Advances and challenges in gene therapy strategies for pediatric cancer: a comprehensive update.

Pediatric cancers represent a tragic but also promising area for gene therapy. Although conventional treatments have improved survival rates, there is still a need for targeted and less toxic interventions. This article critically analyzes recent advances in gene therapy for pediatric malignancies and discusses the challenges that remain. We explore the innovative vectors and delivery systems that have emerged, such as adeno-associated viruses and non-viral platforms, which show promise in addressing the unique pathophysiology of pediatric tumors. Specifically, we examine the field of chimeric antigen receptor (CAR) T-cell therapies and their adaptation for solid tumors, which historically have been more challenging to treat than hematologic malignancies. We also discuss the genetic and epigenetic complexities inherent to pediatric cancers, such as tumor heterogeneity and the dynamic tumor microenvironment, which pose significant hurdles for gene therapy. Ethical considerations specific to pediatric populations, including consent and long-term follow-up, are also analyzed. Additionally, we scrutinize the translation of research from preclinical models that often fail to mimic pediatric cancer biology to the regulatory landscapes that can either support or hinder innovation. In summary, this article provides an up-to-date overview of gene therapy in pediatric oncology, highlighting both the rapid scientific progress and the substantial obstacles that need to be addressed. Through this lens, we propose a roadmap for future research that prioritizes the safety, efficacy, and complex ethical considerations involved in treating pediatric patients. Our ultimate goal is to move from incremental advancements to transformative therapies.

Comparison of the efficiency of ultrafiltration, precipitation, and ultracentrifugation methods for exosome isolation.

Extracellular vesicles (EVs) are enclosed by a lipid-bilayer membrane and secreted by all types of cells. They are classified into three groups: apoptotic bodies, microvesicles, and exosomes. Exosomes play a number of important roles in the intercellular communication and crosstalk between tissues in the body. In this study, we use three common methods based on different principles for exosome isolation, namely ultrafiltration, precipitation, and ultracentrifugation. We use field emission scanning electron microscopy (FESEM) and dynamic light scattering (DLS) analyses for characterization of exosomes. The functionality and effect of isolated exosomes on the viability of hypoxic cells was investigated by alamarBlue and Flow-cytometry. The results of the FESEM study show that the ultrafiltration method isolates vesicles with higher variability of shapes and sizes when compared to the precipitation and ultracentrifugation methods. DLS results show that mean size of exosomes isolated by ultrafiltration, precipitation, and ultracentrifugation methods are 122, 89, and 60 nm respectively. AlamarBlue analysis show that isolated exosomes increase the viability of damaged cells by 11%, 15%, and 22%, respectively. Flow-cytometry analysis of damaged cells also show that these vesicles increase the content of live cells by 9%, 15%, and 20%, respectively. This study shows that exosomes isolated by the ultracentrifugation method are characterized by smaller size and narrow size distribution. Furthermore, more homogenous particles isolated by this method show increased efficiency of the protection of hypoxic cells in comparison with the exosomes isolated by the two other methods.

Differential methylation of DNA promoter sequences in peripheral blood mononuclear cells as promising diagnostic biomarkers for colorectal cancer.

OBJECTIVES: Previous reports have indicated that the methylation profile in peripheral blood mononuclear cells (PBMCs) in different genes and loci is altered in colorectal cancer (CRC). Regarding the high mortality rate and silent nature of CRC, screening and early detection can meaningfully reduce disease-related deaths. Therefore, for the first time, we aimed to evaluate the early non-invasive diagnosis of CRC via quantitative promoter methylation analysis of RUNX3 and RASSF1A genes in PBMCs. MATERIALS AND METHODS: In the present study, we analyzed the methylation status of two important tumor suppressor genes including RUNX3 and RASSF1A in 70 CRC patients and 70 non-malignant subjects using methylation-quantification of endonuclease-resistant DNA (MethyQESD), and a bisulfite conversion-independent method. RESULTS: RUNX3 was significantly hypermethylated in PBMCs of CRC patients compared to healthy controls (P < 0.001). By determining the efficient cutoff value, the sensitivity, and specificity of RUNX3 promoter methylation for CRC diagnosis reached 84.28% and 77.14%, respectively. The receiver operating characteristic (ROC) curve analyses demonstrated that RUNX3 promoter methylation has high accuracy (areas under the curve [AUC] = 0.840, P < 0.001) for discriminating CRC subjects from healthy individuals. Moreover, RUNX3 methylation levels in PBMCs progressively increased with the stage of the disease (P < 0.001). Although the amount of RASSF1A promoter methylation was not significantly different between CRC patients and controls as well as in different stages of the disease (P > 0.05). CONCLUSION: Our findings confirmed that PBMCs are reliable sources of methylation analysis for CRC screening, and RUNX3 promoter methylation can be used as a promising biomarker for early diagnosis of CRC.

Effects of miR-330 restoration on pancreatic cancer cells oncogenesis.

BACKGROUND: Inappropriate expressions of various miRNAs have reported in different human malignancies. Evidence suggested that miR-330 may play as both onco-miR and/or tumor suppressor-miR in different cancers. In the present study, we evaluated effects of miR-330 on proliferation and migration of pancreatic cancer (PC) cells as well as underlying molecular mechanisms. DESIGN: The expression of miR-330 was evaluated in clinical tissue samples of patients with PC. Transfection of the PC cells (PANC-1) by miR-330 was conducted by pCMV vector. The cancer-related genes expression was investigated in mRNA and protein level following transfection of the PC cells. Furthermore, the PC cells viability, invasion, migration, mitochondrial membrane potential, apoptosis, autophagy, and cell cycle profile were investigated after transfection by miR-330. RESULTS: The results indicated that expression of miR-330 downregulated in patients with PC. Stable increase of miR-330 expression after transfection in PC cells reduces viability, mitochondrial membrane potential, invasion, and migration. Further assessments demonstrated that upregulation of miR-330 increases apoptosis and autophagy percentage in the PC cells. Moreover, a cell cycle arrest was observed in G1, Sub-G1, and S phases following transfection of the PC cells. These findings can be explained by modified mRNA and protein expression of apoptosis- and metastasis-related genes. CONCLUSION: Our study suggested that miR-330 acts as a tumor suppressor in PC cells, and revealed that upregulation of miR-330 may provide an effective therapeutic approach for overcoming progression and metastasis in patients with PC.

Hypermethylation of MGMT Gene Promoter in Peripheral Blood Mononuclear Cells as a Noninvasive Biomarker for Colorectal Cancer Diagnosis.

Background: Early colorectal cancer (CRC) diagnosis can drastically reduce CRC-related morbidity and mortality. In this regard, increasing attention is now being directed to DNA-based tests, especially the evaluation of methylation levels, to prioritize high-risk suspected persons for colonoscopy examination. Therefore, we aimed to assess the accuracy of MGMT gene promoter methylation levels in peripheral blood mononuclear cells (PBMCs) for distinguishing CRC patients from healthy people. Materials and Methods: For this study, a total of seventy individuals with CRC and 75 healthy individuals from Iran were included. The methylation level of MGMT in the DNA isolated from PBMCs was evaluated using the methylation quantification endonuclease-resistant DNA technique. To assess the diagnostic capability of the MGMT promoter methylation level, a receiver operating characteristic (ROC) curve was generated. Results: The mean promoter methylation level of MGMT in the CRC and control groups was, respectively, 27.83 ± 22.80 vs. 12.36 ± 14.48. The average percentage of methylation of the MGMT promoter between the CRC and control groups was significantly different (P < 0.001). Also, the MGMT promoter was more hypermethylated in female patients than in males. ROC analyses indicated that the diagnostic power of the MGMT promoter methylation level for CRC was 0.754, with a sensitivity of 81.43% and a specificity of 75.71%, indicating a good biomarker for CRC diagnosis. Conclusion: Methylation evaluation of MGMT in PBMCs could be utilized as a diagnostic biomarker with high accuracy for prioritizing suspected CRC patients before colonoscopy.