A Mitochondria-Targeted NIR-II Molecule Fluorophore for Precise Cancer Phototheranostics.

Subcellular organelle mitochondria are becoming a key player and a driver of cancer. Mitochondrial targeting phototheranostics has attracted increasing attention for precise cancer therapy. However, those phototheranostic systems still face great challenges, including complex and multiple components, light scattering, and insufficient therapeutic efficacy. Herein, a molecular fluorophore IR-TPP-1100 was tactfully designed by molecular engineering for mitochondria-targeted fluorescence imaging-guided phototherapy in the second near-infrared window (NIR-II). IR-TPP-1100 not only exhibited prominent photophysical properties and high photothermal conversion efficiency but also achieved excellent mitochondria-targeting ability. The mitochondria-targeting IR-TPP-1100 enabled NIR-II fluorescence and photoacoustic dual-modality imaging of mitochondria at the organism level. Moreover, it integrated photothermal and photodynamic therapy, obtaining remarkable tumor therapeutic efficacy by inducing mitochondrial apoptosis. These results indicate that IR-TPP-1100 has great potential for precise cancer therapy and provides a promising strategy for developing mitochondria-targeting NIR-II phototheranostic agents.

Targeted Degradation of Signal Transduction and Activator of Transcription 3 by Chaperone-Mediated Autophagy Targeting Chimeric Nanoplatform.

Chaperone-mediated autophagy (CMA) is a lysosomal-dependent proteolysis pathway for the degradation of cytosolic proteins. However, exploiting CMA-mediated proteolysis to degrade proteins of interest in cancer therapy has not been widely applied. In this study, we develop a CMA-targeting chimera (CMATAC) to efficiently and specifically degrade signal transduction and activator of transcription 3 (STAT3) in tumor cells. CMATAC consists of STAT3 and heat shock cognate 70 kDa protein (HSC70) targeting peptides connected by a linker. To efficiently deliver CMATACs into tumor cells, lipid nanoparticles (LNPs) are used to encapsulate CMATACs (nCMATACs) and decorated with an insulin-like growth factor 2 receptor (IGF2R) targeting peptide (InCMATACs) to achieve tumor targeting and precise delivery. The CMA pathway is activated in tumor cells by a fasting-mimicking diet (FMD). Furthermore, FMD treatment strongly enhances the cellular uptake and tumor accumulation of InCMATACs by upregulating the IGF2R expression. As a result, InCMATACs efficiently degrade STAT3 protein in both A549 and HCC827 tumor cells and inhibit tumor growths in vivo. This study demonstrates that InCMATACs can be used for selective proteolysis in cancer therapy.

Mitochondrial Regulation of Ferroptosis in Cancer Therapy.

Ferroptosis, characterized by glutamate overload, glutathione depletion, and cysteine/cystine deprivation during iron- and oxidative-damage-dependent cell death, is a particular mode of regulated cell death. It is expected to effectively treat cancer through its tumor-suppressor function, as mitochondria are the intracellular energy factory and a binding site of reactive oxygen species production, closely related to ferroptosis. This review summarizes relevant research on the mechanisms of ferroptosis, highlights mitochondria's role in it, and collects and classifies the inducers of ferroptosis. A deeper understanding of the relationship between ferroptosis and mitochondrial function may provide new strategies for tumor treatment and drug development based on ferroptosis.

Persistent Degradation of HER2 Protein by Hybrid nanoPROTAC for Programmed Cell Death.

Proteolysis-targeting chimera (PROTAC) has emerged as a promising strategy for degrading proteins of interest. Peptide-based PROTACs offer several advantages over small-molecule-based PROTACs, such as high specificity, low toxicity, and large protein-protein interaction surfaces. However, peptide-based PROTACs have several intrinsic shortcomings that strongly limit their application including poor cell permeability and low stability and potency. Herein, we designed a nanosized hybrid PROTAC (GNCTACs) to target and degrade human epidermal growth factor receptor 2 (HER2) in tumor cells. Gold nanoclusters (GNCs) were utilized to connect HER2-targeting peptides and cereblon (CRBN)-targeting ligands. GNCTACs could overcome the intrinsic barriers of peptide-based PROTACs, efficiently delivering HER2-targeting peptides in the cytoplasm and protecting them from degradation. Furthermore, a fasting-mimicking diet was applied to enhance the cellular uptake and proteasome activity. Consequently, more than 95% of HER2 in SKBR3 cells was degraded by GNCTACs, and the degradation lasted for at least 72 h, showing a catalytic-like reaction.

An Activatable Phototheranostic Nanoplatform for Tumor Specific NIR-II Fluorescence Imaging and Synergistic NIR-II Photothermal-Chemodynamic Therapy.

The phototheranostics in the second near-infrared window (NIR-II) have proven to be promising for the precise cancer theranostics. However, the non-responsive and "always on" imaging mode lacks the selectivity, leading to the poor diagnosis specificity. Herein, a tumor microenvironment (TME) activated NIR-II phototheranostic nanoplatform (Ag2 S-Fe(III)-DBZ Pdots, AFD NPs) is designed based on the principle of Förster resonance energy transfer (FRET). The AFD NPs are fabricated through self-assembly of Ag2 S QDs (NIR-II fluorescence probe) and ultra-small semiconductor polymer dots (DBZ Pdots, NIR-II fluorescence quencher) utilizing Fe(III) as coordination nodes. In normal tissues, the AFD NPs maintain in "off" state, due to the FRET between Ag2 S QDs and DBZ Pdots. However, the NIR-II fluorescence signal of AFD NPs can be rapidly "turn on" by the overexpressed GSH in tumor tissues, achieving a superior tumor-to-normal tissue (T/NT) signal ratio. Moreover, the released Pdots and reduced Fe(II) ions provide NIR-II photothermal therapy (PTT) and chemodynamic therapy (CDT), respectively. The GSH depletion and NIR-II PTT effect further aggravate CDT mediated oxidative damage toward tumors, achieving the synergistic anti-tumor therapeutic effect. The work provides a promising strategy for the development of TME activated NIR-II phototheranostic nanoprobes.

Targeted Degradation of PD-L1 and Activation of the STING Pathway by Carbon-Dot-Based PROTACs for Cancer Immunotherapy.

Proteolysis targeting chimeras (PROTACs) technology is an emerging approach to degrade disease-associated proteins. Here, we report carbon-dot (CD)-based PROTACs (CDTACs) that degrade membrane proteins via the ubiquitin-proteasome system. CDTACs can bind to programmed cell death ligand 1 (PD-L1), recruit cereblon (CRBN) to induce PD-L1 ubiquitination, and degrade them with proteasomes. Fasting-mimicking diet (FMD) is also used to enhance the cellular uptake and proteasome activity. More than 99 % or 90 % of PD-L1 in CT26 or B16-F10 tumor cells can be degraded by CDTACs, respectively. Furthermore, CDTACs can activate the stimulator of interferon genes (STING) pathway to trigger immune responses. Thus, CDTACs with FMD treatment effectively inhibit the growth of CT26 and B16-F10 tumors. Compared with small-molecule-based PROTACs, CDTACs offer several advantages, such as efficient membrane protein degradation, targeted tumor accumulation, immune system activation, and in vivo detection.

Identification of Prognosis Biomarkers for High-Grade Serous Ovarian Cancer Based on Stemness.

In this paper, high-grade serous ovarian cancer (HGSOC) is studied, which is the most common histological subtype of ovarian cancer. We use a new analytical procedure to combine the bulk RNA-Seq sample for ovarian cancer, mRNA expression-based stemness index (mRNAsi), and single-cell data for ovarian cancer. Through integrating bulk RNA-Seq sample of cancer samples from TCGA, UCSC Xena and single-cell RNA-Seq (scRNA-Seq) data of HGSOC from GEO, and performing a series of computational analyses on them, we identify stemness markers and survival-related markers, explore stem cell populations in ovarian cancer, and provide potential treatment recommendation. As a result, 171 key genes for capturing stem cell characteristics are screened and one vital cancer stem cell subpopulation is identified. Through further analysis of these key genes and cancer stem cell subpopulation, more critical genes can be obtained as LCP2, FCGR3A, COL1A1, COL1A2, MT-CYB, CCT5, and PAPPA, are closely associated with ovarian cancer. So these genes have the potential to be used as prognostic biomarkers for ovarian cancer.

Long non-coding RNA NEAT1 promotes proliferation, migration and invasion of human osteosarcoma cells.

Aim: Long non-coding RNAs (LncRNAs) have been identified to play a crucial role in tumorigenesis and the progression of many types of tumors. However, the clinical significance and biological function of lncRNA nuclear-enriched abundant transcript 1(NEAT1) in human osteosarcoma remains unknown. Here, we investigated the role of NEAT1 in human osteosarcoma cell lines and clinical tumor samples. Methods: In this study, expression of NEAT1 was analyzed in 19 osteosarcoma tissues and paired adjacent non-tumor tissues by using quantitative real-time PCR. Additionally, knockdown of NEAT1 expression using Lentivirus-mediated siRNA was performed in order to explore the biological function of NEAT1 on osteosarcoma cell proliferation and metastasis through MTT, colony formation assay and transwell assay. Results: NEAT1 was over-expressed in osteosarcoma tissues compared with adjacent non-tumor tissues. In addition, knockdown of NEAT1 expression could suppress cell proliferation, migration and invasion in vitro. Conclusion: LncRNA NEAT1 was up-regulated in osteosarcoma tissue, promoting proliferation and metastasis of osteosarcoma cells. These findings indicate the role of this substance, as a growth regulator in osteosarcoma, and thus it may serve as a novel biomarker, and drug target for developing osteosarcoma therapies.

MicroRNA­106a regulates the proliferation and invasion of human osteosarcoma cells by targeting VNN2.

MicroRNAs (miRs) serve an essential role in tumorigenesis and are able to act as tumor suppressor genes or oncogenes. miR­106a has been identified generally as an oncogene in multiple types of human cancer; however, its association with osteosarcoma has not previously been understood. Reverse transcription­quantitative polymerase chain reaction (RT­qPCR) was used to detect miR­106a expression in 18 osteosarcoma tissues compared with paired non­cancerous adjacent tissues as well as osteosarcoma cell lines (U2OS, Saos­2 and MG63) compared with a normal osteoblast cell line (hFOB1.19). The biological function of U2OS cells was assessed by using a Transwell cell invasion assay, MTS proliferation assay and flow cytometric analysis following the transfection with lentivirus­mediated small interfering RNA (miR­106a­inhibitor). Western blotting and Luciferase reporters were used to investigate whether VNN2 was a target of miR­106a in osteosarcoma cells. Based on the RT­qPCR data, miR­106a was significantly upregulated in osteosarcoma tissues and osteosarcoma cell lines compared with their control counterparts (P<0.01). The knockdown of miR­106a resulted in cell proliferation and invasion inhibition. Furthermore, apoptosis enhancement and G2/M cell cycle arrest were detected by flow cytometry. The western blot analysis indicated that U2OS cells infected with miR­106a­inhibitor lentivirus had a higher VNN2 protein expression level compared with cells infected with miR­106a­negative control lentivirus. Luciferase reporters containing the 3'­untranslated region sequence of VNN2 messenger RNA demonstrated VNN2 may be a target of miR­106a. In addition, a negative correlation was confirmed between the expression of VNN2 and miR­106a in the tumor samples. The results of the present study indicate that the knockdown of miR­106a overexpressed VNN2 to inhibiting the proliferation, migration and invasion as well as inducing the apoptosis of human osteosarcoma cells.

Long non-coding RNA ANRIL promotes the proliferation, migration and invasion of human osteosarcoma cells.

The long antisense non-coding RNA ANRIL is 3.8 kb in length and serves an important role in the tumorigenesis and progression of a number of malignancies. However, its function in human osteosarcoma remains unknown. The present study investigated the role of ANRIL in human osteosarcoma cell lines and clinical tumor samples. The expression of ANRIL was analyzed in 19 osteosarcoma and paired adjacent non-cancerous tissues using reverse transcription-quantitative polymerase chain reaction. Knockdown of ANRIL expression using lentivirus-mediated small interfering RNA was performed to investigate the role of ANRIL in tumor proliferation and metastasis using MTT, colony formation and transwell assays. The results demonstrated that ANRIL expression was upregulated in osteosarcoma tissues when compared with ANCT samples. In addition, knockdown of ANRIL expression in vitro reduced cell proliferation and invasion. These results indicated that ANRIL is upregulated in osteosarcoma tissues, and may promote the proliferation and metastasis of osteosarcoma cells. Therefore, ANRIL may serve as a novel biomarker and target of novel therapies for the treatment of patients with osteosarcoma.