Potential Molecular Targets in the Treatment of Lung Cancer Using siRNA Technology

The Small RNA Landscape in NSCLC: Current Therapeutic Applications and Progresses

Non-small-cell lung cancer (NSCLC) is the second most diagnosed type of malignancy and the first cause of cancer death worldwide. Despite recent advances, the treatment of choice for NSCLC patients remains to be chemotherapy, often showing very limited effectiveness with the frequent occurrence of drug-resistant phenotype and the lack of selectivity for tumor cells. Therefore, new effective and targeted therapeutics are needed. In this context, short RNA-based therapeutics, including Antisense Oligonucleotides (ASOs), microRNAs (miRNAs), short interfering (siRNA) and aptamers, represent a promising class of molecules. ASOs, miRNAs and siRNAs act by targeting and inhibiting specific mRNAs, thus showing an improved specificity compared to traditional anti-cancer drugs. Nucleic acid aptamers target and inhibit specific cancer-associated proteins, such as "nucleic acid antibodies". Aptamers are also able of receptor-mediated cell internalization, and therefore, they can be used as carriers of secondary agents giving the possibility of producing very highly specific and effective therapeutics. This review provides an overview of the proposed applications of small RNAs for NSCLC treatment, highlighting their advantageous features and recent advancements in the field.

The potential of B7-H6 as a therapeutic target in cancer immunotherapy

Immune checkpoints are vital molecules that regulate T-cell function by activation or inhibition. Among the immune checkpoint molecules, the B7-family proteins are significantly involved in the immune escape of tumor cells. By binding to inhibitory receptors, they can suppress T-cell-mediated immunity. B7-family proteins are found at various stages of tumor microenvironment formation and promote tumorigenesis and tumor progression. B7-H6 (encoded by gene NCR3LG1) is a prominent member of the family. It has unique immunogenic properties and is involved in natural killer (NK) cell immunosurveillance by binding to the NKp30 receptor. High B7-H6 expression in certain tumor types and shortage of or low expression in healthy cells - except in cases of inflammatory or microbial stimulation - have made the protein an attractive target of research activities in recent years. The avoidance of NK-mediated B7-H6 detection is a mechanism through which tumor cells escape immune surveillance. The stimulation of tumorigenesis occurs by suppressing caspase cascade initiation and anti-apoptosis activity stimulation via the STAT3 pathway. The B7-H6-NKp30 complex on the tumor membrane activates the NK cells and releases both tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ). B7-H6 is highly expressed in a wide range of tumor cells, including glioma, hematologic malignant tumors, and breast cancer cells. Clinical examination of cancer patients indicated that the expression of B7-H6 is related to distant metastasis status and permits postoperative prognosis. Because of its unique properties, B7-H6 has a high potential be utilized as a biological marker for cancer diagnosis and prognosis, as well as a target for novel treatment options.

Prospects for Manipulation of Mesenchymal Stem Cells in Tumor Therapy: Anti-Angiogenesis Property on the Spotlight

The interactions between the tumor microenvironment and the tumor cells confers a condition that accelerate or decelerate the development of tumor. Of these cells, mesenchymal stem cells (MSCs) have the potential to modulate the tumor cells. MSCs have been established with double functions, whereby contribute to a tumorigenic or anti-tumor setting. Clinical studies have indicated the potential of MSCs to be used as tool in treating the human cancer cells. One of the advantageous features of MSCs that make them as a well-suited tool for cancer therapy is the natural tumor-trophic migration potential. A key specification of the tumor development has been stablished to be angiogenesis. As a result, manipulation of angiogenesis has become an attractive approach for cancer therapy. This review article will seek to clarify the anti-angiogenesis strategy in modulating the MSCs to treat the tumor cells.

Combination Therapy with KRAS and P38α siRNA Suppresses Colorectal Cancer Growth and Development in SW480 Cell Line

PURPOSE

Colorectal cancer (CRC) is one of the most prevalence malignancies in a different society with a high rate of death. The KRAS and p38α axes have critical roles in the development, migration, and growth of numerous tumors, such as colorectal malignancy. KRAS mutation acts as an oncogene in various cancers and is correlated with the poor prognosis in colorectal tumors. Also, p38α plays different roles and exhibits tissue-dependent activity. In some tissues act as an oncogene while in others act as a tumor suppressor. In this research, we try to understand the effect of the P38α and KRAS genes suppression by specific siRNAs on the SW480 cell line progression.

METHODS

We evaluate the impact of the P38α and KRAS gene knockdown by special siRNA on the growth and development of the SW480 cell line. SW480 cell line was treated with KRAS and P38α siRNAs, and the cell viability, gene expression, migration ability, and rate of apoptosis were evaluated with MTT assay, real-time PCR, scratch test, and flow cytometry.

RESULTS

After treatment of the cancer cell with KRAs and P38α siRNAs, cell viability reduced to 29.16%. Also, the expression levels of the KRAS and P38α genes reduced to 26.34% and 16.06%, respectively. Apoptosis rate after combination therapy with KRAS and P38α siRNAs increased to 72.1. Also, we found that these siRNAs suppress cell migration in SW480 cell lines.

CONCLUSION

The current study showed that combination therapy with p38α and KRAS siRNA may be considered a novel therapy for colorectal tumor in future.

Anticancer Impacts of Terminalia catappa Extract on SW480 Colorectal Neoplasm Cell Line

PURPOSE

Colorectal cancer (CRC) is one of the most lethal and prevalent cancers throughout the world. Despite the remarkable advance in the field, drug resistance still remains as an unresolved problem in cancer. Hence, finding effective compounds with minimal side effects to fight cancer is of central priority. Herbal products have been traditionally used to prevent and treat a variety of diseases.

METHODS

In the present study, the antitumor effect of Terminalia catappa plant ethanolic extract (TCE) was assessed on SW480 CRC model cell line. In this regard, effects of TCE were evaluated on the proliferation, apoptosis, and migration of SW480 cells by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Annexin V/PI flow cytometry, and scratch tests, respectively. Furthermore, changes in the expression of genes involved in these events including Bax, Bcl-2, Caspase 3, Caspase 8, Caspase 9, MMP-13, miR-21, and miR-34a were measured by quantitative real-time PCR (qRT-PCR).

RESULTS

According to the MTT results, TCE reduced the proliferation of SW480 cells significantly. The flow cytometry test also revealed a notable rate of apoptosis induction after TCE treatment. An inhibitory effect on cell migration was also evident in scratch test. Expression patterns of the assessed genes also changed subsequent to TCE treatment.

CONCLUSION

The results of this study indicated that T. catappa could be considered as a potential source of anticancer compounds and a candidate for further investigations.

Long non-coding RNAs as potential biomarkers in the prognosis and diagnosis of lung cancer: A review and target analysis

Long non-coding RNAs (lncRNA) have been emerged as a novel class of molecular regulators in cancer. They are dysregulated in many types of cancer; however, there is not enough knowledge available on their expression and functional profiles. Lung cancer is the leading cause of the cancer deaths worldwide. Generally, lncRNAs may be associated with lung tumor pathogenesis and they may act as biomarkers for the cancer prognosis and diagnosis. Compared to other invasive prognostic and diagnostic methods, detection of lncRNAs might be a user-friendly and noninvasive method. In this review article, we selected 27 tumor-associated lncRNAs by literature reviewing to further discussing in detail for using as diagnostic and prognostic biomarkers in lung cancer. Also, in an in silico target analysis, the "Experimentally supported functional regulation" approach of the LncTarD web tool was used to identifying the target genes and regulatory mechanisms of the selected lncRNAs. The reports on diagnostic and prognostic potential of all selected lncRNAs were discussed. However, the target genes and regulatory mechanisms of the 22 lncRNAs were identified by in silico analysis and we found the pathways that are controlled by each target group of lncRNAs. They use epigenetic mechanisms, ceRNA mechanisms, protein interaction and sponge mechanism. Also, 10, 23, 5, and 28 target genes for each of these mechanisms were identified, respectively. Finally, each group of target genes controls 50, 12, 7, and 2 molecular pathways, respectively. In conclusion, LncRNAs could be used as biomarkers in lung cancer due to their roles in control of several signaling pathways related to lung tumors. Also, it seems that lncRNAs, which use epigenetic mechanisms for modulating a large number of pathways, could be considered as important subjects for lung cancer-related diagnostic and prognostic biomarkers.

Novel genetic variants in HDAC2 and PPARGC1A of the CREB-binding protein pathway predict survival of non-small-cell lung cancer

The CREB-binding protein (CBP) pathway plays an important role in transcription and activity of acetyltransferase that acetylates lysine residues of histones and nonhistone proteins. In the present study, we hypothesized that genetic variants in the CBP pathway genes played a role in survival of non-small-cell lung cancer (NSCLC). We tested this hypothesis using the genotyping data from the genome-wide association study (GWAS) dataset from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. In the single-locus analysis, we evaluated associations between 13 176 (1107 genotyped and 12 069 imputed) single-nucleotide polymorphisms (SNPs) in 72 genes and survival of 1185 patients with NSCLC. The identified 106 significant SNPs in the discovery were further validated in additional genotyping data from another GWAS dataset of 984 patients with NSCLC in the Harvard Lung Cancer Susceptibility Study. The combined results of two datasets showed that two independent, potentially functional SNPs (i.e., HDAC2 rs13213007G>A and PPARGC1A rs60571065T>A) were significantly associated with NSCLC overall survival, with a combined hazards ratio (HR) of 1.26 (95% confidence interval (CI), 1.09-1.45; P = .002) and 1.23 (1.04-1.47; P = .017), respectively. Furthermore, we performed an expression quantitative trait loci analysis and found that the survival-associated HDAC2 rs13213007A allele (GA+AA), but not PPARGC1A rs60571065A allele (TA+AA), was significantly associated with increased messenger RNA expression levels of HDAC2 in 373 lymphoblastoid cell lines. These results indicate that the HDAC2 rs13213007A allele is a potential predictor of NSCLC survival, likely by altering the HDAC2 expression.

Alpha7 nicotinic acetylcholine receptors in lung inflammation and carcinogenesis: Friends or foes?

The lung tissue expresses the cholinergic system including nicotinic acetylcholine receptors (nAChRs) which included in many physiologic and pathologic processes. Mounting evidence revealed that these receptors have important roles in lung carcinogenesis via modulating either stimulatory or inhibitory signaling pathways. Among different members of nicotinic receptors family, alpha7-subtype of nAChR (α7nAChR) is a critical mediator involved in both inflammatory responses and cancers. Several studies have shown that this receptor is the most powerful regulator of responses that stimulate lung cancer processes such as proliferation, angiogenesis, metastasis, and inhibition of apoptosis. Moreover, aside from its roles in the regulation of cancer pathways, there is growing evidence indicating that α7nAChR has profound impacts on lung inflammation through the cholinergic anti-inflammatory pathway. Regarding such diverse effects as well as the critical roles of nicotine as an activator of α7nAChR on lung cancer pathogenesis, its modulation has emerged as a promising target for drug developments. In this review, we aim to highlight the detrimental as well as the possible beneficial influences of α7nAChR downstream signaling cascades in the control of lung inflammation and cancer-associated properties. Consequently, by considering the significant global burden of lung cancer, delineating the complex influences of α7 receptors would be of great interest in designing novel anticancer and anti-inflammatory strategies for the patients suffering from lung cancer.

Synergistic Effect of Novel EGFR Inhibitor AZD8931 and p38α siRNA in Lung Adenocarcinoma Cancer Cells

Background:

Lung cancer is the leading cause of cancer-related death with less than 5-year survival rate for both men and women worldwide. EGFR and MAPK signaling pathways have a critical role in proliferation and progression of various cancers, including lung cancer. P38 map kinase plays different role in various tissue hence showing a tissue-dependent behavior. It acts as an oncogene in some tissues while plays as tumor suppressor in some other tissues. The aim of this study was to investigate the combined effect of P38 αspecific siRNA and EGFR inhibitor on apoptosis and proliferation of A549 lung cancer cell line.

Objective:

This article is dedicated to the synergistic effect of novel EGFR inhibitor AZD8931 and P38 α siRNA in lung adenocarcinoma cancer cells proliferation and apoptosis.

Methods and Materials:

The A549 lung cancer cells were treated with P38 α- siRNA and EGFR inhibitor alone or in combination. The cytotoxic effects of P38 α- siRNA and EGFR inhibitor were determined using MTT assay. Relative P38 α and EGFR mRNA levels were measured by QRT-PCR. Induction of apoptosis were measured by FACS analysis.

Results:

The expression of mRNA related to P38 α, EGFR, and Her2 genes was reduced to 23.4%, 52.4%, and 75, respectively, after treatment of their inhibitors. Also, MTT assay showed that the cell viability after treatment with p38 α SiRNA, EGFR inhibitor and their combination was reduced to 51.02%, 48.9%, and 25.11%, respectively. FACS results indicated that p38 α siRNA, EGFR inhibitor and their combination, reduced the population of live cells to 49.5%, 32.2% and 14.3% in comparison to the population of untreated control cells (99.5%).

Conclusion:

The results of this study indicated that p38 α and EGFR might play an important role in the development and growth of lung cancer and might be a potential therapeutic target for the treatment of lung cancer.

Targeting the KRAS, p38α, and NF-κB in lung adenocarcinoma cancer cells: The effect of combining RNA interferences with a chemical inhibitor

BACKGROUND

Lung cancer is the leading cause of cancer-related death with less than 5-year survival rate for both men and women worldwide. KRAS (Kirsten rat sarcoma), nuclear factor-κB (NF-κB), and mitogen-activated protein kinase (MAPK) signaling pathways have a critical role in the proliferation and progression of various cancers, including lung cancer. The p38 MAPK plays a different role in various tissue hence show a tissue-dependent behavior. It acts as an oncogene in some tissues while plays as a tumor suppressor in some other tissues. Also, KRAS and NF-κB act as an oncogene in various cancer. This study was dedicated to analyzing the combined effect of NF-κB inhibitor, specific KRAS, and p38α small interfering RNA (siRNA) in A549 cell line.

MATERIALS AND METHODS

The cytotoxic effects of p38α siRNA, KRAS siRNA, and NF-κB inhibitor were determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT) assay. Relative p38α, KRAS, and NF-κB messenger RNA (mRNA) levels were measured by quantitative reverse-transcription polymerase chain reaction. Induction of apoptosis by treatments was measured by fluorescence-activated cell sorting (FACS) analysis.

RESULTS

The expression of mRNA related to p38α and KRAS genes was reduced to 23.4% and 26.7%, respectively, after treatment with specific siRNAs. Also, MTT assay showed that the cell viability after treatment with p38α siRNA, KRAS siRNA, NF-κB inhibitor and their combination was reduced. FACS results indicated that p38α siRNA, KRAS siRNA, and NF-κB inhibitor, and their combination, reduced the population of live cells in comparison with the population of untreated control cells (99.5%). The results are expressed as mean ± SD (n = 3); *P < 0.05; ** P < 0.01; *** P < 0.001; **** P < 0.0001 vs control group.

CONCLUSION

The results of this study indicated that p38α, KRAS, and NF-κB signaling pathways might play an important role in the development and growth of lung cancer and might be a potential therapeutic target for treatment of lung cancer.