Cancer stem cells as therapeutic targets of pancreatic cancer

Cell-cell communication in stem cells and cancer: Alone but in touch

BACKGROUND

Cellular communication and signaling pathways are fundamental regulators of stem cell and cancer cell behaviors. This review explores the intricate interplay of these pathways in governing cellular behaviors, focusing on their implications for diseases, particularly cancer.

OBJECTIVES

This comprehensive review aims to elucidate the significance of cellular signaling pathways in regulating the behavior of stem cells and cancer cells. It delves into the alterations in these pathways, their impact on cell fate, and their implications for developing diseases, notably cancer. The objective is to underscore the importance of understanding these signaling pathways for developing targeted therapeutic strategies.

METHODS

The review critically analyzes existing literature and research findings concerning the roles of signaling pathways in stem cell behavior regulation, emphasizing their parallels and disparities in cancer cells. It synthesizes information on both direct and indirect modes of cell communication to delineate the complexity of signaling networks.

RESULTS

Direct and indirect modes of cell communication intricately regulate the complex signaling pathways governing stem cell behaviors, influencing differentiation potential and tissue regeneration. Alterations in these pathways significantly impact stem cell fate, contributing to disease pathogenesis, including cancer. Understanding these signaling cascades offers insights into developing targeted therapies, particularly cancer treatment.

CONCLUSION

Understanding the regulation of signaling pathways in stem cells and the specialized subset of cancer stem cells holds promise for innovative therapeutic approaches. By targeting aberrant signaling pathways, tailored interventions may improve treatment outcomes. This review underscores the critical role of signaling pathways in cellular behaviors, offering a pathway toward developing novel, more effective therapies for diverse diseases and disorders.

Pancreatic cancer stem cell-derived exosomal miR-210 mediates macrophage M2 polarization and promotes gemcitabine resistance by targeting FGFRL1

Pancreatic cancer (PC) is a serious threat to human health, with most patients diagnosed at the advanced stages of the disease. Treatment with gemcitabine (GEM) leads to PC GEM resistance. In addition, cancer stem cell (CSC)-derived exosomes play an important role in cancer progression. We aimed to investigate the role and mechanism of action of PC stem cell-derived exosomes in PC drug resistance and progression. CSC-derived exosomes increased the proportion of F4/80+/CD86 + cells and levels of M2 polarization factors. miR-210 is expressed in CSC-derived exosomes. Thus, following co-culture, miR-210 was taken up by macrophages. Transfection or the addition of miR-210 mimics increased the proportion of F4/80+/CD206 + cells and levels of M2 polarization factors. Further, the miR-210 targets inhibited the levels of FGFRL1. The FGFRL1 overexpression plasmid also inhibited miR-210-mediated M2 polarization. After co-culture of THP-M2 cells with PC cells and treatment with GEM, the survival rate, migration rate, and levels of MDR, YB-1, BCRP, p-PI3K, p-AKT, and p-mTOR in PC cells increased. And THP-M2 increased the tumor volume and MDR, YB-1, BCRP, p-PI3K, p-AKT, and p-mTOR levels. Overall, miR-210 from PC stem cell-derived exosome targets and inhibits FGFRL1 to promote macrophage M2 polarization, which activates the p-PI3K/p-AKT/p-mTOR pathway and increases GEM resistance.

Identification of common factors among fibrosarcoma, rhabdomyosarcoma, and osteosarcoma by network analysis

Sarcoma cancers are uncommon malignant tumors, and there are many subgroups, including fibrosarcoma (FS), which mainly affects middle-aged and older adults in deep soft tissues. Rhabdomyosarcoma (RMS), on the other hand, is the most common soft-tissue sarcoma in children and is located in the head and neck area. Osteosarcomas (OS) is the predominant form of primary bone cancer among young adults, primarily resulting from sporadically random mutations. This frequently results in the dissemination of cancer cells to the lungs, commonly known as metastasis. Mesodermal cells are the origin of sarcoma cancers. In this study, a rather radical approach has been applied. Instead of comparing homogenous cancer types, we focus on three main subtypes of sarcoma: fibrosarcoma, rhabdomyosarcoma, and osteosarcoma, and compare their gene expression with normal cell groups to identify the differentially expressed genes (DEGs). Next, by applying protein-protein interaction (PPI) network analysis, we determine the hub genes and crucial factors, such as transcription factors (TFs), affected by these types of cancer. Our findings indicate a modification in a range of pathways associated with cell cycle, extracellular matrix, and DNA repair in these three malignancies. Results showed that fibrosarcoma (FS), rhabdomyosarcoma (RMS), and osteosarcoma (OS) had 653, 1270, and 2823 differentially expressed genes (DEGs), respectively. Interestingly, there were 24 DEGs common to all three types. Network analysis showed that the fibrosarcoma network had two sub-networks identified in FS that contributed to the catabolic process of collagen via the G-protein coupled receptor signaling pathway. The rhabdomyosarcoma network included nine sub-networks associated with cell division, extracellular matrix organization, mRNA splicing via spliceosome, and others. The osteosarcoma network has 13 sub-networks, including mRNA splicing, sister chromatid cohesion, DNA repair, etc. In conclusion, the common DEGs identified in this study have been shown to play significant and multiple roles in various other cancers based on the literature review, indicating their significance.

GAS6-based CAR-T cells exhibit potent antitumor activity against pancreatic cancer

BACKGROUND

The receptor tyrosine kinases TAM family (TYRO3, AXL, and MERTK) are highly expressed in multiple forms of cancer cells and tumor-associated macrophages and promote the development of cancers including pancreatic tumor. Targeting TAM receptors could be a promising therapeutic option.

METHODS

We designed a novel CAR based on the extracellular domain of growth arrest-specific protein 6 (GAS6), a natural ligand for all TAM members. The ability of CAR-T to kill pancreatic cancer cells is tested in vitro and in vivo, and the safety is evaluated in mice and nonhuman primate.

RESULTS

GAS6-CAR-T cells efficiently kill TAM-positive pancreatic cancer cell lines, gemcitabine-resistant cancer cells, and cancer stem-like cells in vitro. GAS6-CAR-T cells also significantly suppressed the growth of PANC1 xenografts and patient-derived xenografts in mice. Furthermore, these CAR-T cells did not induce obvious side effects in nonhuman primate or mice although the CAR was demonstrated to recognize mouse TAM.

CONCLUSIONS

Our findings indicate that GAS6-CAR-T-cell therapy may be effective for pancreatic cancers with low toxicity.

Association between microRNAs and chemoresistance in pancreatic cancer: Current knowledge, new insights, and forthcoming perspectives

Pancreatic duct adenocarcinoma, commonly known as pancreatic cancer (PC), is a cancer-related cause of death due to delayed diagnosis, metastasis, and drug resistance. Patients with PC suffer from incorrect responses to chemotherapy due to inherent and acquired chemical resistance. Numerous studies have shown the mechanism of the effect of chemoresistance on PC, such as genetic and epigenetic changes or the elucidation of signaling pathways. In this regard, microRNAs (miRNAs) have been identified as essential modulators of gene expression in various cellular functions, including chemoresistance. Thus, identifying the underlying link between microRNAs and PC chemoresistance helps determine the exact pathogenesis of PC. This study aims to classify miRNAs and signaling pathways related to PC chemoresistance, suggesting new therapeutic approaches to overcome PC chemoresistance.

Molecular Radiotherapy with 177Lu-Immunoliposomes Induces Cytotoxicity in Mesothelioma Cancer Stem Cells In Vitro

Malignant mesothelioma (MM) is a lethal tumor originating in the mesothelium with high chemotherapeutic resistance. Cancer stem cells (CSCs) persist in tumors and are critical targets responsible for tumor resistance and recurrence. The identification and characterization of CSCs may help develop effective treatment for MM. The objective of this study was to evaluate the therapeutic effect of molecular targeted radiotherapy by 177Lu-labeled immunoliposomes (177Lu-ILs) on CSCs of mesothelioma. MM CSCs were sorted based on CD26/CD24 expression level and their functional significances were established by small interference RNA. CSC potential of MM was evaluated for drug resistance, cell invasion, and cell growth rate in vitro. CSC metabolism was evaluated with the uptake of 18F-FDG. Therapeutic effects of 177Lu-labeled immunoliposomes targeting CD26 and CD24 were evaluated in vitro through proliferation and apoptotic assays. CSCs sorted from H28 cells exhibited significant drug resistance and enhanced proliferative activity as well as increased metabolism indicated by higher 18F-FDG uptake. Treatment with 177Lu-ILs, compared with 177Lu-CL and ILs, showed enhanced therapeutic effects on inhibition of proliferation, up-regulation of apoptosis, and suppression of CD26 and CD24 expression. Thus, our results suggest that molecular radiotherapy targeting both CD26 and CD24 could be a promising approach for CSC-targeting therapy for MM.

Overcoming the Tumor Microenvironmental Barriers of Pancreatic Ductal Adenocarcinomas for Achieving Better Treatment Outcomes

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with the lowest survival rate among all solid tumors. The lethality of PDAC arises from late detection and propensity of the tumor to metastasize and develop resistance against chemo and radiation therapy. A highly complex tumor microenvironment composed of dense stroma, immune cells, fibroblast, and disorganized blood vessels, is the main obstacle to current PDAC therapy. Despite the tremendous success of immune checkpoint inhibitors (ICIs) in cancers, PDAC remains one of the poorest responders of ICIs therapy. The immunologically "cold" phenotype of PDAC is attributed to the low mutational burden, high infiltration of myeloid-derived suppressor cells and T-regs, contributing to a significant immunotherapy resistance mechanism. Thus, the development of innovative strategies for turning immunologically "cold" tumor into "hot" ones is an unmet need to improve the outcome of PDAC ICIs therapies. Other smart strategies, such as nanomedicines, sonic Hedgehog inhibitor, or smoothened inhibitor, are discussed to enhance chemotherapeutic agents' efficiency by disrupting the PDAC stroma. This review highlights the current challenges and various preclinical and clinical strategies to overcome current PDAC therapy difficulties, thus significantly advancing PDAC research knowledge.

The diverse roles of circular RNAs in pancreatic cancer

Pancreatic cancer is one of the malignant tumors with poor prognosis. The molecular mechanisms of pancreatic oncogenesis and malignant progression are not fully elucidated. Several key signaling pathways, such as Notch, Wnt and hedgehog pathways, are important to drive pancreatic carcinogenesis. Recently, noncoding RNAs, especially circular RNAs (circRNAs), have been characterized to participate into pancreatic cancer development. Therefore, in this review article, we describe the association between circRNAs and pancreatic cancer prognosis. Moreover, we discuss how circRNAs are involved in regulation of cellular processes in pancreatic cancer, including proliferation, apoptosis, cell cycle, migration, invasion, EMT, metastasis, angiogenesis, drug resistance and immune escape. Furthermore, we mention that several compounds could regulate the expression of circRNAs, indicating that targeting circRNAs by compounds might be helpful for treating pancreatic cancer patients.

Vitamin D and Non-coding RNAs: New Insights into the Regulation of Breast Cancer

Breast cancer, a life-threatening serious disease with a high incident rate among women, is responsible for thousands of cancer-associated death worldwide. Numerous investigations have evaluated the possible mechanisms related to this malignancy. Among them, non-coding RNAs (ncRNAs), i.e., microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs have recently attracted attention of researchers. In addition to recent studies for evaluating the role of ncRNAs in breast cancer etiology, some investigations have revealed that vitamin D has regulatory and therapeutic roles in breast cancer. Moreover, an important link between vitamin D and ncRNAs in cancer therapy has been highlighted. Herein, the aim of this study was to discuss the available data on the mentioned link in breast cancer.

Asiaticoside inhibits epithelial-mesenchymal transition and stem cell-like properties of pancreatic cancer PANC-1 cells by blocking the activation of p65 and p38MAPK

Background

To analyze the inhibitory effects of Asiaticoside (ATS) on the epithelial-mesenchymal transition (EMT) and stem cell-like properties of a pancreatic cancer cell line (PANC-1) by blocking the activation of p65 and p38 mitogen-activated protein kinase (p38MAPK).

Methods

ATS concentrations were set at 0, 10, 25, and 50 µmol/L. The survival rate of PANC-1 cells in each group was detected by CCK-8, and CD133 and CD44 positive cells were detected by flow cytometry. The levels of Ki67 and proliferating cell nuclear antigen (PCNA) mRNA were detected by RT-PCR. The expression of E-cadherin, N-cadherin, vimentin, sex-determining region Y-box2 (SOX2), and octamer-binding transcription factor 4 (OCT4) proteins, and the phosphorylation levels of p65 and p38MAPK were detected by western blot. Nude mouse xenograft models of the tumor were established by subcutaneous injection of PANC-1 cells (1×10⁶-1×10⁸/mL), and they were randomly divided into the control group (0 mg/kg), and low-dose, medium-dose, and high-dose ATS groups (2.5, 5, 10 mg/kg). Apoptosis in xenograft tissue was detected by TUNEL, and the expression of vimentin and SOX2 proteins was detected by immunohistochemistry.

Results

As the ATS concentration increased to 25 µmol/L, cell survival rate, levels of Ki67 and PCNA mRNA, expression of N-cadherin, vimentin, SOX2, OCT4, p-p65/p65, and p-p38MAPK/p38MAPK proteins, and the proportions of CD44⁺ and CD133⁺ positive cells significantly decreased (P<0.05), while the expression of E-cadherin protein significantly increased (P<0.05). The results of tumor formation in nude mice showed that with the increase of ATS concentration, at 5 mg/kg the volume of the xenograft significantly decreased (P<0.05), the apoptosis rate significantly increased (P<0.05), and positive expression rates of vimentin and SOX2 proteins significantly decreased (P<0.05).

Conclusions

ATS may inhibit the proliferation, EMT, and stem cell-like properties of pancreatic cancer cells by blocking the phosphorylation of p38MAPK and nuclear factor-κB (NF-κB)/p65 in PANC-1 cells.

Beyond regulations at DNA levels: A review of epigenetic therapeutics targeting cancer stem cells

In the past few years, the paramount role of cancer stem cells (CSCs), in terms of cancer initiation, proliferation, metastasis, invasion and chemoresistance, has been revealed by accumulating studies. However, this level of cellular plasticity cannot be entirely explained by genetic mutations. Research on epigenetic modifications as a complementary explanation for the properties of CSCs has been increasing over the past several years. Notably, therapeutic strategies are currently being developed in an effort to reverse aberrant epigenetic alterations using specific chemical inhibitors. In this review, we summarize the current understanding of CSCs and their role in cancer progression, and provide an overview of epigenetic alterations seen in CSCs. Importantly, we focus on primary cancer therapies that target the epigenetic modification of CSCs by the use of specific chemical inhibitors, such as histone deacetylase (HDAC) inhibitors, DNA methyltransferase (DNMT) inhibitors and microRNA‐based (miRNA‐based) therapeutics.

Desialylation of Sonic-Hedgehog by Neu2 Inhibits Its Association with Patched1 Reducing Stemness-Like Properties in Pancreatic Cancer Sphere-forming Cells

Cancer stem cells (CSCs) are crucial regulators of tumor recurrence/progression. The maintenance of CSCs is dependent on aberrant activation of various pathways, including Hedgehog. Prevalent sialylations contribute to aggressiveness in CSCs. Here, we have addressed the role of sialylation in regulating stemness-like properties of pancreatic cancer sphere-forming cells (PCS) through modulation of the Hedgehog (Hh) pathway. The status of CD133/CD44/surface-sialylation was checked by flow cytometry and effects of Neu2 overexpression in PCS were compared using qPCR, immunoblotting, co-immunoprecipitation and also by colony-formation assays. The work was also validated in a xenograft model after Neu2 overexpression. Neu2 and Shh status in patient tissues were examined by immunohistochemistry. PCS showed higher Hh-pathway activity and sialylation with reduced cytosolic-sialidase (Neu2). Neu2 overexpression caused desialylation of Shh, thereby reducing Shh-Patched1 binding thus causing decreased Hh-pathway activity with lower expression of Snail/Slug/CyclinD1 leading to reduction of stemness-like properties. Neu2-overexpression also induced apoptosis in PCS. Additionally, Neu2-overexpressed PCS demonstrated lower mTORC2 formation and inhibitory-phosphorylation of Gsk3β, reflecting a close relationship with reduced Hh pathway. Moreover, both Neu2 and Rictor (a major component of mTORC2) co-transfection reduced stem cell markers and Hh-pathway activity in PCS. Neu2-overexpressed tumors showed reduction in tumor mass with downregulation of stem cell markers/Shh/mTOR and upregulation of Bax/Caspase8/Caspase3. Thus, we established that reduced sialylation by Neu2 overexpression leads to decreased stemness-like properties by desialylation of Shh, which impaired its association with Patched1 thereby inhibiting the Hh pathway. All these may be responsible for enhanced apoptosis in Neu2-overexpressed PCS.