Immunohistochemical Characterization and Sensitivity to Human Adenovirus Serotypes 3, 5, and 11p of New Cell Lines Derived from Human Diffuse Grade II to IV Gliomas

Abstract

BACKGROUND: Oncolytic adenoviruses show promise in targeting gliomas because they do not replicate in normal brain cells. However, clinical responses occur only in a subset of patients. One explanation could be the heterogenic expression level of virus receptors. Another contributing factor could be variable activity of tumor antiviral defenses in different glioma subtypes. METHODS: We established a collection of primary low-passage cell lines from different glioma subtypes (3 glioblastomas, 3 oligoastrocytomas, and 2 oligodendrogliomas) and assessed them for receptor expression and sensitivity to human adenovirus (HAd) serotypes 3, 5, and 11p. To gauge the impact of antiviral defenses, we also compared the infectivity of the oncolytic adenoviruses in interferon (IFN)-pretreated cells with IFN-sensitive Semliki Forest virus (SFV). RESULTS: Immunostaining revealed generally low expression of HAd5 receptor CAR in both primary tumors and derived cell lines. HAd11p receptor CD46 levels were maintained at moderate levels in both primary tumor samples and derived cell lines. HAd3 receptor DSG-2 was reduced in the cell lines compared to the tumors. Yet, at equal multiplicities of infection, the oncolytic potency of HAd5 in vitro in tumor-derived cells was comparable to HAd11p, whereas HAd3 lysed fewer cells than either of the other two HAd serotypes in 72 hours. IFN blocked replication of SFV, while HAds were rather unaffected. CONCLUSIONS: Adenovirus receptor levels on glioma-derived cell lines did not correlate with infection efficacy and may not be a relevant indicator of clinical oncolytic potency. Adenovirus receptor analysis should be preferentially performed on biopsies obtained perioperatively.

Superior infectivity of the fiber chimeric oncolytic adenoviruses Ad5/35 and Ad5/3 over Ad5-delta-24-RGD in primary glioma cultures

“…In support, Niittykoski et al observed that short-term glioma cell cultures significantly reduced or lost DSG2 but not CD46 expression during passaging compared with their parental tumor tissues. 19 Finally, we found that CD46 was expressed abundantly in all of the tested human cell cultures, consistent with previous reports. 19,20 Altogether, these data imply that for personalized oncolytic virotherapy, if applicable at all, measuring the expression levels of adenoviral receptors perioperatively should be preferable and more relevant from a practical point of view, although the expression levels of CAR, DSG2, and CD46 and integrins aVb3/aVb5 did not predict, at least in vitro, the relative oncolytic efficiency of the fiber-modified rAds tested in our study.…”

“…The expression of CAR in glioma tissues and short-term primary glioma cultures was frequently barely detectable. [19][20][21][22]25 However, in established glioma cell lines and in mouse xenografts of shortterm glioma cultures, CAR expression was found to be upregulated compared with that of their parental tumors. 21 A similar and seemingly contradictory situation with the expression of CAR was also reported for melanoma.…”

“…35 DSG2 and CD46 expression is preserved in tumor cells, 36 including glioma tissues. 19 Importantly, the transduction and cytolytic efficacy of Ad5/3 were superior to those of Ad5RGD in different cancer cell types. [37][38][39][40][41][42][43] Similarly, the transduction efficacy of the Ad5/35 reporter virus was higher than that of Ad5RGD in several tested cancer cell types, [44][45][46] including glioma.…”

“…18 However, the expression of CAR in glioma tissues and short-term cultures was frequently barely detectable. [19][20][21][22] CAR-negative/low cells are generally poorly infected with fiber nonmodified Ad5, although there are exceptions. [22][23][24][25] Ad5-delta-24-RGD harbors an RGD motif-containing integrin-targeting peptide (RGD-4C) 26 in the HI loop of the fiber knob domain that substantially improves the transduction efficacy in CAR-negative/low cell lines and the therapeutic efficacy in in vivo models.…”

An oncolytic adenovirus 11p vector expressing adenovirus death protein in the E1 region showed significant apoptosis and tumour-killing ability in metastatic prostate cells

“…Although several research groups recently reported Ad11-based vectors, RCAd11p vector constructs have marked differences. In general, Ad11 exhibits enticing potential as a virotherapy agent [30]. Accordingly, a variant of Ad11 (ColoAd1) was recently investigated in phase I clinical trials for the treatment of solid tumours [31].…”