Syndecan 1 is a critical mediator of macropinocytosis in pancreatic cancer

Calpain 8 as a potential biomarker regulates the progression of pancreatic cancer via EMT and AKT/ERK pathway

Calpain is a non-lysozyme, calcium-dependent intracellular cysteine protease that has been shown to play a role in tumor proliferation, survival, migration, invasion, and apoptosis. Dysregulation of calpain expression is closely related to tumorigenesis. However, the role of calpain-8 (CAPN8), as a member of the calpain family, in pancreatic cancer (PC) is remains unclear. In elucidating the mechanism of CAPN8 in PC, a comprehensive bioinformatics analysis and in vitro experiments were conducted. The TCGA database was used to explore the expression level of CAPN8, and the results in PC tissues and cell lines were verified. Then, the correlation between CAPN8 and clinicopathological features was analyzed. Additionaly, promoter methylation, immune infiltration, and GO/KEGG enrichment analyses were performed. Lastly, the molecular mechanism of CAPN8 in PC was investigated by using cell counting kit (CCK) 8, transwell, wound healing, Western blot assays, and so on. Results indicate that CAPN8 was highly expressed in PC and correlated with poor prognosis and advanced TNM stage. In addition, a low level of immune infiltration was closely associated with the high expression level of CAPN8. Based on these findings, we hypothesized that CAPN8 is a potential biomarker that regulates progression of PC via EMT and the AKT/ERK pathway. SIGNIFICANCE: Through comprehensive biological information and in vitro experiments, CAPN8 has been confirmed to play an important role in regulating pancreatic cancer (PC) proliferation, migration and invasion. CAPN8 is found to be closely related to the diagnosis, survival and prognosis of PC. Above all, CAPN8 may be a potential biomarker for the diagnosis and prognosis of PC.

Metabolic reprogramming-driven homologous recombination and TCA cycle dysregulation contribute to poor prognoses in lung adenocarcinoma

Increasing evidence has shown that homologous recombination (HR) and metabolic reprogramming are essential for cellular homeostasis. These two processes are independent as well as closely intertwined. Nevertheless, they have rarely been reported in lung adenocarcinoma (LUAD). We analysed the genomic, immune microenvironment and metabolic microenvironment features under different HR activity states. Using cell cycle, EDU and cell invasion assays, we determined the impacts of si-SHFM1 on the LUAD cell cycle, proliferation and invasion. The levels of isocitrate dehydrogenase (IDH) and α-ketoglutarate dehydrogenase (α-KGDH) were determined by ELISA in the NC and si-SHFM1 groups of A549 cells. Finally, cell samples were used to extract metabolites for HPIC-MS/MS to analyse central carbon metabolism. We found that high HR activity was associated with a poor prognosis in LUAD, and HR was an independent prognostic factor for TCGA-LUAD patients. Moreover, LUAD samples with a high HR activity presented low immune infiltration levels, a high degree of genomic instability, a good response status to immune checkpoint blockade therapy and a high degree of drug sensitivity. The si-SHFM1 group presented a significantly higher proportion of cells in the G0/G1 phase, lower levels of DNA replication, and significantly lower levels of cell migration and both TCA enzymes. Our current results indicated that there is a strong correlation between HR and the TCA cycle in LUAD. The TCA cycle can promote SHFM1-mediated HR in LUAD, raising their activities, which can finally result in a poor prognosis and impair immunotherapeutic efficacy.

Macropinocytosis at the crossroad between nutrient scavenging and metabolism in cancer

Macropinocytosis (MP), the actin-dependent bulk uptake of extracellular fluids, plays a central role in nutrient scavenging, allowing cancer cells to sustain their growth in the hypoxic and nutrient-deprived microenvironment often found in solid tumours. The lack of soluble nutrients and several oncogenic signalling pathways, with RAS being the most studied, push MP-dependent internalisation of extracellular proteins, which are then digested in the lysosomes, replenishing the intracellular nutrient pools. This review will highlight recent advances in understanding how MP is regulated in hypoxic cancers, how it impinges on chemoresistance, and how different MP cargos facilitate tumour growth. Finally, I will highlight the crosstalk between MP and extracellular matrix receptors.

ZDHHC20-mediated S-palmitoylation of YTHDF3 stabilizes MYC mRNA to promote pancreatic cancer progression

Post-translational modifications of proteins in malignant transformation and tumor maintenance of pancreatic ductal adenocarcinoma (PDAC) in the context of KRAS signaling remain poorly understood. Here, we use the KPC mouse model to examine the effect of palmitoylation on pancreatic cancer progression. ZDHHC20, upregulated by KRAS, is abnormally overexpressed and associated with poor prognosis in patients with pancreatic cancer. Dysregulation of ZDHHC20 promotes pancreatic cancer progression in a palmitoylation-dependent manner. ZDHHC20 inhibits the chaperone-mediated autophagic degradation of YTHDF3 through S-palmitoylation of Cys474, which can result in abnormal accumulation of the oncogenic product MYC and thereby promote the malignant phenotypes of cancer cells. Further, we design a biologically active YTHDF3-derived peptide to competitively inhibit YTHDF3 palmitoylation mediated by ZDHHC20, which in turn downregulates MYC expression and inhibits the progression of KRAS mutant pancreatic cancer. Thus, these findings highlight the therapeutic potential of targeting the ZDHHC20-YTHDF3-MYC signaling axis in pancreatic cancer.

Prolactin receptor potentiates chemotherapy through miRNAs-induced G6PD/TKT inhibition in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies, with a notoriously dismal prognosis. As a competitive inhibitor of DNA synthesis, gemcitabine is the cornerstone drug for treating PDAC at all stages. The therapeutic effect of gemcitabine, however, is often hindered by drug resistance, and the underlying mechanisms remain largely unknown. It is unclear whether their response to chemotherapeutics is regulated by endocrine regulators, despite the association between PDAC risk and endocrine deregulation. Here, we show that prolactin receptor (PRLR) synergizes with gemcitabine in both in vitro and in vivo treatment of PDAC. Interestingly, PRLR promotes the expression of miR-4763-3p and miR-3663-5p, two novel miRNAs whose functions are unknown. Furthermore, the analysis of transcriptome sequencing data of tumors from lactating mouse models enriches the PPP pathway, a multifunctional metabolic pathway. In addition to providing energy, the PPP pathway mainly provides a variety of raw materials for anabolism. We demonstrate that two key enzymes of the pentose phosphate pathway (PPP), G6PD and TKT, are directly targeted by miR-4763-3p and miR-3663-5p. Notably, miR-4763-3p and miR-3663-5p diminish the nucleotide synthesis of the PPP pathway, thereby increasing gemcitabine sensitivity. As a result, PRLR harnesses these two miRNAs to suppress PPP and nucleotide synthesis, subsequently elevating the gemcitabine sensitivity of PDAC cells. Also, PDAC tissues and tumors from LSL-KrasG12D/+, LSL-Trp53R172H/+, and PDX1-cre (KPC) mice exhibit downregulation of PRLR. Bisulfite sequencing of PDAC tissues revealed that PRLR downregulation is due to epigenetic methylation. In this study, we show for the first time that the endocrine receptor PRLR improves the effects of gemcitabine by boosting two new miRNAs that block the PPP pathway and nucleotide synthesis by inhibiting two essential enzymes concurrently. The PRLR-miRNAs-PPP axis may serve as a possible therapeutic target to supplement chemotherapy advantages in PDAC.

CYRI-B-mediated macropinocytosis drives metastasis via lysophosphatidic acid receptor uptake

Pancreatic ductal adenocarcinoma carries a dismal prognosis, with high rates of metastasis and few treatment options. Hyperactivation of KRAS in almost all tumours drives RAC1 activation, conferring enhanced migratory and proliferative capacity as well as macropinocytosis. Macropinocytosis is well understood as a nutrient scavenging mechanism, but little is known about its functions in trafficking of signalling receptors. We find that CYRI-B is highly expressed in pancreatic tumours in a mouse model of KRAS and p53-driven pancreatic cancer. Deletion of Cyrib (the gene encoding CYRI-B protein) accelerates tumourigenesis, leading to enhanced ERK and JNK-induced proliferation in precancerous lesions, indicating a potential role as a buffer of RAC1 hyperactivation in early stages. However, as disease progresses, loss of CYRI-B inhibits metastasis. CYRI-B depleted tumour cells show reduced chemotactic responses to lysophosphatidic acid, a major driver of tumour spread, due to impaired macropinocytic uptake of the lysophosphatidic acid receptor 1. Overall, we implicate CYRI-B as a mediator of growth and signalling in pancreatic cancer, providing new insights into pathways controlling metastasis.

Peripheral blood syndecan-1 levels after mechanical thrombectomy can predict the clinical prognosis of patients with acute ischemic stroke

BACKGROUND

Previously, we revealed noticeable dynamic fluctuations in syndecan-1 levels in the peripheral blood of post-stroke patients. We further investigated the clinical prognostic value of syndecan-1 as a biomarker of glycoprotein damage in patients with acute ischaemic stroke (AIS).

METHODS

We examined 105 patients with acute large vessel occlusion in the anterior circulation, all of whom underwent mechanical thrombectomy (MT). Peripheral blood syndecan-1 levels were measured 1 day after MT, and patients were categorised into favourable and unfavourable prognostic groups based on the 90-day modified Rankin Scale (mRS) score. Additionally, we compared the clinical outcomes between groups with high and low syndecan-1 concentrations.

RESULTS

The findings revealed a significantly lower syndecan-1 level in the group with an unfavourable prognosis compared to those with a favourable prognosis (p < 0.01). In the multivariable logistic regression analysis, lower syndecan-1 levels were identified as a predictor of unfavourable prognosis (odds ratio (OR) = 0.965, p = 0.001). Patients displaying low syndecan-1 expression in the peripheral blood (< 29.51 ng/mL) experienced a > twofold increase in the rates of unfavourable prognosis and mortality.

CONCLUSIONS

Our study demonstrates that syndecan-1, as an emerging, easily detectable stroke biomarker, can predict the clinical outcomes of patients with AIS. After MT, low levels of syndecan-1 in the peripheral blood on the first day emerged as an independent risk factor for an unfavourable prognosis, suggesting that lower syndecan-1 levels might signify worse clinical presentation and outcomes in stroke patients undergoing this procedure.

A transcription factor complex in Dictyostelium enables adaptive changes in macropinocytosis during the growth-to-development transition

Macropinocytosis, an evolutionarily conserved endocytic pathway, mediates nonselective bulk uptake of extracellular fluid. It is the primary route for axenic Dictyostelium cells to obtain nutrients and has also emerged as a nutrient-scavenging pathway for mammalian cells. How cells adjust macropinocytic activity in various physiological or developmental contexts remains to be elucidated. We discovered that, in Dictyostelium cells, the transcription factors Hbx5 and MybG form a functional complex in the nucleus to maintain macropinocytic activity during the growth stage. In contrast, during starvation-induced multicellular development, the transcription factor complex undergoes nucleocytoplasmic shuttling in response to oscillatory cyclic adenosine 3',5'-monophosphate (cAMP) signals, which leads to increased cytoplasmic retention of the complex and progressive downregulation of macropinocytosis. Therefore, by coupling macropinocytosis-related gene expression to the cAMP oscillation system, which facilitates long-range cell-cell communication, the dynamic translocation of the Hbx5-MybG complex orchestrates a population-level adjustment of macropinocytic activity to adapt to changing environmental conditions.

SiATG5-loaded cancer cell membrane-fused liposomes induced increased uptake of albumin-bound chemotherapeutics by pancreatic cancer cells

Chemotherapeutic efficacy for pancreatic cancer is severely compromised by limited drug availability to tumor cells. Herein, we constructed a cancer cell membrane-fused liposome containing a siATG5-loaded calcium phosphate (CaP) core, termed CLip@siATG5. Through cancer cell membrane camouflage, the liposomes evaded immune clearance, actively infiltrated tumor tissues, and were preferentially taken up by homotypic tumor cells. Then, siATG5 escaped from the endosomes and was liberated in the cytoplasm, mainly benefiting from CaP dissolution-induced endosome rupture and liposome disassembly in acidic endosomes. The released siATG5 silenced autophagy protein 5 (ATG5) to inhibit autophagy, starving tumor cells. An alternative nutrient procurement pathway, macropinocytosis, was then upregulated in the cells, leading to increased uptake of the albumin-bound chemotherapeutic agent (nanoparticle albumin-bound paclitaxel (Nab-PTX)). Finally, in a murine pancreatic cancer model, CLip@siATG5 combined with Nab-PTX exerted superior efficacy to a twofold dose of Nab-PTX while avoiding its toxicity. Overall, we justified enhancing chemotherapeutic delivery by modulating the pancreatic cancer cell metabolism, which will enlighten the development of more effective chemotherapeutic adjuvants for pancreatic cancer in the future.

MZ1, a BRD4 inhibitor, exerted its anti-cancer effects by suppressing SDC1 in glioblastoma

BACKGROUND

Glioblastoma (GBM) is a relatively prevalent primary tumor of the central nervous system in children, characterized by its high malignancy and mortality rates, along with the intricate challenges of achieving complete surgical resection. Recently, an increasing number of studies have focused on the crucial role of super-enhancers (SEs) in the occurrence and development of GBM. This study embarks on the task of evaluating the effectiveness of MZ1, an inhibitor of BRD4 meticulously designed to specifically target SEs, within the intricate framework of GBM.

METHODS

The clinical data of GBM patients was sourced from the Chinese Glioma Genome Atlas (CGGA) and the Gene Expression Profiling Interactive Analysis 2 (GEPIA2), and the gene expression data of tumor cell lines was derived from the Cancer Cell Line Encyclopedia (CCLE). The impact of MZ1 on GBM was assessed through CCK-8, colony formation assays, EdU incorporation analysis, flow cytometry, and xenograft mouse models. The underlying mechanism was investigated through RNA-seq and ChIP-seq analyses.

RESULTS

In this investigation, we made a noteworthy observation that MZ1 exhibited a substantial reduction in the proliferation of GBM cells by effectively degrading BRD4. Additionally, MZ1 displayed a notable capability in inducing significant cell cycle arrest and apoptosis in GBM cells. These findings were in line with our in vitro outcomes. Notably, MZ1 administration resulted in a remarkable decrease in tumor size within the xenograft model with diminished toxicity. Furthermore, on a mechanistic level, the administration of MZ1 resulted in a significant suppression of pivotal genes closely associated with cell cycle regulation and epithelial-mesenchymal transition (EMT). Interestingly, our analysis of RNA-seq and ChIP-seq data unveiled the discovery of a novel prospective oncogene, SDC1, which assumed a pivotal role in the tumorigenesis and progression of GBM.

CONCLUSION

In summary, our findings revealed that MZ1 effectively disrupted the aberrant transcriptional regulation of oncogenes in GBM by degradation of BRD4. This positions MZ1 as a promising candidate in the realm of therapeutic options for GBM treatment.

A Small Molecule with Big Impact: MRTX1133 Targets the KRASG12D Mutation in Pancreatic Cancer

KRAS mutations drive oncogenic alterations in numerous cancers, particularly in human pancreatic ductal adenocarcinoma (PDAC). About 93% of PDACs have KRAS mutations, with G12D (∼42% of cases) and G12V (∼32% of cases) being the most common. The recent approval of sotorasib (AMG510), a small-molecule, covalent, and selective KRASG12C inhibitor, for treating patients with non-small cell lung cancer represents a breakthrough in KRAS targeted therapy. However, there is a need to develop other much-needed KRAS-mutant inhibitors for PDAC therapy. Notably, Mirati Therapeutics recently developed MRTX1133, a small-molecule, noncovalent, and selective KRASG12D inhibitor through extensive structure-based drug design. MRTX1133 has demonstrated potent in vitro and in vivo antitumor efficacy against KRASG12D-mutant cancer cells, especially in PDAC, leading to its recent initiation of a phase I/II clinical trial. Here, we provide a summary of the recent advancements related to the use of MRTX1133 for treating KRASG12D-mutant PDAC, focusing on its efficacy and underlying mechanistic actions. In addition, we discuss potential challenges and future directions for MRTX1133 therapy for PDAC, including overcoming intrinsic and acquired drug resistance, developing effective combination therapies, and improving MRTX1133's oral bioavailability and target spectrum. The promising results obtained from preclinical studies suggest that MRTX1133 could revolutionize the treatment of PDAC, bringing about a paradigm shift in its management.

Modular Self-Assembling Dendrimer Nanosystems for Magnetic Resonance and Multimodality Imaging of Tumors

Bioimaging is a powerful tool for diagnosing tumors but remains limited in terms of sensitivity and specificity. Nanotechnology-based imaging probes able to accommodate abundant imaging units with different imaging modalities are particularly promising for overcoming these limitations. In addition, the nanosized imaging agents can specifically increase the contrast of tumors by exploiting the enhanced permeability and retention effect. A proof-of-concept study is performed on pancreatic cancer to demonstrate the use of modular amphiphilic dendrimer-based nanoprobes for magnetic resonance (MR) imaging (MRI) or MR/near-infrared fluorescence (NIRF) multimodality imaging. Specifically, the self-assembly of an amphiphilic dendrimer bearing multiple Gd3+ units at its terminals, generates a nanomicellar agent exhibiting favorable relaxivity for MRI with a good safety profile. MRI reveals an up to two-fold higher contrast enhancement in tumors than in normal muscle. Encapsulating the NIRF dye within the core of the nanoprobe yields an MR/NIRF bimodal imaging agent for tumor detection that is efficient both for MRI, at Gd3+ concentrations 1/10 the standard clinical dose, and for NIRF imaging, allowing over two-fold stronger fluorescence intensities. These self-assembling dendrimer nanosystems thus constitute effective probes for MRI and MR/NIRF multimodality imaging, offering a promising nanotechnology platform for elaborating multimodality imaging probes in biomedical applications.

Oncogenic KRAS triggers metabolic reprogramming in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with an extremely high lethality rate. Oncogenic KRAS activation has been proven to be a key driver of PDAC initiation and progression. There is increasing evidence that PDAC cells undergo extensive metabolic reprogramming to adapt to their extreme energy and biomass demands. Cell-intrinsic factors, such as KRAS mutations, are able to trigger metabolic rewriting. Here, we update recent advances in KRAS-driven metabolic reprogramming and the associated metabolic therapeutic potential in PDAC.

SDC1 and ITGA2 as novel prognostic biomarkers for PDAC related to IPMN

The existing biomarkers are insufficient for predicting the prognosis of pancreatic ductal adenocarcinoma (PDAC). Intraductal papillary mucinous neoplasm (IPMN) is a precursor to PDAC; therefore, identifying biomarkers from differentially expressed genes (DEGs) of PDAC and IPMN is a new and reliable strategy for predicting the prognosis of PDAC. In this study, four datasets were downloaded from the Gene Expression Omnibus database and standardized using the R package 'limma.' A total of 51 IPMN and 81 PDAC samples were analyzed, and 341 DEGs in PDAC and IPMN were identified; DEGs were involved in the extracellular matrix and tumor microenvironment. An acceptable survival prognosis was demonstrated by SDC1 and ITGA2, which were highly expressed during in vitro PDAC cell proliferation, apoptosis, and migration. SDC1high was enriched in interferon alpha (IFN-α) response and ITGA2high was primarily detected in epithelial-mesenchymal transition (EMT), which was verified using western blotting. We concluded that SDC1 and ITGA2 are potential prognostic biomarkers for PDAC associated with IPMN. Downregulation of SDC1 and ITGA2 expression in PDAC occurs via a mechanism involving possible regulation of IFN-α response, EMT, and immunity, which may act as new targets for PDAC therapy.

Stimuli-Responsive Hydrogel Microcapsules Harnessing the COVID-19 Immune Response for Cancer Therapeutics

The combination of gene therapy and immunotherapy concepts, along recent advances in DNA nanotechnology, have the potential to provide important tools for cancer therapies. We present the development of stimuli-responsive microcapsules, loaded with a viral immunogenetic agent, harnessing the immune response against the Coronavirus Disease 2019, COVID-19, to selectively attack liver cancer cells (hepatoma) or recognize breast cancer or hepatoma, by expression of green fluorescence protein, GFP. The pH-responsive microcapsules, modified with DNA-tetrahedra nanostructures, increased hepatoma permeation by 50 %. Incorporation of a GFP-encoding lentivirus vector inside the tumor-targeting pH-stimulated miRNA-triggered and Alpha-fetoprotein-dictated microcapsules enables the demonstration of neoplasm selectivity, with approximately 5,000-, 8,000- and 50,000-fold more expression in the cancerous cells, respectively. The incorporation of the SARS-CoV-2 spike protein in the gene vector promotes specific recognition of the immune-evading hepatoma by the COVID-19-analogous immune response, which leads to cytotoxic and inflammatory activity, mediated by serum components taken from vaccinated or recovered COVID-19 patients, resulting in effective elimination of the hepatoma (>85 % yield).

Clinical/prognostic significance of Syndecan-1 expression in invasive breast carcinoma with distant metastasis and its correlation with tumor immunity

OBJECTIVE

Breast Cancer (BC) is the most common malignant tumor for women in the world. 90% of BC-associated deaths are attributed to distant metastasis (DM). Therefore, there is an urgent need for a novel molecular target for the treatment of distant metastatic breast cancer (DMBC). Syndecan-1 (SDC-1) is a cell surface heparan sulfate proteoglycan (HSPG). This study aims to study the expression patterns of SDC-1 in invasive breast carcinoma (IBC) with DM and to analyze its relationship with different clinicopathologic features, stromal tumor infiltrating lymphocytes (sTILs) status and the clinical outcomes.

METHODS

A total of 50 DM breast cancer and 100 non-distant metastasis (non-DM) breast cancer patients in West China Hospital, Sichuan University from January 1, 2011 to December 31, 2011 were collected. Immunohistochemical (IHC) method was used to detect the expression of SDC-1, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor-2 (HER2), and Ki-67 in 150 specimens of patients with IBC. STILs were used to evaluate immune cells in the stromal tissue within the tumor. Various clinicopathologic characteristics were retrospectively analyzed, and follow-up information were collected for prognosis analyses. The expression pattern difference of SDC-1 in the DM group and the non-DM group and its correlation with clinicopathologic characteristics of IBC were analyzed.

RESULTS

Compared with the non-DM group, SDC-1 had higher cytoplasmic (90.0%) and stromal diffuse (70.0%) expressions and lower stromal peritumoral (18.0%) expression in the DM group. SDC-1 cytoplasmic expression was significantly associated with HER2-positive and high Ki-67 index in DM group, and with high histological grade and lymph node (LN) metastasis in non-DM group (P < 0.05). Compared with the non-DM group, the membranous expression of SDC-1 in the DM group was related to higher histological grade and T stage, higher frequency of LN involvement. Meanwhile, the expression pattern of SDC-1 in tumor stroma was associated with sTILs status (P < 0.05). The different combinations of SDC-1 staining patterns were correlated with clinicopathological features, biomarkers and sTILs status between DM group and non-DM group.There was no significant difference in overall survival between DMBC with different expression patterns of SDC-1.

CONCLUSION

The cytoplasmic and stromal expressions of SDC-1 in the primary lesion of IBC are closely associated with DM, and the stromal expression of SDC-1 is correlated with tumor immune microenvironment. SDC-1 is expected to be a potential new marker for predicting the risk of DM in IBC.

KRASG12D inhibition reprograms the microenvironment of early and advanced pancreatic cancer to promote FAS-mediated killing by CD8+ T cells

The KRASG12D mutation is present in nearly half of pancreatic adenocarcinomas (PDAC). We investigated the effects of inhibiting the KRASG12D mutant protein with MRTX1133, a non-covalent small molecule inhibitor of KRASG12D, on early and advanced PDAC and its influence on the tumor microenvironment. Employing 16 different models of KRASG12D-driven PDAC, we demonstrate that MRTX1133 reverses early PDAC growth, increases intratumoral CD8+ effector T cells, decreases myeloid infiltration, and reprograms cancer-associated fibroblasts. MRTX1133 leads to regression of both established PanINs and advanced PDAC. Regression of advanced PDAC requires CD8+ T cells and immune checkpoint blockade (ICB) synergizes with MRTX1133 to eradicate PDAC and prolong overall survival. Mechanistically, inhibition of KRASG12D in advanced PDAC and human patient derived organoids induces FAS expression in cancer cells and facilitates CD8+ T cell-mediated death. Collectively, this study provides a rationale for a synergistic combination of MRTX1133 with ICB in clinical trials.

Collagen architecture and signaling orchestrate cancer development

The tumor microenvironment (TME) controls tumor progression and maintenance. Accordingly, tumor-centric cancer treatment must adjust to being more holistic and TME-centric. Collagens are the most abundant TME proteins, and their dynamic remodeling profoundly affects both TME architecture and tumor development. Recent evidence shows that in addition to being structural elements, collagens are an important source of nutrients and decisive growth controlling and immunoregulatory signals. This review focuses on macropinocytosis-dependent collagen support of cancer cell metabolism and the role of collagen fiber remodeling and trimer heterogeneity in control of tumor bioenergetics, growth, progression, and response to therapy. If properly translated, these basic advances may alter the future of cancer treatment.

Pancreatic tumors exhibit myeloid-driven amino acid stress and upregulate arginine biosynthesis

Nutrient stress in the tumor microenvironment requires cancer cells to adopt adaptive metabolic programs for survival and proliferation. Therefore, knowledge of microenvironmental nutrient levels and how cancer cells cope with such nutrition is critical to understand the metabolism underpinning cancer cell biology. Previously, we performed quantitative metabolomics of the interstitial fluid (the local perfusate) of murine pancreatic ductal adenocarcinoma (PDAC) tumors to comprehensively characterize nutrient availability in the microenvironment of these tumors. Here, we develop Tumor Interstitial Fluid Medium (TIFM), a cell culture medium that contains nutrient levels representative of the PDAC microenvironment, enabling us to study PDAC metabolism ex vivo under physiological nutrient conditions. We show that PDAC cells cultured in TIFM adopt a cellular state closer to that of PDAC cells present in tumors compared to standard culture models. Further, using the TIFM model, we found arginine biosynthesis is active in PDAC and allows PDAC cells to maintain levels of this amino acid despite microenvironmental arginine depletion. We also show that myeloid derived arginase activity is largely responsible for the low levels of arginine in PDAC tumors. Altogether, these data indicate that nutrient availability in tumors is an important determinant of cancer cell metabolism and behavior, and cell culture models that incorporate physiological nutrient availability have improved fidelity to in vivo systems and enable the discovery of novel cancer metabolic phenotypes.

Functional and Clinical Proteomic Exploration of Pancreatic Cancer

Pancreatic cancer, most cases being pancreatic ductal adenocarcinoma (PDAC), is one of the most lethal cancers with a median survival time of less than 6 months. Therapeutic options are very limited for PDAC patients, and surgery is still the most effective treatment, making improvements in early diagnosis critical. One typical characteristic of PDAC is the desmoplastic reaction of its stroma microenvironment, which actively interacts with cancer cells to orchestrate key components in tumorigenesis, metastasis, and chemoresistance. Global exploration of cancer-stroma crosstalk is essential to decipher PDAC biology and design intervention strategies. Over the past decade, the dramatic improvement of proteomics technologies has enabled profiling of proteins, post-translational modifications (PTMs), and their protein complexes at unprecedented sensitivity and dimensionality. Here, starting with our current understanding of PDAC characteristics, including precursor lesions, progression models, tumor microenvironment, and therapeutic advancements, we describe how proteomics contributes to the functional and clinical exploration of PDAC, providing insights into PDAC carcinogenesis, progression, and chemoresistance. We summarize recent achievements enabled by proteomics to systematically investigate PTMs-mediated intracellular signaling in PDAC, cancer-stroma interactions, and potential therapeutic targets revealed by these functional studies. We also highlight proteomic profiling of clinical tissue and plasma samples to discover and verify useful biomarkers that can aid early detection and molecular classification of patients. In addition, we introduce spatial proteomic technology and its applications in PDAC for deconvolving tumor heterogeneity. Finally, we discuss future prospects of applying new proteomic technologies in comprehensively understanding PDAC heterogeneity and intercellular signaling networks. Importantly, we expect advances in clinical functional proteomics for exploring mechanisms of cancer biology directly by high-sensitivity functional proteomic approaches starting from clinical samples.

High expression of SDC1 in stromal cells is associated with good prognosis in colorectal cancer

We have previously reported that patients with high Syndecan 1 (SDC1) expression in colorectal cancer (CRC) cells have a favorable prognosis, and we also found that stromal cells showed upregulation of SDC1, but the clinical significance is unclear. The expression of SDC1 in the stroma cells was assessed by immunohistochemistry using a tissue microarray comprising representative cores from 513 CRC patients. The correlation between the expression of SDC1 in the stroma cells and the clinicopathological features of patients was analyzed. The data showed that the expression of SDC1 in the stroma cells was correlated with the degree of differentiation ( P  = 0.012) and tumor location (up or down) ( P  = 0.005). Also, CRCs patients with high expression of SDC1 in the stromal cells have a good prognosis ( P  = 0.0369). Accumulating evidence indicates that SDC1, whether in tumor cells or stromal cells, plays a tumor-suppressor role in CRCs.

Macropinocytosis: mechanisms and regulation

Macropinocytosis is defined as an actin-dependent but coat- and dynamin-independent endocytic uptake process, which generates large intracellular vesicles (macropinosomes) containing a non-selective sampling of extracellular fluid. Macropinocytosis provides an important mechanism of immune surveillance by dendritic cells and macrophages, but also serves as an essential nutrient uptake pathway for unicellular organisms and tumor cells. This review examines the cell biological mechanisms that drive macropinocytosis, as well as the complex signaling pathways - GTPases, lipid and protein kinases and phosphatases, and actin regulatory proteins - that regulate macropinosome formation, internalization, and disposition.

SDC1-dependent TGM2 determines radiosensitivity in glioblastoma by coordinating EPG5-mediated fusion of autophagosomes with lysosomes

Glioblastoma multiforme (GBM) is the most common brain malignancy insensitive to radiotherapy (RT). Although macroautophagy/autophagy was reported to be a fundamental factor prolonging the survival of tumors under radiotherapeutic stress, the autophagic biomarkers coordinated to radioresistance of GBM are still lacking in clinical practice. Here we established radioresistant GBM cells and identified their protein profiles using tandem mass tag (TMT) quantitative proteomic analysis. It was found that SDC1 and TGM2 proteins were overexpressed in radioresistant GBM cells and tissues and they contributed to the poor prognosis of RT. Knocking down SDC1 and TGM2 inhibited the fusion of autophagosomes with lysosomes and thus enhanced the radiosensitivity of GBM cells. After irradiation, TGM2 bound with SDC1 and transported it from the cell membrane to lysosomes, and then bound to LC3 through its two LC3-interacting regions (LIRs), coordinating the encounter between autophagosomes and lysosomes, which should be a prerequisite for lysosomal EPG5 to recognize LC3 and subsequently stabilize the STX17-SNAP29-VAMP8 QabcR SNARE complex assembly. Moreover, when combined with RT, cystamine dihydrochloride (a TGM2 inhibitor) extended the lifespan of GBM-bearing mice. Overall, our findings demonstrated the EPG5 tethering mode with SDC1 and TGM2 during the fusion of autophagosomes with lysosomes, providing new insights into the molecular mechanism and therapeutic target underlying radioresistant GBM.Abbreviations: BafA₁: bafilomycin A₁; CQ: chloroquine; Cys-D: cystamine dihydrochloride; EPG5: ectopic P-granules 5 autophagy tethering factor; GBM: glioblastoma multiforme; GFP: green fluorescent protein; LAMP2: lysosomal associated membrane protein 2; LIRs: LC3-interacting regions; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; NC: negative control; RFP: red fluorescent protein; RT: radiotherapy; SDC1: syndecan 1; SNAP29: synaptosome associated protein 29; SQSTM1/p62: sequestosome 1; STX17: syntaxin 17; TGM2: transglutaminase 2; TMT: tandem mass tag; VAMP8: vesicle associated membrane protein 8; WT: wild type.

RIOK3 promotes mTORC1 activation by facilitating SLC7A2-mediated arginine uptake in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with a poor prognosis. Reprogramming of amino acid metabolism is one of the characteristics of PDAC, in which arginine metabolism is significantly altered in PDAC cells and is involved in important signaling pathways. Current studies have identified arginine deprivation as a potential strategy for PDAC treatment. In this study, we performed Liquid Chromatograph Mass Spectrometer (LC-MS)-based non-targeted metabolomic analysis on PDAC cell lines with stable Rio Kinase 3 (RIOK3) knockdown and PDAC tissues with different RIOK3 expressions and found that RIOK3 expression was significantly correlated with arginine metabolism in PDAC. Subsequent RNA sequencing (RNA-Seq) and Western blot analysis showed that RIOK3 knockdown significantly inhibited the expression of arginine transporter solute carrier family 7 member 2 (SLC7A2). Further studies revealed that RIOK3 promoted arginine uptake, mechanistic target of rapamycin complex 1 (mTORC1) activation, cell invasion, and metastasis in PDAC cells via SLC7A2. Finally, we found that patients with high expression of both RIOK3 and infiltrating Treg cells had a worse prognosis. Overall, our study found that RIOK3 in PDAC cells promotes arginine uptake and mTORC1 activation through upregulation of SLC7A2 expression, and also provides a new therapeutic target for therapeutic strategies targeting arginine metabolism.

Cytoskeletal association of ATP citrate lyase controls the mechanodynamics of macropinocytosis

Macropinocytosis is an actin-dependent mode of nonselective endocytosis that mediates the uptake of extracellular fluid-phase cargoes. It is now well recognized that tumor cells exploit macropinocytosis to internalize macromolecules that can be catabolized and used to support cell growth and proliferation under nutrient-limiting conditions. Therefore, the identification of molecular mechanisms that control macropinocytosis is fundamental to the understanding of the metabolic adaptive landscape of tumor cells. Here, we report that the acetyl-CoA-producing enzyme, ATP citrate lyase (ACLY), is a key regulator of macropinocytosis and describes a heretofore-unappreciated association of ACLY with the actin cytoskeleton. The cytoskeletal tethering of ACLY is required for the spatially defined acetylation of heterodimeric actin capping protein, which we identify as an essential mediator of the actin remodeling events that drive membrane ruffling and macropinocytosis. Furthermore, we identify a requirement for mitochondrial-derived citrate, an ACLY substrate, for macropinocytosis, and show that mitochondria traffic to cell periphery regions juxtaposed to plasma membrane ruffles. Collectively, these findings establish a mode of metabolite compartmentalization that supports the spatiotemporal modulation of membrane-cytoskeletal interactions required for macropinocytosis by coupling regional acetyl-CoA availability with dynamic protein acetylation.

Oncogenic Kras G12D specific non-covalent inhibitor reprograms tumor microenvironment to prevent and reverse early pre-neoplastic pancreatic lesions and in combination with immunotherapy regresses advanced PDAC in a CD8 + T cells dependent manner

Pancreatic ductal adenocarcinoma (PDAC) is associated with mutations in Kras, a known oncogenic driver of PDAC; and the KRAS ^G12D mutation is present in nearly half of PDAC patients. Recently, a non-covalent small molecule inhibitor (MRTX1133) was identified with specificity to the Kras ^G12D mutant protein. Here we explore the impact of Kras ^G12D inhibition by MRTX1133 on advanced PDAC and its influence on the tumor microenvironment. Employing different orthotopic xenograft and syngeneic tumor models, eight different PDXs, and two different autochthonous genetic models, we demonstrate that MRTX1133 reverses early PDAC growth, increases intratumoral CD8 ⁺ effector T cells, decreases myeloid infiltration, and reprograms cancer associated fibroblasts. Autochthonous genetic mouse models treated with MRTX1133 leads to regression of both established PanINs and advanced PDAC. Regression of advanced PDAC requires CD8 ⁺ T cells and immune checkpoint blockade therapy (iCBT) synergizes with MRTX1133 to eradicate PDAC and prolong overall survival. Mechanistically, inhibition of mutant Kras in advanced PDAC and human patient derived organoids (PDOs) induces Fas expression in cancer cells and facilitates CD8 ⁺ T cell mediated death. These results demonstrate the efficacy of MRTX1133 in different mouse models of PDAC associated with reprogramming of stromal fibroblasts and a dependency on CD8 ⁺ T cell mediated tumor clearance. Collectively, this study provides a rationale for a synergistic combination of MRTX1133 with iCBT in clinical trials.

The phospholipid flippase ATP9A enhances macropinocytosis to promote nutrient starvation tolerance in hepatocellular carcinoma

Macropinocytosis is an effective strategy to mitigate nutrient starvation. It can fuel cancer cell growth in nutrient-limited conditions. However, whether and how macropinocytosis contributes to the rapid proliferation of hepatocellular carcinoma cells, which frequently experience an inadequate nutrient supply, remains unclear. Here, we demonstrated that nutrient starvation strongly induced macropinocytosis in some hepatocellular carcinoma cells. It allowed the cells to acquire extracellular nutrients and supported their energy supply to maintain rapid proliferation. Furthermore, we found that the phospholipid flippase ATP9A was critical for regulating macropinocytosis in hepatocellular carcinoma cells and that high ATP9A levels predicted a poor outcome for patients with hepatocellular carcinoma. ATP9A interacted with ATP6V1A and facilitated its transport to the plasma membrane, which promoted plasma membrane cholesterol accumulation and drove RAC1-dependent macropinocytosis. Macropinocytosis inhibitors significantly suppressed the energy supply and proliferation of hepatocellular carcinoma cells characterised by high ATP9A expression under nutrient-limited conditions. These results have revealed a novel mechanism that overcomes nutrient starvation in hepatocellular carcinoma cells and have identified the key regulator of macropinocytosis in hepatocellular carcinoma. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

ATM inhibition drives metabolic adaptation via induction of macropinocytosis

Macropinocytosis is a nonspecific endocytic process that may enhance cancer cell survival under nutrient-poor conditions. Ataxia-Telangiectasia mutated (ATM) is a tumor suppressor that has been previously shown to play a role in cellular metabolic reprogramming. We report that the suppression of ATM increases macropinocytosis to promote cancer cell survival in nutrient-poor conditions. Combined inhibition of ATM and macropinocytosis suppressed proliferation and induced cell death both in vitro and in vivo. Supplementation of ATM-inhibited cells with amino acids, branched-chain amino acids (BCAAs) in particular, abrogated macropinocytosis. Analysis of ATM-inhibited cells in vitro demonstrated increased BCAA uptake, and metabolomics of ascites and interstitial fluid from tumors indicated decreased BCAAs in the microenvironment of ATM-inhibited tumors. These data reveal a novel basis of ATM-mediated tumor suppression whereby loss of ATM stimulates protumorigenic uptake of nutrients in part via macropinocytosis to promote cancer cell survival and reveal a potential metabolic vulnerability of ATM-inhibited cells.

The glycocalyx and immune evasion in cancer

In order to establish malignant lesions, tumors must first evade their detection by immune cells. Tumors achieve this by embellishing and tailoring their glycocalyx, a network of polysaccharides and glycosylated proteins that refracts the phagocytic efforts of myeloid cells, shrouds neoantigens and other ligands from cells of the acquired immune system, and skews immune responses. The barriers imposed by the glycocalyx are biophysical and also linked to the inhibitory receptor signaling pathways of immune cells that engage tumor sialic acids as markers of healthy "self". This would explain the pressure for cancers to upregulate the synthases, transmembrane mucins, and other heavily sialylated glycoproteins involved in establishing a repulsive glycocalyx. Accordingly, individual tumor cells that are best capable of constructing a shielding glycocalyx on their surface show higher metastatic potential in immunocompetent mice. Reciprocally, therapeutics have recently been devised to edit and dismantle the glycocalyx barrier in an effort to invigorate an immune response aimed at tumor destruction. We discuss the features of the tumor-associated glycocalyx that afford immune evasion of cancers and how strategies that target this barrier may potentiate antitumor immunity.

LHPP Inhibits the Viability, Migration, and Proliferation of PDAC Cells and Significantly Affects the Expression of SDC1 and S100p

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with a poor response to chemotherapy and an extremely poor prognosis. Recent studies have revealed that phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPP) can inhibit the growth of various cancers. Therefore, the current study was conducted to investigate the antitumor effects of LHPP in PDAC and to explore its mechanism using proteomics analysis.

METHODS AND RESULTS

Immunohistochemical analysis of clinical samples demonstrated that LHPP expression levels were lower in tumor tissues compared to adjacent nontumor tissues. Moreover, multivariate COX regression analysis showed that LHPP expression level was an independent prognostic factor for the patients with PDAC. Patients with high LHPP expression had a better prognosis. The lentiviral vectors for normal control (NC), LHPP knockdown (KD), and LHPP overexpression (OE) were infected with BxPC-3 and PANC-1 cell lines. Cell counting kit-8 assay, Transwell assay, and flow cytometry analyses showed that LHPP overexpression significantly inhibited the cell viability, migration, and proliferation of BxPC-3 and PANC-1 cells. Moreover, xenograft tumor model demonstrated that LHPP overexpression inhibited xenograft tumor growth in vivo. Subsequently, proteins with significantly altered expression in BxPC-3 cells after lentivirus infection were detected using proteomics analyses. Interestingly, compared to the NC group, the expression of Syndecan 1 (SDC1) was significantly upregulated in the KD group, while that of S100P was significantly downregulated in the OE group.

CONCLUSION

LHPP might emerge as an important target for delaying the advancement of PDAC, thereby providing a novel therapeutic approach for the treatment of PDAC.

Acetyl-Coenzyme A Synthetase 2 Potentiates Macropinocytosis and Muscle Wasting Through Metabolic Reprogramming in Pancreatic Cancer

BACKGROUND & AIMS

Rapid deconditioning, also called cachexia, and metabolic reprogramming are two hallmarks of pancreatic cancer. Acetyl-coenzyme A synthetase short-chain family member 2 (ACSS2) is an acetyl-enzyme A synthetase that contributes to lipid synthesis and epigenetic reprogramming. However, the role of ACSS2 on the nonselective macropinocytosis and cancer cachexia in pancreatic cancer remains elusive. In this study, we demonstrate that ACSS2 potentiates macropinocytosis and muscle wasting through metabolic reprogramming in pancreatic cancer.

METHODS

Clinical significance of ACSS2 was analyzed using samples from patients with pancreatic cancer. ACSS2-knockout cells were established using the clustered regularly interspaced short palindromic repeats-associated protein 9 system. Single-cell RNA sequencing data from genetically engineered mouse models was analyzed. The macropinocytotic index was evaluated by dextran uptake assay. Chromatin immunoprecipitation assay was performed to validate transcriptional activation. ACSS2-mediated tumor progression and muscle wasting were examined in orthotopic xenograft models.

RESULTS

Metabolic stress induced ACSS2 expression, which is associated with worse prognosis in pancreatic cancer. ACSS2 knockout significantly suppressed cell proliferation in 2-dimensional and 3-dimensional models. Macropinocytosis-associated genes are upregulated in tumor tissues and are correlated with worse prognosis. ACSS2 knockout inhibited macropinocytosis. We identified Zrt- and Irt-like protein 4 (ZIP4) as a downstream target of ACSS2, and knockdown of ZIP4 reversed ACSS2-induced macropinocytosis. ACSS2 upregulated ZIP4 through ETV4-mediated transcriptional activation. ZIP4 induces macropinocytosis through cyclic adenosine monophosphate response element-binding protein-activated syndecan 1 (SDC1) and dynamin 2 (DNM2). Meanwhile, ZIP4 drives muscle wasting and cachexia via glycogen synthase kinase-β (GSK3β)-mediated secretion of tumor necrosis factor superfamily member 10 (TRAIL or TNFSF10). ACSS2 knockout attenuated muscle wasting and extended survival in orthotopic mouse models.

CONCLUSIONS

ACSS2-mediated metabolic reprogramming activates the ZIP4 pathway, and promotes macropinocytosis via SDC1/DNM2 and drives muscle wasting through the GSK3β/TRAIL axis, which potentially provides additional nutrients for macropinocytosis in pancreatic cancer.

Functional genomics screening identifies aspartyl-tRNA synthetase as a novel prognostic marker and a therapeutic target for gastric cancers

Efficient molecular targeting therapies for most gastric cancers (GCs) are currently lacking, despite GC being one of the most frequent and often devastating malignancies worldwide. Thus, identification of novel therapeutic targets for GC is in high demand. Recent advancements of high-throughput nucleic acid synthesis methods combined with next-generation sequencing (NGS) platforms have made it feasible to conduct functional genomics screening using large-scale pooled lentiviral libraries aimed at discovering novel cancer therapeutic targets. In this study, we performed NGS-based functional genomics screening for human GC cell lines using an originally constructed 6,399 shRNA library targeting all 2,096 human metabolism genes. Our screening identified aspartyl-tRNA synthetase (DARS) as a possible candidate for a therapeutic target for GC. In-house tissue microarrays containing 346 cases of GC combined with public datasets showed that patients with high expression levels of DARS protein exhibited more advanced clinicopathologic parameters and a worse prognosis, specifically among diffuse-type GC patients. Both in vitro and in vivo experiments concretely evidenced that DARS inhibition achieved robust growth suppression of GC cells. Moreover, RNA sequencing of GC cell lines under shRNA-mediated DARS knockdown suggested that DARS inhibition exerts its effect through the inactivation of multiple p-ERK pathways. This MAPK-related growth suppression by DARS inhibition would also be applicable to other cancers; thus, it is warranted to investigate the expression and clinical significance of DARS in a wide spectrum of malignancies. Taken together, NGS-based high-throughput pooled lentiviral screening showed DARS as a novel prognostic marker and a promising therapeutic target for GC. © 2022 The Authors. The Journal of Pathology published by John Wiley &amp; Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Role of Heparanase and Syndecan-1 in HSV-1 Release from Infected Cells

Herpes Simplex Virus 1 (HSV-1) is a neurotropic human virus that belongs to the Alphaherpesvirinae subfamily of Herpesviridae. Establishment of its productive infection and progression of disease pathologies depend largely on successful release of virions from the virus-producing cells. HSV-1 is known to exploit many host factors for its release. Recent studies have shown that heparanase (HPSE) is one such host enzyme that is recruited for this purpose. It is an endoglycosidase that cleaves heparan sulfate (HS) from the surface of infected cells. HS is a virus attachment coreceptor that is commonly found on cell surfaces as HS proteoglycans e.g., syndecan-1 (SDC-1). The current model suggests that HSV-1 during the late stage of infection upregulates HPSE, which in turn enhances viral release by removing the virus-trapping HS moieties. In addition to its role in directly enabling viral release, HPSE accelerates the shedding of HS-containing ectodomains of SDC-1, which enhances HSV-1 release via a similar mechanism by upregulating CREB3 and COPII proteins. This review outlines the role of HPSE and SDC-1 as newly assigned host factors that facilitate HSV-1 release during a lytic infection cycle.

YY1 promotes pancreatic cancer cell proliferation by enhancing mitochondrial respiration

KRAS-driven metabolic reprogramming is a known peculiarity features of pancreatic ductal adenocarcinoma (PDAC) cells. However, the metabolic roles of other oncogenic genes, such as YY1, in PDAC development are still unclear. In this study, we observed significantly elevated expression of YY1 in human PDAC tissues, which positively correlated with a poor disease progression. Furthermore, in vitro studies confirmed that YY1 deletion inhibited PDAC cell proliferation and tumorigenicity. Moreover, YY1 deletion led to impaired mitochondrial RNA expression, which further inhibited mitochondrial oxidative phosphorylation (OXPHOS) complex assembly and altered cellular nucleotide homeostasis. Mechanistically, the impairment of mitochondrial OXPHOS function reduced the generation of aspartate, an output of the tricarboxylic acid cycle (TCA), and resulted in the inhibition of cell proliferation owing to unavailability of aspartate-associated nucleotides. Conversely, exogenous supplementation with aspartate fully restored PDAC cell proliferation. Our findings suggest that YY1 promotes PDAC cell proliferation by enhancing mitochondrial respiration and the TCA, which favors aspartate-associated nucleotide synthesis. Thus, targeting nucleotide biosynthesis is a promising strategy for PDAC treatment.

Perineural invasion-associated biomarkers for tumor development

Perineural invasion (PNI) is the process of neoplastic invasion of peripheral nerves and is considered to be the fifth mode of cancer metastasis. PNI has been detected in head and neck tumors and pancreatic, prostate, bile duct, gastric, and colorectal cancers. It leads to poor prognostic outcomes and high local recurrence rates. Despite the increasing number of studies on PNI, targeted therapeutic modalities have not been proposed. The identification of PNI-related biomarkers would facilitate the non-invasive and early diagnosis of cancers, the establishment of prognostic panels, and the development of targeted therapeutic approaches. In this review, we compile information on the molecular mediators involved in PNI-associated cancers. The expression and prognostic significance of molecular mediators and their receptors in PNI-associated cancers are analyzed, and the possible mechanisms of action of these mediators in PNI are explored, as well as the association of cells in the microenvironment where PNI occurs.

Targeting the Metabolic Rewiring in Pancreatic Cancer and Its Tumor Microenvironment

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with only a few effective therapeutic options. A characteristic feature of PDAC is its unique tumor microenvironment (TME), termed desmoplasia, which shows extensive fibrosis and extracellular matrix deposition, generating highly hypoxic and nutrient-deprived conditions within the tumor. To thrive in this harsh TME, PDAC undergoes extensive metabolic rewiring that includes the altered use of glucose and glutamine, constitutive activation of autophagy-lysosomal pathways, and nutrient acquisition from host cells in the TME. Notably, these properties support PDAC metabolism and mediate therapeutic resistance, including immune suppression. A deeper understanding of the unique metabolic properties of PDAC and its TME may aid in the development of novel therapeutic strategies against this deadly disease.

GOPC facilitates the sorting of syndecan-1 in polarized epithelial cells

The trans-Golgi network must coordinate sorting and secretion of proteins and lipids to intracellular organelles and the plasma membrane. During polarization of epithelial cells, changes in the lipidome and the expression and distribution of proteins contribute to the formation of apical and basolateral plasma membrane domains. Previous studies using HeLa cells show that the syndecan-1 transmembrane domain confers sorting within sphingomyelin-rich vesicles in a sphingomyelin secretion pathway. In polarized Madin-Darby canine kidney cells, we reveal differences in the sorting of syndecan-1, whereupon the correct trafficking of the protein is not dependent on its transmembrane domain and changes in sphingomyelin content of cells during polarization. Instead, we reveal that correct basolateral targeting of syndecan-1 requires a full-length PDZ motif in syndecan-1 and the PDZ domain golgin protein GOPC. Moreover, we reveal changes in Golgi morphology elicited by GOPC overexpression. These results suggest that the role of GOPC in sorting syndecan-1 is indirect and likely due to GOPC effects on Golgi organization.

Construction of a prognostic model related to copper dependence in breast cancer by single-cell sequencing analysis

Purpose: To explore the clinical significance of copper-dependent-related genes (CDRG) in female breast cancer (BC).

Methods: CDRG were obtained by single-cell analysis of the GSE168410 dataset in the Gene Expression Omnibus (GEO) database. According to a 1:1 ratio, the Cancer Genome Atlas (TCGA) cohort was separated into a training and a test cohort randomly. Based on the training cohort, the prognostic model was built using COX and Lasso regression. The test cohort was used to validate the model. The GSE20685 dataset and GSE20711 dataset were used as two external validation cohorts to further validate the prognostic model. According to the median risk score, patients were classified as high-risk or low-risk. Survival analysis, immune microenvironment analysis, drug sensitivity analysis, and nomogram analysis were used to evaluate the clinical importance of this prognostic model.

Results: 384 CDRG were obtained by single-cell analysis. According to the prognostic model, patients were classified as high-risk or low-risk in both cohorts. The high-risk group had a significantly worse prognosis. The area under the curve (AUC) of the model was around 0.7 in the four cohorts. The immunological microenvironment was examined for a possible link between risk score and immune cell infiltration. Veliparib, Selumetinib, Entinostat, and Palbociclib were found to be more sensitive medications for the high-risk group after drug sensitivity analysis.

Conclusion: Our CDRG-based prognostic model can aid in the prediction of prognosis and treatment of BC patients.

The Role and Therapeutic Potential of Macropinocytosis in Cancer

Macropinocytosis, a unique endocytosis pathway characterized by nonspecific internalization, has a vital role in the uptake of extracellular substances and antigen presentation. It is known to have dual effects on cancer cells, depending on cancer type and certain microenvironmental conditions. It helps cancer cells survive in nutrient-deficient environments, enhances resistance to anticancer drugs, and promotes invasion and metastasis. Conversely, overexpression of the RAS gene alongside drug treatment can lead to methuosis, a novel mode of cell death. The survival and proliferation of cancer cells is closely related to macropinocytosis in the tumor microenvironment (TME), but identifying how these cells interface with the TME is crucial for creating drugs that can limit cancer progression and metastasis. Substantial progress has been made in recent years on designing anticancer therapies that utilize the effects of macropinocytosis. Both the induction and inhibition of macropinocytosis are useful strategies for combating cancer cells. This article systematically reviews the general mechanisms of macropinocytosis, its specific functions in tumor cells, its occurrence in nontumor cells in the TME, and its application in tumor therapies. The aim is to elucidate the role and therapeutic potential of macropinocytosis in cancer treatment.

Elevated plasma syndecan-1 as glycocalyx injury marker predicts unfavorable outcomes after rt-PA intravenous thrombolysis in acute ischemic stroke

Purpose: We aimed to examine the prognostic value of syndecan-1 as a marker of glycocalyx injury in patients with acute ischemic stroke (AIS) receiving rt-PA intravenous thrombolysis.

Methods: The study included 108 patients with AIS treated with rt-PA intravenous thrombolysis and 47 healthy controls. Patients were divided into unfavorable and favorable prognosis groups based on modified Rankin Scale scores. Univariate and multivariate logistic regression analyses were used to determine risk factors affecting prognosis. Risk prediction models presented as nomograms. The predictive accuracy and clinical value of the new model were also evaluated.

Results: Plasma levels of syndecan-1 were significantly higher in patients with AIS than in controls (p < 0.05). Univariate analysis indicated that higher levels of syndecan-1 were more frequent in patients with poor prognosis than in those with good prognosis (t = −4.273, p < 0.001). Syndecan-1 alone and in combination with other factors predicted patient outcomes. After adjusting for confounding factors, syndecan-1 levels remained associated with poor prognosis [odds ratio, 1.024; 95% confidence interval (CI), 1.010–1.038]. The risk model exhibited a good fit, with an area under the receiver operating characteristic curve of 0.935 (95% CI, 0.888–0.981). The categorical net reclassification index (NRI) and continuous NRI values were >0. The integrated discrimination improvement value was 0.111 (95% CI, 0.049–0.174, p < 0.001). Decision curve analysis indicated that the model incorporating syndecan-1 levels was more clinically valuable than the conventional model.

Conclusion: Plasma syndecan-1 levels represent a potential marker of prognosis of AIS following intravenous thrombolysis. Adding syndecan-1 to the conventional model may improve risk stratification.

Exceptional tumour responses to fasting-mimicking diet combined with standard anticancer therapies: A sub-analysis of the NCT03340935 trial

BACKGROUND

Cyclic fasting or calorie-restricted, low-carbohydrate, low-protein diets, collectively referred to as fasting-mimicking diets (FMDs), demonstrated additive or synergistic antitumour effects when combined with chemotherapy, targeted therapies, or immunotherapy in several preclinical in vivo models, including murine models of breast cancer, lung cancer, and colorectal cancer. However, no data on the antitumour efficacy of cyclic FMD in patients with cancer have been published so far. Here, we aim at reporting on patients with advanced cancer achieving complete and long-lasting tumour remissions with cyclic FMD in combination with standard anticancer therapies in the context of the phase Ib NCT03340935 trial.

PATIENTS AND METHODS

The NCT03340935 trial enrolled 101 patients with different tumour types, and it showed that a severely calorie-restricted FMD regimen is safe and feasible in patients with cancer receiving concomitant standard-of-care antineoplastic therapies. In addition, cyclic FMD resulted in positive metabolic and immunologic modifications, thus recapitulating the biological effects that in preclinical models were found to mediate the antitumour effects of fasting/FMD.

RESULTS

Of the 101 patients enrolled in the NCT03340935 trial, we identified five patients with advanced, poor prognosis solid neoplasms (n = 1: extensive stage small cell lung cancer; n = 1: metastatic pancreatic adenocarcinoma; n = 1: metastatic colorectal cancer; n = 2: metastatic triple-negative breast cancer), who achieved complete and long-lasting tumour responses when treated with a combination of cyclic FMD and standard systemic treatments in the context of the NCT03340935 trial.

CONCLUSION

These excellent responses prompt the initiation of clinical trials to investigate cyclic FMD in combination with standard antitumour therapies in specific clinical contexts.

Excavating proteoglycan structure-function relationships: Modern approaches to capture the interactions of ancient biomolecules

Proteoglycans are now well regarded as key facilitators of cell biology. While a majority of their interactions and functions are attributed to the decorating glycosaminoglycan chains, there is a growing appreciation for the roles of the proteoglycan core protein and for considering proteoglycans as replete protein-glycan conjugates. This appreciation, seeded by early work in proteoglycan biology, is now being advanced and exalted by modern approaches in chemical glycobiology. In this review, we discuss up-and-coming methods to unearth the fine-scale architecture of proteoglycans that modulate their functions and interactions. Crucial to these efforts is the production of chemically defined materials, including semi-synthetic proteoglycans and the in situ capture of interacting proteins. Together, the integration of chemical biology approaches promises to expedite the dissection of the structural heterogeneity of proteoglycans and deliver refined insight into their functions.

Eltrombopag binds SDC4 directly and enhances MAPK signaling and macropinocytosis in cancer cells

Syndecan-4 (SDC4) is a single-pass transmembrane glycoprotein implicated in a variety of oncogenic signaling pathways. It is also an intrinsically disordered protein and considered "undruggable". In the present study, we confirmed that knocking out SDC4 in pancreatic cancer cells markedly impaired macropinocytosis, colony formation, as well as xenograft tumor initiation and growth. Quantitative proteomic profiling of Sdc4 knockout (KO) cells revealed significant changes in cell metabolic pathways. In a cellular protein-based ligand interaction screening, we identified that Eltrombopag (ETBP), an FDA-approved agonist of the thrombopoietin receptor (TPOR) for immune thrombocytopenia, could directly bind to SDC4 with a Kd value of ~2 µM. We showed that the transmembrane motif was essential for SDC4 binding to ETBP. Unexpectedly, ETBP not only increased SDC4 abundance, but also enhanced SDC4-associated MAPK signaling pathway and macropinocytosis in cancer cells. Our results indicate that ETBP is a potential agonist of SDC4 in a fashion similar to its original target TPOR, and that caution should be taken when using ETBP for chemotherapy-induced thrombocytopenia in cancer patients.

Syndecan-1 in liver pathophysiology

Syndecan-1 is a heparan sulfate/chondroitin sulfate proteoglycan (PG) of the cell surface and the extracellular matrix, which regulates a broad spectrum of physiological and pathological processes such as cell proliferation, migration, inflammation, matrix remodeling, wound healing, or tumorigenesis. Syndecan-1 represents the major PG of the liver, expressed by hepatocytes and cholangiocytes, and its elevated expression is a characteristic feature of liver diseases. The highest syndecan-1 expression is found in liver cirrhosis and in hepatocellular carcinoma (HCC) developed in cirrhotic livers. In addition, as being a hepatitis C receptor, hepatitis C virus (HCV) infected livers produce extremely large amounts of syndecan-1. The serum levels of the cleaved (shedded) extracellular domain has clinical significance, as its increased concentration reflects on poor prognosis in cirrhosis as well as in cancer. In vivo experiments confirmed that syndecan-1 protects against early stages of fibrogenesis mainly by enhanced clearance of transforming growth factor beta (TGFβ1) and thrombospondin-1 via circulation, and against hepatocarcinogenesis by interfering with several signaling pathways and enhancing cell cycle blockade. In addition, syndecan-1 is capable to hinder lipid metabolism and ribosomal biogenesis in induced cancer models.. These observations together with its participation in the uptake of viruses (e.g. HCV, SARS-CoV-2) indicate that syndecan-1 is a central player in liver pathologies.

Potential prognosis index for m6A-related mRNA in cholangiocarcinoma

Background

Cholangiocarcinoma (CHOL) is a malignant tumor that originates in the extrahepatic bile duct and can extend from the hilar region to the lower end of the common bile duct. The prognosis of CHOL patients is particularly poor; therefore, in this study, we screened mRNAs correlated with N6-methyladenosine (m⁶A) to construct a risk model for prognosis in CHOL.

Methods

The TCGA-CHOL dataset was applied to obtain and analyze the coexpression of 1281 m⁶A-related mRNAs, from which 14 were selected for further analysis through univariate proportional hazards (cox) regression analysis. Aryl hydrocarbon receptor interacting protein (AIP), CCAAT/enhancer binding protein beta (CEBPB), syndecan1 (SDC1), vacuolar protein sorting 25 homolog (VPS25) and syntaxin binding protein 2 (STXBP2) were then screened out through the least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression analysis to develop a precise m⁶A-related mRNA prognosis risk model (MRMRPM) with an area under curve (AUC) of 0.908 and 0.923 after 1 and 2 years, respectively. We divided the samples into high-risk and low-risk groups using the m⁶A-related mRNA prognosis risk model.

Results

Kaplan–Meier analysis indicated poor overall survival (OS) for the high-risk group. Two Gene Expression Omnibus (GEO) datasets (GSE89748 and GSE107943) were used to validate the risk model. The results of drug sensitivity and immune cell infiltration analysis showed that the risk model could serve as a prognosis index of potential immunotherapeutic characteristics and drug sensitivity. Furthermore, the proportion of resting dendritic cells and regulatory T cells was positively associated with an increased expression of four m⁶A-related mRNAs — AIP, CEBPB, SDC1, and VPS25 — in the high-risk CHOL group.

Conclusions

Our findings suggest that this model can be a prognostic indicator for CHOL patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09665-3.

Altered glycosylation in pancreatic cancer and beyond

Pancreatic ductal adenocarcinoma (PDA) is one of the deadliest cancers and is projected to soon be the second leading cause of cancer death. Median survival of PDA patients is 6-10 mo, with the majority of diagnoses occurring at later, metastatic stages that are refractory to treatment and accompanied by worsening prognoses. Glycosylation is one of the most common types of post-translational modifications. The complex landscape of glycosylation produces an extensive repertoire of glycan moieties, glycoproteins, and glycolipids, thus adding a dynamic and tunable level of intra- and intercellular signaling regulation. Aberrant glycosylation is a feature of cancer progression and influences a broad range of signaling pathways to promote disease onset and progression. However, despite being so common, the functional consequences of altered glycosylation and their potential as therapeutic targets remain poorly understood and vastly understudied in the context of PDA. In this review, the functionality of glycans as they contribute to hallmarks of PDA are highlighted as active regulators of disease onset, tumor progression, metastatic capability, therapeutic resistance, and remodeling of the tumor immune microenvironment. A deeper understanding of the functional consequences of altered glycosylation will facilitate future hypothesis-driven studies and identify novel therapeutic strategies in PDA.

Targeting Syndecan-1: New Opportunities in Cancer Therapy

Syndecan-1 (SDC1, CD138) is one of the heparan sulfate proteoglycans and is essential for maintaining normal cell morphology, interacting with extracellular and intracellular protein repertoire as well as mediating signaling transduction upon environmental stimuli. The critical role of SDC1 in promoting tumorigenesis and metastasis has been increasingly recognized in various cancer types, implying a promising potential of utilizing SDC1 as a novel target for cancer therapy. This review summarizes the current knowledge on SDC1 structure and functions, including its role in tumor biology. We also discuss the highlights and limitations of current SDC1-targeted therapies as well as the obstacles in developing new therapeutic methods, offering our perspective on the future directions to target SDC1 for cancer treatment.

Mutant KRAS drives metabolic reprogramming and autophagic flux in premalignant pancreatic cells

Mutational activation of the KRAS gene occurs in almost all pancreatic ductal adenocarcinoma (PDAC) and is the earliest molecular event in their carcinogenesis. Evidence has accumulated of the metabolic reprogramming in PDAC, such as amino acid homeostasis and autophagic flux. However, the biological effects of KRAS mutation on metabolic reprogramming at the earlier stages of PDAC carcinogenesis are unclear. Here we report dynamic metabolic reprogramming in immortalized human non-cancerous pancreatic ductal epithelial cells, in which a KRAS mutation was induced by gene-editing, which may mimic early pancreatic carcinogenesis. Similar to the cases of PDAC, KRAS gene mutation increased the dependency on glucose and glutamine for maintaining the intracellular redox balance. In addition, the intracellular levels of amino acids were significantly decreased because of active protein synthesis, and the cells required greater autophagic flux to maintain their viability. The lysosomal inhibitor chloroquine significantly inhibited cell proliferation. Therefore, metabolic reprogramming is an early event in carcinogenesis initiated by KRAS gene mutation, suggesting a rationale for the development of nutritional interventions that suppress or delay the development of PDAC.

Serum Syndecan-1: A Novel Biomarker for Pancreatic Ductal Adenocarcinoma

INTRODUCTION

Syndecan-1 (SDC1) has multiple functions in tumorigenesis in general and specifically in pancreatic cancer. We aimed to evaluate SDC1 as a diagnostic and prognostic biomarker in patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

In this case-control study, patients newly diagnosed with a biopsy-proven PDAC were enrolled alongside healthy individuals in a derivation-validation cohort design. Serum SDC1 was measured by enzyme-linked immunoassay. The diagnostic accuracy of SDC1 levels for diagnosing PDAC was computed. A unified cohort enriched with additional early-stage patients with PDAC was used to evaluate the association of SDC1 with survival outcomes and patient characteristics.

RESULTS

In the derivation cohort, serum SDC1 levels were significantly higher in patients with PDAC (n = 39) compared with healthy controls (n = 20) (40.1 ng/mL, interquartile range 29.8-95.3 vs 25.6 ng/mL, interquartile range 17.1-29.8, respectively; P < 0.001). The receiver operating characteristic analysis area under the curve was 0.847 (95% confidence interval 0.747-0.947, P < 0.001). These results were replicated in a separate age-matched validation cohort (n = 38 PDAC, n = 38 controls; area under the curve 0.844, 95% confidence interval 0.757-0.932, P < 0.001). In the combined-enriched PDAC cohort (n = 110), using a cutoff of 35 ng/mL, the median overall 5-year survival between patients below and above this cutoff was not significantly different, although a trend for better survival after 1 year was found in the lower level group (P = 0.06). There were 12 of the 110 patients with PDAC (11%) who had normal CA 19-9 in the presence of elevated SDC1.

DISCUSSION

These findings suggest serum SDC1 as a promising novel biomarker for early blood-based diagnosis of pancreatic cancer.

MMP-7 marks severe pancreatic cancer and alters tumor cell signaling by proteolytic release of ectodomains

Pancreatic cancer incurs the worst survival rate of the major cancers. High levels of the protease matrix metalloproteinase-7 (MMP-7) in circulation correlate with poor prognosis and limited survival of patients. MMP-7 is required for a key path of pancreatic tumorigenesis in mice and is present throughout tumor progression. Enhancements to chemotherapies are needed for increasing the number of pancreatic tumors that can be removed and for preventing relapses after surgery. With these ends in mind, selective inhibition of MMP-7 may be worth investigation. An anti-MMP-7 monoclonal antibody was recently shown to increase the susceptibility of several pancreatic cancer cell lines to chemotherapeutics, increase their apoptosis, and decrease their migration. MMP-7 activities are most apparent at the surfaces of innate immune, epithelial, and tumor cells. Proteolytic shedding of multiple protein ectodomains by MMP-7 from such cell surfaces influence apoptosis, proliferation, migration, and invasion. These activities warrant targeting of MMP-7 selectively in pancreatic cancer and other tumors of mucosal epithelia. Competitive and non-competitive modes of MMP-7 inhibition are discussed.