Anlotinib Reverses Multidrug Resistance (MDR) in Osteosarcoma by Inhibiting P-Glycoprotein (PGP1) Function In Vitro and In Vivo

Overexpression of the multidrug resistance (MDR)-related protein P-glycoprotein (PGP1), which actively extrudes chemotherapeutic agents from cells and significantly decreases the efficacy of chemotherapy, is viewed as a major obstacle in osteosarcoma chemotherapy. Anlotinib, a novel tyrosine kinase inhibitor (TKI), has good anti-tumor effects in a variety of solid tumors. However, there are few studies on the mechanism of anlotinib reversing chemotherapy resistance in osteosarcoma. In this study, cellular assays were performed in vitro and in vivo to evaluate the MDR reversal effects of anlotinib on multidrug-resistant osteosarcoma cell lines. Drug efflux and intracellular drug accumulation were measured by flow cytometry. The vanadate-sensitive ATPase activity of PGP1 was measured in the presence of a range of anlotinib concentrations. The protein expression level of ABCB1 was detected by Western blotting and immunofluorescence analysis. Our results showed that anlotinib significantly increased the sensitivity of KHOSR2 and U2OSR2 cells (which overexpress PGP1) to chemotherapeutic agents in vitro and in a KHOSR2 xenograft nude mouse model in vivo. Mechanistically, anlotinib increases the intracellular accumulation of PGP1 substrates by inhibiting the efflux function of PGP1 in multidrug-resistant cell lines. Furthermore, anlotinib stimulated the ATPase activity of PGP1 but affected neither the protein expression level nor the localization of PGP1. In animal studies, anlotinib in combination with doxorubicin (DOX) significantly decreased the tumor growth rate and the tumor size in the KHOSR2 xenograft nude mouse model. Overall, our findings suggest that anlotinib may be useful for circumventing MDR to other conventional antineoplastic drugs.

Regeneration of Subcutaneous Cartilage in a Swine Model Using Autologous Auricular Chondrocytes and Electrospun Nanofiber Membranes Under Conditions of Varying Gelatin/PCL Ratios

The scarcity of ideal biocompatible scaffolds makes the regeneration of cartilage in the subcutaneous environment of large animals difficult. We have previously reported the successful regeneration of good-quality cartilage in a nude mouse model using the electrospun gelatin/polycaprolactone (GT/PCL) nanofiber membranes. The GT/PCL ratios were varied to generate different sets of membranes to conduct the experiments. However, it is unknown whether these GT/PCL membranes can support the process of cartilage regeneration in an immunocompetent large animal model. We seeded swine auricular chondrocytes onto different GT/PCL nanofiber membranes (GT:PCL = 30:70, 50:50, and 70:30) under the sandwich cell-seeding mode. Prior to subcutaneously implanting the samples into an autologous host, they were cultured in vitro over a period of 2 weeks. The results revealed that the nanofiber membranes with different GT/PCL ratios could support the process of subcutaneous cartilage regeneration in an autologous swine model. The maximum extent of homogeneity in the cartilage tissues was achieved when the G5P5 (GT: PC = 50: 50) group was used for the regeneration of cartilage. The formed homogeneous cartilage tissues were characterized by the maximum cartilage formation ratio. The extents of the ingrowth of the fibrous tissues realized and the extents of infiltration of inflammatory cells achieved were found to be the minimum in this case. Quantitative analyses were conducted to determine the wet weight, cartilage-specific extracellular matrix content, and Young’s modulus. The results indicated that the optimal extent of cartilage formation was observed in the G5P5 group. These results indicated that the GT/PCL nanofiber membranes could serve as a potential scaffold for supporting subcutaneous cartilage regeneration under clinical settings. An optimum GT/PCL ratio can promote cartilage formation.

Therapeutic Response of CCKBR-Positive Tumors to Combinatory Treatment with Everolimus and the Radiolabeled Minigastrin Analogue [177Lu]Lu-PP-F11N

The inhibition of the mammalian target of rapamycin complex 1 (mTORC1) by everolimus (RAD001) was recently shown to enhance the tumor uptake of radiolabeled minigastrin. In this paper, we investigate if this finding can improve the in vivo therapeutic response to [177Lu]Lu-PP-F11N treatment. The N-terminal DOTA-conjugated gastrin analogue PP-F11N (DOTA-(DGlu)6-Ala-Tyr-Gly-Trp-Nle-Asp-Phe) was used to evaluate treatment efficacy in the human A431/CCKBR xenograft nude mouse model in combination with RAD001. Both RAD001 and [177Lu]Lu-PP-F11N single treatments as well as their combination inhibited tumor growth and increased survival. In concomitantly treated mice, the average tumor size and median survival time were significantly reduced and extended, respectively, as compared to the monotherapies. The histological analysis of kidney and stomach dissected after treatment with RAD001 and [177Lu]Lu-PP-F11N did not indicate significant adverse effects. In conclusion, our study data demonstrate the potential of mTORC1 inhibition to substantially improve the therapeutic efficacy of radiolabeled minigastrin analogues in CCKBR-positive cancers.

Long Noncoding RNA SNHG1 Regulates LMNB2 Expression by Sponging miR-326 and Promotes Cancer Growth in Hepatocellular Carcinoma

ObjectiveThe purpose of the study is to explore the potential competing endogenous RNA (ceRNA) network and investigate the molecular mechanism of long noncoding RNA (lncRNA) small nucleolar RNA host gene 1 (SNHG1) in hepatocellular carcinoma (HCC) development.MethodsBy analyzing the data of HCC in The Cancer Genome Atlas (TCGA) database, we included differentially expressed lncRNA and microRNA (miRNA) profiles and constructed ceRNA networks related to the prognosis of HCC patients. qRT-PCR, Western blotting, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), transwell assay, and the nude mouse model were employed to test the effects of SNHG1 and LMNB2 on tumor proliferation and growth in vitro and in vivo.ResultsIn the study, we identified 115 messenger RNAs (mRNAs), 12 lncRNAs, and 37 miRNAs by intersecting differentially expressed genes (DEGs) in TCGA and StarBase databases. Then, SNHG1–miR-326–LMNB2 pathway came into notice after further survival analysis and hub gene screening. Our results showed that SNHG1 expression was upregulated significantly in HCC tissues and cell lines. Downregulation of both LMNB2, the target of miR-326 in HCC, and SNHG1 inhibited tumor proliferation and growth in vitro and in vivo. Furthermore, SNHG1 could regulate LMNB2 expression through binding to miR-326 in HCC cell lines.ConclusionSNHG1 is a promising prognostic factor in HCC, and the SNHG1–miR-326–LMNB2 axis may be a potential therapeutic target for HCC.

Downregulation of the Proton-Activated Cl- Channel TMEM206 Inhibits Malignant Properties of Human Osteosarcoma Cells

Transmembrane protein 206 (TMEM206), a proton-activated chloride channel, has been implicated in various biochemical processes, including bone metabolism, and has emerged as a novel cancer-related protein in multiple tumor types. However, its role in primary malignant bone tumors, particularly in osteosarcoma (OS), remains unclear. This study is aimed at exploring the effects of TMEM206 gene silencing on the proliferation, migration, invasion, and metastasis of human OS cells in vitro and in vivo using an shRNA-knockdown strategy. We found that TMEM206 is frequently overexpressed and that high levels of TMEM206 correlated with clinical stage and pulmonary metastasis in patients with OS. We provided evidence that TMEM206-silenced OS cancer cells exhibit decreased proliferation, migration, and invasion in vitro. Mechanistically, we identified β-catenin, a key member of Wnt/β-catenin signaling, as a downstream effector of TMEM206. TMEM206 silencing inhibits the Wnt/β-catenin signaling pathway in expression rescue experiments, confirming that TMEM206 silencing attenuates OS cell tumorigenic behavior, at least in part, via the β-catenin mediated downregulation of Wnt/β-catenin signaling. More importantly, TMEM206 knockdown-related phenotype changes were replicated in a xenograft nude mouse model where pulmonary metastases of OS cells were suppressed. Together, our results demonstrate that silencing TMEM206 negatively modulates the Wnt/β-catenin signaling pathway via β-catenin to suppress proliferation, migration, invasion, and metastasis in OS carcinogenesis, suggesting TMEM206 as a potential oncogenic biomarker and a potential target for OS treatment.

Lupeol-Loaded Nanoparticles Enhance the Radiosensitivity of Hepatocellular Carcinoma by Inhibiting the Hyperactivation in Raf/Mitogen-Activated Protein Kinase and Phospatidylinositol-3 Kinase/mTOR Pathways

Radioresistance limits the effectiveness of radiotherapy for hepatocellular carcinoma. Raf and PI3K signaling cascades promote the formation of radioresistance in hepatocellular carcinoma (HCC). Lupeol has anticancer activity despite itspoor solubility in water and is toxic effect on normal tissue. In this study, nanoparticles (lupeol-NPs) were constructed using PEG-PLGA diblock copolymer vector, and results revealed that Lupeol-NPs reversed the radioresistance of hepatocellular carcinoma by inhibiting cellular proliferation and cell-cycle progression and promoting cellular apoptosis through blocking Raf/MAPK and PI3K/Akt signal transduction in radioresistant Huh-7R cells. In vivo, Lupeol-NPs combined with radiotherapy inhibited the growth of radioresistant hepatocellular carcinoma in a xenogenic nude mouse model. Ki-67 proliferation index decreased significantly (p < 0.05). We conclude that Lupeol-NPs can increase the sensitivity of radioresistant hepatocellular carcinoma to radiotherapy through inhibiting the Raf and PI3K signal cascades.

Cetuximab promotes RSL3-induced ferroptosis by suppressing the Nrf2/HO-1 signalling pathway in KRAS mutant colorectal cancer

Cetuximab is approved for the treatment of metastatic colorectal cancer (mCRC) with RAS wild-type. Nevertheless, the prognosis remains poor and the effectiveness of cetuximab is limited in KRAS mutant mCRC. Recently, emerging evidence has shown that ferroptosis, a newly discovered form of nonapoptotic cell death, is closely related to KRAS mutant cells. Here, we further investigated whether cetuximab-mediated regulation of p38/Nrf2/HO-1 promotes RSL3-induced ferroptosis and plays a pivotal role in overcoming drug resistance in KRAS mutant colorectal cancer (CRC). In our research, we used two KRAS mutant CRC cell lines, HCT116 and DLD-1, as models of intrinsic resistance to cetuximab. The viability of cells treated with the combination of RSL3 and cetuximab was assessed by the CCK-8 and colony formation assays. The effective of cetuximab to promote RSL3-induced ferroptosis was investigated by evaluating lipid reactive oxygen species accumulation and the expression of the malondialdehyde and the intracellular iron assay. Cetuximab therapy contributed to regulating the p38/Nrf2/HO-1 axis, as determined by western blotting and transfection with small interfering RNAs. Cetuximab promoted RSL3-induced ferroptosis by inhibiting the Nrf2/HO-1 in KRAS mutant CRC cells, and this was further demonstrated in a xenograft nude mouse model. Our work reveals that cetuximab enhances the cytotoxic effect of RSL3 on KRAS mutant CRC cells and that cetuximab enhances RSL3-induced ferroptosis by inhibiting the Nrf2/HO-1 axis through the activation of p38 MAPK.

Study of lncRNA TUG1/miR-320 in EPC Transplantation to Improve Lower Limb Ischemia and Promote Angiogenesis in Mice

To The aim of the current study was to investigate the changes in lncRNA TUG1/miR-320 and related proteins with ischaemic time in an ischemia model. A nude mouse model of lower limb ischemia was established by ligating the femoral artery, and laser Doppler measurements were used to demonstrate the successful establishment of the ischemia model. The cells were extracted from the bone marrow of nude mice, and the proliferation, migration and vascular-forming ability of the cells were analysed. When transplanted into ischemia model mice, blood flow measurements indicated that EPCs can speed up blood flow recovery. The results of HE staining indicated an improvement in inflammatory damage, and immunohistochemistry revealed an increase in capillaries. RT-PCR and Western blot experiments showed that the improvement of ischemia was related to an increase in lncRNA TUG1 and a decrease in miR-320 and that the expression of the related downstream proteins STAT3, VEGFR-2, Wnt-5a and β-catenin increased gradually. These changes promoted an increase in capillaries, the recovery of blood flow, and the improvement of muscle damage. Therefore, EPC transplantation can improve the inflammatory response of lower limb muscles by increasing the expression of lncRNA TUG1 and thereby accelerate the recovery of ischaemic limbs.

A Cyclic Peptide Epitope of an Under-Explored VEGF-B Loop 1 Demonstrated In Vivo Anti-Angiogenic and Anti-Tumor Activities

Pathological angiogenesis is mainly initiated by the binding of abnormal expressed vascular endothelial growth factors (VEGFs) to their receptors (VEGFRs). Blocking the VEGF/VEGFR interaction is a clinically proven treatment in cancer. Our previous work by epitope scan had identified cyclic peptides, mimicking the loop 1 of VEGF-A, VEGF-B and placental growth factor (PlGF), inhibited effectively the VEGF/VEGFR interaction in ELISA. We described here the docking study of these peptides on VEGFR1 to identify their binding sites. The cellular anti-angiogenic activities were examined by inhibition of VEGF-A induced cell proliferation, migration and tube formation in human umbilical vein endothelial cells (HUVECs). The ability of these peptides to inhibit MAPK/ERK1/2 signaling pathway was examined as well. On chick embryo chorioallantoic membrane (CAM) model, a cyclic peptide named B-cL1 with most potent in vitro activity showed important in vivo anti-angiogenic effect. Finally, B-cL1 inhibited VEGF induced human gastric cancer SGC-7901 cells proliferation. It showed anti-tumoral effect on SGC-7901 xenografted BALB/c nude mouse model. The cyclic peptides B-cL1 constitutes an anti-angiogenic peptide drug lead for the design of new and more potent VEGFR antagonists in the treatment of angiogenesis related diseases.