Blocking of SIRT7/FOXO3a Axis by miR-152-3p Enhances Cisplatin Sensitivity in Breast Cancer.

BACKGROUND: Cisplatin-based chemoresistance is major obstacle for breast cancer (BC) including Triple-negative breast cancer (TNBC). SIRT7 is reportedly involved in the progression of BC, the underlining mechanism in Cisplatin-based chemoresistance in BC remains unclear. This work is to elucidate effects of SIRT7 on cisplatin resistance in breast cancer regulated by miR-152-3p. METHODS: The RNA expression of SIRT7 and miRNAs in breast cancer were available from TCGA database. SIRT7-targeted miRNAs were predicted by TargetScan, miRanda, miRDB databases. The association of SIRT7 expression with predicted miRNA was validated by Luciferase assay. Cell apoptosis was determined by Flow cytometry. Cell viability was detected by CCK8 assay. The mRNA expression was measured by quantitative real-time polymerase chain reaction (qRT-PCR) assay. Protein expression was determined by Western blotting assay. RESULTS: SIRT7 mRNA levels were dramatically enhanced in BC tissues compared to para-carcinoma tissues, also increased in BC patients with Cisplatin-based chemotherapy containing TNBC compared with those without. The increase of SIRT7 expression was obviously relevant to shorter survive time of them. Importantly, SIRT7 inhibition facilitated Cisplatin-induced cell apoptosis of TNBC (MDA-MB-231 and MDA-MB-468) and non- TNBC (MCF-7). Notably, miR-152-3p was predicted as a negative regulator of SIRT7 by overlapping downregulated miRNAs in BC patients treated with Cisplatin-based chemotherapy and miRNAs to target SIRT7. Mechanically, miR-152-3p blocked SIRT7 to stimulate an activation of FOXO3a, cleaved PARP1 and Caspase-3, sensitizing Cisplatin-induced apoptosis of BC cells. CONCLUSIONS: Inhibition of SIRT7 by miR-152-3p may be a promising strategy against the resistance to cisplatin-based chemotherapy in BC containing TNBC.

circEPB41L2 blocks the progression and metastasis in non-small cell lung cancer by promoting TRIP12-triggered PTBP1 ubiquitylation.

The metastasis of non-small cell lung cancer (NSCLC) is the leading death cause of NSCLC patients, which requires new biomarkers for precise diagnosis and treatment. Circular RNAs (circRNAs), the novel noncoding RNA, participate in the progression of various cancers as microRNA or protein sponges. We revealed the mechanism by which circEPB41L2 (hsa_circ_0077837) blocks the aerobic glycolysis, progression and metastasis of NSCLC through modulating protein metabolism of PTBP1 by the E3 ubiquitin ligase TRIP12. With ribosomal RNA-depleted RNA seq, 57 upregulated and 327 downregulated circRNAs were identified in LUAD tissues. circEPB41L2 was selected due to its dramatically reduced levels in NSCLC tissues and NSCLC cells. Interestingly, circEPB41L2 blocked glucose uptake, lactate production, NSCLC cell proliferation, migration and invasion in vitro and in vivo. Mechanistically, acting as a scaffold, circEPB41L2 bound to the RRM1 domain of the PTBP1 and the E3 ubiquitin ligase TRIP12 to promote TRIP12-mediated PTBP1 polyubiquitylation and degradation, which could be reversed by the HECT domain mutation of TRIP12 and circEPB41L2 depletion. As a result, circEPB41L2-induced PTBP1 inhibition led to PTBP1-induced PKM2 and Vimentin activation but PKM1 and E-cadherin inactivation. These findings highlight the circEPB41L2-dependent mechanism that modulates the "Warburg Effect" and EMT to inhibit NSCLC development and metastasis, offering an inhibitory target for NSCLC treatment.

Magnetic iron oxide nanoparticle-loaded hydrogels for photothermal therapy of cancer cells.

Introduction: Non-invasive photothermal therapy (PTT) is a competitive treatment for solid tumors, while the efficacy is largely dependent on the effective retention of photothermal converters in tumor tissues. Methods: Herein, the development of iron oxide (Fe3O4) nanoparticle-loaded alginate (ALG) hydrogel platform for PTT of colorectal cancer cells is reported. Fe3O4 nanoparticles synthesized via coprecipitation method after reaction of 30 min have a small size (61.3 nm) and more suitable surface potential, and can mediate PTT under near-infrared (NIR) laser irradiation. The premix of Fe3O4 nanoparticles and ALG hydrogel precursors can be gelatinized by Ca2+-mediated cross-linking to form this therapeutic hydrogel platform. Results: The formed Fe3O4 nanoparticles can be effectively taken up by CT26 cancer cells and induce the death of CT26 cells in vitro under NIR laser irradiation because of their excellent photothermal property. In addition, Fe3O4 nanoparticle-loaded ALG hydrogels show negligible cytotoxicity at the studied concentration range, but can significantly kill cancer cells after PTT effect. Conclusion: This ALG-based hydrogel platform provides a valuable reference for subsequent in vivo studies and other related studies on Fe3O4 nanoparticle-loaded hydrogels.

Cell sheet-based multilayered liver tumor models for anti-cancer drug screening.

OBJECTIVE: To fabricate in vitro cell-dense, three-dimensional (3D) tumor models by employing a cell sheet technology for testing anti-cancer drug efficacy. RESULTS: The stratified liver tumor models were fabricated by stacking contiguous HepG2 cell sheets. Triple-layer (3L), double-layer (2L), single-layer (1L) cell sheet-based liver tumor models (CSLTMs) demonstrated 106, 96, 85% cell viability, respectively, after 3 days treatment of 10 µM doxorubicin hydrochloride (DOX), while cell viability in two-dimensional (2D) conventional culture (control) was 27%. After 7 days of DOX treatment, the viabilities of 3L, 2L, 1L, control were 24, 14, 3 and 4%, respectively. Probable explanations were blocked diffusion of DOX by the intact and multilayered structure and also hypoxia in the bottom of multilayered cell sheets. CONCLUSION: CSLTMs showed a thickness-dependent cytotoxic efficacy of DOX and greater drug resistance than the control, thereby providing useful information toward the development of improved biomimetic tumor models.

Purification, Preliminary Characterization, and Immunological Activity of Polysaccharides from Crude Drugs of Sijunzi Formula.

Sijunzi Decoction (SJZD) is a conventional prescription for curing spleen deficiency in Traditional Chinese Medicine and polysaccharide is its main ingredient. In order to explore the effective ingredients contributing to the immunological activity of SJZD, we isolated and purified seven homogeneous polysaccharides from Radix Ginseng (RS-3-1 and RS-3-2), Rhizoma Atractylodis Macrocephalae (BZ-3-1, BZ-3-2, and BZ-3-3), Poria (FL-3-1), and Radix Glycyrrhizae (GC-3-1) decoctions, respectively. The molecular weight of seven homogeneous polysaccharides ranged from 5.42 × 104 to 5.65 × 104 Da. Monosaccharide composition determined by GC-MS analysis showed that these polysaccharides were primarily composed of Rha, Ara, Xyl, Man, Glc, and Gal with various ratios. Immunological activity assay revealed that polysaccharides from four crude drug components of SJZD displayed inhibitory effects on the complement system. RS-3-1, BZ-3-1, FL-3-1, and GC-3-1 could significantly enhance the phagocytosis and increase the NO production and tumor necrosis factor (TNF-α) level in RAW 264.7 cells (p < 0.05). These results demonstrated the immunological activities of these polysaccharides from the four crude drugs. This study supports the therapeutic effect of SJZD in clinical use and is essential for further identification the immunopolysaccharide from SJZD decoction.