EML4-ALK G1202R and EML4-ALK L1196M mutations induce crizotinib resistance in non-small cell lung cancer cells through activating epithelial-mesenchymal transition mediated by MDM2/MEK/ERK signal axis.

Crizotinib, as the first-generation of anaplastic lymphoma kinase (ALK) inhibitor, effectively improves the survival time of ALK-positive non-small cell lung cancer (NSCLC) patients. However, its efficacy is severely limited by drug resistance caused by secondary mutations. G1202R and L1196M are classical mutation sites located in ALK kinase domain. They may hinder the binding of ALK inhibitors to the target kinase domain, resulting in drug resistance in patients. However, the exact mechanism of drug resistance mediated by these mutations remains unclear. In this study, we aimed to evaluate how G1202R and L1196M mutations mediate crizotinib resistance. To explore the resistance mechanism, we constructed EML4-ALK G1202R and L1196M mutant cell lines with A549 cells. The results showed that the mutant cells exhibited significant epithelial-mesenchymal transition (EMT) and metastasis compared to control (A549-vector) or wild type (A549-EML4-ALK) cells. Subsequently, it was found that the occurrence of EMT was correlated to the high expression of murine double minute 2 (MDM2) protein and the activation of mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) pathway in mutant cells. Down-regulation of MDM2 inhibited the activation of MEK/ERK pathway, thus reversed the EMT process and markedly increased the inhibitory effect of crizotinib on the growth of mutant cells. Collectively, resistance of ALK-positive NSCLC cells to crizotinib is induced by G1202R and L1196M mutations through activation of the MDM2/MEK/ERK signalling axis, promoting EMT process and metastasis. These findings suggest that the combination of MDM2 inhibitors and crizotinib could be a potential therapeutic strategy.

Anoikis resistant gastric cancer cells promote angiogenesis and peritoneal metastasis through C/EBPß-mediated PDGFB autocrine and paracrine signaling.

Anoikis is a type of programmed cell death induced by loss of anchorage to the extracellular matrix (ECM). Anoikis resistance (AR) is crucial for the survival of metastatic cancer cells in blood, lymphatic circulation and distant organs. Compared to ordinary cancer cells, anoikis resistant cancer cells undergo various cellular and molecular alterations, probably characterizing the cells with unique features not limited to anoikis resistance. However, the molecular mechanisms connecting anoikis resistance to other metastatic properties are still poorly understood. Here, the biological interaction between anoikis resistance and angiogenesis as well as their involvement into peritoneal metastasis of gastric cancer (GC) were investigated in vitro and in vivo. The prognostic value of key components involved in this interaction was evaluated in the GC cohort. Compared to ordinary GC cells, GCAR cells exhibited stronger metastatic and pro-angiogenic traits corresponding to elevated PDGFB secretion. Mechanistically, transcription factor C/EBPß facilitated PDGFB transcription by directly binding to and interacting with PDGFB promoter elements, subsequently increasing PDGFB secretion. Secreted PDGFB promoted the survival of detached GC cells through a C/EBPß-dependent self-feedback loop. Moreover, secreted PDGFB promoted angiogenesis in metastases via activation of the MAPK/ERK signaling pathway in vascular endothelial cells. Both C/EBPß activation level and PDGFB expression were significantly elevated in GC and correlated with metastatic progression and poor prognosis of patients with GC. Overall, interaction between GCAR cells and vascular endothelial cells promotes angiogenesis and peritoneal metastasis of GC based on C/EBPß-mediated PDGFB autocrine and paracrine signaling. C/EBPß-PDGFB-PDGFRß-MAPK axis promises to be potential prognostic biomarkers and therapeutic targets for peritoneal metastasis of GC.

ATF6 promotes liver fibrogenesis by regulating macrophage-derived interleukin-1α expression.

Macrophages contribute to liver fibrogenesis by the production of a large variety of cytokines. ATF6 is associated with the activation of macrophages. The present study aimed to investigate the role of ATF6 in the expression of macrophage-derived cytokines and liver fibrogenesis after acute liver injury. Following thioacetamide (TAA)-induced acute liver injury, the characteristics of the occurrence of liver fibrosis and the secretion of cytokines by macrophages were first described. Then, the role of various cytokines secreted by macrophages in activating hepatic stellate cells (HSCs) was tested in vitro. Finally, endoplasmic reticulum stress (ER-stress) signals in macrophages were detected following liver injury. siRNA was used to interfere with the expression of ATF6 in macrophages to verify the influence of ATF6 on cytokine expression and liver fibrogenesis after liver injury. A single intraperitoneal injection of TAA induced acute liver injury. The depletion of macrophages attenuated acute liver injury, while it inhibited liver fibrogenesis. During acute liver injury, macrophages secrete a variety of cytokines. Most of these cytokines promoted the activation of HSCs, but the effect of IL-1α was most significant. In the early stage of acute liver injury, ER-stress signals in macrophages were activated. Interference of ATF6 expression suppressed the secretion of cytokines by macrophages and attenuated liver fibrogenesis. Overall, in the early stage of acute liver injury, ATF6 signals promoted the expression of macrophage-derived cytokines to participate in liver fibrogenesis, and IL-1α exhibited the most significant role in promoting the activation of HSCs and liver fibrogenesis.

[Feeding status of 0～23-month-old infants in poor rural areas of Gansu Province from 2018 to 2019].

OBJECTIVE: To investigate the feeding status of infants and their feeder's feeding literacy in poor rural areas of Gansu Province. METHODS: From November 2018 to January 2019, a multi-stage cluster random sampling method was used to select 1200 infant and child families aged 0 to 23 months in 40 villages of Gansu Province. A standardized questionnaire from the Chinese Nutrition Society(CNS)was used to investigate the basic situation of infant and young children's families, the situation of breastfeeding and the addition of supplementary food, and parents feeding knowledge, attitude behavior(KAP). Using chi-square test, logistic regression and other method to statistically describe and infer the collected data. RESULTS: A total of 1193 infants and 1165 feeders were investigated. The exclusive breastfeeding rate of infants and young children under the age of 6 months was 39. 02%. The rate of continuous breastfeeding at 1 year old was 37. 40%, and the rate of continuous breastfeeding at 2 years old was 20. 88%, the difference between the two was significant(χ~2=13. 498, P<0. 01). The supplementary food supplement rate of infants and children over 6 months was 94. 37%, the highest supplementary supplement for cereals and potatoes(98. 01%), and the lowest percentage for beans and nuts(23. 51%), and the distribution of supplementary foods at different ages was significantly different(χ~2=52. 336, P<0. 01). The qualification rate of infants and young children's minimum dietary diversity was 64. 13%, the minimum eating frequency qualification rate was 70. 64%, the minimum acceptable dietary intake qualification rate was 42. 16%, and the qualification rates of various indicators were significantly different between different months(χ~2=85. 421, P<0. 01;χ~2=19. 66, P<0. 01; χ~2=17. 261, P<0. 01). The KAP score passing rate of infant caregivers was 37. 34%, and there was a statistical difference between the age of infants and young children, the education level and the sex of the caregiver(χ~2=9. 411, P<0. 05;χ~2=25. 901, P<0. 01;χ~2=3. 874, P<0. 05). Taking low-month-old infants and young children, low education and male caregivers as controls, infants and young children aged over 12 months, high school education and female caregivers were the protective factors of KAP scores(P<0. 05). CONCLUSION: The problems of infant breastfeeding and supplementary feeding in poor rural areas of Gansu Province were serious, and the knowledge and skills of raising people were scarce, which were related to the age of infants and young children, the education and the sex of raising people.

[Analysis of microwave-induced thermoacoustic signals and research-development preprocessor].

According to the results of analyzing the microwave-induced thermoacoustic signals, the amplitude and frequency were estimated and the designing parameters of preprocessor were decided. Based on the parameters, the signals preprocessor was designed with the band pass frequency ranging from 50 KHz to 3MHz, the gain ranging from 55 dB to 105 dB and the output noise being 1.32 V when the input was zero and the gain was 105 dB. The de-noising method of thermoacoustic signals was also discussed. The signals can be picked up by the preprocessor combined with the digital multipoint average method. The amplitude of signals is only 5 microV or even less. The results indicated that the preprocessor can meet the needs of thermoacoustic signals acquisition in bandwidth, gain and noise control.