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Axon guidance molecules are frequently altered in pancreatic ductal adenocarcinoma (PDA) and influence PDA progression. However, the molecular mechanism remained unclear. Using genetically engineered mouse models to examine semaphorin 3D (SEMA3D), we identified a dual role for tumor- and nerve-derived SEMA3D in the malignant transformation of pancreatic epithelial cells and invasive PDA development. Pancreatic-specific knockout of the SEMA3D gene from the KRAS G12D and TP53 R172H mutation knock-in, PDX1-Cre(KPC) mouse model demonstrated delayed tumor initiation, prolonged survival, absence of metastasis, and reduced M2 macrophage expression. Mechanistically, tumor- and nerve-derived SEMA3D indirectly reprograms macrophages through KRAS MUT -dependent ARF6 signaling in PDA cells, resulting in increased lactate production, which is sensed by GPCR132 on macrophages to stimulate protumorigenic M2 polarization. Multiplex immunohistochemistry demonstrated increased M2-polarized macrophages proximal to nerves in SEMA3D-expressing human PDA tissue. This study suggests that altered SEMA3D expression leads to an acquisition of cancer-promoting functions, and nerve-derived SEMA3D is "hijacked" by PDA cells to support growth and metastasis in a KRAS MUT -dependent manner.

Background: The efficacy of different nucleos(t)ide analogs in the treatment of chronic hepatitis B virus (CHB) with severe acute exacerbation (SAE) remained unclear. Thus, this study aimed to compare the short-term efficacy of tenofovir disoproxil fumarate (TDF) and entecavir (ETV) in patients having CHB with SAE., Methods: We analyzed consecutive patients with treatment-naive CHB receiving TDF (n = 36) or ETV (n = 65) for SAE. The primary endpoint was overall mortality or receipt of liver transplantation (LT) by 24 weeks. The secondary endpoints are the comparison of ETV vs. TDF influences on renal function and virological and biochemical responses at 4, 12, 24, and 48 weeks., Results: The baseline characteristics were comparable between the two groups. By 24 weeks, 8 (22%) patients in the TDF group and 10 (15%) patients in the ETV group had either died (n = 15) or received LT (n = 3) ( P  = 0.367). Cox-regression multivariate analysis revealed age ( P  = 0.003), baseline international normalized ratio of prothrombin time ( P  = 0.024), and early presence of hepatic encephalopathy ( P  = 0.003) as independent factors associated with mortality or LT. The two groups of patients achieved comparable biochemical and virological responses at 48 weeks. No significant difference was found in the estimated glomerular filtration rate (eGFR) between the TDF and the ETV groups. However, a significant reduction in the eGFR at 48 weeks, as compared with the baseline, was found in each group., Conclusion: TDF and ETV achieved similar short-term clinical outcomes and treatment responses in CHB patients with SAE., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Axon guidance molecules were found to be the gene family most frequently altered in pancreatic ductal adenocarcinoma (PDA) through mutations and copy number changes. However, the exact molecular mechanism regarding PDA development remained unclear. Using genetically engineered mouse models to examine one of the axon guidance molecules, semaphorin 3D (SEMA3D), we found a dual role for tumor-derived SEMA3D in malignant transformation of pancreatic epithelial cells and a role for nerve-derived SEMA3D in PDA development. This was demonstrated by the pancreatic-specific knockout of the SEMA3D gene from the KRAS G12D and TP53 R 172 H mutation knock-in, PDX1-Cre (KPC) mouse model which demonstrated a delayed tumor initiation and growth comparing to the original KPC mouse model. Our results showed that SEMA3D knockout skews the macrophages in the pancreas away from M2 polarization, providing a potential mechanistic role of tumor-derived SEMA3D in PDA development. The KPC mice with the SEMA3D knockout remained metastasis-free, however, died from primary tumor growth. We then tested the hypothesis that a potential compensation mechanism could result from SEMA3D which is naturally expressed by the intratumoral nerves. Our study further revealed that nerve-derived SEMA3D does not reprogram macrophages directly, but reprograms macrophages indirectly through ARF6 signaling and lactate production in PDA tumor cells. SEMA3D increases tumor-secreted lactate which is sensed by GPCR132 on macrophages and subsequently stimulates pro-tumorigenic M2 polarization in vivo. Tumor intrinsic- and extrinsic-SEMA3D induced ARF6 signaling through its receptor Plexin D1 in a mutant KRAS-dependent manner. Consistently, RNA sequencing database analysis revealed an association of higher KRAS MUT expression with an increase in SEMA3D and ARF6 expression in human PDAs. Moreover, multiplex immunohistochemistry analysis showed an increased number of M2-polarized macrophages proximal to nerves in human PDA tissue expressing SEMA3D. Thus, this study suggests altered expression of SEMA3D in tumor cells lead to acquisition of cancer-promoting functions and the axon guidance signaling originating from nerves is "hijacked" by tumor cells to support their growth. Other axon guidance and neuronal development molecules may play a similar dual role which is worth further investigation., One Sentence Summary: Tumor- and nerve-derived SEMA3D promotes tumor progression and metastasis through macrophage reprogramming in the tumor microenvironment., Statement of Significance: This study established the dual role of axon guidance molecule, SEMA3D, in the malignant transformation of pancreatic epithelial cells and of nerve-derived SEMA3D in PDA progression and metastasis. It revealed macrophage reprogramming as the mechanism underlying bothroles. Together, this research elucidated how inflammatory responses promote invasive PDA progression and metastasis through an oncogenic process.