Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer deaths due to its highly aggressive biological nature and resistance to chemotherapy. Previous studies indicate that miR-21 is an important regulator in the activation of cancer-associated fibroblasts (CAFs). However, whether miR-21 in CAFs would regulate PDAC’s tumor microenvironment and lead to drug resistance remain unknown. In this study, we evaluated the relationship between CAF activation, miR-21 expression, and drug resistance using tumor samples from PDAC patients. We changed the miR-21 expression level in CAFs and tested its roles in regulating the function of CAFs. In addition, we explored the roles of miR-21 in CAFs in the development of PDAC using an animal model. We found that PDAC patients who were resistant to gemcitabine treatment tended to have higher miR-21 expression and more activated CAFs. An in vitro study showed that CAFs with high miR-21 expression had elevated MMP-3, MMP-9, PDGF, and CCL-7 expression and promoted the invasion of PDAC cell lines. miR-21 overexpression also contributed to the activation of CAFs by regulating the PDCD4 gene. The in vivo study showed that upregulating miR-21 in CAFs promoted PDAC desmoplasia and increased its drug resistance to gemcitabine treatment, but downregulating miR-21 in CAFs suppressed desmoplasia and enhanced the effect of gemcitabine. We concluded that miR-21 promoted the activation of CAFs and contributed to the drug resistance of PDAC.

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AIMTo detect the expression of pleiotrophin (PTN) and N-syndecan in pancreatic cancer and analyze their association with tumor progression and perineural invasion (PNI).METHODSAn orthotopic mouse model of pancreatic cancer was created by injecting tumor cells subcapsularly in a root region of the pancreas beneath the spleen. Pancreatic cancer tissues were taken from 36 mice that survived for more than 90 d. PTN and N-syndecan proteins were detected by immunohistochemistry and analyzed for their correlation with pathological features, PNI, and prognosis.RESULTSThe expression rates of PTN and N-syndecan proteins were 66.7% and 61.1%, respectively, in cancer tissue. PTN and N-syndecan expression was associated with PNI (P = 0.019 and P = 0.032, respectively). High PTN expression was closely associated with large bloody ascites (P = 0.009), liver metastasis (P = 0.035), and decreased survival time (P = 0.022). N-syndecan expression was significantly associated with tumor size (P = 0.025), but not with survival time (P = 0.539).CONCLUSIONHigh PTN and N-syndecan expression was closely associated with metastasis and poor prognosis, suggesting that they may promote tumor progression and PNI in the orthotopic mouse model of pancreatic cancer.

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Nowadays, the global energy and environmental problems are becoming more and more serious, which promotes the development and utilization of renewable and clean energy in various countries. Intelligent car involves many subjects such as electronic technology, artificial intelligence, automatic control technology, sensor technology and computer technology and has become an important part of the application of artificial intelligence. Solar cell is a necessary part of the normal operation of the solar intelligent car, which can provide clean energy for the intelligent car. In this paper, the image recognition technology is used to design the intelligent vehicle control system. According to the intelligent vehicle path recognition, the scale invariant feature transform (SIFT) algorithm is improved to improve the accuracy of intelligent vehicle recognition. Data fusion is used to process the data detected by multi-sensor, and the running state of intelligent vehicle is studied. An evaluation method of intelligent vehicle navigation parameters based on association rules and belief network is proposed. The maximum power point tracking control is realized by using the interference observation method to ensure that the intelligent vehicle can track the maximum power point of the solar cell.