Reversal of Chemoresistance via Staged Liberation of Chemodrug and siRNA in Hierarchical Response to ROS Gradient.

P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) often leads to the failure of antitumor chemotherapy, and codelivery of chemodrug with P-gp siRNA (siP-gp) represents a promising approach for treating chemoresistant tumors. To maximize the antitumor efficacy, it is desired that the chemodrug be latently released upon completion of siP-gp-mediated gene silencing, which however, largely remains an unmet demand. Herein, core-shell nanocomplexes (NCs) are developed to overcome MDR via staged liberation of siP-gp and chemodrug (doxorubicin, Dox) in hierarchical response to reactive oxygen species (ROS) concentration gradients. The NCs are constructed from mesoporous silica nanoparticles (MSNs) surface-decorated with cRGD-modified, PEGylated, ditellurium-crosslinked polyethylenimine (RPPT), wherein thioketal-linked dimeric doxorubicin (TK-Dox2) and photosensitizer are coencapsulated inside MSNs while siP-gp is embedded in the RPPT polymeric layer. RPPT with ultrahigh ROS-sensitivity can be efficiently degraded by the low-concentration ROS inside cancer cells to trigger siP-gp release. Upon siP-gp-mediated gene silencing and MDR reversal, light irradiation is performed to generate high-concentration, lethal amount of ROS, which cleaves thioketal with low ROS-sensitivity to liberate the monomeric Dox. Such a latent release profile greatly enhances Dox accumulation in Dox-resistant cancer cells (MCF-7/ADR) in vitro and in vivo, which cooperates with the generated ROS to efficiently eradicate MCF-7/ADR xenograft tumors.

miR-522 regulates cell proliferation, migration, invasion capacities and acts as a potential biomarker to predict prognosis in triple-negative breast cancer.

This study was designed to explore the cell functions and prognostic significance of miR-522 in triple-negative breast cancer. The expression levels of miR-522 in triple-negative breast cancer tissues and cell lines were detected by quantitative real-time PCR analysis. Kaplan-Meier curve and Cox regression analysis were used to investigate the relationship between miR-522 expression and prognosis of patients, and to evaluate the possibility of miR-522 as a potential indicator for predicting the prognosis of triple-negative breast cancer. The CCK-8 and transwell assays were used to assess cell proliferation, migration, and invasion abilities. The expression of miR-522 in triple-negative breast cancer tissues was significantly higher than that in adjacent tissues and its high expression was closely associated with the high incidence of lymph node metastasis, advanced TNM stage, and BRCA1/2 mutation status. High expression of miR-522 is correlated with poor overall survival in patients with triple-negative breast cancer. Besides, functional studies in two triple-negative breast cancer cell lines showed that overexpression of miR-522 significantly promoted cell proliferation, migration, and invasion in vitro. BRCA1 was a potential direct target of miR-522. Our findings indicated that miR-522 was highly expressed in triple-negative breast cancer and was associated with poor prognosis of patients. The upregulation of miR-522 accelerated the progression of triple-negative breast cancer by targeting BRCA1. Therefore, miR-522 provides valuable information for the development of prevention and treatment strategies.

A near-infrared light-controlled, oxygen-independent radical generating nano-system toward cancer therapy.

Anti-tumor treatment based on free radicals is often inefficient in hypoxic tumors, mainly because of the oxygen-dependent generation mechanism of reactive oxygen species (ROS). Herein, we report an NIR laser-controlled nano-system that is capable of generating alkyl radicals in situ in an oxygen-independent approach. Hollow mesoporous Prussian blue nanoparticles (HPB NPs) were developed to co-encapsulate the azo initiator (AIBI) and 1-tetradecanol as the phase change material (PCM, melting point of ∼39 °C), obtaining the AP@HPB NPs. At normal body temperature, the PCM remained in the solid state to prevent the pre-leakage of AIBI. Upon NIR laser irradiation (808 nm) at the tumor site, AP@HPB NPs generated heat upon photothermal conversion, which melted the PCM to release AIBI and decomposed AIBI to produce toxicity free alkyl radicals under both normoxic and hypoxic conditions. The alkyl free radicals efficiently killed tumor cells by causing oxidative stress and damaging DNA. Meanwhile, NIR light-induced hyperthermia cooperated with free radicals to efficiently eradicate tumors. This study therefore provides a promising strategy toward oxygen-independent free radical therapy, especially for the treatment of hypoxic tumors.

MicroRNA-432 Acts as a Prognostic Biomarker and an Inhibitor of Cell Proliferation, Migration, and Invasion in Breast Cancer.

BACKGROUND: Accumulating studies have demonstrated that microRNAs (miRNAs) are involved in the progression of various cancers. This study aimed to investigate the potential clinical and functional role of miR-432 in breast cancer. MATERIALS AND METHODS: We evaluated the expression of miR-432 in 117 breast cancer samples and paired nontumor tissue samples, as well as 4 breast cancer cell lines using RT-qPCR analysis. Kaplan-Meier survival curve and multivariate Cox regression analysis were used to evaluate the prognostic significance of miR-432 in breast cancer patients. CCK-8 assay and Transwell assays were used to evaluate the biological function of miR-432 in the progression of breast cancer. RESULTS: miR-432 was downregulated in breast cancer tissues and cell lines, and its exotic expression was associated with tumor size, lymph node metastasis, and TNM stage. In addition, breast cancer patients with low miR-432 expression exhibited a shorter overall survival outcome. Further experiments revealed that overexpression of miR-432 inhibited the cell proliferation, migration, and invasion of breast cancer cells, while knockdown of miR-432 promoted these cellular activities. AXL was a direct target of miR-432 in breast cancer cells. CONCLUSION: The present study suggested that miR-432 may be a tumor suppressor in the progression of breast cancer through inhibiting cell proliferation, migration, and invasion by targeting AXL. And miR-432 might be a prognostic biomarker and therapeutic target for the treatment of breast cancer. This study provided a novel insight into breast cancer prognosis and treatment.

Light-assisted hierarchical intratumoral penetration and programmed antitumor therapy based on tumor microenvironment (TME)-amendatory and self-adaptive polymeric nanoclusters.

The anticancer performance of nanomedicine is largely impeded by insufficient intratumoral penetration. Herein, tumor microenvironment (TME)-amendatory and self-adaptive nanoclusters (NCs) capable of cancer-associated fibroblasts (CAFs) depletion and size/charge conversion were engineered to mediate light-assisted, hierarchical intratumoral penetration. Particularly, large-sized NCs (~50 nm) were prepared via self-assembly of FAP-α-targeting peptide-modified, 1O2-sensitive polymers, which were further used to envelope small-sized dendrimer (~5 nm) conjugated with Ce6 and loaded with DOX (DC/D). After systemic administration, the NCs efficiently targeted CAFs and generated lethal levels of 1O2 upon light irradiation, which depleted CAFs and concomitantly dissociated the NCs to liberate small-sized, positively charged DC/D. Such stroma attenuation and NCs transformation collectively facilitated the delivery of DC/D into deeper regions of CAF-rich tumors, where DOX and 1O2 provoked synergistic anti-cancer efficacies. This study provides an effective approach to facilitate the tumor penetration of nanomedicine by concurrently and spatiotemporally reconfiguring the nano-properties and remodeling the TME.

Prognostic role of Tif1γ expression and circulating tumor cells in patients with breast cancer.

Transcription intermediary factor 1γ (Tif1γ), a ubiquitous nuclear protein, is a regulator of transforming growth factor­ß (TGF­ß)/Smad signaling. Tif1γ can function as an oncogene and as a tumor suppressor. In the present study, Tif1γ levels were measured in the plasma of patients with breast cancer in order to investigate the association of Tif1γ with overall survival (OS). The results indicated that Tif1γ is an independent prognostic and predictive factor in breast cancer, and thus, a promising target protein for use in diagnostics and patient follow­up. Plasma levels of Tif1γ were measured in samples obtained from 110 patients with operable breast cancer and in 110 healthy volunteers at the Breast Cancer Department of Yangpu Hospital between 2008 and 2016. The association between Tif1γ levels and clinicopathologic parameters, and the OS in a follow­up period of 98 months was evaluated. The prognostic significance was assessed using the Kaplan­Meier method. The levels of Tif1γ were significantly lower in patients with breast cancer compared with healthy controls. The average concentration of 18.40 ng/ml was used to discriminate between Tif1γ­positive (52) and Tif1γ­negative patients (58). Tif1γ­positive patients had a significantly improved OS compared with Tif1γ­negative patients. In the multivariate analysis, Tif1γ was an independent predictor of a favorable OS in a prospective follow­up setting; thus, Tif1γ plasma levels are an independent prognostic factor for patients with breast cancer. These findings support the potential of using measurements of Tif1γ plasma levels to guide breast cancer therapy and monitoring. Further studies are required to validate Tif1γ as an easily detectable, non­invasive prognostic biomarker for breast cancer.

Photodynamic therapy-mediated remote control of chemotherapy toward synergistic anticancer treatment.

Stimuli-responsive nanomedicine (NM) with an on-demand drug release property has demonstrated promising utility toward cancer therapy. However, sensitivity and cancer selectivity still remain critical challenges for intelligent NM, which will compromise its therapeutic efficacy and lead to undesired toxicity to normal tissues. Herein, we report a convenient and universal approach to spatiotemporally control the chemodrug release via the photodynamic therapy (PDT)-mediated alteration of the tumor microenvironment. An arylboronic ester (BE)-modified amphiphilic copolymer (mPEG-PBAM) was designed to form micelles and encapsulate doxorubicin (Dox) and hematoporphyrin (Hp). The Dox/Hp co-encapsulated micelles (PB-DH) were stable under normal physiological environment with a uniform size distribution (∼100 nm). In contrast, under tumor-specific light irradiation, extensive reactive oxygen species (ROS) will be generated from Hp in the tumor sites, thus quickly dissociating the micelles and selectively releasing the chemodrug Dox as a consequence of the ROS-mediated cleavage of the hydrophobic BE moieties on the polymers. As such, synergistic anti-cancer efficacy was achieved between the Dox-mediated chemotherapy and the Hp-mediated PDT. This study therefore provides a useful approach to realize the precise and selective control over chemodrug delivery, and it renders promising utilities for the programmable combination of PDT and chemotherapy.

Engineering the Aromaticity of Cationic Helical Polypeptides toward "Self-Activated" DNA/siRNA Delivery.

The development of potent yet nontoxic membrane-penetrating materials is in high demand for effective intracellular gene delivery. We have recently developed α-helical polypeptides which afford potent membrane activities to facilitate intracellular DNA delivery via both endocytosis and the nonendocytic "pore formation" mechanism. Endocytosis will cause endosomal entrapment of the DNA cargo, while excessive "pore formation" would cause appreciable cytotoxicity. Additionally, helical polypeptides with stiff, rodlike structure suffer from low siRNA binding affinity. To address such critical issues, we herein incorporated various aromatic domains (benzyl, naphthyl, biphenyl, anthryl, and pyrenyl) into the side-chain terminals of guanidine-rich, helical polypeptides, wherein the flat-rigid shape, π-electronic structures of aromatic motifs "self-activated" the membrane-penetrating capabilities of polypeptides to promote intracellular gene delivery. Benzyl (Bn)- and naphthyl (Naph)-modified polypeptides demonstrated the highest DNA uptake level that outperformed the unmodified polypeptide, P2, by ∼4 fold. More importantly, compared with P2, Bn- and Naph-modified polypeptides allowed more DNA cargos to be internalized via the nonendocytic pathway, which significantly bypassed the endosomal entrapment and accordingly enhanced the transfection efficiency by up to 42 fold, outperforming PEI 25k as the commercial reagent by 3-4 orders of magnitude. The aromatic modification also improved the siRNA condensation capability of polypeptides, achieving notably enhanced gene-silencing efficiency against tumor necrosis factor-α to treat acute hepatic inflammation. Furthermore, we revealed that aromaticity-augmented membrane activity was accompanied by comparable or even significantly reduced "pore formation" capability, thus leading to diminished cytotoxicity at high concentrations. This study therefore provides a promising approach to manipulate the membrane activities and penetration mechanisms of polycations, which overcomes the multiple critical barriers preventing effective and safe gene delivery.

Association between vitamin D receptor gene Cdx2 polymorphism and breast cancer susceptibility.

Vitamin D receptor (VDR) gene polymorphisms have been reported to influence susceptibility to breast cancer. However, published findings on the association between VDR Cdx2 polymorphism and breast cancer susceptibility are conflicting. To get a precise estimation of the association between VDR Cdx2 polymorphism and breast cancer susceptibility, we conducted a meta-analysis of four case-control studies with a total of 8,880 subjects (3,841 cases and 5,039 controls). The results showed that VDR Cdx2 polymorphism was not associated with risk of breast cancer (A versus G: OR = 0.96, 95% CI 0.84-1.09; AA versus GG: OR = 0.97, 95% CI 0.64-1.45; AA/GA versus GG: OR = 0.94, 95% CI 0.80-1.10; AA versus GG/GA: OR = 0.99, 95% CI 0.65-1.51). Subgroup analysis in Caucasians also showed that VDR Cdx2 polymorphism was not associated with risk of breast cancer in Caucasians. However, there was a significant association in Africans (A versus G: OR = 0.75, 95% CI 0.60-0.94; AA versus GG: OR = 0.53, 95% CI 0.29-0.99; AA/GA versus GG: OR = 0.75, 95% CI 0.57-0.97). Therefore, the association between VDR Cdx2 polymorphism and breast cancer susceptibility is only found in Africans. More studies are needed to further assess the association in Asians or Africans.

Characteristics of Notch2(+) pancreatic cancer stem-like cells and the relationship with centroacinar cells.

Notch2, a surface marker in cell lines, is used to isolate, identify and localise pancreatic cancer stem-like cells and is a target for therapy of these cells. Sphere formation was induced in Panc-1 and Bxpc-3 pancreatic cancer cell lines, and Notch2(+) cells were separated from Bxpc-3 and Panc-1 cell lines by magnetic activated cell sorting (MACS). Expression of stem cell-related markers, OCT4, Nanog and PDX1, were measured by immunofluorescent (IF) staining. Expression of Notch2 was also determined immunohistochemically in pancreatic tissues. Notch2(+) cells were transplanted in subcutaneous of mice. AQP1 and AQP5 were also measured by IF in Bxpc-3 cells. The Notch signal pathway inhibitor, Compound E (CE), was used to treat Notch2(+) Bxpc-3 cells, and their vitalities were subsequently measured by the CCK-8 method. Positive expression of OCT4, Nanog and PDX1 was observed in Notch2(+) cells. Notch2(+) cells at centroacinar cell (CAC) and terminal ductal locations expressed AQP1 and AQP5. They were strongly tumourigenic in mice, and CE inhibited proliferation of Notch2(+) Bxpc-3 cells to some degree. OCT4 and Nanog can be used as markers of self-renewal in pancreatic cancer stem cells. Notch2(+) cells in human pancreatic cancer Bxpc-3 and Panc-1 cell lines had the properties of cancer stem cells. The results suggest that Notch2(+) pancreatic cancer stem-like cells had a close relationship with CAC.