Small interfering RNA targeting of the survivin gene inhibits human tumor cell growth in vitro

Mifepristone inhibits hepatoma growth by enhancing the GR-HSP60-survivin interaction to facilitate survivin degradation

Silencing of heat shock protein 60 (HSP60) suppresses the growth of hepatocellular carcinoma (HCC). Mifepristone inhibits HSP60 mRNA expression in Chlamydophila-infected epithelial cells. The aim of this study was to determine whether mifepristone could inhibit the growth of HCC cells by affecting the functions of HSP60. The effect of mifepristone on cell viability was examined by flow cytometry and a cell proliferation assay. Protein-protein interactions were examined using the immunoprecipitation assay. The anti-tumor effect of mifepristone was evaluated using a xenograft model. Our results indicated that mifepristone induces cell cycle arrest at the G1 phase and early-stage apoptosis in HCC cells. Instead of reducing the total amount of HSP60, mifepristone induced the release of mitochondrial HSP60 into the cytosol by causing a loss of ΔΨm, thereby enhancing glucocorticoid receptor (GR)-HSP60-survivin complex formation as well as survivin degradation. Animal models have confirmed the growth inhibitory effects of mifepristone on HCC, including changes in the abundance of HSP60 in mitochondria and cytosol, decreased survivin and Ki-67-positive cells, as well as increased cell apoptosis. In conclusion, the inhibition of HCC growth by mifepristone may be achieved by altering the subcellular distribution of HSP60 to enhance the formation of cytosolic GR-HSP60-survivin complexes in the cells, leading to the degradation of survivin.

Liposomal delivery of gene therapy for ovarian cancer: a systematic review

OBJECTIVE

To systematically identify and narratively synthesize the evidence surrounding liposomal delivery of gene therapy and the outcome for ovarian cancer.

METHODS

An electronic database search of the Embase, MEDLINE and Web of Science from inception until July 7, 2023, was conducted to identify primary studies that investigated the effect of liposomal delivery of gene therapy on ovarian cancer outcomes. Retrieved studies were assessed against the eligibility criteria for inclusion.

RESULTS

The search yielded 564 studies, of which 75 met the inclusion criteria. Four major types of liposomes were identified: cationic, neutral, polymer-coated, and ligand-targeted liposomes. The liposome with the most evidence involved cationic liposomes which are characterized by their positively charged phospholipids (n = 37, 49.3%). Similarly, those with neutrally charged phospholipids, such as 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine, were highly researched as well (n = 25, 33.3%). Eight areas of gene therapy research were identified, evaluating either target proteins/transcripts or molecular pathways: microRNAs, ephrin type-A receptor 2 (EphA2), interleukins, mitogen-activated protein kinase (MAPK), human-telomerase reverse transcriptase/E1A (hTERT/EA1), suicide gene, p53, and multidrug resistance mutation 1 (MDR1).

CONCLUSION

Liposomal delivery of gene therapy for ovarian cancer shows promise in many in vivo studies. Emerging polymer-coated and ligand-targeted liposomes have been gaining interest as they have been shown to have more stability and specificity. We found that gene therapy involving microRNAs was the most frequently studied. Overall, liposomal genetic therapy has been shown to reduce tumor size and weight and improve survivability. More research involving the delivery and targets of gene therapy for ovarian cancer may be a promising avenue to improve patient outcomes.

Survivin Small Molecules Inhibitors: Recent Advances and Challenges

Survivin, as a member of the inhibitor of apoptosis proteins (IAPs) family, acts as a suppressor of apoptosis and plays a central role in cell division. Survivin has been considered as an important cancer drug target because it is highly expressed in many types of human cancers, while it is effectively absent from terminally differentiated normal tissues. Moreover, survivin is involved in tumor cell resistance to chemotherapy and radiation. Preclinically, downregulation of survivin expression or function reduced tumor growth induced apoptosis and sensitized tumor cells to radiation and chemotherapy in different human tumor models. This review highlights the role of survivin in promoting cellular proliferation and inhibiting apoptosis and summarizes the recent advances in and challenges of developing small-molecule survivin inhibitors.

Synthesis and anti-tumor activity of derivatives of ring A of asiatic acid

Based on the simulation of the docking of survivin protein with known small molecule inhibitors, the active groups which can bind to target proteins were analyzed by the techniques of computer-aided drug design (CADD). These active groups were introduced into the A-ring of asiatic acid and their C-28 sites were reconstructed simultaneously. Ten asiatic acid derivatives were designed and synthesized, and their structures were confirmed by MS and NMR. The inhibitory activities of the asiatic acid derivatives against HepG2 and SGC7901 cell lines were evaluated and confirmed by the tetrazolium bromidesalt (MTT) assay. The results showed that compounds I₆ and II₄ exhibited more potent cytotoxicity than the positive control drug gefitinib, which was comparable to that of adriamycin.[Formula: see text].

Chloroquine in combination with aptamer-modified nanocomplexes for tumor vessel normalization and efficient erlotinib/Survivin shRNA co-delivery to overcome drug resistance in EGFR-mutated non-small cell lung cancer

Although novel molecular targeted drugs have been recognized as an effective therapy for non-small cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) activating mutations, their efficacy fails to meet the expectation due to the acquired resistance in tumors. Up-regulation of the anti-apoptotic protein Survivin was shown to contribute to the resistance to EGFR tyrosine kinase inhibitors (TKI) in EGFR mutation-positive NSCLC. However, the unorganized tumor blood vessels impeded drug penetration into tumor tissue. The resulting insufficient intracellular drug/gene delivery in drug-resistant cancer cells remarkably weakened the drug efficacy in NSCLC. In this work, a multi-functional drug delivery system AP/ES was developed by using anti-EGFR aptamer (Apt)-modified polyamidoamine to co-deliver erlotinib and Survivin-shRNA. Chloroquine (CQ) was used in combination with AP/ES to normalize tumor vessels for sufficient drug/gene delivery to overcome drug resistance in NSCLC cells. The obtained AP/ES possessed desired physicochemical properties, good biostability, controlled drug release profiles, and strong selectivity to EGFR-mutated NSCLC mediated by Apt. CQ not only enhanced endosomal escape ability of AP/ES for efficient gene transfection to inhibit Survivin, but also showed strong vessel-normalization ability to improve tumor microcirculation, which further promoted drug delivery and enhanced drug efficacy in erlotinib-resistant NSCLC cells. Our innovative gene/drug co-delivery system in combination with CQ showed a promising outcome in fighting against erlotinib resistance both in vitro and in vivo. This work indicates that normalization of tumor vessels could help intracellular erlotinib/Survivin-shRNA delivery and the down-regulation of Survivin could act synergistically with erlotinib for reversal of erlotinib resistance in EGFR mutation-positive NSCLC.

STATEMENT OF SIGNIFICANCE

NSCLC patients who benefited from EGFR-TKIs inevitably developed acquired resistance. Previous research focused on synthesis of new generation of molecular targeted drugs that could irreversibly inhibit EGFR with a particular gene mutation to overcome drug resistance. However, they failed to inhibit EGFR with other gene mutations. Activation of bypass signaling pathway and the changes of tumor microenvironment are identified as two of the mechanisms of acquired resistance to EGFR-TKIs. We therefore constructed multifunctional gene/drug co-delivery nanocomplexes AP/ES co-formulated with chloroquine that could target the both two mechanisms. We found that chloroquine not only enhanced endosomal escape ability of AP/ES for efficient gene transfection to inhibit Survivin, but also showed strong vessel-normalization ability to improve tumor microcirculation, which further promoted drug delivery into tumor tissue and enhanced drug efficacy in erlotinib-resistant NSCLC.

[Expressions of survivin, PI3K and AKT in keratinocytes in skin lesions and their pathogenic role in psoriasis vulgaris]

OBJECTIVE

To explore the role of survivin and PI3K/AKT pathway in the pathogenesis of psoriasis vulgaris (PV).

METHODS

Plaque-like lesions collected from 22 patients with PV in progressive stage and 18 normal control skin specimens were examined using immunohistochemical staining, Western blotting and real-time quantitative PCR for expressions of survivin, PI3K and AKT in the keratinocytes, and their correlation was analyzed. A small interfering RNA (siRNA) was used to knock down AKT in cultured HaCaT cells, and Western blotting was used to detect the changes in the expression of survivin. RESULTS Compared with normal skin, PV lesions showed obviously up-regulated expressions of survivin, PI3K and AKT in the keratinocytes. Survivin expression was positively correlated with PI3K (r=0.4510, P=0.0351) and AKT (r=0.4423, P=0.0393) in the keratinocytes in PV lesions. In cultured HaCaT cells, siRNA-mediated knockdown of AKT caused down-regulation of survivin expression.

CONCLUSION

Survivin and PI3K/AKT signaling pathway may participate in the occurrence and progression of PV.

COPB2 suppresses cell proliferation and induces cell cycle arrest in human colon cancer by regulating cell cycle-related proteins

Coat proteins (COPs), including the major types clathrin, COPI and COPII, play a considerable role in intracellular transport by initiating the formation of transport vesicles. Coatomer protein complex subunit β2 (COPB2) is one of the seven subunits that make up a COPI complex. In the present study, we found that COPB2 was highly expressed in human colon cancer specimens. However, to date, there have been no reports describing the functions of COPB2 in human colon cancer cells. In this study, we analyzed the functions of COPB2 in the proliferation and cell cycle arrest of human RKO and HCT116 colon cancer cells by using lentivirus-mediated RNAi infection. Our results demonstrated that the silencing of COPB2 in vitro could inhibit the proliferation and colony formation abilities of RKO and HCT116 cells. Furthermore, measurement of cell cycle distribution indicated that the downregulation of COPB2 could induce G0/G1 or S phase cell cycle arrest by regulating cell cycle-related proteins. In conclusion, our results suggest that COPB2 plays a key role in the proliferation and cell cycle progression of human RKO and HCT116 colon cancer cells, thus indicating that COPB2 might be a potential therapeutic target for the treatment of human colon cancer.