovirukset, jotka on kohdennettu esim. integriineihin tai hepariinisulfaattiproteoglykaaneihin viruksen primäärireseptorin asemesta infektoivat tehokkaammin ei pienisoluisen keuhkosyövän soluja ja lisääntyvät niissä. Cox-2 promoottorin todettiin aktivoituvan adenovirus infektiosta, mutta spesifisyys saatiin palautettua 3'UTR säätelytekijän avulla. Lisäksi adenovirukset saatiin mesenkymaalisien kantasolujen avulla kuljetettua tehokkaammin tuumorikudokseen. Osoitimme myös, että adenoviruksen fiberin vaihtaminen injektiokertojen välillä auttaa virusta välttämään ensimmäisellä kerralla nousseen immuunivasteen vaikutuksen. Yhteenvetona voidaan todeta, että adenoviruksien geeninsiirto tehokuutta ja spesifisyyttä voidaan lisätä käyttämällä muokattuja adenoviruksia ja mesenkymaalisia kantasoluja kuljettimina sekä samanaikaisesti vähentää vasta-aineiden vaikutusta adenoviruksien infektointitehokkuuteen

The putative tumor suppressor gene EphA3 fails to demonstrate a crucial role in murine lung tumorigenesis or morphogenesis

Treatment of non-small cell lung cancer (NSCLC) is based on histological analysis and molecular profiling of targetable driver oncogenes. Therapeutic responses are further defined by the landscape of passenger mutations, or loss of tumor suppressor genes. We report here a thorough study to address the physiological role of the putative lung cancer tumor suppressor EPH receptor A3 (EPHA3), a gene that is frequently mutated in human lung adenocarcinomas. Our data shows that homozygous or heterozygous loss of EphA3 does not alter the progression of murine adenocarcinomas that result from Kras mutation or loss of Trp53, and we detected negligible postnatal expression of EphA3 in adult wildtype lungs. Yet, EphA3 was expressed in the distal mesenchyme of developing mouse lungs, neighboring the epithelial expression of its Efna1 ligand; this is consistent with the known roles of EPH receptors in embryonic development. However, the partial loss of EphA3 leads only to subtle changes in epithelial Nkx2-1, endothelial Cd31 and mesenchymal Fgf10 RNA expression levels, and no macroscopic phenotypic effects on lung epithelial branching, mesenchymal cell proliferation, or abundance and localization of CD31-positive endothelia. The lack of a discernible lung phenotype in EphA3-null mice might indicate lack of an overt role for EPHA3 in the murine lung, or imply functional redundancy between EPHA receptors. Our study shows how biological complexity can challenge in vivo functional validation of mutations identified in sequencing efforts, and provides an incentive for the design of knock-in or conditional models to assign the role of EPHA3 mutation during lung tumorigenesis