Cancer is the second cause of death worldwide, surpassed only by cardiovascular diseases, due to the lack of early diagnosis, and high relapse rate after conventional therapies. Chemotherapy inhibits the rapid growth of cancer cells, but it also affects normal cells with fast proliferation rate. Therefore, it is imperative to develop other safe and more effective treatment strategies, such as gene therapy, in order to significantly improve the survival rate and life expectancy of patients with cancer. The aim of gene therapy is to transfect a therapeutic gene into the host cells to express itself and cause a beneficial biological effect. However, the efficacy of the proposed strategies has been insufficient for delivering the full potential of gene therapy in the clinic. The type of delivery vehicle (viral or non viral) chosen depends on the desired specificity of the gene therapy. The first gene therapy trials were performed with therapeutic genes driven by viral promoters such as the CMV promoter, which induces non-specific toxicity in normal cells and tissues, in addition to cancer cells. The use of tumor-specific promoters over-expressed in the tumor, induces specific expression of therapeutic genes in a given tumor, increasing their localized activity. Several cancer- and/or tumor-specific promoters systems have been developed to target cancer cells. This review aims to provide up-to-date information concerning targeting gene therapy with cancer- and/or tumor-specific promoters including cancer suppressor genes, suicide genes, anti-tumor angiogenesis, gene silencing, and gene-editing technology, as well as the type of delivery vehicle employed. Gene therapy can be used to complement traditional therapies to provide more effective treatments.

MicroRNAs (miRNAs) are small, non-coding RNA molecules that play crucial roles in regulating gene expression, and their dysregulation is implicated in various human diseases. Over the years, several research groups have identified miRNAs as promising therapeutic targets for intervention. Therapeutic strategies involve either overexpression or knockdown of specific miRNAs. This review aims to provide a comprehensive overview of synthetic poly-miRNAs and miRNA sponges, highlighting their therapeutic applications. It begins with an introduction to miRNAs and their role in human diseases, followed by a detailed discussion on synthetic poly-miRNAs and miRNA sponges by exploring their application in cardiovascular, inflammatory, autoimmune, and metabolic disorders, as well as in cancer therapy. Additionally, strategies for targeted delivery, challenges, and limitations of these therapies are addressed.

One of the major challenges in gene therapy is the efficient and safe introduction of nucleic acids into eukaryotic cells. This process requires overcoming various biological barriers and navigating complex pathways to reach target cells and achieve their biological function. To address this obstacle, numerous transfection methods have been developed, including physical techniques and the use of genetic vectors, both viral and non-viral. However, to date, no transfection method is 100% safe and efficient. Within the spectrum of non-viral genetic vectors, cationic liposomes formed by cationic lipids stand out for their ability to protect and deliver therapeutic NA. These liposomes offer greater biocompatibility and lower immunogenicity compared to viral vectors, although they still do not match the efficiency of viral delivery systems. Consequently, ongoing research focuses on synthesizing a wide variety of cationic lipids in the search for compounds that provide high transfection efficiency with minimal cytotoxicity. This study aimed to design and synthesize a novel cationic lipid (CholCadLys) derived from natural cellular molecules for transferring genetic material to eukaryotic cells. The lipid was synthesized using cholesteryl chloroformate for the hydrophobic region, cadaverine as a linker, and lysine for the polar region, connected by carbamate and amide bonds, respectively. Identification was confirmed through thin-layer chromatography, purification through preparative chromatography, and characterization via infrared spectroscopy and mass spectrometry. The synthesis yielded a 60% success rate, with stable nanoliposomes averaging 76 nm in diameter. Liposomes were formed using this CL and commercial neutral lipids, characterized by transmission electron microscopy and Nanoparticle Tracking Analysis. These liposomes, combined with plasmid DNA, formed lipoplexes used to transfect Hek-293 FT cells, achieving up to 40% transfection efficiency without cytotoxicity in the mixture of CholCadLys and CholCad. This novel CL demonstrates potential as an efficient, safe, and cost-effective gene transfer system, facilitating further development in gene therapy.

Atherosclerosis is the leading cause of cardiovascular diseases in Mexico and worldwide. The membrane transporters ABCA1 and ABCG1 are involved in the reverse transport of cholesterol and stimulate the HDL synthesis in hepatocytes, therefore the deficiency of these transporters promotes the acceleration of atherosclerosis. MicroRNA-33 (miR-33) plays an important role in lipid metabolism and exerts a negative regulation on the transporters ABCA1 and ABCG1. It is known that by inhibiting the function of miR-33 with antisense RNA, HDL levels increase and atherogenic risk decreases. Therefore, in this work, a genetic construct, pPEPCK-antimiR-33-IRES2-EGFP, containing a specific antimiR-33 sponge with two binding sites for miR-33 governed under the PEPCK promoter was designed, constructed, and characterized, the identity of which was confirmed by enzymatic restriction, PCR, and sequencing. Hep G2 and Hek 293 FT cell lines, as well as a mouse hepatocyte primary cell culture were transfected with this plasmid construction showing expression specificity of the PEPCK promoter in hepatic cells. An analysis of the relative expression of miR-33 target messengers showed that the antimiR-33 sponge indirectly induces the expression of its target messengers (ABCA1 and ABCG1). This strategy could open new specific therapeutic options for hypercholesterolemia and atherosclerosis, by blocking the miR-33 specifically in hepatocytes.

Background: Genomic instability, a hallmark of cancer, leads to copy number variations disrupting gene dosage balance and contributing to tumor progression. One of the most affected oncogenes is MYC, whose overexpression is tightly regulated to avoid cytotoxicity. In aneuploid cancer cells, gene dosage compensation mechanisms involving microRNAs (miRNAs) from the miR-17/92 cluster contribute in regulating MYC expression. Targeting this miRNA-mediated compensation system represents a promising therapeutic strategy leading to an uncontrolled and lethal MYC overexpression. Results: Synthetic miRNA sponges targeting miR-17, miR-19a, and miR-20a, key regulators of MYC dosage compensation, were designed and validated. Breast cancer cells (MCF7) with stable exogenous MYC overexpression were used to assess the impact of sponge constructs on MYC regulation. Quantitative RT-PCR revealed a significant reduction in miRNA expression and a corresponding increase in endogenous MYC levels upon sponge treatment. Functional assays in multiple colorectal cancer cell lines with varying MYC copy numbers demonstrated a time-dependent increase in cell death following sponge transfection. Cytotoxic effects increased with MYC copy number, confirming a correlation between gene dosage sensitivity and therapeutic response. Conclusions: Our findings demonstrate that miRNA sponges targeting the miR-17/92 cluster can effectively disrupt MYC dosage compensation, leading to selective cytotoxicity in MYC-amplified cancer cells.

One of the major challenges in gene therapy (GT) is the efficient and safe introduction of nucleic acids (NA) into eukaryotic cells. This process requires overcoming various biological barriers and navigating complex pathways to reach target cells and achieve their biological function. To address this obstacle, numerous transfection methods have been developed, including physical techniques and the use of genetic vectors, both viral and non-viral. However, until now, no transfection method is 100% safe and efficient. Within the spectrum of non-viral genetic vectors, cationic liposomes formed by cationic lipids (CL), stand out for their ability to protect and deliver therapeutic NA. These liposomes offer greater biocompatibility and lower immunogenicity compared to viral vectors, although they still do not match the efficiency of viral delivery systems. Consequently, ongoing research focuses on synthesizing a wide variety of cationic lipids in the search for compounds that provide high transfection efficiency with minimal cytotoxicity. This study aimed to design and synthesize a novel CL (CholCadLys) derived from natural cellular molecules for transferring genetic material to eukaryotic cells. The lipid was synthesized using: cholesteryl chloroformate for the hydrophobic region, cadaverine as a linker, and lysine for the polar region, connected by carbamate and amide bonds, respectively. Identification was confirmed through thin-layer chromatography, purification by preparative chromatography, and characterization via infrared spectroscopy and mass spectrometry. The synthesis yielded a 60% success rate, with stable nanoliposomes averaging 76 nm in diameter. Liposomes were formed using this CL and commercial neutral lipids, characterized by transmission electron microscopy and Nanoparticle Tracking Analysis. These liposomes, combined with plasmid DNA, formed lipoplexes used to transfect Hek-293 FT cells, achieving up to 40% transfection efficiency without cytotoxicity in the mixture of CholCadLys and CholCad. This novel CL demonstrates potential as an efficient, safe, and cost-effective gene transfer system, facilitating further development in gene therapy.