Hypoxia is a common feature of solid tumors and is associated with aggressiveness and poor patient outcomes. Exosomes, initially considered to be cellular "garbage dumpsters," are now implicated in mediating interactions with the cellular environment. However, the mechanisms underlying the association between exosomes and hypoxia during cancer progression remain poorly understood. In this study, we found that exosomes derived from hypoxic oral squamous cell carcinoma (OSCC) cells increased the migration and invasion of OSCC cells in a HIF1a and HIF-2a-dependent manner. Given that exosomes have been shown to transport miRNAs to alter cellular functions, we performed miRNA sequencing of normoxic and hypoxic OSCCderived exosomes. Of the 108 miRNAs that were differentially expressed, miR-21 stood out as one of the most significantly upregulated miRNAs under hypoxic conditions. miR-21 depletion in hypoxic OSCC cells led to decreased miR-21 levels in exosomes and significantly reduced cell migration and invasion. Conversely, restoration of miR-21 expression in HIF-1a and HIF2a-depleted exosomes rescued OSCC cell migration and invasion. Moreover, exosomal miR-21 markedly enhanced snail and vimentin expression, while significantly decreasing E-cadherin levels in OSCC cells, in vitro and in vivo. Finally, circulating exosomal miR-21 levels were closely associated with HIF-1a/ HIF-2a expression, T stage, and lymph node metastasis in patients with OSCC. In conclusion, our findings suggest that the hypoxic microenvironment may stimulate tumor cells to generate miR-21-rich exosomes that are delivered to normoxic cells to promote prometastatic behaviors and prompt further investigation into the therapeutic value of exosome inhibition for cancer treatment.

No abstract

SUMMARY Bone metastasis is a major health threat to breast cancer patients. Tumor-derived Jagged1 represents a central node in mediating tumor-stromal interactions that promote osteolytic bone metastasis. Here, we report the development of a highly effective fully human monoclonal antibody against Jagged1 (clone 15D11). In addition to its inhibitory effect on bone metastasis of Jagged1-expressing tumor cells, 15D11 dramatically sensitizes bone metastasis to chemotherapy, which induces Jagged1 expression in osteoblasts to provide a survival niche for cancer cells. We further confirm the bone metastasis-promoting function of osteoblast-derived Jagged1 using osteoblast-specific Jagged1 transgenic mouse model. These findings establish 15D11 as a potential therapeutic agent for the prevention or treatment of bone metastasis.

Neuropathic pain resulting from nerve lesions or dysfunction represents one of the most challenging neurological diseases to treat. A better understanding of the molecular mechanisms responsible for causing these maladaptive responses can help develop novel therapeutic strategies and biomarkers for neuropathic pain. We performed a miRNA expression profiling study of dorsal root ganglion (DRG) tissue from rats four weeks post spinal nerve ligation (SNL), a model of neuropathic pain. TaqMan low density arrays identified 63 miRNAs whose level of expression was significantly altered following SNL surgery. Of these, 59 were downregulated and the ipsilateral L4 DRG, not the injured L5 DRG, showed the most significant downregulation suggesting that miRNA changes in the uninjured afferents may underlie the development and maintenance of neuropathic pain. TargetScan was used to predict mRNA targets for these miRNAs and it was found that the transcripts with multiple predicted target sites belong to neurologically important pathways. By employing different bioinformatic approaches we identified neurite remodeling as a significantly regulated biological pathway, and some of these predictions were confirmed by siRNA knockdown for genes that regulate neurite growth in differentiated Neuro2A cells. In vitro validation for predicted target sites in the 3′-UTR of voltage-gated sodium channel Scn11a, alpha 2/delta1 subunit of voltage-dependent Ca-channel, and purinergic receptor P2rx ligand-gated ion channel 4 using luciferase reporter assays showed that identified miRNAs modulated gene expression significantly. Our results suggest the potential for miRNAs to play a direct role in neuropathic pain.

Critical cytotoxicity evaluation of pharmaceuticals is necessary for the clinical practice of chemotherapy. To quantitatively evaluate cell viability, currently there are two main types of sensitive methods including real-time cell analysis (RTCA) and CCK-8 assay, in which RTCA records electrochemical signal changes around an incubated cell, whereas CCK-8 is based on the colorimetric method. Despite the different detection principles adopted for the cytotoxicity assessment, the comparison of the two methods in terms of the application scope is lacking. In this study, comparison studies were conducted between the RTCA and CCK-8 assays using anticancer drugs including doxorubicin hydrochloride, curcumin, irinotecan (CPT-11), taxol, and oxaliplatin, which are classified into two groups of drug molecules in the absence and presence of additives. The cytotoxicity evaluation of these drugs on cancer cells revealed that the physicochemical properties of drug formulations such as optical and electrochemical properties are closely linked with the readout of cytotoxic methods. The experimental results suggested that the preselection of cytotoxic assay is critical for the quantitative measurement of cytotoxicity of anticancer drugs, which is of clinical importance for their therapeutic usage.

Malignant tumors reprogram cellular metabolism to support cancer cell proliferation and survival. Although most cancers depend on a high rate of aerobic glycolysis, many cancer cells also display addiction to glutamine. Mounting evidence indicates key roles of glutamine transporters and glutaminase activity in cancer glutamine metabolism. Here, we show that the EphA2 receptor tyrosine kinase activates YAP and TAZ (YAP/TAZ), transcriptional co-activators of the TEAD family of transcription factors, to promote glutamine metabolism in models of HER2-positive breast cancer. EphA2 overexpression induced nuclear accumulation of YAP and TAZ and increased expression of YAP/TAZ target genes. Inhibition of Rho or ROCK kinase abolished EphA2-dependent YAP/TAZ nuclear localization, suggesting Rho signaling as a critical intermediary. Silencing of YAP or TAZ significantly reduced intracellular glutamate, through differential regulation of SLC1A5 and GLS, respectively. Indeed, the regulatory DNA elements of both SLC1A5 and GLS contain TEAD binding sites and were bound by TEAD4 in an EphA2-dependent manner. In human breast cancer, EphA2 expression positively correlates with YAP and TAZ, as well as GLS and SLC1A5. While high expression of EphA2 predicts enhanced metastatic potential and poor survival, increased EphA2 expression rendered HER2-positive breast cancer cells more sensitive to glutaminase inhibition. Together, these findings define a novel mechanism of EphA2-mediated YAP/TAZ activation to promote glutaminolysis through upregulation of GLS and SLC1A5 in HER2+ breast cancer.

No abstract

This study aims to investigate the human immunodeficiency virus (HIV) transmission rate in HIV serodiscordant couples, in addition to the relevant influencing factors. From January 1999 to August 2016, patients with HIV/AIDS (index cases) along with their fixed partners were registered and monitored to determine the rate of HIV transmission between couples, as well as relevant influencing factors. A total of 231 HIV-positive couples were investigated, of these, 45-negative (19.48%) partners were infected with HIV via sexual transmission prior to diagnosis of the first case detected in couples. After diagnosis, the transmission rate between spouses was 0.39 per 100 person-years (2/507.7), and the cumulative transmission rate was 1.08% (2/186), which was significantly lower than the transmission rate before diagnosis (χ2 = 35.714, P < 0.001). Among the 119 HIV/AIDS patients who received antiretroviral therapy (ART), the transmission rate was 0 (0/119), whereas the transmission rate was 2.99% (2/67) in HIV/AIDS patients who did not receive ART. In addition, HIV transmission rate in serodiscordant couples was high prior to diagnosis of the index case. However, following diagnosis, the transmission rate was reduced, and the risk of transmission in the index case with antiviral treatment was null. Therefore, a prompt intervention in HIV discordant couples with ART of index case is vital to reduce the risk of HIV transmission.