PARP inhibitors in pancreatic cancer: molecular mechanisms and clinical applications

Development of a Novel Protocol for Germline Testing in Pancreatic Cancer

BACKGROUND

Guidelines now recommend universal germline genetic testing (GGT) for all pancreatic ductal adenocarcinoma (PDAC) patients. Testing provides information on actionable pathogenic variants and guides management of patients and family. Since traditional genetic counseling (GC) models are time-intensive and GC resources are sparse, new approaches are needed to comply with guidelines without overwhelming available resources.

METHODS

A novel protocol was developed for physician-led GGT. Completed test kits were delivered to the GC team, who maintained a prospective database and mailed all orders. If results revealed pathogenic variants for PDAC, patients were offered comprehensive GC, whereas negative and variant of uncertain significance (VUS) test results were reported to patients via brief calls.

RESULTS

During protocol implementation between January 2020 and December 2022, 310 (81.5%) patients underwent GGT, with a physician compliance rate of 82.6% and patient compliance rate of 98.7%. Of 310 patients tested, 44 (14.2%) patients had detection of pathogenic variants, while 83 (26.8%) patients had VUS. Pathogenic variants included BRCA1/BRCA2/PALB2 (n = 18, 5.8%), ATM (n = 9, 2.9%), CFTR (n = 4, 1.3%), EPCAM/MLH1/MSH2/MSH6/PMS2 (n = 3, 1.0%), and CDKN2A (n = 2, 0.7%). The GC team successfully contacted all patients with pathogenic variants to discuss results and offer comprehensive GC.

CONCLUSION

Our novel protocol facilitated GGT with excellent compliance despite limited GC resources. This framework for GGT allocates GC resources to those patients who would benefit most from GC. As we continue to expand the program, we seek to implement methods to ensure compliance with cascade testing of high-risk family members.

Consensus, debate, and prospective on pancreatic cancer treatments

Pancreatic cancer remains one of the most aggressive solid tumors. As a systemic disease, despite the improvement of multi-modality treatment strategies, the prognosis of pancreatic cancer was not improved dramatically. For resectable or borderline resectable patients, the surgical strategy centered on improving R0 resection rate is consensus; however, the role of neoadjuvant therapy in resectable patients and the optimal neoadjuvant therapy of chemotherapy with or without radiotherapy in borderline resectable patients were debated. Postoperative adjuvant chemotherapy of gemcitabine/capecitabine or mFOLFIRINOX is recommended regardless of the margin status. Chemotherapy as the first-line treatment strategy for advanced or metastatic patients included FOLFIRINOX, gemcitabine/nab-paclitaxel, or NALIRIFOX regimens whereas 5-FU plus liposomal irinotecan was the only standard of care second-line therapy. Immunotherapy is an innovative therapy although anti-PD-1 antibody is currently the only agent approved by for MSI-H, dMMR, or TMB-high solid tumors, which represent a very small subset of pancreatic cancers. Combination strategies to increase the immunogenicity and to overcome the immunosuppressive tumor microenvironment may sensitize pancreatic cancer to immunotherapy. Targeted therapies represented by PARP and KRAS inhibitors are also under investigation, showing benefits in improving progression-free survival and objective response rate. This review discusses the current treatment modalities and highlights innovative therapies for pancreatic cancer.

Advances of immune-checkpoint inhibition of CTLA-4 in pancreatic cancer

Targeting checkpoints for immune cell activation has been acknowledged known as one of the most effective way to activate anti-tumor immune responses. Among them, drugs targeting cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) are approved for clinical treatment though several more are in advanced stages of development, which demonstrated durable response rates and manageable safety profile. However, its therapy efficacy is unsatisfactory in pancreatic cancer (PC), which can be limited by the overall condition of patients, the pathological type of PC, the expression level of tumor related genes, etc. To improve clinical efficiency, various researches have been conducted, and the efficacy of combination therapy showed significantly improvement compared to monotherapy. This review analyzed current strategies based on anti-CTLA-4 combination immunotherapy, providing totally new idea for future research.

Synergistic induction of ferroptosis by targeting HERC1-NCOA4 axis to enhance the photodynamic sensitivity of osteosarcoma

Over the past 30 years, the survival rate for osteosarcoma (OS) has remained stagnant, indicating persistent challenges in diagnosis and treatment. Photodynamic therapy (PDT) has emerged as a novel and promising treatment modality for OS. Despite apoptosis being the primary mechanism attributed to PDT, it fails to overcome issues such as low efficacy and resistance. Ferroptosis, a Fe2+-dependent cell death process, has the potential to enhance PDT's efficacy by increasing reactive oxygen species (ROS) through the Fenton reaction. In this study, we investigated the anti-tumor mechanism of PDT and introduced an innovative therapeutic strategy that synergistically induces apoptosis and ferroptosis. Furthermore, we have identified HERC1 as a pivotal protein involved in the ubiquitination and degradation of NCOA4, while also uncovering a potential regulatory factor involving NRF2. Ultimately, by targeting the HERC1-NCOA4 axis during PDT, we successfully achieved full activation of ferroptosis, which significantly enhanced the anti-tumor efficacy of PDT. In conclusion, these findings provide new theoretical evidence for further characterizing mechanism of PDT and offer new molecular targets for the treatment of OS.

Sarcomatoid carcinoma of the pancreas (Review)

Sarcomatoid carcinoma of the pancreas (SCP) is a rare and aggressive subtype of undifferentiated pancreatic ductal adenocarcinoma, with a generally poor prognosis and only sporadic cases reported worldwide. Histologically, the most notable feature of SCP is the presence of abundant of mesenchymatoid spindle tumor cells in the tumor, which lack glandular differentiation. Immunohistochemically, SCP is characterized by the expression of both mesenchymal and epithelial markers. With only a few reported cases, there is limited knowledge about its molecular and clinicopathological characteristics. Therefore, the present study performed a literature search to identify all relevant published studies. The present review provides an overview of the histogenesis, diagnosis, genetic features, prognosis and treatment of SCP, specifically focusing on the molecular alterations. Furthermore, a single-center experience is reported, which adds to the limited evidence available in the literature.

Molecular mechanism of PARP inhibitor resistance

Poly (ADP-ribose) polymerases (PARP) inhibitors (PARPi) are the first-approved anticancer drug designed to exploit synthetic lethality. PARPi selectively kill cancer cells with homologous recombination repair deficiency (HRD), as a result, PARPi are widely employed to treated BRCA1/2-mutant ovarian, breast, pancreatic and prostate cancers. Currently, four PARPi including Olaparib, Rucaparib, Niraparib, and Talazoparib have been developed and greatly improved clinical outcomes in cancer patients. However, accumulating evidences suggest that required or de novo resistance emerged. In this review, we discuss the molecular mechanisms leading to PARPi resistances and review the potential strategies to overcome PARPi resistance.

Veliparib exerts protective effects in intracerebral hemorrhage mice by inhibiting the inflammatory response and accelerating hematoma resolution

Poly (ADP-ribose) polymerase (PARP) inhibitors have potent anti-inflammatory effects, including the suppression of brain microglial activation. Veliparib, a well-known PARP1/2 inhibitor, exhibits particularly high brain penetration, but its effects on stroke outcome is unknown. Here, the effects of veliparib on the short-term outcome of intracerebral hemorrhage (ICH), the most lethal type of stroke, were investigated. Collagenase-induced mice ICH model was applied, and the T2-weighted magnetic resonance imaging was performed to evaluate lesion volume. Motor function and hematoma volume were also measured. We further performed immunofluorescence, enzyme linked immunosorbent assay, flow cytometry, and blood-brain barrier assessment to explore the potential mechanisms. Our results demonstrated veliparib reduced the ICH lesion volume dose-dependently and at a dosage of 5 mg/kg, veliparib significantly improved mouse motor function and promoted hematoma resolution at days 3 and 7 post-ICH. Veliparib inhibited glial activation and downregulated the production of pro-inflammatory cytokines. Veliparib significantly decreased microglia counts and inhibited peripheral immune cell infiltration into the brain on day 3 after ICH. Veliparib improved blood-brain barrier integrity at day 3 after ICH. These findings demonstrate that veliparib improves ICH outcome by inhibiting inflammatory responses and may represent a promising novel therapy for ICH.

Unveiling the resistance to therapies in pancreatic ductal adenocarcinoma

Despite the ongoing advances in interventional strategies (surgery, chemotherapy, radiotherapy, and immunotherapy) for managing pancreatic ductal adenocarcinoma (PDAC), the development of therapy refractory phenotypes remains a significant challenge. Resistance to various therapeutic modalities in PDAC emanates from a combination of inherent and acquired factors and is attributable to cancer cell-intrinsic and -extrinsic mechanisms. The critical determinants of therapy resistance include oncogenic signaling and epigenetic modifications that drive cancer cell stemness and metabolic adaptations, CAF-mediated stromagenesis that results in ECM deposition altered mechanotransduction, and secretome and immune evasion. We reviewed the current understanding of these multifaceted mechanisms operating in the PDAC microenvironment, influencing the response to chemotherapy, radiotherapy, and immunotherapy regimens. We then describe how the lessons learned from these studies can guide us to discover novel therapeutic regimens to prevent, delay, or revert resistance and achieve durable clinical responses.

Repurposing existing drugs for the treatment ofCOVID-19/SARS-CoV-2: A review of pharmacological effects and mechanism of action

Following the coronavirus disease-2019 outbreak caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), there is an ongoing need to seek drugs that target COVID-19. First off, novel drugs have a long development cycle, high investment cost, and are high risk. Second, novel drugs must be evaluated for activity, efficacy, safety, and metabolic performance, contributing to the development cycle, investment cost, and risk. We searched the Cochrane COVID-19 Study Register (including PubMed, Embase, CENTRAL, ClinicalTrials.gov, WHO ICTRP, and medRxiv), Web of Science (Science Citation Index, Emerging Citation Index), and WHO COVID-19 Coronaviral Disease Global Literature to identify completed and ongoing studies as of February 20, 2024. We evaluated the pharmacological effects, in vivo and in vitro data of the 16 candidates in the paper. The difficulty of studying these candidates in clinical trials involving COVID-19 patients, dosage of repurposed drugs, etc. is discussed in detail. Ultimately, Metformin is more suitable for prophylactic administration or mildly ill patients; the combination of Oseltamivir, Tamoxifen, and Dexamethasone is suitable for moderately and severely ill patients; and more clinical trials are needed for Azvudine, Ribavirin, Colchicine, and Cepharanthine to demonstrate efficacy.

NLRP4 renders pancreatic cancer resistant to olaparib through promotion of the DNA damage response and ROS-induced autophagy

Olaparib has been approved as a therapeutic option for metastatic pancreatic ductal adenocarcinoma patients with BRCA1/2 mutations. However, a significant majority of pancreatic cancer patients have inherent resistance or develop tolerance to olaparib. It is crucial to comprehend the molecular mechanism underlying olaparib resistance to facilitate the development of targeted therapies for pancreatic cancer. In this study, we conducted an analysis of the DepMap database to investigate gene expression variations associated with olaparib sensitivity. Our findings revealed that NLRP4 upregulation contributes to increased resistance to olaparib in pancreatic cancer cells, both in vitro and in vivo. RNA sequencing and Co-IP MS analysis revealed that NLRP4 is involved in the DNA damage response and autophagy pathway. Our findings confirmed that NLRP4 enhances the capacity for DNA repair and induces the production of significant levels of reactive oxygen species (ROS) and autophagy in response to treatment with olaparib. Specifically, NLRP4-generated mitochondrial ROS promote autophagy in pancreatic cancer cells upon exposure to olaparib. However, NLRP4-induced ROS do not affect DNA damage. The inhibition of mitochondrial ROS using MitoQ and autophagy using chloroquine (CQ) may render cells more susceptible to the effects of olaparib. Taken together, our findings highlight the significant roles played by NLRP4 in the processes of autophagy and DNA repair when pancreatic cancer cells are treated with olaparib, thereby suggesting the potential therapeutic utility of olaparib in pancreatic cancer patients with low NLRP4 expression.

The recent advance and prospect of poly(ADP-ribose) polymerase inhibitors for the treatment of cancer

Chemotherapies are commonly used in cancer therapy, their applications are limited to low specificity, severe adverse reactions, and long-term medication-induced drug resistance. Poly(ADP-ribose) polymerase (PARP) inhibitors are a novel class of antitumor drugs developed to solve these intractable problems based on the mechanism of DNA damage repair, which have been widely applied in the treatment of ovarian cancer, breast cancer, and other cancers through inducing synthetic lethal effect and trapping PARP-DNA complex in BRCA gene mutated cancer cells. In recent years, PARP inhibitors have been widely used in combination with various first-line chemotherapy drugs, targeted drugs and immune checkpoint inhibitors to expand the scope of clinical application. However, the intricate mechanisms underlying the drug resistance to PARP inhibitors, including the restoration of homologous recombination, stabilization of DNA replication forks, overexpression of drug efflux protein, and epigenetic modifications pose great challenges and desirability in the development of novel PARP inhibitors. In this review, we will focus on the mechanism, structure-activity relationship, and multidrug resistance associated with the representative PARP inhibitors. Furthermore, we aim to provide insights into the development prospects and emerging trends to offer guidance for the clinical application and inspiration for the development of novel PARP inhibitors and degraders.

Methylation synthetic lethality: Exploiting selective drug targets for cancer therapy

In cancer, synthetic lethality refers to the drug-induced inactivation of one gene and the inhibition of another in cancer cells by a drug, resulting in the death of only cancer cells; however, this effect is not present in normal cells, leading to targeted killing of cancer cells. Recent intensive epigenetic research has revealed that aberrant epigenetic changes are more frequently observed than gene mutations in certain cancers. Recently, numerous studies have reported various methylation synthetic lethal combinations involving DNA damage repair genes, metabolic pathway genes, and paralogs with significant results in cellular models, some of which have already entered clinical trials with promising results. This review systematically introduces the advantages of methylation synthetic lethality and describes the lethal mechanisms of methylation synthetic lethal combinations that have recently demonstrated success in cellular models. Furthermore, we discuss the future opportunities and challenges of methylation synthetic lethality in targeted anticancer therapies.

Effect of Ferulic Acid Loaded in Nanoparticle on Tissue Transglutaminase Expression Levels in Human Glioblastoma Cell Line

Glioblastoma (GBM) is one of the most aggressive cancers, characterized by a decrease in antioxidant levels. Evidence has demonstrated that ferulic acid (FA), a natural antioxidant particularly abundant in vegetables and fruits, could be a promising candidate for GBM treatment. Since FA shows a high instability that compromises its therapeutic application, it has been encapsulated into Nanostructured Lipid Carriers (NLCs) to improve its bioavailability in the brain. It has been demonstrated that tissue transglutaminase (TG2) is a multi-functional protein implicated in many physiological and pathological processes, including cancer. TG2 is also involved in GBM correlated with metastasis formation and drug resistance. Therefore, the evaluation of TG2 expression levels and its cellular localization are important to assess the anti-cancer effect of FA against GBM cancer. Our results have demonstrated that treatment with free FA and FA-NLCs in the U87-MG cancer cell line differently modified TG2 localization and expression levels. In the cells treated with free FA, TG2 appeared expressed both in the cytosol and in the nucleus, while the treatment with FA-NLCs showed that the protein is exclusively localized in the cytosol, exerting its pro-apoptotic effect. Therefore, our data suggest that FA loaded in NLCs could represent a promising natural agent for supplementing the current anti-cancer drugs used for the treatment of GBM.

New Horizons of Synthetic Lethality in Cancer: Current Development and Future Perspectives

In recent years, synthetic lethality has been recognized as a solid paradigm for anticancer therapies. The discovery of a growing number of synthetic lethal targets has led to a significant expansion in the use of synthetic lethality, far beyond poly(ADP-ribose) polymerase inhibitors used to treat BRCA1/2-defective tumors. In particular, molecular targets within DNA damage response have provided a source of inhibitors that have rapidly reached clinical trials. This Perspective focuses on the most recent progress in synthetic lethal targets and their inhibitors, within and beyond the DNA damage response, describing their design and associated therapeutic strategies. We will conclude by discussing the current challenges and new opportunities for this promising field of research, to stimulate discussion in the medicinal chemistry community, allowing the investigation of synthetic lethality to reach its full potential.

Unraveling the role of Major Vault Protein as a novel immune-related biomarker that promotes the proliferation and migration in pancreatic adenocarcinoma

Background

Pancreatic adenocarcinoma (PAAD) is a formidable challenge in oncology research, with a complex pathogenesis that requires to be explored. Major Vault Protein (MVP) is the principal structural component of the vault complex, and its expression level is remarkably upregulated in various cancers. Extensive investigations have been conducted to explore the role of MVP in specific cancer contexts, yet the potential molecular mechanisms and biological functions of MVP in PAAD still remain considerably elusive. This study aims to explore the role of MVP as a novel immune-related biomarker in the pathogenesis and clinical treatment of PAAD.

Methods

Gene expression data and clinical information were collected from TCGA, GTEx and GEO databases. Survival, prognostic and functional enrichment analysis were employed with R software. Immunological correlation analysis was performed using TIMER2.0, TIDE scores, TISIDB and TISCH. Epigenetic analysis was implemented by MethSurv, CPTAC, UALCAN, and cBioPortal. Drug analysis was conducted using Enrichr and CellMiner. Moreover, cellular experiments, like RNA interference, qRT-PCR, Western blot, cell cycle analysis, cell apoptosis analysis, colony formation assay, transwell assay, and wound healing assay, were performed for verifying the functional properties of MVP in the PAAD progression.

Results

We demonstrated an abnormally upregulated expression of MVP in PAAD tissues, which notably correlated with an adverse prognosis in PAAD patients. Functional analysis suggested the conceivable involvement of MVP in immune modulation, and immunotherapy. Additionally, we identified genetic alterations, reduced promoter methylation, and heightened phosphorylation in MVP. We also clarified Suloctidil and Tetradioxin as the most notable potential drugs targeting MVP in PAAD. Moreover, our experimental observations consistently highlighted the significant impact of MVP deficiency on impeding PAAD cell proliferation, inhibiting cell migration, and accelerating cell apoptosis. Interestingly, a potential link between MVP and ERK or AKT pathways was displayed, which opens new avenues for further exploration of the molecular mechanisms of MVP-targeted therapies in PAAD.

Conclusions

This study systematically describes MVP as an immune-related biomarker with remarkable potential for predicting the prognosis, tumor progression and immunotherapeutic efficacy in PAAD.

Transcription factor FOXF2 promotes the development and progression of pancreatic cancer by targeting MSI2

Pancreatic cancer (PC) is a malignant tumor possessing high mortality. The role of transcription factor Forkhead Box F2 (FOXF2) in PC remains unverified. The current study investigated the roles of FOXF2 in developing PC in vitro and in vivo. A xenograft tumor model was constructed with nude mice injected using FOXF2‑overexpressing PC cells or FOXF2‑silenced PC cells. High FOXF2 expression significantly enhanced the proliferation ability of PC cells in vitro and pancreatic tumor growth in vivo. The cell cycle analysis indicated that transition of G1‑S phase was promoted by FOXF2. The cell cycle‑associated proteins cyclin D1, CDK2, phosphorylated (p)‑CDK2 and p‑RB were upregulated in the FOXF2‑overexpressing cells and downregulated in the cells with FOXF2 knockdown. Flow cytometric analysis and Hoechst staining showed that the percentage of apoptotic cells was significantly increased after FOXF2 was silenced. FOXF2 knockdown promoted expression of pro‑apoptotic proteins (Bad, Bax and cleaved caspase‑3) while suppressing the anti‑apoptotic proteins (Bcl‑2 and Bcl‑xl) at the protein level. FOXF2 improved the migration and invasion of PC cells in vitro. Moreover, luciferase and chromatin immunoprecipitation assays revealed that FOXF2 binds to the MSI2 promoter, promoting its transcriptional expression. FOXF2 knockdown inhibited the MSI2 protein translation while enhancing the translation of NUMB protein, suppressing PC development in vivo. MSI2 silencing reversed the promotive effect mediated by FOXF2 on cell proliferation. These results demonstrated that FOXF2 is essential in PC progression, and the potential mechanism includes regulating MSI2 transcription.

Network-driven cancer cell avatars for combination discovery and biomarker identification for DNA damage response inhibitors

Combination therapy is well established as a key intervention strategy for cancer treatment, with the potential to overcome monotherapy resistance and deliver a more durable efficacy. However, given the scale of unexplored potential target space and the resulting combinatorial explosion, identifying efficacious drug combinations is a critical unmet need that is still evolving. In this paper, we demonstrate a network biology-driven, simulation-based solution, the Simulated Cell™. Integration of omics data with a curated signaling network enables the accurate and interpretable prediction of 66,348 combination-cell line pairs obtained from a large-scale combinatorial drug sensitivity screen of 684 combinations across 97 cancer cell lines (BAC = 0.62, AUC = 0.7). We highlight drug combination pairs that interact with DNA Damage Response pathways and are predicted to be synergistic, and deep network insight to identify biomarkers driving combination synergy. We demonstrate that the cancer cell 'avatars' capture the biological complexity of their in vitro counterparts, enabling the identification of pathway-level mechanisms of combination benefit to guide clinical translatability.

PARP inhibitor synthetic lethality in ATM biallelic mutant cancer cell lines is associated with BRCA1/2 and RAD51 downregulation

Background

Ataxia telangiectasia-mutated (ATM) kinase is a central regulator of the DNA damage response (DDR) signaling pathway, and its function is critical for the maintenance of genomic stability in cells that coordinate a network of cellular processes, including DNA replication, DNA repair, and cell cycle progression. ATM is frequently mutated in human cancers, and approximately 3% of lung cancers have biallelic mutations in ATM, i.e., including 3.5% of lung adenocarcinomas (LUAD) and 1.4% of lung squamous cell carcinomas (LUSC).

Methods

We investigated the potential of targeting the DDR pathway in lung cancer as a potential therapeutic approach. In this context, we examined whether ATM loss is synthetically lethal with niraparib monotherapy. This exploration involved the use of hATM knockout (KO) isogenic cell lines containing hATM homozygous (-/-) and heterozygous (+/-) generated via CRISPR/Cas9 gene knockout technology in DLD-1, a human colorectal adenocarcinoma cell line. Subsequently, we extended our investigation to non-small cell lung cancer (NSCLC) patient derived xenograft (PDX) models for further validation of poly ADP-ribose polymerase inhibitor (PARPi) synthetic lethality in ATM mutant NSCLC models.

Results

Here, we demonstared that biallelic hATM deletion (-/-) in DLD-1 impairs homologous recombination (HR) repair function and sensitizes cells to the PARPi, niraparib. Niraparib also caused significant tumor regression in one-third of the NSCLC PDX models harboring deleterious biallelic ATM mutations. Loss of hATM (-/-) was concomitantly associated with low BRCA1 and BRCA2 protein expression in both the hATM (-/-) DLD-1 cell line and PARPi-sensitive ATM mutant NSCLC PDX models, suggesting a downstream effect on the impairment of HR-mediated DNA checkpoint signaling. Further analysis revealed that loss of ATM led to inhibition of phosphorylation of MRN (Mre11-Rad50-NBS1) complex proteins, which are required for ATM-mediated downstream phosphorylation of p53, BRCA1, and CHK2.

Conclusions

Taken together, our findings highlight that the synthetic lethality of niraparib in ATM-deficient tumors can be regulated through a subsequent effect on the modulation of BRCA1/2 expression and its effect on HR function.

Corosolic acid delivered by exosomes from Eriobotrya japonica decreased pancreatic cancer cell proliferation and invasion by inducing SAT1-mediated ferroptosis

BACKGROUND

In this study, we investigated whether Exo regulate the proliferation and invasion of PC.

METHODS

In this study, we isolated the Eriobotrya japonica Exo using Ultra-high speed centrifugal method. Mass spectrum were used for Exo active components analysis. PC (Capan-1 and Bxpc-3) cells proliferation, migration, and apoptosis were detected using CCK8, ethynyldeoxyuridine, transwell, wound healing, and flow cytometry analyses. We also constructed a lung metastatic mouse model and subcutaneous tumor model to illustrate the regulation effect of Exo or active components. Proteomics were used to reveal the regulatory mechanism responsible for the observed effects.

RESULTS

We isolated Eriobotrya japonica Exo and found that Exo treatment significantly suppressed cell migration and proliferation in both in vivo and in vitro using Capan-1. Mass spectrum for Exo active components analysis found that Exo contains high amounts of corosolic acid (CRA). The further study found that CRA treatment inhibit the proliferation, migration, and increased cell death of both Capan-1 and Bxpc-3 cells in a concentration-dependent manner. In vivo experiments confirmed that CRA inhibited pulmonary metastasis by decreasing the number of metastatic foci. Cell proteomics analysis showed that CRA treatment induced spermidine/spermine N1-acetyltransferase 1 (SAT1)-dependent ferroptosis. Treatment with the ferroptosis suppressor ferrostatin-1 significantly reversed CRA-induced cell apoptosis.

CONCLUSION

The data suggested that corosolic acid delivered by exosomes from Eriobotrya japonica decreased pancreatic cancer cell proliferation and invasion by inducing SAT1-mediated ferroptosis.

Chemical Composition, Pharmacological Effects and Clinical Applications of Cinobufacini

Chinese medicine cinobufacini is an extract from the dried skin of Bufo bufo gargarizans Cantor, with active ingredients of bufadienolides and indole alkaloids. With further research and clinical applications, it is found that cinobufacini alone or in combination with other therapeutic methods can play an anti-tumor role by controlling proliferation of tumor cells, promoting apoptosis, inhibiting formation of tumor neovascularization, reversing multidrug resistance, and regulating immune response; it also has the functions of relieving cancer pain and regulating immune function. In this paper, the chemical composition, pharmacological effects, clinical applications, and adverse reactions of cinobufacini are summarized. However, the extraction of monomer components of cinobufacini, the relationship between different mechanisms, and the causes of adverse reactions need to be further studied. Also, high-quality clinical studies should be conducted.

Genetic Signature of Human Pancreatic Cancer and Personalized Targeting

Pancreatic cancer is a highly lethal disease with a 5-year survival rate of around 11-12%. Surgery, being the treatment of choice, is only possible in 20% of symptomatic patients. The main reason is that when it becomes symptomatic, IT IS the tumor is usually locally advanced and/or has metastasized to distant organs; thus, early diagnosis is infrequent. The lack of specific early symptoms is an important cause of late diagnosis. Unfortunately, diagnostic tumor markers become positive at a late stage, and there is a lack of early-stage markers. Surgical and non-surgical cases are treated with neoadjuvant and/or adjuvant chemotherapy, and the results are usually poor. However, personalized targeted therapy directed against tumor drivers may improve this situation. Until recently, many pancreatic tumor driver genes/proteins were considered untargetable. Chemical and physical characteristics of mutated KRAS are a formidable challenge to overcome. This situation is slowly changing. For the first time, there are candidate drugs that can target the main driver gene of pancreatic cancer: KRAS. Indeed, KRAS inhibition has been clinically achieved in lung cancer and, at the pre-clinical level, in pancreatic cancer as well. This will probably change the very poor outlook for this disease. This paper reviews the genetic characteristics of sporadic and hereditary predisposition to pancreatic cancer and the possibilities of a personalized treatment according to the genetic signature.

HJURP is recruited to double-strand break sites and facilitates DNA repair by promoting chromatin reorganization

HJURP is overexpressed in several cancer types and strongly correlates with patient survival. However, the mechanistic basis underlying the association of HJURP with cancer aggressiveness is not well understood. HJURP promotes the loading of the histone H3 variant, CENP-A, at the centromeric chromatin, epigenetically defining the centromeres and supporting proper chromosome segregation. In addition, HJURP is associated with DNA repair but its function in this process is still scarcely explored. Here, we demonstrate that HJURP is recruited to DSBs through a mechanism requiring chromatin PARylation and promotes epigenetic alterations that favor the execution of DNA repair. Incorporation of HJURP at DSBs promotes turnover of H3K9me3 and HP1, facilitating DNA damage signaling and DSB repair. Moreover, HJURP overexpression in glioma cell lines also affected global structure of heterochromatin independently of DNA damage induction, promoting genome-wide reorganization and assisting DNA damage response. HJURP overexpression therefore extensively alters DNA damage signaling and DSB repair, and also increases radioresistance of glioma cells. Importantly, HJURP expression levels in tumors are also associated with poor response of patients to radiation. Thus, our results enlarge the understanding of HJURP involvement in DNA repair and highlight it as a promising target for the development of adjuvant therapies that sensitize tumor cells to irradiation.

Novel Carrier-Free Nanodrug Enhances Photodynamic Effects by Blocking the Autophagy Pathway and Synergistically Triggers Immunogenic Cell Death for the Efficient Treatment of Breast Cancer

Photosensitizers have been widely used to cause intratumoral generation of reactive oxygen species (ROS) for cancer therapy, but they are easily disturbed by the autophagy pathway, a self-protective mechanism by mitigating oxidative damage. Hereby, we reported a simple and effective strategy to construct a carrier-free nanodrug, Ce6@CQ namely, based on the self-assembly of the photosensitizer chlorin e6 (Ce6) and the autophagy inhibitor chloroquine (CQ). Specifically, Ce6@CQ avoided the unexpected toxicity caused by the regular nanocarrier and also ameliorated its stability in different conditions. Light-activated Ce6 generated cytotoxic ROS and elicited part of the immunogenic cell death (ICD). Moreover, CQ induced autophagy dysfunction, which hindered self-healing in tumor cells and enhanced photodynamic therapy (PDT) to exert a more potent killing effect and more efficient ICD. Also, Ce6@CQ could effectively accumulate in the xenograft breast tumor site in a mouse model through the enhanced permeability and retention (EPR) effect, and the growth of breast tumors was effectively inhibited by Ce6@CQ with light. Such a carrier-free nanodrug provided a new strategy to improve the efficacy of PDT via the suppression of autophagy to digest ROS-induced toxic substances.

ADP-ribosylation: An emerging direction for disease treatment

ADP-ribosylation (ADPr) is a dynamically reversible post-translational modification (PTM) driven primarily by ADP-ribosyltransferases (ADPRTs or ARTs), which have ADP-ribosyl transfer activity. ADPr modification is involved in signaling pathways, DNA damage repair, metabolism, immunity, and inflammation. In recent years, several studies have revealed that new targets or treatments for tumors, cardiovascular diseases, neuromuscular diseases and infectious diseases can be explored by regulating ADPr. Here, we review the recent research progress on ART-mediated ADP-ribosylation and the latest findings in the diagnosis and treatment of related diseases.

Therapeutic evolution in HR+/HER2- breast cancer: from targeted therapy to endocrine therapy

Breast cancer, a complex and varied disease, has four distinct subtypes based on estrogen receptor and human epidermal growth factor receptor 2 (HER2) levels, among which a significant subtype known as HR+/HER2-breast cancer that has spurred numerous research. The prevalence of breast cancer and breast cancer-related death are the most serious threats to women's health worldwide. Current progress in treatment strategies for HR+/HER2-breast cancer encompasses targeted therapy, endocrine therapy, genomic immunotherapy, and supplementing traditional methods like surgical resection and radiotherapy. This review article summarizes the current epidemiology of HR+/HER2-breast cancer, introduces the classification of HR+/HER2-breast cancer and the commonly used treatment methods. The mechanisms of action of various drugs, including targeted therapy drugs and endocrine hormone therapy drugs, and their potential synergistic effects are deeply discussed. In addition, clinical trials of these drugs that have been completed or are still in progress are included.

Combined Therapy of Chemotherapy and Radiofrequency Ablation for Pancreatic Cancer Patients With Metachronous Hepatic Metastatic Lesions After Radical Pancreatic Resection

PURPOSE

Hepatic metastasis frequently occurs in patients who have undergone radical pancreatic resection for pancreatic cancer. Besides chemotherapy, various local treatment approaches targeting hepatic lesions have been explored. However, research on radiofrequency ablation (RFA) as a localized therapy for hepatic metastasis is limited. Therefore, we conducted this retrospective study to provide clinical evidence.

METHODS

This is a single-center, retrospective, cohort study. After radical pancreaticoduodenectomy, 32 patients developed metachronous hepatic metastasis with fewer than 3 lesions, the largest of which was less than 3 cm in diameter. These patients underwent combined treatment with chemotherapy and RFA. After 8 weeks of chemotherapy, patients received RFA for hepatic lesions. Additional chemotherapy was administered, and the patients' tumor status and survival were monitored. The primary endpoint of this study was overall survival (OS). Factors affecting OS were analyzed using the Cox risk model.

RESULTS

Among the 32 patients, the mean OS was 28.4 months. Univariate and multivariate Cox regression analysis revealed that the time (in months) of liver metastasis (HR = 0.04, 95% CI: 0.01 to 0.19; P < 0.001), the number of liver metastases (HR = 7.08, 95% CI: 1.85 to 27.08, P = 0.004), and PD (progressive disease) response to the second round of chemotherapy (HR = 29.50, 95% CI: 1.46 to 597.27; P = 0.027) were independent predictors of poorer survival.

CONCLUSION

Combined therapy with RFA and chemotherapy is safe in patients with hepatic metastasis after radical pancreaticoduodenectomy. Early recurrence (≤12 months), three liver metastatic lesions, and a poor response to the second round of chemotherapy were associated with poor survival.

An overview of up-and-coming immune checkpoint inhibitors for pancreatic cancer

INTRODUCTION

Immune checkpoint inhibitors (ICIs) targeting programmed cell death protein-1 (PD-1/PD-L1) pathway as well as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) have demonstrated substantial potential in several malignancies. Pancreatic adenocarcinoma (PC) still carries a high mortality despite tremendous advances in the anti-cancer arsenal.

AREAS COVERED

In this review, we discuss completed and ongoing studies on various ICIs in PC. ICIs have not yielded significant benefits as monotherapy. However, the combination with currently utilized therapies as well as with several other newer forms of therapy has delineated encouraging results. Larger trials are currently underway to definitively characterize the utility of ICIs in the treatment algorithm of PC. ICIs are approved for cancers with mismatch repair deficiency (dMMR) or microsatellite instability-high tumors (MSI-H) as a tumor-agnostic treatment strategy usually referred to as hot tumors.

EXPERT OPINION

Studies evaluating different drugs to transform the tumor microenvironment (TME) from 'cold' to 'hot' have not shown promise in PC. There still needs to be more prospective trials evaluating the efficacy of the combination of ICIs with different therapeutic modalities in PC that can augment the immunogenic potential of those 'cold' tumors. Exploratory biomarker analysis may help us identify those subsets of PC patients who may particularly benefit from ICIs.

Hypereosinophilia as a presenting sign of advanced pancreatic adenocarcinoma: a rare, severe presentation

Pancreatic adenocarcinoma (PA) is the third most lethal malignancy worldwide with only a 7.7% 5-year survival rate. Prognosis is poor with more than 50% of patients presenting with stage IV disease. Despite focused attention on early detection and treatment, pathogenesis and early symptomatology are not well described. In addition to prodromal symptoms, hypereosinophilia has been identified as a marker of malignancy in both PA and other solid tumour and haematological malignancies. Peripheral hypereosinophilia (PH) secondary to solid organ tumours, however, is rare, with only four cases of PA reported to date. We present a case of advanced PA with associated severe PH in a man in his early 50s. Time from diagnosis to death in this patient was only 6 weeks, emphasising the need to consider malignancy in the differential diagnosis for a patient that presents with a severe PH of unknown origin.

Current and future directions of USP7 interactome in cancer study

The ubiquitin-proteasome system (UPS) is an essential protein quality controller for regulating protein homeostasis and autophagy. Ubiquitination is a protein modification process that involves the binding of one or more ubiquitins to substrates through a series of enzymatic processes. These include ubiquitin-activating enzymes (E1), ubiquitin-conjugating enzymes (E2), and ubiquitin ligases (E3). Conversely, deubiquitination is a reverse process that removes ubiquitin from substrates via deubiquitinating enzymes (DUBs). Dysregulation of ubiquitination-related enzymes can lead to various human diseases, including cancer, through the modulation of protein ubiquitination. The most structurally and functionally studied DUB is the ubiquitin-specific protease 7 (USP7). Both the TRAF and UBL domains of USP7 are known to bind to the [P/A/E]-X-X-S or K-X-X-X-K motif of substrates. USP7 has been shown to be involved in cancer pathogenesis by binding with numerous substrates. Recently, a novel substrate of USP7 was discovered through a systemic analysis of its binding motif. This review summarizes the currently discovered substrates and cellular functions of USP7 in cancer and suggests putative substrates of USP7 through a comprehensive systemic analysis.

Evaluation of the liver targeting and anti‑liver cancer activity of artesunate‑loaded and glycyrrhetinic acid‑coated nanoparticles

Globally, liver cancer ranks among the most lethal cancers, with chemotherapy being one of its primary treatments. However, poor selectivity, systemic toxicity, a narrow treatment window, low response rate and multidrug resistance limit its clinical application. Liver-targeted nanoparticles (NPs) exhibit excellent targeted delivery ability and promising effectivity in treating liver cancer. The present study aimed to investigate the liver-targeting and anti-liver cancer effect of artesunate (ART)-loaded and glycyrrhetinic acid (GA)-decorated polyethylene glycol (PEG)-poly (lactic-co-glycolic acid) (PLGA) (ART/GA-PEG-PLGA) NPs. GA-coated NPs significantly increased hepatoma-targeted cellular uptake, with micropinocytosis and caveolae-mediated endocytosis as its chief internalization pathways. Moreover, ART/GA-PEG-PLGA NPs exhibited pro-apoptotic effects on HepG2 cells, mainly via the induction of a high level of reactive oxygen species, decline in mitochondrial membrane potential and induction of cell cycle arrest. Additionally, ART/GA-PEG-PLGA NPs induced internal apoptosis pathways by upregulating the activity of cleaved caspase-3/7 and expression of cleaved poly (ADP-Ribose)-polymerase and Phos-p38 mitogen-activated protein kinase in HepG2 cells. Furthermore, ART/GA-PEG-PLGA NPs exhibited higher liver accumulation and longer mean retention time, resulting in increased bioavailability. Finally, ART/GA-PEG-PLGA NPs promoted the liver-targeting distribution of ART, increased the retention time and promoted its antitumour effects in vivo. Therefore, ART/GA-PEG-PLGA NPs afforded excellent hepatoma-targeted delivery and anti-liver cancer efficacy, and thus, they may be a promising strategy for treating liver cancer.

CRISPR/Cas9-mediated knock-in of BRCA1/2 mutations restores response to olaparib in pancreatic cancer cell lines

Pancreatic cancer is one of the most aggressive diseases with a very poor outcome. Olaparib, a PARP inhibitor, as maintenance therapy showed benefits in patients with metastatic pancreatic adenocarcinoma bearing germline BRCA1/2 mutations. However, germline BRCA mutation has been described in only 4-7% of patients with pancreatic adenocarcinoma. A CRISPR/Cas9-mediated system was used to knock-in the c.763G > T p.(Glu255*) and c.2133C > A p.(Cys711*) mutations in cell lines to obtain truncated BRCA1 and BRCA2 proteins, respectively. A CRISPR/Cas9 ribonucleoprotein complex was assembled for each mutation and transfected into two pancreatic cell lines (T3M4 and Capan-2) and into a breast cancer cell lines (MCF7) as control. BRCA protein levels were significantly decreased in all BRCA-depleted cells (P < 0.05), proving the transfection efficiency of our CRISPR/Cas9 systems. As expected, the calculated olaparib IC50 were significantly reduced for all cell lines harbored BRCA1 or BRCA2 mutations compared to wild-type BRCA1/2 cells (P < 0.01). Furthermore, we observed a higher induction of apoptosis after 72 h olaparib treatment in BRCA-depleted cells than in wild-type cells. This strategy might offer new insights into the management of patients with pancreatic cancer and open up new perspectives based on the in vivo use of CRISPR/Cas9 strategy.

Src is a target molecule of mannose against pancreatic cancer cells growth in vitro & in vivo

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant cancer with limited treatment options. Mannose, a common monosaccharide taken up by cells through the same transporters as glucose, has been shown to induce growth retardation and enhance cell death in response to chemotherapy in several cancers, including PDAC. However, the molecular targets and mechanisms underlying mannose's action against PDAC are not well understood. In this study, we used an integrative approach of network pharmacology, bioinformatics analysis, and experimental verification to investigate the pharmacological targets and mechanisms of mannose against PDAC. Our results showed that the protein Src is a key target of mannose in PDAC. Additionally, computational analysis revealed that mannose is a highly soluble compound that meets Lipinski's rule of five and that the expression of its target molecules is correlated with survival rates and prognosis in PDAC patients. Finally, we validated our findings through in vitro and in vivo experiments. In conclusion, our study provides evidence that mannose plays a critical role in inhibiting PDAC growth by targeting Src, suggesting that it may be a promising therapeutic candidate for PDAC.

Efficacy of poly (ADP-ribose) polymerase inhibitors monotherapy and the impact to subsequent platinum-based chemotherapy in breast cancer susceptibility genes1/2-mutated ovarian cancer patients with secondary platinum-sensitive relapse

BACKGROUND

The therapeutic effect of poly (ADP-ribose) polymerase inhibitors (PARPi) monotherapy compared with platinum-based chemotherapy, and the impact to subsequent platinum-based chemotherapy after PARPi resistance were inconclusive in breast cancer susceptibility genes (BRCA)1/2-mutated ovarian cancer patients with secondary platinum-sensitive relapse.

METHODS

BRCA1/2-mutated patients with secondary platinum-sensitive relapse included in this study did not receive any maintenance regimen after first- and second-line platinum-based chemotherapy, and the secondary platinum-free interval (PFI) was more than 6 months. Patients in study group were treated with PARPi monotherapy until disease progression, and patients in control group were treated with platinum-based chemotherapy without restriction. Progression-free survival (PFS) was defined as the time from third-line therapy to disease progression or death, PFS2 was defined as the time from platinum-based chemotherapy after PARPi resistance to next subsequent therapy or death. Post-recurrence survival (PRS) refers to the survival time after secondary platinum-sensitive relapse.

RESULTS

A total of 119 patients were retrospectively analyzed, including 71 (59.7%) in study group and 48 (40.3%) in control group. The objective response rate (ORR: 77.5% vs. 80.0%, p=0.766) and PFS (median: 11.2 vs. 11.0 months, p=0.962) were comparable. The benefit of subsequent platinum-based chemotherapy after PARPi resistance was more pronounced in patients with PARPi treatment for more than 12 months (median PFS2: 8.6 vs. 4.3 months, p=0.040). PARPi monotherapy had no adverse effect on PRS compared with platinum-based chemotherapy (median PRS:41.2 vs. 42.8 months, p=0.323). Compared to patients in control group who had never received PARPi, PARPi monotherapy (median PRS: 41.2 vs. 33.7 months, p=0.019) and post-line treatment with PARPi in the control group (median PRS: 48.1 vs. 33.7 months, p=0.002) could prolong PRS for patients with secondary platinum-sensitive relapse.

CONCLUSIONS

PARPi monotherapy was similar to platinum-based chemotherapy for BRCA1/2-mutated ovarian cancer patients with secondary platinum-sensitive recurrence, and could improve prognosis.

DNA damage repair mutations in pancreatic cancer- prognostic or predictive?

Objective

The efficacy of platinum-based chemotherapy (PtCh) for pancreatic cancer (PC) patients with DNA damage repair gene mutations (DDRm) compared to those without DDRm remains uncertain.

Methods

After a thorough database searching in PubMed, Embase, and Web of Science, a total of 19 studies that met all the inclusion criteria were identified. The primary outcomes were overall survival (OS) and progression-free survival (PFS) for PC patients with DDRm versus those without DDRm after PtCh.

Results

Patients with advanced-stage PC who have DDRm tend to have longer OS compared to patients without DDRm, regardless of their exposure to PtCh (HR=0.63; I2 = 66%). Further analyses indicated that the effectiveness of PtCh for OS was modified by DDRm (HR=0.48; I2 = 59%). After the first- line PtCh (1L-PtCh), the PFS of advanced-stage PC with DDRm was also significantly improved (HR=0.41; I2 = 0%). For patients with resected PC, regardless of their exposure to PtCh, the OS for patients with DDRm was comparable to those without DDRm (HR=0.82; I2 = 71%). Specifically, for patients with resected PC harboring DDRm who received PtCh (HR=0.85; I2 = 65%) and for those after non-PtCh (HR=0.87; I2 = 0%), the presence of DDRm did not show a significant association with longer OS.

Conclusion

1L-PtCh treatment is correlated with favorable survival for advanced-stage PC patients with DDRm. For resected-stage PC harboring DDRm, adjuvant PtCh had limited effectiveness. The prognostic value of DDRm needs to be further verified by prospective randomized controlled trials.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022302275.

Poly (ADP-Ribose) polymerase 1 and parthanatos in neurological diseases: From pathogenesis to therapeutic opportunities

Poly (ADP-ribose) polymerase-1 (PARP-1) is the most extensively studied member of the PARP superfamily, with its primary function being the facilitation of DNA damage repair processes. Parthanatos is a type of regulated cell death cascade initiated by PARP-1 hyperactivation, which involves multiple subroutines, including the accumulation of ADP-ribose polymers (PAR), binding of PAR and apoptosis-inducing factor (AIF), release of AIF from the mitochondria, the translocation of the AIF/macrophage migration inhibitory factor (MIF) complex, and massive MIF-mediated DNA fragmentation. Over the past few decades, the role of PARP-1 in central nervous system health and disease has received increasing attention. In this review, we discuss the biological functions of PARP-1 in neural cell proliferation and differentiation, memory formation, brain ageing, and epigenetic regulation. We then elaborate on the involvement of PARP-1 and PARP-1-dependant parthanatos in various neuropathological processes, such as oxidative stress, neuroinflammation, mitochondrial dysfunction, excitotoxicity, autophagy damage, and endoplasmic reticulum (ER) stress. Additional highlight contains PARP-1's implications in the initiation, progression, and therapeutic opportunities for different neurological illnesses, including neurodegenerative diseases, stroke, autism spectrum disorder (ASD), multiple sclerosis (MS), epilepsy, and neuropathic pain (NP). Finally, emerging insights into the repurposing of PARP inhibitors for the management of neurological diseases are provided. This review aims to summarize the exciting advancements in the critical role of PARP-1 in neurological disorders, which may open new avenues for therapeutic options targeting PARP-1 or parthanatos.

Histone and DNA Methylation as Epigenetic Regulators of DNA Damage Repair in Gastric Cancer and Emerging Therapeutic Opportunities

Gastric cancer (GC), one of the most common malignancies worldwide, is a heterogeneous disease developing from the accumulation of genetic and epigenetic changes. One of the most critical epigenetic alterations in GC is DNA and histone methylation, which affects multiple processes in the cell nucleus, including gene expression and DNA damage repair (DDR). Indeed, the aberrant expression of histone methyltransferases and demethylases influences chromatin accessibility to the DNA repair machinery; moreover, overexpression of DNA methyltransferases results in promoter hypermethylation, which can suppress the transcription of genes involved in DNA repair. Several DDR mechanisms have been recognized so far, with homologous recombination (HR) being the main pathway involved in the repair of double-strand breaks. An increasing number of defective HR genes are emerging in GC, resulting in the identification of important determinants of therapeutic response to DDR inhibitors. This review describes how both histone and DNA methylation affect DDR in the context of GC and discusses how alterations in DDR can help identify new molecular targets to devise more effective therapeutic strategies for GC, with a particular focus on HR-deficient tumors.

Unveiling poly(rC)-binding protein 2 as the target protein for curcusone C against prostate cancer: mechanism validation through click chemistry-activity based proteomics profiling approach

BACKGROUND

Prostate cancer is a disease that seriously troubles men. However, there are some inevitable limitations in interventional therapy for prostate cancer patients at present, most of which are caused by low selectivity and high toxic side effects due to unclear drug targets. In this study, we identified the target protein of Curcusone C with anti-prostate cancer potential activity and verified its target and mechanism of action.

METHODS

Click chemistry-activity based proteomics profiling (CC-ABPP) method was used to find target protein of Curcusone C against prostate cancer. Competitive CC-ABPP, drug affinity responsive target stability (DARTS) and surface plasmon resonance (SPR) methods were used to verifying the target protein. Moreover, potential mechanism was validated by western blot in vitro and by hematoxylin-eosin (HE) staining, detection of apoptosis in tumor tissue (TUNEL), and immunohistochemical (IHC) in vivo.

RESULTS

We found that poly(rC)-binding protein 2 (PCBP2) was the target protein of Curcusone C. In addition, Curcusone C might disrupt the Bax/Bcl-2 balance in PC-3 cells by inhibiting the expression of the target protein PCBP2, thereby inducing mitochondrial damage and activation of the mitochondrial apoptosis pathway, and ultimately inducing apoptosis of prostate cancer cells.

CONCLUSIONS

Curcusone C is a potential compound with anti-prostate cancer activity, and this effect occurs by targeting the PCBP2 protein, which in turn may affect the TGF/Smad signaling pathway and Bax/Bcl-2 balance. Our results laid a material and theoretical foundation for Curcusone C, to be widely used in anti-prostate cancer.

STAT3 inhibition enhances gemcitabine sensitivity in pancreatic cancer by suppressing EMT, immune escape and inducing oxidative stress damage

Pancreatic cancer (PC) is a highly-malignant tumor of the digestive system with a very poor prognosis and high mortality. Chemotherapy and PD-1/PD-L1 immune checkpoint blockade are important treatment strategies for advanced PC. However, chemotherapy resistance and poor therapeutic effect of immune checkpoint inhibitors is are the main clinical problems to be solved urgently at present. The effects of combined application of gemcitabine and STAT3 inhibition on the proliferation, apoptosis, migration, and invasion of PC cells (PCCs) were investigated. In addition, oxidative stress (OS), ferroptosis, immune escape, and the epithelial-mesenchymal transition (EMT) were evaluated. STAT3 inhibition with Stattic enhanced the inhibitory activity of gemcitabine on PCC proliferation by regulating the cell cycle. STAT3 inhibition enhanced mitochondrial-dependent apoptosis in gemcitabine-treated PCCs, but did not induce autophagy and ferroptosis. Further study showed that the anti-proliferative and pro-apoptotic effects may be associated with increased OS damage by inactivating Nrf2-HO-1 signaling, as well as DNA damage by inducing the imbalance between ATM andATR-Chk1 pathway. In addition, STAT3 inhibition strengthened gemcitabine-mediated suppression in PCC invasion and migration by antagonizing Smad2/3-dependent EMT. Moreover, the anti-tumorimmuneresponse of gemcitabine was upregulated by Stattic through reducing the expression of PD-L1 and CD47. Mechanistically, combined application of gemcitabine and Stattic suppressed the phosphorylation and nuclear expression of STAT3. Interestingly, the activities of AKT and β-catenin signaling were also regulated, suggesting that drug combination has a broad-spectrum signal regulation effect. STAT3 inhibition enhanced the sensitivity of PCCs to the chemotherapy drug gemcitabine by suppressing EMT and immune escape and inducing OS damage.

Prognostic value and immune infiltration of ARMC10 in pancreatic adenocarcinoma via integrated bioinformatics analyses

Background

Armadillo repeat-containing 10 (ARMC10) is involved in the progression of multiple types of tumors. Pancreatic adenocarcinoma (PAAD) is a lethal disease with poor survival and prognosis.

Methods

We acquired the data of ARMC10 in PAAD patients from the cancer genome atlas (TCGA) and gene expression omnibus (GEO) datasets and compared the expression level with normal pancreatic tissues. We evaluated the relevance between ARMC10 expression and clinicopathological factors, immune infiltration degree and prognosis in PAAD.

Results

High expression of ARMC10 was relevant to T stage, M stage, pathologic stage, histologic grade, residual tumor, primary therapy outcome (P < 0.05) and related to lower Overall-Survival (OS), Disease-Specific Survival (DSS), and Progression-Free Interval (PFI). Gene set enrichment analysis showed that ARMC10 was related to methylation in neural precursor cells (NPC), G alpha (i) signaling events, APC targets, energy metabolism, potassium channels and IL10 synthesis. The expression level of ARMC10 was positively related to the abundance of T helper cells and negatively to that of plasmacytoid dendritic cells (pDCs). Knocking down of ARMC10 could lead to lower proliferation, invasion, migration ability and colony formation rate of PAAD cells in vitro.

Conclusions

Our research firstly discovered ARMC10 as a novel prognostic biomarker for PAAD patients and played a crucial role in immune regulation in PAAD.

BHLHE40, a potential immune therapy target, regulated by FGD5-AS1/miR-15a-5p in pancreatic cancer

Pancreatic cancer, as one of the neoplasms with the highest degree of malignancy, has become a main disease of concerns in recent years. BHLHE40, a critical transcription factor for remodeling of the tumor immune microenvironment, has been described to be substantially increased in a variety of tumor-associated immune cells. Nevertheless, the pro-cancer biological functions and underlying molecular mechanisms of BHLHE40 for pancreatic cancer and its unique microenvironment are unclear. Hereby, we investigated the pro-oncogenic role of BHLHE40 in the pancreatic cancer microenvironment by bioinformatics analysis and cell biology experiments and determined that the expression of BHLHE40 was obviously elevated in pancreatic cancer tissues than in adjacent normal tissues. In parallel, Kaplan-Meier survival analysis unveiled that lower expression of BHLHE40 was strongly associated with better prognosis of patients. Receiver operating characteristic (ROC) curve analysis confirmed the accuracy of the BHLHE40-related prediction model. Subsequent, spearman correlation analysis observed that higher expression of BHLHE40 might be involved in immunosuppression of pancreatic cancer. Silencing of BHLHE40 could inhibit proliferation, invasion, and apoptosis of pancreatic cancer in vitro and in vivo, implying that BHLHE40 is expected to be a potential therapeutic target for pancreatic cancer. In addition, we explored and validated the FGD5-AS1/miR-15a-5p axis as a potential upstream regulatory mode for high expression of BHLHE40 in pancreatic cancer. In summary, our data showed that ceRNA involved in the regulation of BHLHE40 contributes to the promotion of immunosuppressive response in pancreatic and is expected to be a diagnostic marker and potential immunotherapeutic target for pancreatic cancer.

YCH1899, a Highly Effective Phthalazin-1(2H)-one Derivative That Overcomes Resistance to Prior PARP Inhibitors

Poly(ADP-ribose) polymerase inhibitors (PARPi) have significant efficacy in treating BRCA-deficient cancers, although resistance development remains an unsolved challenge. Herein, a series of phthalazin-1(2H)-one derivatives with excellent enzymatic inhibitory activity were designed and synthesized, and the structure-activity relationship was explored. Compared with olaparib and talazoparib, compound YCH1899 exhibited distinct antiproliferation activity against olaparib- and talazoparib-resistant cells, with IC50 values of 0.89 and 1.13 nM, respectively. Studies of the cellular mechanism revealed that YCH1899 retained sensitivity in drug-resistant cells with BRCA1/2 restoration or 53BP1 loss. Furthermore, YCH1899 had acceptable pharmacokinetic properties in rats and showed prominent dose-dependent antitumor activity in olaparib- and talazoparib-resistant cell-derived xenograft models. Overall, this study suggests that YCH1899 is a new-generation antiresistant PARPi that could provide a valuable direction for addressing drug resistance to existing PARPi drugs.

Combining Olaparib and Ascorbic Acid on Nanoparticles to Enhance the Drug Toxic Effects in Pancreatic Cancer

Introduction

Pancreatic cancer (PC) shows a very poor response to current treatments. Development of drug resistance is one of the causes of the therapy failure, being PARP1 (poly ADP-ribose polymerase 1) a relevant protein in the resistance mechanism. In this work, we have functionalized calcium phosphate-based nanoparticles (NPs) with Olaparib (OLA, a PARP-1 inhibitor) in combination with ascorbic acid (AA), a pro-oxidative agent, to enhance their individual effects.

Methods

Amorphous Calcium Phosphate (ACP) NPs were synthesized through a biomimetic approach and then functionalized with OLA and AA (NP-ACP-OLA-AA). After evaluation of the loading capacity and release kinetic, cytotoxicity, cell migration, immunofluorescence, and gene expression assays were performed using pancreatic tumor cell lines. In vivo studies were carried out on tumors derived from the PANC-1 line in NOD SCID gamma (NSG) mice.

Results

NP-ACP-OLA-AA was loaded with 13%wt of OLA (75% loading efficiency) and 1% of AA, respectively. The resulting dual nanosystem exhibited a gradual release of OLA and AA, being the latter protected from degradation in solution. This ensured the simultaneous availability of OLA and AA for a longer period, at least, during the entire time of in vitro cell experiments (72 hours). In vitro studies indicated that NP-ACP-OLA-AA showed the best cytotoxic effect outperforming that of the free OLA and a higher genotoxicity and apoptosis-mediated cytotoxic effect in human pancreatic ductal adenocarcinoma cell line. Interestingly, the in vivo assays using immunosuppressed mice with PANC-1-induced tumors revealed that NP-ACP-OLA-AA produced a higher tumor volume reduction (59.1%) compared to free OLA (28.3%) and increased the mice survival.

Conclusion

Calcium phosphate NPs, a highly biocompatible and biodegradable system, were an ideal vector for the OLA and AA co-treatment in PC, inducing significant therapeutic benefits relative to free OLA, including cytotoxicity, induction of apoptosis, inhibition of cell migration, tumor growth, and survival.

How ligands regulate the binding of PARP1 with DNA: Deciphering the mechanism at the molecular level

The catalytic (CAT) domain is a key region of poly (ADP-ribose) polymerase 1 (PARP1), which has crucial interactions with inhibitors, DNA, and other domains of PARP1. To facilitate the development of potential inhibitors of PARP1, it is of great significance to clarify the differences in structural dynamics and key residues between CAT/inhibitors and DNA/PARP1/inhibitors through structure-based computational design. In this paper, conformational changes in PAPR1 and differences in key residue interactions induced by inhibitors were revealed at the molecular level by comparative molecular dynamics (MD) simulations and energy decomposition. On one hand, PARP1 inhibitors indirectly change some residues of the CAT domain which interact with DNA and other domains. Furthermore, the interaction between ligands and catalytic binding sites can be transferred to the DNA recognition domain of PARP1 by a strong negative correlation movement among multi-domains of PARP1. On the other hand, it is not reliable to use the binding energy of CAT/ligand as a measure of ligand activity, because it may in some cases differs greatly from the that of PARP1/DNA/ligand. For PARP1/DNA/ligand, the stronger the binding stability between the ligand and PARP1, the stronger the binding stability between PARP1 and DNA. The findings of this work can guide further novel inhibitor design and the structural modification of PARP1 through structure-based computational design.

Unravelling the Role of PARP1 in Homeostasis and Tumorigenesis: Implications for Anti-Cancer Therapies and Overcoming Resistance

Detailing the connection between homeostatic functions of enzymatic families and eventual progression into tumorigenesis is crucial to our understanding of anti-cancer therapies. One key enzyme group involved in this process is the Poly (ADP-ribose) polymerase (PARP) family, responsible for an expansive number of cellular functions, featuring members well established as regulators of DNA repair, genomic stability and beyond. Several PARP inhibitors (PARPi) have been approved for clinical use in a range of cancers, with many more still in trials. Unfortunately, the occurrence of resistance to PARPi therapy is growing in prevalence and requires the introduction of novel counter-resistance mechanisms to maintain efficacy. In this review, we summarize the updated understanding of the vast homeostatic functions the PARP family mediates and pin the importance of PARPi therapies as anti-cancer agents while discussing resistance mechanisms and current up-and-coming counter-strategies for countering such resistance.

Enhancing the anti-tumor response by combining DNA damage repair inhibitors in the treatment of solid tumors

The anti-cancer efficacy of anti-malignancy therapies is related to DNA damage. However, DNA damage-response mechanisms can repair DNA damage, failing anti-tumor therapy. The resistance to chemotherapy, radiotherapy, and immunotherapy remains a clinical challenge. Thus, new strategies to overcome these therapeutic resistance mechanisms are needed. DNA damage repair inhibitors (DDRis) continue to be investigated, with polyadenosine diphosphate ribose polymerase inhibitors being the most studied inhibitors. Evidence of their clinical benefits and therapeutic potential in preclinical studies is growing. In addition to their potential as a monotherapy, DDRis may play an important synergistic role with other anti-cancer therapies or in reversing acquired treatment resistance. Here we review the impact of DDRis on solid tumors and the potential value of combinations of different treatment modalities with DDRis for solid tumors.

Relative Biological Effectiveness (RBE) of [64Cu]Cu and [177Lu]Lu-NOTA-panitumumab F (ab')2 radioimmunotherapeutic agents vs. γ-radiation for decreasing the clonogenic survival in vitro of human pancreatic ductal adenocarcinoma (PDAC) cells

INTRODUCTION

Our objective was to compare [64Cu]Cu-NOTA-panitumumab F(ab')2 and [177Lu]Lu-NOTA-panitumumab F(ab')2 radioimmunotherapy (RIT) agents for decreasing the clonogenic survival fraction (SF) in vitro of EGFR-positive human pancreatic ductal adenocarcinoma (PDAC) cell lines and estimate the relative biological effectiveness (RBE) vs. γ-radiation (XRT).

METHODS

EGFR-positive PDAC cell lines (AsPC-1, PANC-1, MIAPaCa-2, Capan-1) and EGFR-knockout PANC-1 EGFR KO cells were treated in vitro for 18 h with (0-19.65 MBq; 72 nmols/L) of [64Cu]Cu-NOTA-panitumumab F(ab')2 or [177Lu]Lu-NOTA-panitumumab F(ab')2 or XRT (0-8 Gy) followed by clonogenic assay. The SF was determined after culturing single treated cells for 14 d. Cell fractionation studies were performed for cells incubated with 1 MBq (72 nmols/L) of [64Cu]Cu-NOTA-panitumumab F(ab')2 or [177Lu]Lu-NOTA-panitumumab F(ab')2 for 1, 4, or 24 h to estimate the time-integrated activity (Ã) on the cell surface, cytoplasm, nucleus and medium. Radiation absorbed doses in the nucleus were calculated by multiplying à by S-factors calculated by Monte Carlo N Particle (MCNP) modeling using monolayer cell culture geometry. The SF of PDAC cells was plotted vs. dose and fitted to a linear quadratic model to estimate the dose required to decrease the SF to 0.1 (D10). The D10 for RIT agents were compared to XRT to estimate the RBE. DNA double-strand breaks (DSBs) caused by [64Cu]Cu-NOTA-panitumumab F(ab')2 or [177Lu]Lu-NOTA-panitumumab F(ab')2 continuous exposure for 5 h or 20 h were probed by immunofluorescence for γ-H2AX. Relative EGFR expression of PDAC cells was assessed by flow cytometry (scored + to +++) and cell doubling times for untreated cells were determined.

RESULTS

The D10 for [64Cu]Cu-NOTA-panitumumab F(ab')2 ranged from 9.1 Gy (PANC-1) to 39.9 Gy (Capan-1). The D10 for [177Lu]Lu-NOTA-panitumumab F(ab')2 ranged from 11.7 Gy (AsPC-1) to 170.8 Gy (Capan-1). The D10 for XRT ranged from 2.5 Gy (Capan-1) to 6.7 Gy (PANC-1 EGFR KO). D10 values were not correlated with EGFR expression over a relatively narrow range (++ to +++) or with cell doubling times. Based on D10 values, PANC-1 EGFR KO cells were 1.6-fold less sensitive than PANC-1 cells to [64Cu]Cu-NOTA-panitumumab F(ab')2 and 1.9-fold less sensitive to [177Lu]Lu-NOTA-panitumumab F(ab')2. The RBE for [64Cu]Cu-NOTA-panitumumab F(ab')2 ranged from 0.06 for Capan-1 cells to 0.45 for PANC-1 cells. The RBE for [177Lu]Lu-NOTA-panitumumab F(ab')2 ranged from 0.015 for Capan-1 cells to 0.28 for AsPC-1 cells. DNA DSBs were detected in PDAC cells exposed to [64Cu]Cu-NOTA-panitumumab F(ab')2 or [177Lu]Lu-NOTA-panitumumab F(ab')2 but were not correlated with the SF of the cells.

CONCLUSIONS

We conclude that at the same dose delivered to the cell nucleus [64Cu]Cu-NOTA-panitumumab F(ab')2 and [177Lu]Lu-NOTA-panitumumab F(ab')2 were less radiobiologically effective than XRT for decreasing the SF of human PDAC cells, but [64Cu]Cu-NOTA-panitumumab F(ab')2 was more cytotoxic than [177Lu]Lu-NOTA-panitumumab F(ab')2 except for AsPC-1 cells which were more sensitive to [177Lu]Lu-NOTA-panitumumab F(ab')2.

ADVANCES IN KNOWLEDGE AND IMPLICATIONS FOR PATIENT CARE

This study demonstrates that higher radiation doses may be required for RIT than XRT to achieve radiobiologically equivalent effects when used to treat PDAC.

UHRF2 promotes the malignancy of hepatocellular carcinoma by PARP1 mediated autophagy

Autophagy have critical implications in the proliferation and metastasis of HCC. In the current study, we aimed to explore the underlying mechanisms of UHRF2 regulates HCC cell autophagy and HCC progression. We initially determined the relationship between UHRF2 and HCC autophagy, oncogenicity and patient survival through GSEA database and TCGA database. We mainly investigated the effect of UHRF2 on HCC development and autophagy through western blot, electron microscopy, and immunofluorescence. Functionally, UHRF2 was positively involved in the autophagy activation. Overexpression of UHRF2 reduced apoptosis in HCC cells, and promote the malignancy phenotype of HCC both in vitro and in vivo. Mechanistically, PRDX1 bound to UHRF2 and upregulated its protein expression to facilitate the biological function of UHRF2 in HCC. Meanwhile, UHRF2 bound to autophagy-related protein PARP1 and upregulated PARP1 protein level. The results showed that UHRF2 promoted autophagy and contributed to the malignant phenotype of hepatocellular carcinoma by regulating PARP1 levels. In summary, a novel interaction between PRDX1, UHRF2, and PARP1 was revealed, suggesting that UHRF2 could inspire a potential biomarker and potential therapeutic target for HCC.

DNA repair pathways in breast cancer: from mechanisms to clinical applications

BACKGROUND

Breast cancer (BC) is a complex disease with various subtypes and genetic alterations that impact DNA repair pathways. Understanding these pathways is essential for developing effective treatments and improving patient outcomes.

AREA COVERED

This study investigates the significance of DNA repair pathways in breast cancer, specifically focusing on various pathways such as nucleotide excision repair, base excision repair, mismatch repair, homologous recombination repair, non-homologous end joining, fanconi anemia pathway, translesion synthesis, direct repair, and DNA damage tolerance. The study also examines the role of these pathways in breast cancer resistance and explores their potential as targets for cancer treatment.

CONCLUSION

Recent advances in targeted therapies have shown promise in exploiting DNA repair pathways for BC treatment. However, much research is needed to improve the efficacy of these therapies and identify new targets. Additionally, personalized treatments that target specific DNA repair pathways based on tumor subtype or genetic profile are being developed. Advances in genomics and imaging technologies can potentially improve patient stratification and identify biomarkers of treatment response. However, many challenges remain, including toxicity, resistance, and the need for more personalized treatments. Continued research and development in this field could significantly improve BC treatment.

Sequential therapy for pancreatic cancer patients with synchronous oligo-hepatic metastatic lesions

BACKGROUND

Treatments for patients suffering from pancreatic cancer with oligo-hepatic metastasis have always been a cause of certain controversy. Herein, we reported 15 pancreatic cancer patients with oligo-hepatic metastasis who accepted sequential therapy of chemotherapy, radiofrequency ablation (RFA), and radical resection of the primary tumor.

METHODS

A total of 87 pancreatic cancer patients with synchronous oligo-metastatic hepatic lesions who received treatments in the 2nd Affiliated Hospital of Zhejiang University between January 2017 and July 2020 were enrolled. The chemotherapy regimens included modified folfirinox (54/87) and gemcitabine plus nab-paclitaxel (33/87). Test of blood tumor markers and contrast-enhanced computed tomography (CT) or magnetic resonance (MR) scan was performed at diagnosis and after eight weeks of chemotherapy.

RESULTS

Thirty-five patients received just chemotherapy because of poor reaction to the first round of chemotherapy(Overall survival (OS), 6.47±1.80 months); 15 patients reassessed as stable disease (SD)/partial response (PR) continued chemotherapy (OS, 10.35±3.15); nine patients reassessed as progressive disease (PD) after RFA and continued chemotherapy (OS, 10.90±2.60). The primary tumors in 13 patients were unresectable after chemotherapy and RFA (OS, 12.92±2.47), while 15 patients completed the sequential therapy of chemotherapy, radio-frequency ablation, and radical resection (OS, 16.76±6.55).

CONCLUSIONS

Sequential chemotherapy and RFA is a good treatment strategy to select the best candidates for surgical treatment among patients with pancreatic cancer with oligo-hepatic metastasis.

Retinoic Acid Prevents α-Synuclein Preformed Fibrils-Induced Toxicity via Inhibiting STAT1-PARP1 Signaling

Parkinson's disease (PD), the second-most prevalent neurodegenerative disorder, is characterized by the aberrant deposition of α-synuclein (α-Syn) aggregation in neurons. Recent reports have shown that retinoic acid (RA) ameliorates motor deficits. However, the underlying molecular mechanisms remain unclear. In this article, we investigated the effects of RA on cellular and animal models of PD. We found that RA is beneficial for neuronal survival in PD-associated models. In α-Syn preformed fibrils-treated mice, RA administration relieved the formation of intracellular inclusions, dopaminergic neuronal loss, and behavioral deficits. α-Syn preformed fibrils-treated SH-SY5Y cells manifested decreased cell viability, apoptosis, α-Syn aggregation, and autophagy defects. All these negative phenomena were alleviated by RA. More importantly, RA could inhibit the neurotoxicity via inhibiting α-Syn preformed fibrils-induced STAT1-PARP1 signaling, which could also be antagonized by IFN-γ. In conclusion, RA could hinder α-Syn preformed fibrils-induced toxicity by inhibiting STAT1-PARP1 signaling. Thus, we present new insight into RA in PD management.