Non-small lung cancer cells are prime targets for p53 gene transfer mediated by a recombinant adeno-associated virus type-2 vector

Oncolytic viruses in lung cancer treatment: a review article

Lung cancer has a high morbidity rate worldwide due to its resistance to therapy. So new treatment options are needed to improve the outcomes of lung cancer treatment. This study aimed to evaluate the effectiveness of oncolytic viruses (OVs) as a new type of cancer treatment. In this study, 158 articles from PubMed and Scopus from 1994 to 2022 were reviewed on the effectiveness of OVs in the treatment of lung cancer. The oncolytic properties of eight categories of OVs and their interactions with treatment options were investigated. OVs can be applied as a promising immunotherapy option, as they are reproduced selectively in different types of cancer cells, cause tumor cell lysis and trigger efficient immune responses.

Nisin ZP, an Antimicrobial Peptide, Induces Cell Death and Inhibits Non-Small Cell Lung Cancer (NSCLC) Progression in vitro in 2D and 3D Cell Culture

Lung cancer is the leading cause of cancer deaths globally with most of the reported cases (> 85%) associated with non-small cell lung cancer (NSCLC). Current therapies have enhanced the overall survival rate of patients but treatment-related adverse effects and increase in drug-resistance limit the success of these treatment options. Antimicrobial peptides (AMPs) have gained interest as anticancer agents as they selectively target cancer cells and decrease the possibility of resistance. Nisin ZP is a polycyclic antimicrobial peptide produced by the Gram-positive bacterium, Lactococcus lactis and is commonly used as a food preservative. Nisin ZP has recently demonstrated anticancer activity in melanoma, head and neck squamous cell carcinoma, hepatic, colon, and blood cancer. In this study, we evaluated the anticancer potential of nisin ZP and assessed the underlying mechanisms in NSCLC cells. The results revealed that nisin ZP induced selective toxicity in cancer (A549 and H1299) cells compared to healthy (HEK293) cells after 48 h of treatment. Nisin ZP exposure induced apoptosis and cell cycle arrest (G0/G1 phase) in NSCLC cells irrespective of tumor protein p53 expression. The cancer cell proliferation was inhibited via non-membranolytic pathways by mitochondrial membrane depolarization and elevation in reactive oxygen species (ROS) generation. Furthermore, nisin ZP decreased cancer cells' clonal expansion and migration, demonstrating potential use against highly metastatic NSCLC. The 3D spheroid growth and cell viability of the A549 cells were significantly inhibited by nisin ZP compared to control. Overall, the results suggest an excellent antitumor potential in vitro and, thus, can further be developed as a novel therapeutic for NSCLC.

Role of gambogic acid and NaI131 in A549/DDP cells

Resistance to platinum in tumor tissue is a considerable barrier against effective lung cancer treatment. Radionuclide therapy is the primary adjuvant treatment, however, the toxic side effects limit its dosage in the clinical setting. Therefore, the present study aimed to determine whether an NaI¹³¹ radiosensitizer could help reduce the toxic side effects of radionuclide therapy. In vitro experiments were conducted to determine whether NaI¹³¹ can inhibit platinum resistance in A549/DDP cells, which are cisplatin-resistant non-small cell lung cancer cells, and whether gambogic acid (GA) is an effective NaI¹³¹ radiosensitizer. Cell proliferation following drug intervention was analyzed using MTT and isobolographic analysis. Apoptosis was assessed by flow cytometry. In addition, the mechanisms of drug intervention were analyzed by measuring the expression of P-glycoprotein (P-gP), B cell lymphoma 2 (Bcl-2), Bcl2-associated X protein (Bax) and P53 using western blot analysis and immunocytochemistry. According to isobolographic analysis, a low concentration of NaI¹³¹ combined with GA had a synergistic effect on the inhibition of A549/DDP cell proliferation, which was consistent with an increased rate of apoptosis. Furthermore, the overexpression of Bax, and the downregulation of P-gP, P53 and Bcl-2 observed demonstrated the potential mechanism(s) of NaI¹³¹ and GA intervention. NaI¹³¹ may induce apoptosis in A549/DDP cells by regulating apoptosis-related proteins. A low concentration combination of NaI¹³¹ and GA was able to significantly inhibit A549/DDP cell proliferation and induce cell apoptosis. Thus, the two drugs appear to have a synergistic effect on apoptosis of A549/DDP cells.

Comparative analysis of the transduction efficiency of five adeno associated virus serotypes and VSV-G pseudotype lentiviral vector in lung cancer cells

BACKGROUND

Lung cancer is the leading cause of cancer-related deaths in the US. Recombinant vectors based on adeno-associated virus (AAV) and lentivirus are promising delivery tools for gene therapy due to low toxicity and long term expression. The efficiency of the gene delivery system is one of the most important factors directly related to the success of gene therapy.

METHODS

We infected SCLC cell lines, SHP-77, DMS 53, NCI-H82, NCI-H69, NCI-H727, NCI-H1155, and NSCLC cell lines, NCI-H23, NCI-H661, and NCI-H460 with VSV-G pseudo-typed lentivirus or 5 AAV serotypes, AAV2/1, AAV2/2, AAV2/4, AAV2/5, and AAV2/8 expressing the CMV promoter mCherry or green fluorescent protein transgene (EGFP). The transduction efficiency was analyzed by fluorescent microscopy and flow cytometry.

RESULTS

Of all the serotypes of AAV examined, AAV2/1 was the optimal serotype in most of the lung cancer cell lines except for NCI-H69 and NCI-H82. The highest transduction rate achieved with AAV2/1 was between 30-50% at MOI 100. Compared to all AAV serotypes, lentivirus had the highest transduction efficiency of over 50% at MOI 1. Even in NCI-H69 cells resistant to all AAV serotypes, lentivirus had a 10-40% transduction rate. To date, AAV2 is the most widely-used serotype to deliver a transgene. Our results showed the transduction efficiency of AAVs tested was AAV2/1 > AA2/5 = AAV2/2> > AAV2/4 and AAV2/8.

CONCLUSIONS

This study demonstrated that VSV-G pseudotyped lentivirus and AAV2/1 can mediate expression of a transgene for lung cancer gene therapy. Overall, our results showed that lentivirus is the best candidate to deliver a transgene into lung cancer cells for treatment.

Tumor and host factors that may limit efficacy of chemotherapy in non-small cell and small cell lung cancer

While chemotherapy provides useful palliation, advanced lung cancer remains incurable since those tumors that are initially sensitive to therapy rapidly develop acquired resistance. Resistance may arise from impaired drug delivery, extracellular factors, decreased drug uptake into tumor cells, increased drug efflux, drug inactivation by detoxifying factors, decreased drug activation or binding to target, altered target, increased damage repair, tolerance of damage, decreased proapoptotic factors, increased antiapoptotic factors, or altered cell cycling or transcription factors. Factors for which there is now substantial clinical evidence of a link to small cell lung cancer (SCLC) resistance to chemotherapy include MRP (for platinum-based combination chemotherapy) and MDR1/P-gp (for non-platinum agents). SPECT MIBI and Tc-TF scanning appears to predict chemotherapy benefit in SCLC. In non-small cell lung cancer (NSCLC), the strongest clinical evidence is for taxane resistance with elevated expression or mutation of class III beta-tubulin (and possibly alpha tubulin), platinum resistance and expression of ERCC1 or BCRP, gemcitabine resistance and RRM1 expression, and resistance to several agents and COX-2 expression (although COX-2 inhibitors have had minimal impact on drug efficacy clinically). Tumors expressing high BRCA1 may have increased resistance to platinums but increased sensitivity to taxanes. Limited early clinical data suggest that chemotherapy resistance in NSCLC may also be increased with decreased expression of cyclin B1 or of Eg5, or with increased expression of ICAM, matrilysin, osteopontin, DDH, survivin, PCDGF, caveolin-1, p21WAF1/CIP1, or 14-3-3sigma, and that IGF-1R inhibitors may increase efficacy of chemotherapy, particularly in squamous cell carcinomas. Equivocal data (with some positive studies but other negative studies) suggest that NSCLC tumors with some EGFR mutations may have increased sensitivity to chemotherapy, while K-ras mutations and expression of GST-pi, RB or p27kip1 may possibly confer resistance. While limited clinical data suggest that p53 mutations are associated with resistance to platinum-based therapies in NSCLC, data on p53 IHC positivity are equivocal. To date, resistance-modulating strategies have generally not proven clinically useful in lung cancer, although small randomized trials suggest a modest benefit of verapamil and related agents in NSCLC.

RNA aptamer-targeted inhibition of NF-kappa B suppresses non-small cell lung cancer resistance to doxorubicin

Due to the prevalence of tumor chemoresistance, the clinical response of advanced non-small cell lung cancer (NSCLC) to chemotherapy is poor. We suppressed tumor resistance to doxorubicin (Dox) in A549 cells, a human NSCLC cell line, both in vitro and in vivo in a lung tumor xenograft model, using a novel adenoviral expression system to deliver an RNA aptamer (A-p50) that specifically inhibits nuclear factor-kappaB (NF-kappaB) activation. By achieving selective, targeted, and early inhibition of NF-kappaB activity, we demonstrate that NF-kappaB plays a critical role in Dox-induced chemoresistance by regulating genes involved in proliferation (Ki-67), response to DNA damage (GADD153), antiapoptosis (Bcl-XL), and pH regulation (CA9). This Dox-induced NF-kappaB activation and subsequent chemoresistance is dependent on expression of p53. We also demonstrate that NF-kappaB promotes angiogenesis in the presence of Dox via the hypoxia-inducible factor-1alpha/vascular endothelial growth factor (HIF-1alpha/VEGF) pathway, revealing a previously unknown mechanism of NSCLC resistance to Dox. These studies provide important insights into the mechanisms of Dox-induced chemoresistance, and they demonstrate a novel, effective, and clinically practical strategy for interfering with these processes.

Clinical significance of the p53 pathway and associated gene therapy in non-small cell lung cancers

Many molecules, including several regulators and various target genes, are involved in the biological functions of p53, thus making the p53 pathway rather complicated. However, recent clinical studies have demonstrated that most human cancers have an abnormality in some of the molecules associated with the p53 pathway. Most non-small cell lung cancers (NSCLCs) have either mutations of p53, a reduced p14 alternate reading frame expression, a reduced herpesvirus-associated ubiquitin-specific protease expression or a reduced p33 inhibitor of growth gene1b expression. As a result, the balance of expression of p53 target genes, such as p21, Bax and PUMA, regulates the biological behavior and determines the fate of tumor cells. To date, many studies on cancer gene therapy using these molecules associated with the p53 pathway have been performed to develop new strategies for treating NSCLC patients. Thus, the establishment of a comprehensive and simple evaluation protocol for the p53 pathway is required for clinical use.

The proteasome inhibitor bortezomib acts differently in combination with p53 gene transfer or cytotoxic chemotherapy on NSCLC cells

In this report, the effects of a combined treatment with the proteasome inhibitor bortezomib and either a recombinant adeno-associated virus type 2 (rAAV-2)-mediated p53 gene transfer or chemotherapeutic agents, docetaxel and pemetrexed, were tested on p53 positive and p53negative non-small cell lung cancer (NSCLC) cell lines. The combination of bortezomib and rAAV-p53 led to a significant synergistic inhibition of cell growth between 62-82% depending on the p53 status of the cell line and drug concentration. Surviving cells of the combined treatment showed a significant reduced ability to form colonies. Enhanced cell toxicity was associated with a 5.3-14.4-fold increase of the apoptotic rate and intracellular p53 level up to 50.4% following vector-mediated p53 restoration and bortezomib treatment. In contrast, an antagonistic effect on tumor cell growth and colony formation was observed for the combination of bortezomib and docetaxel or pemetrexed as a reduction of cell growth between 31 and 48% was found in comparison to 50% using the single agents. Lower cytotoxic effects were associated with significantly reduced apoptosis and an increase of clonogenic growth. The observed antagonistic effects between bortezomib and docetaxel or pemetrexed might influence clinical trials using these compounds. Conversely, p53 restoration and bortezomib treatment led to enhanced, synergistic tumor cell toxicity.

Quantitative real-time PCR for titration of infectious recombinant AAV-2 particles

In this report, we present a fast, reliable and easy to perform method to quantify infectious titers of recombinant AAV-2 (rAAV-2) particles using the LightCycler technology, which is independent from the therapeutic transgene and without the presence of a marker gene. The method is based on the life cycle of AAV-2: after infection of the host cell, the single stranded (ss) AAV-2 genome is converted into a double stranded (ds) form. Following infection with rAAV-2, HeLa cells were lysed and ssDNA of transcriptionally inactive particles were efficiently removed by ssDNA-specific S1 nuclease digestion. The remaining viral dsDNA can be quantified by quantitative real-time PCR (qPCR). For validation of the new method, rAAV-2 preparations were analyzed by two other standard methods for titration of infectious particles in parallel, i.e. the infectious center assay (ICA) as well as flow cytometry using GFP as a marker. Comparing the infectious titers of 40 different AAV-2 fractions assessed by qPCR with the titers determined by FACS analysis a significant correlation (r=0.87, p<0.001) with a mean ratio of the titers assessed by qPCR and FACS of 1.92 (S.D.+/-1.59) was found. Further, the titers of seven rAAV-2 fractions using qPCR and ICA covering 5 log ranges were compared and a significant correlation was found between the results (r=0.80, p<0.001) with a mean ratio of 3.38 (S.D.+/-1.79), respectively.

Replacement and Suicide Gene Therapy for Targeted Treatment of Lung Cancer

Lung cancer is the leading cause of cancer-related death in the developed world; consequently, novel therapeutic strategies are in high demand. A major problem with the present treatment modalities is the lack of tumor specificity giving rise to dose-limiting toxicity and side effects. Gene therapy constitutes an experimental approach gaining increased attention as a putative future cancer therapeutic strategy. Using this strategy, cancer cytotoxicity can be obtained by replacing mutated genes with functional analogues or introducing a suicide gene into the malignant cells. Insight into the molecular biology of cancer cells has identified a number of regulatory gene sequences, which can be used to selectively activate the therapeutic gene specifically in cancer cells, thereby reducing nonspecific toxicity. Although further improvements are necessary, recent encouraging results have shown promise for future clinical application of gene therapy. This article presents an update on the experimental and clinical results obtained within the field of lung cancer gene therapy, concentrating on strategies to specifically activate expression of the therapeutic gene in cancer cells. Furthermore, status of the development of delivery vector constructs for lung cancer gene therapy will be presented.