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Ferroptosis, a novel form of cell death triggered by iron-dependent phospholipid peroxidation, presents significant therapeutic potential across diverse cancer types. Central to cellular metabolism, the metabolic pathways associated with ferroptosis are discernible in both cancerous and immune cells. This review begins by delving into the intricate reciprocal regulation of ferroptosis between cancer and immune cells. It subsequently details how factors within the tumor microenvironment (TME) such as nutrient scarcity, hypoxia, and cellular density modulate ferroptosis sensitivity. We conclude by offering a comprehensive examination of distinct immunophenotypes and environmental and metabolic targets geared towards enhancing ferroptosis responsiveness within the TME. In sum, tailoring precise ferroptosis interventions and combination strategies to suit the unique TME of specific cancers may herald improved patient outcomes. [ABSTRACT FROM AUTHOR]

Pancreatic cancer is an inflammatory malignancy, and tumor-associated macrophages (TAMs) are the predominant inflammatory cells in tumor tissue. TAMs have complicated interactions with pancreatic cancer cells, however, the details and mechanisms remain largely unknown. In this study, transcriptomics and proteomics analyses were performed to explore the interactions between murine pancreatic cancer cells and TAMs. Dopamine (DA) has been reported to suppress inflammations. However, its roles in TAMs of pancreatic cancer have not been reported. Herein, the roles and mechanisms of DA to affect the chemotherapeutic efficacy for pancreatic cancer were studied. Multi-omics results revealed that there was a tumor-promoting vicious cycle involving murine pancreatic cancer cells and TAMs. DA substantially improved the chemotherapeutic efficacy both in vitro study and in immunocompetent murine pancreatic cancer models by suppression of the M2 characters of TAMs. Further studies found that activation of DRD4 by DA led to the decrease of cAMP, and then inhibited the activation of PKA/p38 signal pathway, which suppressed the tumor-promoting inflammation of TAMs. This study uncovers the reciprocal interactions between TAMs and pancreatic cancer cells using multi-omics techniques and presents that DA has synergistic roles with chemotherapy for pancreatic cancer by suppressing of TAM-derived inflammations. [ABSTRACT FROM AUTHOR]

Traditionally, immunoglobulin (Ig) was believed to be produced by only B-lineage cells. However, increasing evidence has revealed a high level of Ig expression in cancer cells, and this Ig is named cancer-derived Ig. Further studies have shown that cancer-derived Ig shares identical basic structures with B cell-derived Ig but exhibits several distinct characteristics, including restricted variable region sequences and aberrant glycosylation. In contrast to B cell-derived Ig, which functions as an antibody in the humoral immune response, cancer-derived Ig exerts profound protumorigenic effects via multiple mechanisms, including promoting the malignant behaviors of cancer cells, mediating tumor immune escape, inducing inflammation, and activating the aggregation of platelets. Importantly, cancer-derived Ig shows promising potential for application as a diagnostic and therapeutic target in cancer patients. In this review, we summarize progress in the research area of cancer-derived Ig and discuss the perspectives of applying this novel target for the management of cancer patients. [ABSTRACT FROM AUTHOR]

The interactions between tumor immune microenvironment (TIME) and pancreatic cancer cells can affect chemotherapeutic efficacy; however, the mechanisms still remain largely unknown. Thirty items in TIME were comprehensively screened by using tissue microarray from pancreatic cancer patients. Their expressions, interconnections and predictive roles for survival were analyzed. Twenty-one of 30 items could stratify the survival of the patients; however, multivariate analysis found that only 5 independent risk factors could predict worse survival (M2-polarized tumor-associated macrophages (TAMs), IgG4 positive cells, TGF-β1, GM-CSF and lymphangiogenesis). They had a much higher expression levels in tumoral tissue, compared to peritumoral tissue. The Spearman analysis showed that M2-polarized TAM, TGF-β1 and GM-CSF were positively correlated with pancreatic cancer stem cells (PCSC), angiogenesis and lymphangiogenesis. Both human and murine pancreatic cancer cells could induce M2-polarized TAM, which showed substantial roles to decease chemotherapeutic effects. After treated by gemcitabine, both human and murine pancreatic cancer cell lines expressed higher level of immune check points, PCSC markers and varieties of immunosuppressive factors; however, TGF-β1 and GM-CSF had the highest increase. Based on the above results, TGF-β1 and GM-CSF were proposed to be the optimal potential targets to improve chemotherapeutic effects. In immunocompetent murine models, we demonstrated that combined blockade of TGF-β1 and GM-CSF improved the chemotherapeutic effects by inhibition of M2-polarized TAM and induction of CD8 positive T cells. This study presents a novel promising combined strategy to improve the chemotherapeutic effects for pancreatic cancer. [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) are small non-coding RNAs with a unique ring structure and play important roles as gene regulators. Disturbed expressions of circRNAs is closely related to varieties of pathological processes. The roles of circRNAs in cancers have gained increasing concerns. The communications between the cancer cells and tumor microenvironment (TME) play complicated roles to affect the malignant behaviors of cancers, which potentially present new therapeutic targets. Herein, we reviewed the roles of circRNAs in the TME. [ABSTRACT FROM AUTHOR]

Low-molecular-weight (LMW) thiols are important small molecules that regulate or maintain redox homeostasis in physiological and pathological processes. Assessing the concentrations of LMW thiols in biological systems may provide valuable information regarding physiological processes and the early diagnosis of some diseases. Here, we developed a method to simultaneously determine the concentrations of multiple LWM thiols in single cells by chemical derivatization assisted liquid chromatography-mass spectrometry (LC-MS). In this method, we synthesized a pair of stable isotope reagents, N-(acridin-9-yl)-2-bromoacetamide (AYBA) and N-(1,2,3,4-[2H4]-acridin-9-yl)-2-bromoacetamide ([2H4]AYBA). AYBA was used to derivatize LWM thiols in human cervical cancer (HeLa) cells, while [2H4]AYBA was used to derivatize standard LWM thiols to prepare internal standards for the LC-MS method development. The proposed AYBA derivatization greatly enhanced the detection sensitivity of LWM thiols by LC-MS, and thereby achieved the simultaneous detection of multiple LWM thiols by LC-MS in ∼1000 HeLa cells. Finally, the developed method was successfully utilized for the quantitative analysis of multiple LWM thiols in a single HeLa cell and the content changes of LWM thiols in a single HeLa cell before and after oxidative stress treatment. Accordingly, six LMW thiols were detected, including cysteamine, cysteine, glutathione, homocysteine, hydrogen sulfide, and pantetheine. [ABSTRACT FROM AUTHOR]

Interactions between pancreatic cancer cells and inflammatory cells play crucial roles in the biological behavior of pancreatic cancer. Abundant infiltration of immunoglobulin G4 (IgG4)-positive plasma cells in the pancreas is the most significant feature of autoimmune pancreatitis; however, the clinical significance of IgG4-positive plasma cell infiltration in pancreatic cancer has not previously been reported. Herein, we analyzed intratumoral and peritumoral infiltrations of IgG4-positive plasma cells in 95 pancreatic cancer cases after curative resection. The correlations between IgG4-positive plasma cell infiltration and the clinicopathologic traits and overall survival of pancreatic cancer were investigated. IgG4-positive plasma cells were found in 86 % of tumor tissue samples compared with 69 % of peritumoral tissue samples ( P = 0.0063). The high-level infiltration of intratumoral IgG4-positive plasma cells was positively correlated with poor histological grade ( P = 0.017). The high-level infiltration of intratumoral IgG4-positive plasma cells was significantly correlated with worse prognosis ( P = 0.01) in multivariate analysis. We further found that intratumoral M2-polarized tumor-associated macrophages (TAMs) were positively, linearly correlated with IgG4-positive plasma cells. In conclusion, IgG4-positive plasma cell infiltration is correlated with the clinicopathologic traits and overall survival of pancreatic cancer. High-level intratumoral infiltration of IgG4-positive plasma cells is an independent predictor for poor overall survival in pancreatic cancer patients after curative resection. Intratumoral M2-polarized TAMs probably induce IgG4-positive plasma cells. [ABSTRACT FROM AUTHOR]

The mechanisms of distant metastasis of malignancies largely remain unknown. Circulating tumor cells (CTC) derived from the primary cancer initiate distant metastasis by entering and traversing the bloodstream. Current methods to detect CTC are based on the notion that CTC do not express the common leukocyte antigen CD45. However, these methods neglect the fact that CTC can directly adhere to platelets and immune cells and therefore appear to be CD45-positive. The potential effects of interactions between CTC and adhesive immune cells have been largely overlooked, despite the fact that most CTC are killed by immune effector cells and only those that evade immune surveillance result in clonal expansion and metastatic lesions. It is crucial to define the characteristics that allow a select CTC population to escape immune surveillance; particularly, it must be determined whether interactions between CTC and adhesive immune cells provide a protective effect on CTC survival. If interactions between CTC and adhesive immune cells offer a selective advantage to those CTC cells, the next consideration is which characteristics of a CTC-immune cell population allow sufficient protection to facilitate immune evasion. Myeloid-derived suppressor cells (MDSC) are a large heterogeneous population of immature myeloid cells that accumulate during cancer progression to induce extensively systemic and local immunosuppression, a phenomenon that has been demonstrated to facilitate cancer distant metastasis. We hypothesize, therefore, that CTC populations interacting with adhesive immune cells will have different biological behavior than CTC populations alone. Further, we hypothesize that CTC can create a defensive shield consisting of adhesive MDSC, which allows evasion of immune surveillance and therefore facilitates distant metastatic lesions. This possibility highlights the importance of direct interactions between CTC and adhesive immune cells and suggests the potential target that the CTC-MDSC cluster represents for prevention and treatment of distant metastasis of malignancies. [ABSTRACT FROM AUTHOR]

Pancreatic cancer is characterized as inflammatory malignancy with a dismal prognosis. There is abundant intratumoral infiltration of macrophages, and most of these tumor associated macrophages (TAM) are induced to be M2 phenotype. The M2 polarized TAM has been demonstrated to promote progression and induce chemo-resistance of pancreatic cancer. Interleukin (IL)-27 is a novel member of IL-12 cytokine family and its roles in regulation of phenotypes and functions of TAM remain largely unknown. In this study, we demonstrated IL-27 significantly inhibited the M2 macrophages polarization and dampened the proliferation, migration and metastasis of pancreatic cancer cells and as well enhanced the efficacy of gemcitabine. IL-27 could be potential to improve the treatment of pancreatic cancer by targeting M2 polarized TAMs. [ABSTRACT FROM AUTHOR]

Background: Chemoresistance is an important clinical problem in pancreatic cancer. As the mitogen-activated protein kinases (MAPKs) have been found to be involved in the development of chemoresistance in a variety of cancer cell lines, the aim of the current study was to assess the role and mechanism of MAPK signaling in mediating chemoresistance in pancreatic cancer cells. Materials and methods: The effects of pharmacological inhibition of MAPKs on resistance of pancreatic cancer cells to apoptosis induced by treatment with chemotherapeutic drugs were analyzed. Results: Compared with parental cells, the activity of extracellular signal-regulated kinase (ERK) was elevated in all of the three chemoresistant sublines at basal conditions. Inhibition of the ERK pathway by PD98059 sensitized cells to 5-fluorouracil (5-FU), whereas cells became more resistant to Adriamycin (ADM; Meiji Seika, Tokyo, Japan) and gemcitabine (GEM). 5-FU induced apoptosis primarily via a caspase-8-dependent pathway, and ADM and GEM via caspase-9. PD98059 enhanced the activity of caspase-8 and inhibited the activation of caspase-9. In addition, PD98059 regulated the level of phospho-Bcl-2. Conclusions: These data suggest that although constitutive activation of the ERK pathway might be a marker of chemoresistance, the effects of this pathway on chemoresistance of pancreatic cancer cells are drug dependent. This study also provides evidence for a possible link between the ERK pathway and activation of the caspases and Bcl-2. [Copyright &y& Elsevier]