Pancreatic ductal adenocarcinoma (PDAC), the most common histological subtype of pancreatic cancer, is an aggressive malignancy expected to become the second leading cause of cancer-related deaths by 2040. A hallmark of PDACs is the highly desmoplastic and hypovascularized nature of its microenvironment, which enables PDAC cells to adapt and survive under conditions of low oxygen and nutrient deprivation through various cellular mechanisms. Among these processes, autophagy has emerged as a key response mechanism to cope with these adverse conditions. Consequently, a deeper understanding of the molecular events driving autophagy could pave the way for the development of new and more effective treatments for PDAC. In this context, we provide evidence of novel pathway mediated by extracellular vesicles (EVs) that promotes autophagy in a paracrine manner in PDAC cells in response to starvation. Our findings indicate that, under starvation conditions, EVs-associated tetraspanins, namely CD9, CD63 and CD81, mobilize towards domains-like structures within the plasma membrane of PDAC cells. Correspondingly, a specific release of small EVs (sEVs) is observed in the starved cells. Notably, sEVs derived from starved cells, but not those from cells at basal conditions, strongly induce the autophagy pathway in PDAC cells cultured with optimal nutritional media. Interestingly, this ability to induce autophagy is specific to CD63/CD81 double-positive sEVs and is effective even in non-tumoral pancreatic cells. This sEVs-mediated autophagy is, at least partially, mediated by the activation of the FOXO3a pathway. It is worth noting that, although EVs release returns to basal level after 1 h of recovery following starvation, these EVs retain a capacity to induce autophagy, suggesting a decupling between quantity and quality of secreted vesicles. Our results demonstrate that pancreatic cancer cells in nutrient-deprived environments release specific sEVs that, in turn, activate the FOXO3a pathway and autophagy flux in recipient cells.

Cellular senescence has emerged as a context-dependent determinant of pancreatic ductal adenocarcinoma (PDAC) progression and therapeutic response. In early pancreatic tumorigenesis, oncogene-induced senescence acts as a robust tumor-suppressive mechanism that limits KRAS-driven malignant transformation. However, this protective barrier is progressively circumvented during disease evolution. In established PDAC, senescence acquires predominantly pro-tumorigenic functions, particularly within the stromal compartment. Senescent cancer-associated fibroblasts reshape the tumor microenvironment through the senescence-associated secretory phenotype (SASP), fostering desmoplasia, immune evasion, and resistance to therapy. In parallel, conventional chemotherapy and targeted treatments induce therapy-induced senescence in tumor cells, contributing to tumor persistence and relapse. Recent advances in senescence-associated gene signatures and SASP profiling have enabled the stratification of PDAC patients according to prognosis and immune landscape. This review critically discusses the dual roles of senescence in PDAC and evaluates emerging senescence-targeted therapeutic strategies, including senolytic and senomorphic approaches, as promising avenues to improve treatment efficacy.

BACKGROUND:Emerging evidence suggests that chemotherapy can accumulate senescent-like cells within tumor tissues, a phenomenon linked to therapy resistance. The aim of this study is to analyze the senescence-like state of after-treatment persistent cells associated with KRAS mutational status to offer a therapeutic strategy to target these cells in pancreatic ductal adenocarcinoma (PDAC). EXPERIMENTAL DESIGN:Three commercial cell lines and five patient-derived primary cell cultures with different KRAS statuses were studied following gemcitabine treatment. Senescence-like status was assessed using SA-β-gal, together with cell cycle regulators such as p21. Additionally, KRAS mutations were modulated using MRTX1133 and AMG-510, and the signaling pathways ERK and AKT were analyzed and modulated in vitro. Finally, p21 expression, associated with the senescence-like state, on patient outcomes and treatment response was analyzed in publicly available bulk RNA-seq and single-nucleus datasets. RESULTS:We observed an overexpression of p21 alongside an increase in SA-β-gal signal in response to gemcitabine treatment, indicating the induction of a senescence-like state. Specific inhibition of KRAS G12D or G12C mutations reduced SA-β-gal signal and sensitized PDAC cells to gemcitabine. Moreover, ERK inhibition but not AKT inhibition decreased SA-β-gal signal. Additionally, we characterized p21 expression levels in relation to patient outcomes and found that they are modulated by treatment. CONCLUSIONS:This dual-targeted therapeutic strategy holds promises for overcoming the challenges posed by KRAS-driven cancers, particularly in addressing the formidable obstacle of pancreatic cancer.

Activation of oncogenes, such as through mutations in Kirsten rat sarcoma viral oncogene homolog (KRAS), triggers profound disruptions in cellular homeostasis that set off a cascade of stress responses. These responses enable cells to cope with the array of challenges encountered during tumorigenesis by activating defense mechanisms that promote adaptation and survival. Key components of this oncogenic stress response include heat shock proteins, the ubiquitin-proteasome system, autophagy, nuclear factor erythroid 2-related factor 2-antioxidant response element signaling, DNA damage response proteins, p53, redox-regulating proteins, and stress granules. This review concentrates on KRAS-driven oncogenic transformation, as KRAS mutations are among the most common in human cancers, accounting for over 90% of pancreatic ductal adenocarcinoma cases, around 30% of lung cancers, and approximately 50% of colorectal cancers. We examine the intricate molecular interplay between oncogenic stress and the associated cellular defense mechanisms, emphasizing the key molecular events that follow KRAS activation. Importantly, the very pathways that allow cancer cells to adapt to oncogenic stress also offer novel therapeutic opportunities. By selectively targeting pivotal regulators within these stress response pathways, we can potentially disrupt the survival mechanisms of cancer cells. This strategy not only promises to enhance the effectiveness of existing treatments but also paves the way for the development of innovative therapies designed to combat tumor progression. In essence, exploiting oncogenic stress responses represents an original and promising therapeutic approach in the fight against cancer.

PDF file, 232K, Predicted pathways regulated by Nupr1.

PDF file, 355K, mRNA expression in glucose starvation- and hypoxia-treated pancreatic cancer cells expressing or not Nupr1.

PDF file, 137K, Protective role of Nupr1 and AURKA in BxPC-3 cells.

PDF file, 57K, siRNA sequences used for silencing Nupr1, Beclin1, ATG5 and AURKA mRNA and Primer sequences used to amplify human genes.

PDF file, 222K, Protective role of Nupr1 and AURKA in Panc-1 cells.

Aberrant activation of the Hedgehog (Hh) signaling pathway, through which the GLI family of transcription factors (TF) is stimulated, is commonly observed in cancer cells. One well-established mechanism of this increased activity is through the inactivation of Suppressor of Fused (SUFU), a negative regulator of the Hh pathway. Relief from negative regulation by SUFU facilitates GLI activity and induction of target gene expression. Here, we demonstrate a novel role for SUFU as a promoter of GLI activity in pancreatic ductal adenocarcinoma (PDAC). In non-ciliated PDAC cells unresponsive to Smoothened agonism, SUFU overexpression increases GLI transcriptional activity. Conversely, knockdown (KD) of SUFU reduces the activity of GLI in PDAC cells. Through array PCR analysis of GLI target genes, we identified B-cell lymphoma 2 (BCL2) among the top candidates down-regulated by SUFU KD. We demonstrate that SUFU KD results in reduced PDAC cell viability, and overexpression of BCL2 partially rescues the effect of reduced cell viability by SUFU KD. Further analysis using as a model GLI1, a major TF activator of the GLI family in PDAC cells, shows the interaction of SUFU and GLI1 in the nucleus through previously characterized domains. Chromatin immunoprecipitation (ChIP) assay shows the binding of both SUFU and GLI1 at the promoter of BCL2 in PDAC cells. Finally, we demonstrate that SUFU promotes GLI1 activity without affecting its protein stability. Through our findings, we propose a novel role of SUFU as a positive regulator of GLI1 in PDAC, adding a new mechanism of Hh/GLI signaling pathway regulation in cancer cells.

PDF file, 231K, Protective role of Nupr1 and AURKA on MiaPaCa2 cells in control experiment using additional siRNA sequences.

PDF file, 192K, Nupr1 is required to maintain DNA repair activity in response to hypoxia and glucose starvation.

Se conoce bien que diferentes sistemas de uso y manejos de suelos afectan la abundancia, la actividad y la composición de la comunidad microbiana del suelo. En este trabajo se estudió el comportamiento de las poblaciones bacterianas cultivables y, en particular, las bacterias solubilizadoras de P (BSP) en muestras de suelo provenientes de un ensayo de larga duración con diferentes secuencias de cultivo. Los resultados obtenidos ponen en evidencia que el desmonte y el uso agrícola posterior luego de 11 años generó una disminución de la población de bacterias cultivables en general, y de las bacterias solubilizadoras de P en particular, con respecto al suelo prístino. Se obtuvieron aislamientos con una alta eficiencia de solubilización de P de los suelos provenientes de las diferentes rotaciones. Estos aislamientos eficientes se clasificaron taxonómicamente mediante análisis 16S RNA como pertenecientes a los géneros Bacillus, Paenibacillus, Pseudomonas y Xanthomonas. En particular, la caracterización de los sobrenadantes de cultivos de los aislamientos Pseudomonas koreensis y Paenibacillus pabuli mostraron que son productoras de ácidos orgánicos. Los ensayos de inoculación combinada de estas dos cepas sobre plantas de maíz en cámara de cultivo pusieron de manifiesto un efecto sinérgico sobre la promoción del crecimiento de esta especie. Los resultados aquí presentados sugieren que si bien las poblaciones de BSP son más numerosas en suelos prístinos, determinadas rotaciones de cultivos a largo plazo favorecen el incremento de bacterias solubilizadoras más eficientes, un aspecto que debería tenerse en cuenta al diseñar futuras estrategias de búsqueda de potenciales bioinoculantes.

Cystic echinococcosis is a zoonotic disease caused by the larval stage of the parasite Echinococcus granulosus sensu lato . The available anti-parasitic treatment is mostly limited to a continuous administration of albendazole. However, due to its numerous side-effects and efficacy of around 50%, there is a need to find new drugs to improve the treatment for this disease. In the current study, the in vitro and in vivo efficacy of a Stevia multiaristata extract against E. granulosus sensu stricto ( s.s. ) was demonstrated. Stevia multiaristata extract (100 and 50 μ g mL −1 ) caused a quick viability decrease on protoscoleces which was consistent with the observed tegumental alterations. Loss of turgidity was detected in 95 ± 3.4% of cysts incubated with S. multiaristata extract during 2 days (100 μ g mL −1 ) and the collapse of the germinal layer was observed in 60 ± 9.3% of cysts treated with 100 μ g mL −1 of the S. multiaristata extract during 4 days. The half maximal effective concentration value was 69.6 μ g mL −1 and the selectivity index for E. granulosus s.s. cysts was 1.9. In this clinical efficacy study, the treatment of infected mice with the S. multiaristata extract (50 mg kg −1 ) caused a significant decrease in the weight of the cysts compared with the control group. These results coincided with the tissue damage observed in the cysts at the ultrastructural level. In conclusion, we observed high protoscolicidal and cysticidal effects, and significant reduction in the weight of the cysts in experimentally infected mice following treatment with the S. multiaristata extract.

Autophagy is a critical metabolic process that supports homeostasis at a basal level and is dynamically regulated in response to various physiological and pathological processes. Autophagy has some etiologic implications that support certain pathological processes due to alterations in the lysosomal-degradative pathway. Some of the conditions related to autophagy play key roles in highly relevant human diseases, e.g., cardiovascular diseases (15.5%), malignant and other neoplasms (9.4%), and neurodegenerative conditions (3.7%). Despite advances in the discovery of new strategies to treat these age-related diseases, autophagy has emerged as a therapeutic option after preclinical and clinical studies. Here, we discuss the pitfalls and success in regulating autophagy initiation and its lysosome-dependent pathway to restore its homeostatic role and mediate therapeutic effects for cancer, neurodegenerative, and cardiac diseases. The main challenge for the development of autophagy regulators for clinical application is the lack of specificity of the repurposed drugs, due to the low pharmacological uniqueness of their target, including those that target the PI3K/AKT/mTOR and AMPK pathway. Then, future efforts must be conducted to deal with this scenery, including the disclosure of key components in the autophagy machinery that may intervene in its therapeutic regulation. Among all efforts, those focusing on the development of novel allosteric inhibitors against autophagy inducers, as well as those targeting autolysosomal function, and their integration into therapeutic regimens should remain a priority for the field.

Pancreas ductal adenocarcinoma is a highly aggressive cancer with an incredible poor lifespan. Different chemotherapeutic agents’ schemes have been tested along the years without significant success. Furthermore, immunotherapy also fails to cope with the disease, even in combination with other standard approaches. Autophagy stands out as a chemoresistance mechanism and is also becoming relevant as responsible for the inefficacy of immunotherapy. In this complex scenario, exosomes have emerged as a new key player in tumor environment. Exosomes act as messengers among tumor cells, including tumor microenvironment immune cells. For instance, tumor-derived exosomes are capable of generating a tolerogenic microenvironment, which in turns conditions the immune system behavior. But also, immune cells-derived exosomes, under non-tolerogenic conditions, induce tumor suppression, although they are able to promote chemoresistance. In that way, NK cells are well known key regulators of carcinogenesis and the inhibition of their function is detrimental for tumor suppression. Additionally, increasing evidence suggests a crosstalk between exosome biogenesis and the autophagy pathway. This mini review has the intention to summarize the available data in the complex relationships between the autophagy pathway and the broad spectrum of exosomes subpopulations in pancreatic cancer, with focus on the NK cells response.

Cancer is considered an age-related disease that, over the next 10 years, will become the most prevalent health problem worldwide. Although cancer therapy has remarkably improved in the last few decades, novel treatment concepts are needed to defeat this disease. Photodynamic Therapy (PDT) signalize a pathway to treat and manage several types of cancer. Over the past three decades, new light sources and photosensitizers (PS) have been developed to be applied in PDT. Nevertheless, there is a lack of knowledge to explain the main biochemical routes needed to trigger regulated cell death mechanisms, affecting, considerably, the scope of the PDT. Although autophagy modulation is being raised as an interesting strategy to be used in cancer therapy, the main aspects referring to the autophagy role over cell succumbing PDT-photoinduced damage remain elusive. Several reports emphasize cytoprotective autophagy, as an ultimate attempt of cells to cope with the photo-induced stress and to survive. Moreover, other underlying molecular mechanisms that evoke PDT-resistance of tumor cells were considered. We reviewed the paradigm about the PDT-regulated cell death mechanisms that involve autophagic impairment or boosted activation. To comprise the autophagy-targeted PDT-protocols to treat cancer, it was underlined those that alleviate or intensify PDT-resistance of tumor cells. Thereby, this review provides insights into the mechanisms by which PDT can be used to modulate autophagy and emphasizes how this field represents a promising therapeutic strategy for cancer treatment.

EDITORIAL article Front. Oncol., 07 July 2021Sec. Molecular and Cellular Oncology Volume 11 - 2021 | https://doi.org/10.3389/fonc.2021.726989

Mitophagy and zymophagy are selective autophagy pathways early induced in acute pancreatitis that may explain the mild, auto limited, and more frequent clinical presentation of this disease. Adequate mitochondrial bioenergetics is necessary for cellular restoration mechanisms that are triggered during the mild disease. However, mitochondria and zymogen contents are direct targets of damage in acute pancreatitis. Cellular survival depends on the recovering possibility of mitochondrial function and efficient clearance of damaged mitochondria. This work aimed to analyze mitochondrial dynamics and function during selective autophagy in pancreatic acinar cells during mild experimental pancreatitis in rats. Also, using a cell model under the hyperstimulation of the G-coupled receptor for CCK (CCK-R), we aimed to investigate the mechanisms involved in these processes in the context of zymophagy. We found that during acute pancreatitis, mitochondrial O-2 consumption and ATP production significantly decreased early after induction of acute pancreatitis, with a consequent decrease in the ATP/O ratio. Mitochondrial dysfunction was accompanied by changes in mitochondrial dynamics evidenced by optic atrophy 1 (OPA-1) and dynamin-related protein 1 (DRP-1) differential expression and ultrastructural features of mitochondrial fission, mitochondrial elongation, and mitophagy during the acute phase of experimental mild pancreatitis in rats. Mitophagy was also evaluated by confocal assay after transfection with the pMITO-RFP-GFP plasmid that specifically labels autophagic degradation of mitochondria and the expression and redistribution of the ubiquitin ligase Parkin1. Moreover, we report for the first time that vacuole membrane protein-1 (VMP1) is involved and required in the mitophagy process during acute pancreatitis, observable not only by repositioning around specific mitochondrial populations, but also by detection of mitochondria in autophagosomes specifically isolated with anti-VMP1 antibodies as well. Also, VMP1 downregulation avoided mitochondrial degradation confirming that VMP1 expression is required for mitophagy during acute pancreatitis. In conclusion, we identified a novel DRP1-Parkin1-VMP1 selective autophagy pathway, which mediates the selective degradation of damaged mitochondria by mitophagy in acute pancreatitis. The understanding of the molecular mechanisms involved to restore mitochondrial function, such as mitochondrial dynamics and mitophagy, could be relevant in the development of novel therapeutic strategies in acute pancreatitis.