Codelivery of STAT3 siRNA and BV6 by carboxymethyl dextran trimethyl chitosan nanoparticles suppresses cancer cell progression

Codelivery of HIF-1α siRNA and Dinaciclib by Carboxylated Graphene Oxide-Trimethyl Chitosan-Hyaluronate Nanoparticles Significantly Suppresses Cancer Cell Progression

PURPOSE

Hypoxia-inducible factor (HIF) is one of the critical components of the tumor microenvironment that is involved in tumor development. HIF-1α functionally and physically interacts with CDK1, 2, and 5 and stimulates the cell cycle progression and Cyclin-Dependent Kinase (CDK) expression. Therefore, hypoxic tumor microenvironment and CDK overexpression lead to increased cell cycle progression and tumor expansion. Therefore, we decided to suppress cancer cell expansion by blocking HIF-1α and CDK molecules.

METHODS

In the present study, we used the carboxylated graphene oxide (CGO) conjugated with trimethyl chitosan (TMC) and hyaluronate (HA) nanoparticles (NPs) loaded with HIF-1α-siRNA and Dinaciclib, the CDK inhibitor, for silencing HIF-1α and blockade of CDKs in CD44-expressing cancer cells and evaluated the impact of combination therapy on proliferation, metastasis, apoptosis, and tumor growth.

RESULTS

The results indicated that the manufactured NPs had conceivable physicochemical properties, high cellular uptake, and low toxicity. Moreover, combination therapy of cancer cells using CGO-TMC-HA NPs loaded with HIF-1α siRNA and Dinaciclib (SCH 727965) significantly suppressed the CDKs/HIF-1α and consequently, decreased the proliferation, migration, angiogenesis, and colony formation in tumor cells.

CONCLUSIONS

These results indicate the ability of CGO-TMC-HA NPs for dual drug/gene delivery in cancer treatment. Furthermore, the simultaneous inhibition of CDKs/HIF-1α can be considered as a novel anti-cancer treatment strategy; however, further research is needed to confirm this treatment in vivo. Graphical Abstract The suppression of HIF-1α and CDKs inhibits cancer growth. HIF-1α is overexpressed by the cells present in the tumor microenvironment. The hypoxic environment elevates mitochondrial ROS production and increases p38 MAP kinase, JAK/STAT, ERK, JNK, and Akt/PI3K signaling, resulting in cyclin accumulation and aberrant cell cycle progression. Furthermore, the overexpression of HIF-1α/CDK results in increased expression of genes such as BCL2, Bcl-xl, Ki-67, TGFβ, VEGF, FGF, MMP2, MMP9, and, HIF-1α and consequently raise the survival, proliferation, angiogenesis, metastasis, and invasion of tumor cells. In conclusion, HIF-1α-siRNA/Dinaciclib-loaded CGO-TMC-HA NPs can inhibit the tumor expansion by blockage of CDKs and HIF-1α (JAK: Janus kinase, STAT: Signal transducer and activator of transcription, MAPK: mitogen-activated protein kinase, ERK: extracellular signal-regulated kinase, JNK: c-Jun N-terminal kinase, PI3K: phosphatidylinositol 3-kinase).

Blockade of CTLA-4 increases anti-tumor response inducing potential of dendritic cell vaccine

The immunosuppressive state of the tumor microenvironment diminishes the efficacy of dendritic cell (DC)-based cancer immunotherapy. Inhibitory immune checkpoint molecules expressed on tumor-infiltrating T lymphocytes, such as cytotoxic T-lymphocyte antigen 4 (CTLA-4) molecules are one of the main barriers in priming T cells by DCs. Therefore, it seems that blockade of such molecules facilitates the T cells activation by the DC vaccine. In this study, we intended to suppress the expression of CTLA-4 molecule on tumor-infiltrating T cells by siRNA-loaded chitosan-lactate (CL) nanoparticles to facilitate priming anti- tumor T cells by tumor lysate-loaded DC vaccine. Nanoparticles (NPs) have also provided an opportunity for specific drug delivery into the tumor site. CL NPs exhibited favorable physicochemical characteristics (size about 75 nm, polydispersive index<0.2, and a zeta potential about 14), which were associated with a high transfection rate and low toxicity. Moreover, the administration of anti-CTLA-4 siRNA-loaded NPs into CT26 and 4 T1 tumor -bearing mice led to the downregulation of CTLA-4 on tumor -infiltrating T cells, which was associated with tumor regression and increased mice survival. Moreover, while the treatment of tumor -bearing mice with DC vaccine had mild therapeutic outcomes, its combination with siRNA-loaded NPs may exhibit synergistic anti- tumor effects. This possible synergistic ameliorating effect is achieved through the reduction of immunosuppressive cells, the improved cytotoxicity of T lymphocytes, decreased inhibitory and increased inflammatory cytokines, and reduced angiogenesis and metastasis processes. These results indicate that the silencing of CTLA-4 can potentiate the T cell priming capacity of the DC vaccine, proposing a practical anti-cancer therapeutic approach.

Silencing of HIF-1α/CD73 axis by siRNA-loaded TAT-chitosan-spion nanoparticles robustly blocks cancer cell progression

Induction of Hypoxia Inducible Factor (HIF) as a direct consequence of oxygen deficiency in tumor tissues is a potent stimulus of CD73 (ecto-5'-nucleotidase) expression. Hypoxic environment and CD73 overexpression are associated with altered metabolism, elevated cancer cell proliferation, and tumor vascularization. Herein, a delivery system was developed for silencing CD73 and HIF-1α gene using siRNA-loaded Superparamagnetic iron oxide (SPION) nanocarriers for cancer treatment. SPIONs were encapsulated with thiolated chitosan (TC) and trimethyl chitosan (TMC) for improving their stabilization and functionalization. The nanoparticles (NPs) were about 133 nm in size, spherical, and non-toxic, and the addition of TAT peptide (derived from HIV-1 TAT protein) to TMC-TC-SPIONs significantly increased their cellular uptake by cancer cells. The produced NPs could efficiently accumulate in the tumor site, indicating their stability and targeting ability in reaching the tumor region. TAT-conjugated TMC-TC-SPIONs containing siRNAs could significantly reduce the HIF-1α and CD73 expression levels in cancer cells. Following transfection, cancer cells showed a significant reduction in migration and proliferation. Moreover, siRNA-loaded NPs could effectively reduce tumor growth and angiogenesis, as investigated by the chick chorioallantoic membrane (CAM) assay. This study suggested that TAT-TMC-TC-SPIONs can be potential nanocarrier for gene transfection in cancer therapy. Moreover, the co-silencing of CD73 and HIF-1α can be assumed as a novel anti-cancer treatment strategy with high tumor suppression potential.

Silencing adenosine A2a receptor enhances dendritic cell-based cancer immunotherapy

Overexpression of adenosine in the tumor region leads to suppression of various immune cells, particularly T cells through ligation with adenosine 2a receptor (A2aR). In this study, we intended to increase the efficacy of tumor lysate-loaded DC vaccine by silencing the expression of A2aR on T cells through the application of A2aR-specific siRNA-loaded PEG-chitosan-lactate (PCL) nanoparticles (NPs) in the 4T1 breast tumor-bearing mice. Combination therapy by DC vaccine and siRNA-loaded NPs markedly induced tumor regression and increased survival time of mice. These ameliorative effects were partly via downregulation of immunosuppressive cells, increased function of cytotoxic T lymphocytes, and induction of immune-stimulatory cytokines. Moreover, combination therapy could markedly suppress angiogenesis and metastasis processes. These results imply the efficacy of novel combination therapy for the treatment of breast cancer by using A2aR siRNA-loaded NPs and DC vaccine which can be translated into the initial phase of clinical trials in the near future.