Mammalian mitochondrial ribosomes translate 13 proteins encoded by mitochondrial genes, all of which play roles in the mitochondrial respiratory chain. After a long period of reconstruction, mitochondrial ribosomes are the most protein-rich ribosomes. Mitochondrial ribosomal proteins (MRPs) are encoded by nuclear genes, synthesized in the cytoplasm and then, transported to the mitochondria to be assembled into mitochondrial ribosomes. MRPs not only play a role in mitochondrial oxidative phosphorylation (OXPHOS). Moreover, they participate in the regulation of cell state as apoptosis inducing factors. Abnormal expressions of MRPs will lead to mitochondrial metabolism disorder, cell dysfunction, etc. Many researches have demonstrated the abnormal expression of MRPs in various tumors. This paper reviews the basic structure of mitochondrial ribosome, focuses on the structure and function of MRPs, and their relationships with cell apoptosis and diseases. It provides a reference for the study of the function of MRPs and the disease diagnosis and treatment.
P73, has two distinct promoters, which allow the formation of two protein isoforms: full-length transactivating (TA) p73 and an N-terminally truncated p73 species (referred to as DNp73) that lacks the N-terminal transactivating domain. Although the exact cellular function of DNp73 is unclear, the high expression levels of the genes have been observed in a variety of human cancers and cancer cell lines and have been connected to pro-tumor activities. Hence the aim of this review is to summarize DNp73 expression status in cancer in the current literature. Furthermore, we also focused on recent findings of DNp73 related to the biological functions from apoptosis, chemosensitivity, radiosensitibity, differentiation, development, etc. Thus this review highlights the significance of DNp73 as a marker for disease severity in patients and as target for cancer therapy.
Cell can integrate the caspase family and mammalian target of rapamycin (mTOR) signaling in response to cellular stress triggered by environment. It is necessary here to elucidate the direct response and interaction mechanism between the two signaling pathways in regulating cell survival and determining cell fate under cellular stress. Members of the caspase family are crucial regulators of inflammation, endoplasmic reticulum stress response and apoptosis. mTOR signaling is known to mediate cell growth, nutrition and metabolism. For instance, over-nutrition can cause the hyperactivation of mTOR signaling, which is associated with diabetes. Nutrition deprivation can inhibit mTOR signaling via SH3 domain-binding protein 4. It is striking that Ras GTPase-activating protein 1 is found to mediate cell survival in a caspase-dependent manner against increasing cellular stress, which describes a new model of apoptosis. The components of mTOR signaling-raptor can be cleaved by caspases to control cell growth. In addition, mTOR is identified to coordinate the defense process of the immune system by suppressing the vitality of caspase-1 or regulating other interferon regulatory factors. The present review discusses the roles of the caspase family or mTOR pathway against cellular stress and generalizes their interplay mechanism in cell fate determination.
Liposomal nanocarriers are able to carry peptides for efficient and selective delivery of radioactive tracer and drugs into the tumors. Angiopoietin 2 (ANGPT2) is an excellent biomarker for precise diagnosis and therapy of glioma. The present study aimed to design ANGPT2-specific peptides to modify the surface of nanoliposomes containing doxorubicin (Dox) for integrative imaging and targeting therapy of glioma. The targeted ANGPT2 peptides were designed using the molecular operating environment. Peptide-conjugated PEGlated liposomes containing Dox (peptide-Lipo@Dox) were prepared for radionuclide and drug delivery. Glioma cell functions were determined based on cell cycle and viability, apoptosis, cell invasion and migration, and colony-formation assays. The anti-tumor effect of peptide-Lipo@Dox was validated in intracranial U87-MG cell glioma-bearing mice in vivo. The peptides GSFIHSVPRH (GSF) and HSVPRHEV (HSV) showed specific affinity for ANGPT2 and a better cellular uptake in U87-MG cells. Micro-positron emission tomography (PET)/computed tomography (CT) imaging was used to visualize the orthotopic transplantation of glioma in the brain 1 h after injection of radionuclide 68Ga-labeled peptide-Lipo@Dox. Lipo@Dox with peptide modification demonstrated stable Dox loading, small sizes (<40 nm), and enrichment in the tumor region of the mouse brain. Peptide-Lipo@Dox treatment inhibited the Tie-2/Akt/Foxo-1 pathway, thereby inhibiting cell invasion and migration, cell viability, and colony-forming ability of U87-MG cells. Lipo@Dox peptide modification showed a better suppression of glioma development than Lipo@Dox. Thus, the ANGPT2-specific peptides were successfully designed, and the PEGylated liposome modified with ANGPT2-specific peptide served as part of a potent delivery method for integrative glioma-targeted imaging and therapy.