Experimental adenovirus gene therapy for cancer patients with advanced tumors : Translational medicine from basic research to the patient's bedside
Year: 2013
Type: dissertation
Abstract: The treatment results of many cancers have improved, but there are still challenges, such as metastatic cancers that mostly lack curative treatments. Oncolytic adenoviruses provide a new therapeutic option. Adenoviruses can be modified to replicate specifically in cancer cells and thereby causing the death of cancer cells (oncolysis). Adenovirus treatments are well tolerated and they can be combined with conventional treatments. In the pre-clinical section of this thesis we evaluated the combination of adenoviruses and radiotherapy. We studied the mechanism of radiation-mediated upregulation of adenoviral transgenes. Three cancer cell lines were used: M4A4-LM3 (breast cancer), PC-3MM2 (prostate cancer) and LNM35/eGFP (lung cancer). Cancer cells were exposed to radiation and infected with various replication-deficient adenoviruses. The transgene expression with or without radiation was evaluated. The radiation response was also modulated by DNA protein kinase-, heat shock protein 90- and topoisomerase-I inhibitor. Radiation increased adenovirus transgene expression (luciferase or GFP) regardless of the transgene, promoter, cancer cell line or radiation dose. We showed that enhancement of transgene expression is mediated through genotoxic stress regulation and repair. This synergy can be used for therapeutic benefit. In the clinical section 157 cancer patients with advanced solid tumors were treated with different oncolytic adenoviruses. The safety, efficacy and immunological responses of treatments were evaluated. The safety was monitored by clinical chemistry, cytokine measurements and CTCAE analysis for adverse events. Immunological responses were quantified by neutralizing antibodies, viral genomes in the blood and measuring responses in tumor- and adenovirus-specific T-cells. RECIST analysis and tumor markers were applied to treatment efficacy analysis. We also compared the safety and efficacy of a serial treatment scheme, three rounds of virus, to a single treatment. Adenovirus treatments were well tolerated and commonly detected clinical adverse events were of grade 2 or less including injection or tumor site pain, nausea, fever and fatigue. Six out of 157 treated patients (3.8 %) experienced a grade 4 adverse event. Serious adverse events were seen in 11 patients (7.0 %). No treatment related deaths occurred. According to RECIST analysis disease control (= stable disease or better) was seen in 40.0 - 74.0 % of patients and a stabilization or a decrease in tumor markers for 23.1 - 70.6 % of patients. Serial treatment was as well tolerated as single treatment, but results suggested a better median survival even though statistical significance was not reached. These findings represent a good justification for forthcoming clinical trials.
Source: Työväentutkimus Vuosikirja
Author: Petri Nokisalmi
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W1500928632