Glucose and Lactate Transport in Pancreatic Cancer: Glycolytic Metabolism Revisited

Ribosome biogenesis, altered metabolism and ribotoxic stress response in pancreatic ductal adenocarcinoma tumor microenvironment

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy with a poor overall survival rate. Cellular stress response pathways promoting cancer cell fitness in harsh tumor microenvironment (TME) play a critical role in cancer growth and survival. The influence of oncogenic Kras, multi-functional heterogeneous cancer-associated fibroblasts (CAFs), and immunosuppressive TME on cancer cells makes the disease more complex and difficult to treat. The desmoplastic reaction by CAFs comprises approximately 90 % of the tumor, with only 10 % of cancer cells making things even more complicated, resulting in therapy resistance. Consistently increasing fibrosis creates a hypoxic environment and elevated interstitial fluid pressure inside the tumor constraining vascular supply. Stress conditions in TME alter translation efficiency and metabolism to fulfill the energy requirements of rapidly growing cancer cells. Extensive research has been conducted on multiple molecular and metabolic regulators in PDAC TME. However, the role of TME in influencing translation programs, a prerequisite for cell cycle progression and functional/growth requirements for cancer cells, remains elusive. This review highlights the recent advancements in understanding altered translational programs in PDAC TME. We emphasize the role of ribosome biogenesis, ribosome-induced stress response, and the concept of specialized ribosomes and their probable role in mutationally rewiring the pancreatic TME.

Canonical WNT/β-catenin signaling upregulates aerobic glycolysis in diverse cancer types

Despite many efforts, a comprehensive understanding and clarification of the intricate connections within cancer cell metabolism remain elusive. This might pertain to intracellular dynamics and the complex interplay between cancer cells, and cells with the tumor stroma. Almost a century ago, Otto Warburg found that cancer cells exhibit a glycolytic phenotype, which continues to be a subject of thorough investigation. Past and ongoing investigations have demonstrated intricate mechanisms by which tumors modulate their functionality by utilizing extracellular glucose as a substrate, thereby sustaining the essential proliferation of cancer cells. This concept of "aerobic glycolysis," where cancer cells (even in the presence of enough oxygen) metabolize glucose to produce lactate plays a critical role in cancer progression and is regulated by various signaling pathways. Recent research has revealed that the canonical wingless-related integrated site (WNT) pathway promotes aerobic glycolysis, directly and indirectly, thereby influencing cancer development and progression. The present review seeks to gather knowledge about how the WNT/β-catenin pathway influences aerobic glycolysis, referring to relevant studies in different types of cancer. Furthermore, we propose the concept of impeding the glycolytic phenotype of tumors by employing specific inhibitors that target WNT/β-catenin signaling.

Targeting Glucose Metabolism in Cancer Cells as an Approach to Overcoming Drug Resistance

The "Warburg effect" consists of a metabolic shift in energy production from oxidative phosphorylation to glycolysis. The continuous activation of glycolysis in cancer cells causes rapid energy production and an increase in lactate, leading to the acidification of the tumour microenvironment, chemo- and radioresistance, as well as poor patient survival. Nevertheless, the mitochondrial metabolism can be also involved in aggressive cancer characteristics. The metabolic differences between cancer and normal tissues can be considered the Achilles heel of cancer, offering a strategy for new therapies. One of the main causes of treatment resistance consists of the increased expression of efflux pumps, and multidrug resistance (MDR) proteins, which are able to export chemotherapeutics out of the cell. Cells expressing MDR proteins require ATP to mediate the efflux of their drug substrates. Thus, inhibition of the main energy-producing pathways in cancer cells, not only induces cancer cell death per se, but also overcomes multidrug resistance. Given that most anticancer drugs do not have the ability to distinguish normal cells from cancer cells, a number of drug delivery systems have been developed. These nanodrug delivery systems provide flexible and effective methods to overcome MDR by facilitating cellular uptake, increasing drug accumulation, reducing drug efflux, improving targeted drug delivery, co-administering synergistic agents, and increasing the half-life of drugs in circulation.

Unveiling the intricate causal nexus between pancreatic cancer and peripheral metabolites through a comprehensive bidirectional two-sample Mendelian randomization analysis

Aim: Pancreatic cancer (PC) is a devastating malignancy characterized by its aggressive nature and poor prognosis. However, the relationship of PC with peripheral metabolites remains not fully investigated. The study aimed to explore the causal linkage between PC and peripheral metabolite profiles. Methods: Employing publicly accessible genome-wide association studies (GWAS) data, we conducted a bidirectional two-sample Mendelian randomization (MR) analysis. The primary analysis employed the inverse-variance weighted (IVW) method. To address potential concerns about horizontal pleiotropy, we also employed supplementary methods such as maximum likelihood, weighted median, MR-Egger regression, and MR pleiotropy residual sum and outlier (MR-PRESSO). Results: We ascertained 20 genetically determined peripheral metabolites with causal linkages to PC while high-density lipoprotein (HDL) and very low-density lipoprotein (VLDL) particles accounted for the vast majority. Specifically, HDL particles exhibited an elevated PC risk while VLDL particles displayed an opposing pattern. The converse MR analysis underscored a notable alteration in 17 peripheral metabolites due to PC, including branch chain amino acids and derivatives of glycerophospholipid. Cross-referencing the bidirectional MR results revealed a reciprocal causation of PC and X-02269 which might form a self-perpetuating loop in PC development. Additionally, 1-arachidonoylglycerophosphocholine indicated a reduced PC risk and an increase under PC influence, possibly serving as a negative feedback regulator. Conclusion: Our findings suggest a complex interplay between pancreatic cancer and peripheral metabolites, with potential implications for understanding the etiology of pancreatic cancer and identifying novel early diagnosis and therapeutic targets. Moreover, X-02269 may hold a pivotal role in PC onset and progression.

Targeting the metabolism and immune system in pancreatic ductal adenocarcinoma: Insights and future directions

Pancreatic cancer, specifically pancreatic ductal adenocarcinoma (PDAC), presents a challenging landscape due to its complex nature and the highly immunosuppressive tumor microenvironment (TME). This immunosuppression severely limits the effectiveness of immune-based therapies. Studies have revealed the critical role of immunometabolism in shaping the TME and influencing PDAC progression. Genetic alterations, lysosomal dysfunction, gut microbiome dysbiosis, and altered metabolic pathways have been shown to modulate immunometabolism in PDAC. These metabolic alterations can significantly impact immune cell functions, including T-cells, myeloid-derived suppressor cells (MDSCs), and macrophages, evading anti-tumor immunity. Advances in immunotherapy offer promising avenues for overcoming immunosuppressive TME and enhancing patient outcomes. This review highlights the challenges and opportunities for future research in this evolving field. By exploring the connections between immunometabolism, genetic alterations, and the microbiome in PDAC, it is possible to tailor novel approaches capable of improving immunotherapy outcomes and addressing the limitations posed by immunosuppressive TME. Ultimately, these insights may pave the way for improved treatment options and better outcomes for PDAC patients.

Pancreatic Cystic Neoplasms: Diagnosis and Management

Pancreatic cancer is one of the most lethal cancers, largely related to the difficulties with early detection, as it typically presents in later stages. Pancreatic cystic neoplasms (PCN) are commonly diagnosed as incidental findings on routine imaging. PCN is becoming more frequently detected with the increasing ease and frequency of obtaining cross-sectional images. Certain subtypes of pancreatic cysts have the potential to progress to malignancy, and therefore, clinicians are tasked with creating a patient-centered management plan. The decision of whether to undergo surgical resection or interval surveillance can be challenging given the criteria, including PCN size, pancreatic duct dilation, presence of a mural nodule, and clinical symptoms that play a potential role in risk stratification. Furthermore, the guidelines available from the major gastrointestinal societies all differ in their management recommendations. In this review, we detail an overview of the different types of PCNs and compare major guidelines for both diagnosis and management. We include emerging evidence for next-generation sequencing as well as confocal needle endomicroscopy to aid in the diagnosis and determination of malignancy potential and diagnosis.

Molecular underpinnings of exceptional response in primary malignant melanoma of the esophagus to anti-PD-1 monotherapy

BACKGROUND

Accumulating data suggest that mucosal melanoma, well known for its poor response to immune checkpoint blockade (ICB) and abysmal prognosis, is a heterogeneous subtype of melanoma with distinct genomic and clinical characteristics between different anatomic locations of the primary lesions. Primary malignant melanoma of the esophagus (PMME) is a rare, highly aggressive disease with a poorer prognosis compared with that of non-esophageal mucosal melanoma (NEMM). In this study, we retrospectively analyzed the efficacy of anti-programmed death (PD)-1 in patients with PMME and explored its molecular basis.

METHODS

The response and survival of patients with PMME and NEMM under anti-PD-1 monotherapy were retrospectively analyzed. To explore the molecular mechanisms of the difference in therapeutic efficacy between PMME and NEMM, we performed genomic analysis, bulk RNA sequencing, and multiplex immunohistochemistry staining.

RESULTS

We found that PMME (n=28) responded better to anti-PD-1 treatment than NEMM (n=64), with a significantly higher objective response rate (33.3% (95% CI 14.3% to 52.3%) vs 6.6% (95% CI 0.2% to 12.9%)) and disease control rate (74.1% (95% CI 56.4% to 91.7%) vs 37.7% (95% CI 25.2% to 50.2%)). Genomic sequencing analysis revealed that the genomic aberration landscape of PMME predominated in classical cancer driver genes, with approximately half of PMME cases harboring mutations in BRAF, N/KRAS, and NF1. In contrast, most NEMM cases were triple wild-type. Transcriptome analysis revealed that, compared with NEMM, PMME displayed more significant proliferation and inflammatory features with higher expression of genes related to antigen presentation and differentiation, and a less immunosuppressive signature with lower expression of inhibitory immune checkpoints and dedifferentiation-related genes. The multiplex immunohistochemical analysis also demonstrated higher CD8⁺ T-cell infiltration in PMME than in NEMM.

CONCLUSIONS

PMME is an outlier of mucosal melanoma showing a malicious phenotype but a particularly high response rate to ICB because of its distinct molecular characteristics. Patient stratification based on anatomic origin can facilitate clinical decision-making in patients with mucosal melanoma following the verification of our results in future prospective studies.

Lactate Rewrites the Metabolic Reprogramming of Uveal Melanoma Cells and Induces Quiescence Phenotype

Uveal melanoma (UM), the most common primary intraocular cancer in adults, is among the tumors with poorer prognosis. Recently, the role of the oncometabolite lactate has become attractive due to its role as hydroxycarboxylic acid receptor 1 (HCAR1) activator, as an epigenetic modulator inducing lysine residues lactylation and, of course, as a glycolysis end-product, bridging the gap between glycolysis and oxidative phosphorylation. The aim of the present study was to dissect in UM cell line (92.1) the role of lactate as either a metabolite or a signaling molecule, using the known modulators of HCAR1 and of lactate transporters. Our results show that lactate (20 mM) resulted in a significant decrease in cell proliferation and migration, acting and switching cell metabolism toward oxidative phosphorylation. These results were coupled with increased euchromatin content and quiescence in UM cells. We further showed, in a clinical setting, that an increase in lactate transporters MCT4 and HCAR1 is associated with a spindle-shape histological type in UM. In conclusion, our results suggest that lactate metabolism may serve as a prognostic marker of UM progression and may be exploited as a potential therapeutic target.

Review of the endocrine organ-like tumor hypothesis of cancer cachexia in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most fatal types of solid tumors, associated with a high prevalence of cachexia (~80%). PDAC-derived cachexia (PDAC-CC) is a systemic disease involving the complex interplay between the tumor and multiple organs. The endocrine organ-like tumor (EOLT) hypothesis may explain the systemic crosstalk underlying the deleterious homeostatic shifts that occur in PDAC-CC. Several studies have reported a markedly heterogeneous collection of cachectic mediators, signaling mechanisms, and metabolic pathways, including exocrine pancreatic insufficiency, hormonal disturbance, pro-inflammatory cytokine storm, digestive and tumor-derived factors, and PDAC progression. The complexities of PDAC-CC necessitate a careful review of recent literature summarizing cachectic mediators, corresponding metabolic functions, and the collateral impacts on wasting organs. The EOLT hypothesis suggests that metabolites, genetic instability, and epigenetic changes (microRNAs) are involved in cachexia development. Both tumors and host tissues can secrete multiple cachectic factors (beyond only inflammatory mediators). Some regulatory molecules, metabolites, and microRNAs are tissue-specific, resulting in insufficient energy production to support tumor/cachexia development. Due to these complexities, changes in a single factor can trigger bi-directional feedback circuits that exacerbate PDAC and result in the development of irreversible cachexia. We provide an integrated review based on 267 papers and 20 clinical trials from PubMed and ClinicalTrials.gov database proposed under the EOLT hypothesis that may provide a fundamental understanding of cachexia development and response to current treatments.

Glycolytic Inhibitors Potentiated the Activity of Paclitaxel and Their Nanoencapsulation Increased Their Delivery in a Lung Cancer Model

Antiglycolytic agents inhibit cell metabolism and modify the tumor’s microenvironment, affecting chemotherapy resistance mechanisms. In this work, we studied the effect of the glycolytic inhibitors 3-bromopyruvate (3BP), dichloroacetate (DCA) and 2-deoxyglucose (2DG) on cancer cell properties and on the multidrug resistance phenotype, using lung cancer cells as a model. All compounds led to the loss of cell viability, with different effects on the cell metabolism, migration and proliferation, depending on the drug and cell line assayed. DCA was the most promising compound, presenting the highest inhibitory effect on cell metabolism and proliferation. DCA treatment led to decreased glucose consumption and ATP and lactate production in both A549 and NCI-H460 cell lines. Furthermore, the DCA pretreatment sensitized the cancer cells to Paclitaxel (PTX), a conventional chemotherapeutic drug, with a 2.7-fold and a 10-fold decrease in PTX IC₅₀ values in A549 and NCI-H460 cell lines, respectively. To increase the intracellular concentration of DCA, thereby potentiating its effect, DCA-loaded poly(lactic-co-glycolic acid) nanoparticles were produced. At higher DCA concentrations, encapsulation was found to increase its toxicity. These results may help find a new treatment strategy through combined therapy, which could open doors to new treatment approaches.

Colourful fluorescence-based carbon dots for tumour imaging-guided nanosurgery

Fluorescent-intraoperative navigation is a visual technique that allows surgeons to accurately distinguish malignant and normal tissues during surgery. It has the advantages of immediacy, high resolution, and high specificity. However, a single fluorescent source cannot provide sufficient surgical information. Multicolour carbon dots (CDs) are more suitable since they provide outstanding water solubility, photostability, and multicolour-fluorescence imaging. Here, we prepared an optical probe with CD-based multicolour-fluorescence imaging via a hydrothermal method. CDs can be endocytosed by tumour cells, and after intravenous injection, they can effectively accumulate at the tumour site. In a pancreatic cancer mouse model, we demonstrated the multicolour-fluorescence imaging capabilities of CDs, which aided the accurate resection of tumours under fluorescent-intraoperative navigation. Stereoscopic fluorescence microscopy imaging and H&E staining proved that the removed tissue belonged to the pancreatic tumour. This study emphasizes the potential of CDs for fluorescence-guided intraoperative resection and expands the application of CDs in biological fields.

Connecting the Human Microbiome and Pancreatic Cancer

Pancreatic cancer is a deadly disease that is increasing in incidence throughout the world. There are no clear causal factors associated with the incidence of pancreatic cancer; however, some correlation to smoking, diabetes and alcohol has been described. Recently, a few studies have linked the human microbiome (oral and gastrointestinal tract) to pancreatic cancer development. A perturbed microbiome has been shown to alter normal cells while promoting cancer-related processes such as increased cell signaling, immune system evasion and invasion. In this article, we will review in detail the alterations within the gut and oral microbiome that have been linked to pancreatic cancer and explore the ability of other microbiomes, such as the lung and skin microbiome, to contribute to disease development. Understanding ways to identify a perturbed microbiome can result in advancements in pancreatic cancer research and allow for prevention, earlier detection and alternative treatment strategies for patients.

Circ_0072008, an oncogene in pancreatic ductal adenocarcinoma, contributes to tumour cell malignant progression and glycolysis by regulating miR-545-3p/SLC7A11 axis

BACKGROUND

The hsa_circRNA_103809 (circ_0072088) has been an emerging tumour regulator in human cancers, and is identified as one most aberrantly expressed circRNA in patients with pancreatic ductal adenocarcinoma (PDAC). However, the role of circ_0072088 remains unclear in PDAC cells.

METHODS

Expression of circ_0072088, microRNA (miR)-545-3p and solute carrier family 7 member 11 (SLC7A11) was detected by real-time quantitative PCR and western blotting. Cell progression was measured by cell counting kit (CCK)-8 assay, transwell assays and flow cytometry, as well as xenograft tumour models. Glycolysis was evaluated by commercial assay kits. The interaction among circ_0072088, miR-545-3p and SLC7A11 was confirmed by dual-luciferase reporter assay.

RESULTS

Circ_0072088 was upregulated in PDAC tumours and cells; besides, high circ_0072088 level was associated with high tumour-node-metastasis (TNM) stage. The circ_0072088 siRNA suppressed cell viability, migration, invasion, extracellular acidification rate (ECAR), lactate production, glucose uptake, and ATP generation, but promoted apoptosis rate and oxygen consumption rate (OCR) in SW1990 and PANC-1 cells. In vivo, circ_0072088 knockdown retarded tumour growth of PANC-1 cells. Overexpressing miR-545-3p mimicked circ_0072088 siRNA-induced actions, and inhibited cell progression and glycolysis of SW1990 and PANC-1 cells. Moreover, SLC7A11 downregulation could be mediated by both circ_0072008 siRNA and miR-545-3p mimic, and participating in suppressive role in cell progression and glycolysis of SW1990 and PANC-1 cells. In mechanism, miR-545-3p was targeted by circ_0072008, and SLC7A11 was target of miR-545-3p.

CONCLUSION

Circ_0072088 elicited oncogenic role in malignant cell progression and glycolysis of PDAC cells through circ_0072088/miR-545-3p/SLC7A11 pathway.HighlightsCirc_0072088 was upregulated in PDAC tumours and was associated with high tumour burden.Blocking circ_0072088 suppressed cell proliferation, migration, invasion, and glycolysis in PDAC cells.Circ_0072088 could directly regulate miR-545-3p, and SLC7A11 was a target of miR-545-3p.Restoring miR-545-3p mimicked the effects of circ_0072088 knockdown in PDAC cell in vitro.

Molecular aspects of pancreatic cancer: focus on reprogrammed metabolism in a nutrient-deficient environment and potential therapeutic targets

Pancreatic ductal adenocarcinoma (PDAC) is still burdened with high mortality (5-year survival rate < 9%) due to late diagnosis, aggressiveness, and a lack of more effective treatment methods. Early diagnosis and new therapeutic approaches based on the reprogrammed metabolism of the tumor in a nutrient-deficient environment are expected to improve the future treatment of PDAC patients. Research results suggest that genetic and metabolic disorders may precede the onset of neoplastic changes, which should allow for earlier appropriate treatment. Glycolysis and glutaminolysis are the most investigated pathways associated with the highest aggressiveness of pancreatic tumors. Blocking of selected metabolic pathways related to the local adaptive metabolic activity of pancreatic cancer cells improving nutrient acquisition and metabolic crosstalk within the microenvironment to sustain proliferation may inhibit cancer development, increase cancer cells death, and increase sensitivity to other forms of treatment (e.g., chemotherapy). Depriving cancer cells of important nutrients (glucose, glutamine) revealed tumor “checkpoints” for the mechanisms that drive cell proliferation and metastasis formation in order to determine its accuracy for individualization of the therapeutic approach. The present review highlights selected metabolic signaling pathways and their regulators aimed at inhibiting the neoplastic process. Particular attention has been paid to the adaptive metabolism of pancreatic cancer, which promotes its development in an oxygen-deficient and nutrient-poor environment.

The Glycolytic Pathway as a Target for Novel Onco-Immunology Therapies in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDA) is one of the most lethal forms of human cancer, characterized by unrestrained progression, invasiveness and treatment resistance. To date, there are limited curative options, with surgical resection as the only effective strategy, hence the urgent need to discover novel therapies. A platform of onco-immunology targets is represented by molecules that play a role in the reprogrammed cellular metabolism as one hallmark of cancer. Due to the hypoxic tumor microenvironment (TME), PDA cells display an altered glucose metabolism-resulting in its increased uptake-and a higher glycolytic rate, which leads to lactate accumulation and them acting as fuel for cancer cells. The consequent acidification of the TME results in immunosuppression, which impairs the antitumor immunity. This review analyzes the genetic background and the emerging glycolytic enzymes that are involved in tumor progression, development and metastasis, and how this represents feasible therapeutic targets to counteract PDA. In particular, as the overexpressed or mutated glycolytic enzymes stimulate both humoral and cellular immune responses, we will discuss their possible exploitation as immunological targets in anti-PDA therapeutic strategies.

Molecular and Metabolic Subtypes Correspondence for Pancreatic Ductal Adenocarcinoma Classification

Pancreatic ductal adenocarcinoma (PDAC), the most common form of pancreatic cancer, is an extremely lethal disease due to late diagnosis, aggressiveness and lack of effective therapies. Considering its intrinsic heterogeneity, patient stratification models based on transcriptomic and genomic signatures, with partially overlapping subgroups, have been established. Besides molecular alterations, PDAC tumours show a strong desmoplastic response, resulting in profound metabolic reprogramming involving increased glucose and amino acid consumption, as well as lipid scavenging and biosynthesis. Interestingly, recent works have also revealed the existence of metabolic subtypes with differential prognosis within PDAC, which correlated to defined molecular subclasses in patients: lipogenic subtype correlated with a classical/progenitor signature, while glycolytic tumours associated with the highly aggressive basal/squamous profile. Bioinformatic analyses have demonstrated that the representative genes of each metabolic subtype are up-regulated in PDAC samples and predict patient survival. This suggests a relationship between the genetic signature, metabolic profile, and aggressiveness of the tumour. Considering all this, defining metabolic subtypes represents a clear opportunity for patient stratification considering tumour functional behaviour independently of their mutational background.

Role of different immune cells and metabolic pathways in modulating the immune response in pancreatic cancer (Review)

Pancreatic cancer is an aggressive cancer, making it a leading cause of cancer‑related deaths. It is characteristically resistant to treatment, which results in low survival rates. In pancreatic cancer, immune cells undergo transitions that can inhibit or promote their functions, enabling treatment resistance and tumor progression. These transitions can be fostered by metabolic pathways that are dysregulated during tumorigenesis. The present review aimed to summarize the different immune cells and their roles in pancreatic cancer. The review also highlighted the individual metabolic pathways in pancreatic cancer and how they enable transitions in immune cells. Finally, the potential of targeting metabolic pathways for effective therapeutic strategies was considered.

Emerging Kinase Therapeutic Targets in Pancreatic Ductal Adenocarcinoma and Pancreatic Cancer Desmoplasia

Kinase drug discovery represents an active area of therapeutic research, with previous pharmaceutical success improving patient outcomes across a wide variety of human diseases. In pancreatic ductal adenocarcinoma (PDAC), innovative pharmaceutical strategies such as kinase targeting have been unable to appreciably increase patient survival. This may be due, in part, to unchecked desmoplastic reactions to pancreatic tumors. Desmoplastic stroma enhances tumor development and progression while simultaneously restricting drug delivery to the tumor cells it protects. Emerging evidence indicates that many of the pathologic fibrotic processes directly or indirectly supporting desmoplasia may be driven by targetable protein tyrosine kinases such as Fyn-related kinase (FRK); B lymphoid kinase (BLK); hemopoietic cell kinase (HCK); ABL proto-oncogene 2 kinase (ABL2); discoidin domain receptor 1 kinase (DDR1); Lck/Yes-related novel kinase (LYN); ephrin receptor A8 kinase (EPHA8); FYN proto-oncogene kinase (FYN); lymphocyte cell-specific kinase (LCK); tec protein kinase (TEC). Herein, we review literature related to these kinases and posit signaling networks, mechanisms, and biochemical relationships by which this group may contribute to PDAC tumor growth and desmoplasia.

Dietary Polyphenols in Cancer Chemoprevention: Implications in Pancreatic Cancer

Naturally occurring dietary agents present in a wide variety of plant products, are rich sources of phytochemicals possessing medicinal properties, and thus, have been used in folk medicine for ages to treat various ailments. The beneficial effects of such dietary components are frequently attributed to their anti-inflammatory and antioxidant properties, particularly in regards to their antineoplastic activities. As many tumor types exhibit greater oxidative stress levels that are implicated in favoring autonomous cell growth activation, most chemotherapeutic agents can also enhance tumoral oxidative stress levels in part via generating reactive oxygen species (ROS). While ROS-mediated imbalance of the cellular redox potential can provide novel drug targets, as a consequence, this ROS-mediated excessive damage to cellular functions, including oncogenic mutagenesis, has also been implicated in inducing chemoresistance. This remains one of the major challenges in the treatment and management of human malignancies. Antioxidant-enriched natural compounds offer one of the promising approaches in mitigating some of the underlying mechanisms involved in tumorigenesis and metastasis, and therefore, have been extensively explored in cancer chemoprevention. Among various groups of dietary phytochemicals, polyphenols have been extensively explored for their underlying chemopreventive mechanisms in other cancer models. Thus, the current review highlights the significance and mechanisms of some of the highly studied polyphenolic compounds, with greater emphasis on pancreatic cancer chemoprevention.

High glucose microenvironment accelerates tumor growth via SREBP1-autophagy axis in pancreatic cancer

Background

Diabetes is recognized to be a risk factor of pancreatic cancer, but the mechanism has not been fully elucidated. Sterol regulatory element binding protein 1 (SREBP1) is an important transcription factor involved in both lipid metabolism and tumor progression. However, the relationship between high glucose microenvironment, SREBP1 and pancreatic cancer remains to be explored.

Methods

Clinical data and surgical specimens were collected. Pancreatic cancer cell lines BxPc-3 and MiaPaCa-2 were cultured in specified medium. Immunohistochemistry (IHC) and western blotting were performed to detect the expression of SREBP1. MTT and colony formation assays were applied to investigate cell proliferation. Immunofluorescence, mRFP-GFP adenoviral vector and transmission electron microscopy were performed to evaluate autophagy. We used streptozotocin (STZ) to establish a high glucose mouse model for the in vivo study.

Results

We found that high blood glucose levels were associated with poor prognosis in pancreatic cancer patients. SREBP1 was overexpressed in both pancreatic cancer tissues and pancreatic cancer cell lines. High glucose microenvironment promoted tumor proliferation, suppressed apoptosis and inhibited autophagy level by enhancing SREBP1 expression. In addition, activation of autophagy accelerated SREBP1 expression and suppressed apoptosis. Moreover, high glucose promotes tumor growth in vivo by enhancing SREBP1 expression.

Conclusion

Our results indicate that SREBP1-autophagy axis plays a crucial role in tumor progression induced by high glucose microenvironment. SREBP1 may represent a novel target for pancreatic cancer prevention and treatment.

Genomic stratification and liquid biopsy in a rare adrenocortical carcinoma (ACC) case, with dual lung metastases

Adrenocortical carcinoma is a rare malignancy with a poor prognosis and few treatment options. Molecular characterization of this cancer remains limited. We present a case of an adrenocortical carcinoma (ACC) in a 37-yr-old female, with dual lung metastases identified 1 yr following commencement of adjuvant mitotane therapy. As standard therapeutic regimens are often unsuccessful in ACC, we undertook a comprehensive genomic study into this case to identify treatment options and monitor disease progress. We performed targeted and whole-genome sequencing of germline, primary tumor, and both metastatic tumors from this patient and monitored recurrence over 2 years using liquid biopsy for ctDNA and steroid hormone measurements. Sequencing revealed the primary and metastatic tumors were hyperhaploid, with extensive loss of heterozygosity but few structural rearrangements. Loss-of-function mutations were identified in MSH2, TP53, RB1, and PTEN, resulting in tumors with mismatch repair signatures and microsatellite instability. At the cellular level, tumors were populated by mitochondria-rich oncocytes. Longitudinal ctDNA mutation and hormone profiles were unable to detect micrometastatic disease, consistent with clinical indicators of disease remission. The molecular signatures in our ACC case suggested immunotherapy in the event of disease progression; however, the patient remains free of cancer. The extensive molecular analysis presented here could be applied to other rare and/or poorly stratified cancers to identify novel or repurpose existing therapeutic options, thereby broadly improving diagnoses, treatments, and prognoses.

Ping-Pong-Tumor and Host in Pancreatic Cancer Progression

Metastasis is the main cause of high pancreatic cancer (PaCa) mortality and trials dampening PaCa mortality rates are not satisfying. Tumor progression is driven by the crosstalk between tumor cells, predominantly cancer-initiating cells (CIC), and surrounding cells and tissues as well as distant organs, where tumor-derived extracellular vesicles (TEX) are of major importance. A strong stroma reaction, recruitment of immunosuppressive leukocytes, perineural invasion, and early spread toward the peritoneal cavity, liver, and lung are shared with several epithelial cell-derived cancer, but are most prominent in PaCa. Here, we report on the state of knowledge on the PaCIC markers Tspan8, alpha6beta4, CD44v6, CXCR4, LRP5/6, LRG5, claudin7, EpCAM, and CD133, which all, but at different steps, are engaged in the metastatic cascade, frequently via PaCIC-TEX. This includes the contribution of PaCIC markers to TEX biogenesis, targeting, and uptake. We then discuss PaCa-selective features, where feedback loops between stromal elements and tumor cells, including distorted transcription, signal transduction, and metabolic shifts, establish vicious circles. For the latter particularly pancreatic stellate cells (PSC) are responsible, furnishing PaCa to cope with poor angiogenesis-promoted hypoxia by metabolic shifts and direct nutrient transfer via vesicles. Furthermore, nerves including Schwann cells deliver a large range of tumor cell attracting factors and Schwann cells additionally support PaCa cell survival by signaling receptor binding. PSC, tumor-associated macrophages, and components of the dysplastic stroma contribute to perineural invasion with signaling pathway activation including the cholinergic system. Last, PaCa aggressiveness is strongly assisted by the immune system. Although rich in immune cells, only immunosuppressive cells and factors are recovered in proximity to tumor cells and hamper effector immune cells entering the tumor stroma. Besides a paucity of immunostimulatory factors and receptors, immunosuppressive cytokines, myeloid-derived suppressor cells, regulatory T-cells, and M2 macrophages as well as PSC actively inhibit effector cell activation. This accounts for NK cells of the non-adaptive and cytotoxic T-cells of the adaptive immune system. We anticipate further deciphering the molecular background of these recently unraveled intermingled phenomena may turn most lethal PaCa into a curatively treatable disease.

Hypoxia-inducible Factor-1α Mediates Hyperglycemia-induced Pancreatic Cancer Glycolysis

BACKGROUND

Recent studies have suggested that 85% of pancreatic cancer patients accompanied with impaired glucose tolerance or even Diabetes Mellitus (DM) and the invasive and migratory abilities of pancreatic cancer could be enhanced by high glucose. This study aimed to investigate whether Hypoxia- Inducible Factor-1α (HIF-1α) mediates hyperglycemia-induced pancreatic cancer glycolysis.

METHODS

The cellular glycolytic activity was assessed by determining lactate production, glucose uptake and lactate dehydrogenase enzymatic activity. Pancreatic cancer cells (BxPC-3 cells) were transfected with short hairpin RNA targeting the HIF-1α.

RESULTS

Hyperglycemia promotes pancreatic cancer glycolysis. Lactate dehydrogenase A (LDHA) activity and hexokinase 2 (HK2), platelet-type of phosphofructokinase (PFKP) expression were significantly upregulated under hyperglycemic conditions. HIF-1α knockdown prominently down-regulated the activity of LDHA and the expression of HK2, PFKP and decreased lactate production in BxPC-3 cells. Under hypoxia condition, hyperglycemia induced pancreatic glycolysis by mechanisms that are both dependent on HIF-1α and independent of it.

CONCLUSION

The accumulation of HIF-1α induced by hyperglycemia increases LDHA activity and HK2, PFKP expression, thereby promoting pancreatic glycolysis to facilitate cancer progression.