Pancreatic cancer (PC) is among the deadliest malignancies with a 5-year survival rate of nearly 12%. Malignant proliferating cancer cells usually exhibit metabolism reprogramming, which is distinct from their normal counterparts, resulting in therapeutic vulnerabilities. However, the underlying mechanisms of aberrant cholesterol metabolism regulating PC progression are poorly understood. In the present study, we aimed to identify and investigate the role of a key cholesterol metabolic enzyme squalene epoxidase (SQLE) in tumorigenesis of PC. Integrating analysis of The Cancer Genome Atlas (TCGA) cohort and multiple Gene Expression Omnibus (GEO) datasets was used to find the top up-regulated cholesterol homeostasis-related gene in PC. The IHC staining of tissue microarray composed of human PC samples were used to identify the clinical significance of SQLE in PC patients. The biological functions of SQLE and the potential therapeutic efficiency of SQLE inhibitors were assessed both in vitro and in vivo. Transcriptome analysis, untargeted metabolomics analysis, and related lipid detection were further performed to clarify the molecular mechanism of SQLE on PC development. We found SQLE expression was highly expressed in PC tissues compared with normal pancreatic tissues, and the upregulated SQLE predicted poor outcomes in PC patients. Additionally, we demonstrated that SQLE promoted the growth of PC both in vitro and in vivo. Mechanistically, inhibition of SQLE caused squalene accumulation-induced endoplasmic reticulum (ER) stress occurrence and subsequent cell apoptosis. Moreover, SQLE increased cholesterol de novo biosynthesis and maintained the stability of lipid rafts, which in turn activated Src/PI3K/Akt signalling. Finally, we found that pharmacological blockade of SQLE with terbinafine or NB-598 profoundly suppressed PC cell proliferation and xenograft tumor growth. Our findings demonstrated the oncogenic role and tumor promoting mechanism of SQLE in PC. SQLE promotes PC growth by attenuating ER stress and promoting lipid rafts-regulated Src/PI3K/Akt signaling pathway, suggesting SQLE as a potential therapeutic target for PC.

Obesity amplifies the risk for various cancers, including pancreatic cancer (PC). Due to limited early screening methods, this study seeks to investigate the effects of obesity-related metabolic disorders on PC initiation and offer novel insights into early detection and diagnosis in obese populations. Human pancreatic Nestin-expressing ductal cells (HPNE) were cultured with human serum obtained from obese patients and healthy individuals. Transcriptomics, untargeted metabolomics, and joint-pathway analyses were conducted to examine the impacts of obesity-related metabolic disorders on pancreatic carcinogenesis. Multiomics analysis results were validated using cells of varying genetic backgrounds, while their mechanisms and roles in PDAC development were explored in obese transgenic mouse models. Clinical relevance and translational value were also corroborated using public databases and human samples. Multiomic assessment revealed heightened cytokine signalling and ferroptosis defence in HPNE cells exposed to obesity serum. In vitro tests showed that upregulated interleukin 34 (IL-34) strengthens ferroptosis defence through oxidative stress, while the enhanced ferroptosis defence reciprocally raises IL-34 levels. Our study demonstrated that augmented IL-34 signalling and ferroptosis defence hasten PDAC initiation in diet-induced obese mice by increasing immunosuppressive macrophages infiltration. Public databases revealed a strong correlation between elevated IL-34 and glutathione peroxidase 4 (GPX4) expression in pancreatic tumors vs. normal tissues. Gene signature expression displayed substantial correlations as well. Cohort validation and single-cell analysis suggested a positive association between IL-34 signalling and ferroptosis defence enhancement with PDAC patients' body mass index (BMI). Obesity elevates IL-34 signalling and ferroptosis defence, thereby promoting PDAC development via macrophage-induced immunosuppression. The observed positive correlations between IL-34 and BMI, as well as GPX4 and BMI in PDAC patients underscore their potential roles in early PC screening among the obese population.

Pancreatic cancer is a highly fatal and aggressive disease due to its discouraging mortality and clinical treatment efficacy. Pancreas is composed of endocrine and exocrine parts, and the interlacing structure of them reminds us of the potential interaction between endocrine and exocrine cells in the oncogenesis and development of pancreatic cancer. We depicted the changes of pancreatic endocrine cells in pancreatic cancer tissues by single-cell transcriptome sequencing, spatial transcriptome sequencing and multiplexed immunohistochemistry in human as well as in mouse models. After that, the interaction and sequence between pancreatic cancer oncogenesis and endocrine changes was explored in orthotopic transplantation mice and KPC mice. Finally, we proved the mechanism of the interaction between endocrine and exocrine parts of the pancreas through islet isolation, co-culture in vitro and co-injection in vivo. We found that, compared with normal pancreatic tissue, pancreatic endocrine cells displayed significantly different transcriptomic characteristics and increased interaction with exocrine part in pancreatic cancer tissues. Specifically, pancreatic polypeptide positive (PP+) cells showed a sharp increment accompanied with the progression of the cancer lesion. From an evolutionary perspective, the increased PP+ cells might be derived from the trans differentiation of α and β cells. Interestingly, in vivo and in vitro experiments proved that pancreatic cancer cells were able to induce the trans differentiation of α cells and β cells into GCG+PP+ and INS+PP+ double-positive cells, which further promoted pancreatic cancer proliferation in a paracrine-dependent manner and formed a positive feedback loop. Our study systematically mapped the changes of pancreatic endocrine cells in pancreatic cancer and elucidated their relationship with pancreatic cancer oncogenesis and development. Meanwhile, we first time defined and characterized cancer-associated endocrine cells (CAE), which indicated that pancreatic endocrine cells should be an important component of pancreatic cancer microenvironment, thereby providing novel ideas for early diagnosis and targeted therapy of pancreatic cancer.

The presence of minimal intra-pancreatic fat deposition (IPFD) in the healthy human pancreas has been demonstrated in numerous studies. But excess IPFD, leads to a wide array of diseases, including but not limited to diabetes, pancreatitis, and pancreatic cancer (PC). Remarkably, PC patients with excessive intra-pancreatic fat accumulation are commonly associated with a poor prognosis compared to those with minimal IPFD. However, the interaction between tumor and IPFD remains elusive. Here, we evaluated the pancreatic fat infiltration in normal people and patients with PC respectively, and explored how intra-pancreatic fat accelerates tumor progression. Magnetic resonance imaging (MRI) and clinical biopsy specimens were used to assess the degree of pancreatic fat infiltration in PC patients and healthy control individuals. The KC, KPC, KCO, and AAV8-ADIPOQ-DTA mice were established to demonstrate that IPFD promoted tumor progression. The single-nucleus sequencing of pancreatic fat tissue and proteomic of PC cell lines were performed to identify the mechanism of interaction between cancer cells and adipocytes. We found that patients with PC presented excess intra-pancreatic fat deposition more frequently than control individuals, and the degree of fat infiltration was positively correlated with the tumor size of PC patients. High-fat diet KPC mice or KCO mice showed a higher degree of IPFD, which contributed to tumor growth and low survival rates of mice. Besides, the expression of uncoupling protein 1 (UCP1) was upregulated in PC patients or spontaneous tumor mice compared to normal controls. Constantly, the single-nucleus sequencing of pancreatic fat tissue of PC patients demonstrated the increase in thermogenesis features. Specifically, we revealed that PC cells improved the thermogenesis of intra-pancreatic adipose tissue, which in turn promoted PC cell proliferation. We demonstrated that excess intra-pancreatic fat infiltration fuels the progression of PC, and selectively eliminating fat in the pancreas inhibits tumor growth. Mechanistically, PC cells promote the browning of adipocytes, and then the activated adipocytes enhance the proliferation and migration of cancer cells in response.

Objective: To investigate the tumor immunity-related pathologic features and clinical significance in pancreatic ductal adenocarcinoma (PDAC). Methods: All pathologic materials and clinical information of 192 PDAC patients from the Cancer Hospital of the University of Chinese Academy of Sciences from January 2010 to December 2020 were collected. The onco-immune microenvironment associated morphologic features were evaluated, and MHC-Ⅰ, PD-L1, CD3, and CD8 expression were detected by immunohistochemistry (IHC). Then the correlation between the factors and their influence on prognosis was analyzed. Results: There were 163 cases of non-specific adenocarcinoma (163/192, 84.90%), 18 cases of adeno-squamous carcinoma (18/192, 9.37%), and 11 cases of other rare subtypes (11/192, 5.73%). Perineural invasion was observed in 110 cases (110/192, 57.29%) and vascular invasion in 86 cases (86/192, 44.79%). There were 84 cases (84/182, 46.15%) with severe chronic inflammation. Tumor infiltrating immune cell numbers (TII-N) were increased in 52 cases (52/192, 27.08%). Lymphocytes and plasma cells were the main infiltrating immune cells in 60 cases (60/192, 31.25%), whereas in 34 cases (34/192, 17.71%) the tumors were mainly infiltrated by granulocytes, and 98 cases (98/192, 51.04%) showed mixed infiltration. CD3+T cells were deficient in 124 cases (124/192, 66.31%). CD8+T cells were deficient in 152 cases (152/192, 79.58%). MHC-Ⅰ expression was down-regulated in 156 cases (156/192, 81.25%), and PD-L1 was positive (CPS≥1) in 46 cases (46/192, 23.96%). Statistical analysis showed that TII-N was negatively correlated with vascular invasion (P=0.035), perineural invasion (P=0.002), stage (P=0.004) and long-term alcohol consumption (P=0.039). The type of immune cells correlated positively with chronic pancreatic inflammation (P=0.002), and negatively with tumor differentiation (P=0.024). CD8+T cells were positively correlated with CD3+T cells (P=0.032), MHC-Ⅰ expression (P<0.001) and PD-L1 expression (P=0.001), and negatively correlated with long-term smoking (P=0.016). Univariate analysis showed that histological nonspecific type (P=0.013) and TII-N (P<0.001) were the factors for good prognosis. Vascular invasion (P=0.032), perineural invasion (P=0.001), high stage (P=0.003) and long-term alcohol consumption (P=0.004) were adverse prognostic factors. COX multivariate risk analysis found that TII-N was an independent favorable factor for PDAC, while perineural invasion was an independent adverse risk factor. Conclusions: TII-N is an independent superior prognostic factor for PDAC, and significantly correlated with many factors; chronic alcohol consumption and smoking may inhibit onco-immunity in PDAC patients.

MicroRNAs have emerged as crucial regulators of cardiac homeostasis and remodeling in various cardiovascular diseases. We previously demonstrated that miR-221 regulated cardiac hypertrophy in vitro. In the present study, we demonstrated that the cardiac-specific overexpression of miR-221 in mice evoked cardiac dysfunction and heart failure. The lipidated form of microtubule-associated protein 1 light chain 3 was significantly decreased and sequestosome 1 was accumulated in cardiac tissues of transgenic (TG) mice, indicating that autophagy was impaired. Overexpression of miR-221 in vitro reduced autophagic flux through inhibiting autophagic vesicle formation. Furthermore, mammalian target of rapamycin (mTOR) was activated by miR-221, both in vivo and in vitro. The inactivation of mTOR abolished the miR-221-induced inhibition of autophagy and cardiac remodeling. Our previous study has demonstrated that cyclin-dependent kinase (CDK) inhibitor p27 was a direct target of miR-221 in cardiomyocytes. Consistently, the expression of p27 was markedly suppressed in the myocardia of TG mice. Knockdown of p27 by siRNAs was sufficient to mimic the effects of miR-221 overexpression on mTOR activation and autophagy inhibition, whereas overexpression of p27 rescued miR-221-induced autophagic flux impairment. Inhibition of CDK2 restored the impaired autophagic flux and rescued the cardiac remodeling induced by either p27 knockdown or miR-221 overexpression. These findings reveal that miR-221 is an important regulator of autophagy balance and cardiac remodeling by modulating the p27/CDK2/mTOR axis, and implicate miR-221 as a therapeutic target in heart failure.

BACKGROUND:CD44, a transmembrane glycoprotein expressed in a variety of cells and tissues, has been implicated in tumour metastasis. But the molecular mechanisms of CD44-mediated tumour cell metastasis remain to be elucidated.METHODS:The downregulation of CD44 was determined by immunofluorescence. Moreover, the motility of breast cancer cells was detected by wound-healing and transwell experiments. Then the spontaneous metastasis of CD44-silenced MDA-MB-231 cells was tested by histology with BALB/c nude mice.RESULTS:A positive correlation between CD44 and Na(+)/H(+) exchanger isoform 1 (NHE1) was found in two breast cancer cells. CD44 downregulation could inhibit the metastasis of MDA-MB-231 cells and the expressions of Na(+)/H(+) exchanger 1. Moreover, CD44 overexpression upregulated the metastasis of MCF-7 cells, but the elevated metastatic ability was then inhibited by Cariporide. Interestingly, during these processes only the p-ERK1/2 was suppressed by CD44 downregulation and the expression of matrix metalloproteinases and metastatic capacity of MDA-MB-231 cells were greatly inhibited by the MEK1 inhibitor PD98059, which even had a synergistic effect with Cariporide. Furthermore, CD44 downregulation inhibits breast tumour outgrowth and spontaneous lung metastasis.CONCLUSIONS:Taken together, this work indicates that CD44 regulates the metastasis of breast cancer cells through regulating NHE1 expression, which could be used as a novel strategy for breast cancer therapy.

The mBin1b is a beta-defensin gene identified in the mouse epididymis. In the current report, its expression pattern and antibacterial activities were characterized, and a transgenic (TG) mouse model was developed in which mBin1b was exclusively overexpressed by up to 50-fold over normal levels in the caput epididymis. The experimental animals are healthy with normal reproductive activity, but are more resistant to epididymal infection from Escherichia coli than normal animals. The expression of IL1α and IL1β in the epididymis was decreased in the TG mice, which suggests that mBin1b has a role in the regulation of inflammatory response in the epididymis.

Histone deacetylase (HDAC) inhibitors are a class of promising anticancer reagents. They are able to induce apoptosis in embryonic carcinoma (EC) cells. However, the underlying mechanism remains poorly understood. Here we show that increased expression of zinc-finger protein regulator of apoptosis and cell-cycle arrest (Zac1) is implicated in HDAC inhibitor-induced apoptosis in F9 and P19 EC cells. By chromatin immunoprecipitation analysis we identified that increased Zac1 expression is mediated by histone acetylation of the Zac1 promoter region. Knockdown of Zac1 inhibited HDAC inhibitor-induced cell apoptosis. Moreover, HDAC inhibitors repressed nuclear factor-κB (NF-κB) activity, and this effect is abrogated by Zac1 knockdown. Consistently, Zac1 overexpression suppressed cellular NF-κB activity. Further investigation showed that Zac1 inhibits NF-κB activity by interacting with the C-terminus of the p65 subunit, which suppresses the phosphorylation of p65 at Ser468 and Ser536 residues. These results indicate that Zac1 is a histone acetylation-regulated suppressor of NF-κB, which is induced and implicated in HDAC inhibitor-mediated EC cell apoptosis.

Wnt-1, the vertebrate counterpart of the Drosophila wingless gene, plays an important role in the early morphogenesis of neural tissues. In this report, we have shown that overexpression of Wnt-1 can direct embryonic carcinoma P19 cells to differentiate into neuron-like cells in the absence of retinoic acid. Immunocytochemistry showed that these cells expressed neuronal markers, such as the neurofilament (NF) and microtubule-associated protein 2 (MAP2), but failed to express the glial cell marker, glial fibrillary acidic protein (GFAP). RT-PCR revealed that two basic helix-loop-helix (bHLH) genes, Mash-1 and Ngn-1, were up-regulated during the differentiation stage of Wnt-1-overexpressing P19 cells. These results suggest that the Wnt-1 gene promotes neuronal differentiation and inhibits gliogenesis during the neural differentiation of P19 cells, and that neural bHLH genes might be involved in this process.

The effect of sepia on the intracellular Ca2+ concentration, nuclear Ca2+/Mg(2+)-ATPase activities and the expression of c-jun were studied in H22 cancer cells by using fluorescent probe and immunohistochemical method. The results showed that intracellular Ca2+ concentration decreased 69% and 79%, nuclear Ca2+/Mg(2+)-ATPase activities diminished 21% and 37%, c-jun expression decreased obviously. The results suggested that sepia probably diminished the intracellular Ca2+ concentration, affected Ca(2+)-dependent nuclear Ca2+/Mg(2+)-ATPase activities, thus reduced the amount of Ca2+ transporting into nuclei, so lessened the promoting effect of Ca2+ on c-jun expression, and therefore inhibited cellular differentiation and proliferation. This might be one of the possible anti-cancer mechanisms of sepia.

In this report, multiplication of the Peking strain of Japanese B encephalitis virus was de-monstrated by different methods in all the different extra central nervous tissues tested (liver,spleen, heart, kidney, adrenal and subcutaneous tissue). After large inoculum of the virus subcutaneously, a dark phase was demonstrated between3—10 hours after inoculation. The lowest level of virus was found on the 5th—6th hour. On the24th hour after infection the titer of virus in all the tissues tested had practically reached themaximum level. The multiplication of the virus in the brain took place 2 days after the multi-plication of the virus in the extra central nervous tissue. The titer of virus in the blood droppedmarkedly on the 4th day and from the 5th day on practically no virus was demonstrated whilevirus was still found in the heart, kidney, etc. even on the 7th day.