Phase separation of RNF214 promotes the progression of hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors, and the expression and function of an uncharacterized protein RNF214 in HCC are still unknown. Phase separation has recently been observed to participate in the progression of HCC. In this study, we investigated the expression, function, and phase separation of RNF214 in HCC. We found that RNF214 was highly expressed in HCC and associated with poor prognosis. RNF214 functioned as an oncogene to promote the proliferation, migration, and metastasis of HCC. Mechanically, RNF214 underwent phase separation, and the coiled-coil (CC) domain of RNF214 mediated its phase separation. Furthermore, the CC domain was necessary for the oncogenic function of RNF214 in HCC. Taken together, our data favored that phase separation of RNF214 promoted the progression of HCC. RNF214 may be a potential biomarker and therapeutic target for HCC.

Inhibiting the Activity of ABCG2 by KU55933 in Colorectal Cancer.

BACKGROUND: Therapeutic resistance is a frequent problem of cancer treatment and a leading cause of mortality in patients with metastatic colorectal cancer (CRC). Recent insight into the mechanisms that confer multidrug resistance has elucidated that the ATP-binding cassette (ABC) superfamily G member 2 (ABCG2) assists cancer cells in escaping therapeutic stress caused by toxic chemotherapy. Therefore, it is necessary to develop ABCG2 inhibitors. OBJECTIVES: In the present study, we investigated the inhibitory effect of KU55933 on ABCG2 in CRC. METHODS: The cytotoxicity assay and drug accumulation assay were used to examine the inhibitory effect of KU55933 on ABCG2. The protein expressions were detected by Western blot assay. The docking assay was performed to predict the binding site and intermolecular interactions between KU55933 and ABCG2. RESULTS: KU55933 was more potent than the known ABCG2 inhibitor fumitremorgin C to enhance the sensitivity of mitoxantrone and doxorubicin and the intracellular accumulation of mitoxantrone, doxorubicin and rhodamine 123 inside CRC cells with ABCG2 overexpression. Moreover, KU55933 did not affect the protein level of ABCG2. Furthermore, the docking data showed that KU55933 was tightly located in the drug-binding pocket of ABCG2. CONCLUSION: In summary, our data presented that KU55933 could effectively inhibit the drug pump activity of ABCG2 in colorectal cancer, which is further supported by the predicted model that showed the hydrophobic interactions of KU55933 within the drug-binding pocket of ABCG2. KU55933 can potently inhibit the activity of ABCG2 in CRC.

AZ32 Reverses ABCG2-Mediated Multidrug Resistance in Colorectal Cancer.

Colorectal cancer is a common malignancy with the third highest incidence and second highest mortality rate among all cancers in the world. Chemotherapy resistance in colorectal cancer is an essential factor leading to the high mortality rate. The ATP-binding cassette (ABC) superfamily G member 2 (ABCG2) confers multidrug resistance (MDR) to a range of chemotherapeutic agents by decreasing their intracellular content. The development of novel ABCG2 inhibitors has emerged as a tractable strategy to circumvent drug resistance. In this study, an ABCG2-knockout colorectal cancer cell line was established to assist inhibitor screening. Additionally, we found that ataxia-telangiectasia mutated (ATM) kinase inhibitor AZ32 could sensitize ABCG2-overexpressing colorectal cancer cells to ABCG2 substrate chemotherapeutic drugs mitoxantrone and doxorubicin by retaining them inside cells. Western blot assay showed that AZ32 did not alter the expression of ABCG2. Moreover, molecule docking analysis predicted that AZ32 stably located in the transmembrane domain of ABCG2. In conclusion, our result demonstrated that AZ32 could potently reverse ABCG2-mediated MDR in colorectal cancer.

Autophagic degradation of PML promotes susceptibility to HSV-1 by stress-induced corticosterone.

Rationale: Herpes simplex virus type 1 (HSV-1) is a neurotropic virus that can cause a variety of clinical syndromes including mucocutaneous disease and HSV-1 encephalitis (HSE). Here, we characterize the molecular mechanisms underlying the susceptibility to HSV-1 under stressful conditions. Methods: Restraint stress and corticosterone (CORT, a primary stress hormone) were respectively used to establish HSV-1 susceptible model in vivo and in vitro. Viral titers were determined by plaque assay. Western blotting, immunofluorescence, transmission electron microscopy (TEM), qRT-PCR, H&E staining, IHC staining and flow cytometry were employed to evaluate virus-related protein expressions and detect the activation of autophagy. Loss- and gain-function assays, co-immunoprecipitation (co-IP) technique and autophagy agonist/antagonist treatments were applied in mechanistic experiments. Results: Restraint stress increased the susceptibility of mouse brain to HSV-1. Similarly, CORT treatment enhanced the susceptibility of neural cells to HSV-1. Furthermore, PML protein level in HSV-1 infected brain tissues and neural cells was remarkably decreased by stress treatment in vivo or CORT treatment in vitro, while its transcriptional level was not affected. Notably, a striking decline in protein expressions of ICP27 and gB was observed in PML-overexpressing cells, which was reversed by CORT treatment. By contrast, protein expression of gB was increased by knockdown with si-PML in virus-infected SH-SY5Y cells. We further discovered that CORT-driven PML degradation was dependent on the activation of autophagy in a ULK1-independent manner, rather than proteasome pathway. Bafilomycin A1 (BaF1) attenuated the augmentation effect of CORT on HSV-1 infection. The expressions of viral proteins were reduced in LC3-depleted cells, and the degradation of PML by CORT-induced autophagy was prevented in cells with LC3 knockdown by RNAi. Interestingly, PML was revealed to interact with the autophagic cargo receptor P62 and the autophagic effector protein LC3. Additionally, CORT failed to increase gB protein level when PML was silenced, providing direct evidence linking autophagic degradation of PML and CORT-induced virus susceptibility. Conclusion: Our results revealed that restraint stress/CORT increased HSV-1 susceptibility by delivering PML into autolysosomes for degradation. The results obtained from in vitro and in vivo models not only demonstrated the adverse effects of stress on HSV-1 infection, but also systematically investigated the underlying molecular mechanisms. These discoveries broaden our understanding of the interplay between host and viruses, and a comprehensive understanding of the role of autophagy in viral infection will provide information for future development of innovative drugs against viral infection.

[The quantitative measurement of several main contaminants in sealed cabin].

OBJECTIVE: To establish a standardized analytical method of chromatography used for separating and determining six target contaminants including methyl alcohol, ethanol, glycol, acetic acid, acetone and benzene in space cabin simultaneously. METHOD: Optimal separating and examining conditions were determined through experiments by gas chromatography. Retention time was used to determine the nature of contamination and the method of extended standard to quantify accurately the six mixed contaminants. The method of five-point calibration was used. RESULT: Non-polar capillary GC column (30.00 m x 0.25 micrometers x 250 micrometers) was selected. Oven temperature was -30 degrees C initially and then hoisted to 80 degrees C at a rate of 4 degrees C/min, to 150 degrees C at 6 degrees C/min, to 250 degrees C at 10 degrees C/min and kept for 5 min. The temperature of flame ionization detector was 200 degrees C and that of back inlet adopting split mode was 150 degrees C. The linear correlation of calibration curve was satisfied and the precision of this method was high. CONCLUSION: Under optimal experimental conditions the chromatographic peaks of six contaminants were separated so completely that they were quantified accurately simultaneously. The results showed this method was simple, quick and accurate.