Knockdown of Obg-like ATPase 1 enhances sorafenib sensitivity by inhibition of GSK-3ß/ß-catenin signaling in hepatocellular carcinoma cells.

Background: To clarify the molecular mechanism of hepatocellular carcinoma (HCC), conducive to developing an effective HCC therapy. Owing to the severe drug resistance, the clinical use of sorafenib, which is approved for HCC treatment, is limited. The precise molecular mechanisms of sorafenib drug resistance remain unclear. In the current work, we evaluated the role of Obg-like ATPase 1 (OLA1) in sorafenib resistance in HCC. Methods: The survival of HCC patients between OLA1 expression and sorafenib treatment was analyzed by Kaplan-Meier plotter. Cell viability was measured by cell counting kit-8 (CCK-8) and colony formation assays. Cell death was detected by propidium iodide (PI) and trypan blue staining. The mRNA and protein levels were measured by real-time quantitative polymerase chain reaction (RT-qPCR) and western blot (WB), respectively. Results: We found that OLA1 was highly correlated with sorafenib resistance of HCC through a public database. Further study showed that knockdown of OLA1 enhanced cell proliferation inhibition and cell death induced by sorafenib, along with a reduction of proliferation-associated proteins (c-Myc and cyclin D1) and increase of apoptosis-related proteins (cleaved caspase-3 and cleaved PARP) in HCC cells. In addition, knockdown of OLA1 reduced the activation of glycogen synthase kinase 3ß (GSK-3ß)/ß-catenin. Conclusions: Our results proved that OLA1 can be a potential target to enhance sorafenib sensitivity in HCC.

Photodynamic therapy synergizes with PD-L1 checkpoint blockade for immunotherapy of CRC by multifunctional nanoparticles.

Checkpoint inhibitors, such as anti-PD-1/PD-L1 antibodies, have been shown to be extraordinarily effective, but their durable response rate remains low, especially in colorectal cancer (CRC). Recent studies have shown that photodynamic therapy (PDT) could effectively enhance PD-L1 blockade therapeutic effects, although the reason is still unclear. Here, we report the use of multifunctional nanoparticles (NPs) loaded with photosensitized mTHPC (mTHPC@VeC/T-RGD NPs)-mediated PDT treatment to potentiate the anti-tumor efficacy of PD-L1 blockade for CRC treatment and investigate the underlying mechanisms of PDT enhancing PD-L1 blockade therapeutic effect in this combination therapy. In this study, the mTHPC@VeC/T-RGD NPs under the 660-nm near infrared (NIR) laser could kill tumor cells by inducing apoptosis and/or necrosis and stimulating systemic immune response, which could be further promoted by the PD-L1 blockade to inhibit primary and distant tumor growth, as well as building long-term host immunological memory to prevent tumor recurrence. Furthermore, we detected that mTHPC@VeC/T-RGD NP-mediated PDT sensitizes tumors to PD-L1 blockade therapy mainly because PDT-mediated hypoxia could induce the hypoxia-inducible factor 1α (HIF-1α) signaling pathway that upregulates PD-L1 expression in CRC. Taken together, our work demonstrates that mTHPC@VeC/T-RGD NP-mediated PDT is a promising strategy that may potentiate the response rate of anti-PD-L1 checkpoint blockade immunotherapies in CRC.

A combination of LightOn gene expression system and tumor microenvironment-responsive nanoparticle delivery system for targeted breast cancer therapy.

A light-switchable transgene system called LightOn gene expression system could regulate gene expression with a high on/off ratio under blue light, and have great potential for spatiotemporally controllable gene expression. We developed a nanoparticle drug delivery system (NDDS) to achieve tumor microenvironment-responsive and targeted delivery of diphtheria toxin A (DTA) fragment-encoded plasmids to tumor sites. The expression of DTA was induced by exposure to blue light. Nanoparticles composed of polyethylenimine and vitamin E succinate linked by a disulfide bond, and PEGylated hyaluronic acid modified with RGD peptide, accumulated in tumor tissues and were actively internalized into 4T1 cells via dual targeting to CD44 and α v ß 3 receptors. The LightOn gene expression system was able to control target protein expression through regulation of the intensity or duration of blue light exposure. In vitro studies showed that light-induced DTA expression reduced 4T1 cell viability and induced apoptosis. Furthermore, the LightOn gene expression system enabled spatiotemporal control of the expression of DTA in a mouse 4T1 tumor xenograft model, which resulted in excellent antitumor effects, reduced tumor angiogenesis, and no systemic toxicity. The combination of the LightOn gene expression system and NDDS may be an effective strategy for treatment of breast cancer.

Safe and Efficacious Diphtheria Toxin-Based Treatment for Melanoma: Combination of a Light-On Gene-Expression System and Nanotechnology.

The controversy surrounding the use of diphtheria toxin (DT) as a therapeutic agent against tumor cells arises mainly from its unexpected harmfulness to healthy tissues. We encoded the cytotoxic fragment A of DT (DTA) as an objective gene in the Light-On gene-expression system to construct plasmids pGAVPO (pG) and pU5-DTA (pDTA). Meanwhile, a cRGD-modified ternary complex comprising plasmids, chitosan, and liposome (pG&pDTA@cRGD-CL) was prepared as a nanocarrier to ensure transfection efficiency. Benefiting from spatiotemporal control of this light-switchable transgene system and the superior tumor targeting of the carrier, toxins were designed to be expressed selectively in illuminated lesions. In vitro studies suggested that pG&pDTA@cRGD-CL exerted arrest of the S phase in B16F10 cells upon blue light irradiation and, ultimately, induced the apoptosis and necrosis of tumor cells. Such DTA-based treatment exerted enhanced antitumor activity in mice bearing B16F10 xenografts and displayed prolonged survival time with minimal side effects. Hence, we described novel DTA-based therapy combined with nanotechnology and the Light-On gene-expression system: such treatment could be a promising strategy against melanoma.

cRGD-Conjugated Fe3O4@PDA-DOX Multifunctional Nanocomposites for MRI and Antitumor Chemo-Photothermal Therapy.

BACKGROUND: Photothermal therapy (PTT) has great potential in the clinical treatment of tumors. However, most photothermal materials are difficult to apply due to their insufficient photothermal conversion efficiencies (PCEs), poor photostabilities and short circulation times. Furthermore, tumor recurrence is likely to occur using PTT only. In the present study, we prepared cyclo (Arg-Gly-Asp-d-Phe-Cys) [c(RGD)] conjugated doxorubicin (DOX)-loaded Fe3O4@polydopamine (PDA) nanoparticles to develop a multifunctional-targeted nanocomplex for integrated tumor diagnosis and treatment. MATERIALS AND METHODS: Cytotoxicity of Fe3O4@PDA-PEG-cRGD-DOX against HCT-116 cells was determined by cck-8 assay. Cellular uptake was measured by confocal laser scanning microscope (CLSM). Pharmacokinetic performance of DOX was evaluated to compare the differences between free DOX and DOX in nanocarrier. Performance in magnetic resonance imaging (MRI) and antitumor activity of complex nanoparticles were evaluated in tumor-bearing nude mice. RESULTS: Fe3O4@PDA-PEG-cRGD-DOX has a particle size of 200-300 nm and a zeta potential of 22.7 mV. Further studies in vitro and in vivo demonstrated their excellent capacity to target tumor cells and promote drug internalization, and significantly higher cytotoxicity with respect to that seen in a control group was shown for the nanoparticles. In addition, they have good thermal stability, photothermal conversion efficiencies (PCEs) and pH responsiveness, releasing more DOX in a mildly acidic environment, which is very conducive to their chemotherapeutic effectiveness in the tumor microenvironment. Fe3O4@PDA-PEG-cRGD-DOX NPs were used in a subcutaneous xenograft tumor model of nude mouse HCT-116 cells showed clear signal contrast in T2-weighted images and effective anti-tumor chemo-photothermal therapy under NIR irradiation. CONCLUSION: According to our results, Fe3O4@PDA-PEG-cRGD-DOX had a satisfactory antitumor effect on colon cancer in nude mice and could be further developed as a potential integrated platform for the diagnosis and treatment of cancer to improve its antitumor activity against colon cancer.