The sensitivity of acute myeloid leukemia cells to cytarabine is increased by suppressing the expression of Heme oxygenase-1 and hypoxia-inducible factor 1-alpha.

BACKGROUND: Acute myeloid leukemia (AML), a malignancy Often resistant to common chemotherapy regimens (Cytarabine (Ara-c) + Daunorubicin (DNR)), is accompanied by frequent relapses. Many factors are involved in causing chemoresistance. Heme Oxygenase-1 (HO-1) and Hypoxia-Inducible Factor 1-alpha (HIF-1α) are two of the most well-known genes, reported to be overexpressed in AML and promote resistance against chemotherapy according to several studies. The main chemotherapy agent used for AML treatment is Ara-c. We hypothesized that simultaneous targeting of HO-1 and HIF-1α could sensitize AML cells to Ara-c. METHOD: In this study, we used our recently developed, Trans-Activator of Transcription (TAT) - Chitosan-Carboxymethyl Dextran (CCMD) - Poly Ethylene Glycol (PEG) - Nanoparticles (NPs), to deliver Ara-c along with siRNA molecules against the HO-1 and HIF-1α genes to AML primary cells (ex vivo) and cell lines including THP-1, KG-1, and HL-60 (in vitro). Subsequently, the effect of the single or combinational treatment on the growth, proliferation, apoptosis, and Reactive Oxygen Species (ROS) formation was evaluated. RESULTS: The designed NPs had a high potential in transfecting cells with siRNAs and drug. The results demonstrated that treatment of cells with Ara-c elevated the generation of ROS in the cells while decreasing the proliferation potential. Following the silencing of HO-1, the rate of apoptosis and ROS generation in response to Ara-c increased significantly. While proliferation and growth inhibition were considerably evident in HIF-1α-siRNA-transfected-AML cells compared to cells treated with free Ara-c. We found that the co-inhibition of genes could further sensitize AML cells to Ara-c treatment. CONCLUSIONS: As far as we are aware, this study is the first to simultaneously inhibit the HO-1 and HIF-1α genes in AML using NPs. It can be concluded that HO-1 causes chemoresistance by protecting cells from ROS damage. Whereas, HIF-1α mostly exerts prolific and direct anti-apoptotic effects. These findings imply that simultaneous inhibition of HO-1 and HIF-1α can overcome Ara-c resistance and help improve the prognosis of AML patients.

The Prognostic and therapeutic value and clinical implications of fibroblast activation protein-α as a novel biomarker in colorectal cancer.

The identification of contributing factors leading to the development of Colorectal Cancer (CRC), as the third fatal malignancy, is crucial. Today, the tumor microenvironment has been shown to play a key role in CRC progression. Fibroblast-Activation Protein-α (FAP) is a type II transmembrane cell surface proteinase expressed on the surface of cancer-associated fibroblasts in tumor stroma. As an enzyme, FAP has di- and endoprolylpeptidase, endoprotease, and gelatinase/collagenase activities in the Tumor Microenvironment (TME). According to recent reports, FAP overexpression in CRC contributes to adverse clinical outcomes such as increased lymph node metastasis, tumor recurrence, and angiogenesis, as well as decreased overall survival. In this review, studies about the expression level of FAP and its associations with CRC patients' prognosis are reviewed. High expression levels of FAP and its association with clinicopathological factors have made as a potential target. In many studies, FAP has been evaluated as a therapeutic target and diagnostic factor into which the current review tries to provide a comprehensive insight. Video Abstract.

Dual Blockade of PD-1 and LAG3 Immune Checkpoints Increases Dendritic Cell Vaccine Mediated T Cell Responses in Breast Cancer Model.

PURPOSE: Increasing the efficiency of unsuccessful immunotherapy methods is one of the most important research fields. Therefore, the use of combination therapy is considered as one of the ways to increase the effectiveness of the dendritic cell (DC) vaccine. In this study, the inhibition of immune checkpoint receptors such as LAG3 and PD-1 on T cells was investigated to increase the efficiency of T cells in response to the DC vaccine. METHODS: We used trimethyl chitosan-dextran sulfate-lactate (TMC-DS-L) nanoparticles (NPs) loaded with siRNA molecules to quench the PD-1 and LAG3 checkpoints' expression. RESULTS: Appropriate physicochemical characteristics of the generated NPs led to efficient inhibition of LAG3 and PD-1 on T cells, which was associated with increased survival and activity of T cells, ex vivo. Also, treating mice with established breast tumors (4T1) using NPs loaded with siRNA molecules in combination with DC vaccine pulsed with tumor lysate significantly inhibited tumor growth and increased survival in mice. These ameliorative effects were associated with increased anti-tumor T cell responses and downregulation of immunosuppressive cells in the tumor microenvironment and spleen. CONCLUSION: These findings strongly suggest that TMC-DS-L NPs loaded with siRNA could act as a novel tool in inhibiting the expression of immune checkpoints in the tumor microenvironment. Also, combination therapy based on inhibition of PD-1 and LAG3 in combination with DC vaccine is an effective method in treating cancer that needs to be further studied.

Combination Cancer Immunotherapy with Dendritic Cell Vaccine and Nanoparticles Loaded with Interleukin-15 and Anti-beta-catenin siRNA Significantly Inhibits Cancer Growth and Induces Anti-Tumor Immune Response.

PURPOSE: The invention and application of new immunotherapeutic methods can compensate for the inefficiency of conventional cancer treatment approaches, partly due to the inhibitory microenvironment of the tumor. In this study, we tried to inhibit the growth of cancer cells and induce anti-tumor immune responses by silencing the expression of the ß-catenin in the tumor microenvironment and transmitting interleukin (IL)-15 cytokine to provide optimal conditions for the dendritic cell (DC) vaccine. METHODS: For this purpose, we used folic acid (FA)-conjugated SPION-carboxymethyl dextran (CMD) chitosan (C) nanoparticles (NPs) to deliver anti-ß-catenin siRNA and IL-15 to cancer cells. RESULTS: The results showed that the codelivery of ß-catenin siRNA and IL-15 significantly reduced the growth of cancer cells and increased the immune response. The treatment also considerably stimulated the performance of the DC vaccine in triggering anti-tumor immunity, which inhibited tumor development and increased survival in mice in two different cancer models. CONCLUSIONS: These findings suggest that the use of new nanocarriers such as SPION-C-CMD-FA could be an effective way to use as a novel combination therapy consisting of ß-catenin siRNA, IL-15, and DC vaccine to treat cancer.