Synthetic lethal interaction of CDK inhibition and autophagy inhibition in human solid cancer cell lines

Pharmacological modulation of RB1 activity mitigates resistance to neoadjuvant chemotherapy in locally advanced rectal cancer

Resistance to neoadjuvant chemotherapy leads to poor prognosis of locally advanced rectal cancer (LARC), representing an unmet clinical need that demands further exploration of therapeutic strategies to improve clinical outcomes. Here, we identified a noncanonical role of RB1 for modulating chromatin activity that contributes to oxaliplatin resistance in colorectal cancer (CRC). We demonstrate that oxaliplatin induces RB1 phosphorylation, which is associated with the resistance to neoadjuvant oxaliplatin-based chemotherapy in LARC. Inhibition of RB1 phosphorylation by CDK4/6 inhibitor results in vulnerability to oxaliplatin in both intrinsic and acquired chemoresistant CRC. Mechanistically, we show that RB1 modulates chromatin activity through the TEAD4/HDAC1 complex to epigenetically suppress the expression of DNA repair genes. Antagonizing RB1 phosphorylation through CDK4/6 inhibition enforces RB1/TEAD4/HDAC1 repressor activity, leading to DNA repair defects, thus sensitizing oxaliplatin treatment in LARC. Our study identifies a RB1 function in regulating chromatin activity through TEAD4/HDAC1. It also provides the combination of CDK4/6 inhibitor with oxaliplatin as a potential synthetic lethality strategy to mitigate oxaliplatin resistance in LARC, whereby phosphorylated RB1/TEAD4 can serve as potential biomarkers to guide the patient stratification.

The prolyl hydroxylase OGFOD1 promotes cancer cell proliferation by regulating the expression of cell cycle regulators

OGFOD1, a prolyl-hydroxylase, has been reported to translocate from the nucleus to the cytoplasm in response to cellular stress. Here, we demonstrate that OGFOD1 regulates the transcription and post-transcriptional stabilization of cell cycle-related genes. OGFOD1 knockdown in lung cancer cells induced cell cycle arrest through the specific depletion of cyclin-dependent kinase (CDK) 1, CDK2 and cyclin B1 (CCNB1) mRNAs and the nuclear accumulation of p21^Cip1 . Analysis of the mRNA dynamics in these cells revealed that CDK1 decreased in a time-dependent manner, reflecting post-transcriptional regulation by OGFOD1 and the RNA-binding protein HuR. In contrast, the depletion of CDK2 and CCNB1 resulted from decreased transcription mediated by OGFOD1. These results indicate that OGFOD1 is required to maintain the function of specific cell cycle regulators during cancer cell proliferation.

Flavopiridol Protects against Fungal Keratitis due to Aspergillus fumigatus by Alleviating Inflammation through the Promotion of Autophagy

Fungal keratitis is a serious infectious keratopathy related to fungal virulence and excessive inflammatory responses. Autophagy exhibits a potent ability to resolve inflammation during fungal infection. This study aimed to investigate the protective function of flavopiridol in Aspergillus fumigatus keratitis and explore its effects on autophagy. In our study, the corneas of the fungal keratitis mouse model were treated with 5 μM flavopiridol. In vitro, RAW 264.7 cells were pretreated with 200 nM flavopiridol before fungal stimulation. A. fumigatus was incubated with flavopiridol, and the antifungal activity of flavopiridol was detected. Our results indicated that flavopiridol treatment notably reduced clinical scores as well as cytokines expression of infected corneas. In infected RAW 264.7 cells, flavopiridol treatment inhibited IL-1β, IL-6, and TNF-α expression but promoted IL-10 expression. Transmission electron microscopy (TEM) images showed that more autolysosomes were present in infected corneas and RAW 264.7 cells after flavopiridol treatment. Flavopiridol treatment notably upregulated the protein expression of LC3, Beclin-1, and Atg-7. 3-Methyladenine (3-MA, an inhibitor of autophagy) pretreatment counteracted the cytokine regulation induced by flavopiridol. Moreover, flavopiridol promoted the phagocytosis of RAW 264.7 cells. Flavopiridol also exhibited antifungal activity by restricting fungal growth and limiting fungal biofilm formation and conidial adhesion. In conclusion, flavopiridol significantly alleviated the inflammation of fungal keratitis by activating autophagy. In addition, flavopiridol promoted the phagocytosis of RAW 264.7 cells and exhibited antifungal function, indicating the potential therapeutic role of flavopiridol in fungal keratitis.

CDK4/6 inhibitor enhances the radiosensitization of esophageal squamous cell carcinoma (ESCC) by activating autophagy signaling via the suppression of mTOR

OBJECTIVE

To investigate the radiosensitizing effect of cyclin D-cyclin dependent kinase (CDK) 4/6 inhibitor palbociclib on esophageal squamous cell carcinoma (ESCC) and its underlying mechanisms.

METHODS

The effect of palbociclib on ESCC cell radiosensitivity was detected by cell counting kit-8 (CCK-8) and clonogenic assay. γH2AX immunofluorescent staining was used to assess the repair of DNA damage induced by radiation. The expression of DNA repair proteins were examined by western blotting. Subsequently, immunoblotting and autophagy inhibitors were used to evaluate the underlying mechanisms of palbociclib triggered radiosensitization. Finally, the xenografts of ESCC were established to study the radiosensitizing effect of palbociclib in vivo.

RESULTS

Palbociclib combined with irradiation significantly inhibited the cell viability of ESCC in vitro. The expression level of γH2AX showed that radiation induced DNA damage repair was inhibited by palbociclib treatment. Palbociclib also suppressed the expression of RAD51 and phosphorylated DNA-dependent protein kinase catalytic subunit (p-DNA-PKcs) after irradiation. Mechanically, palbociclib enhanced the radiosensitization of ESCC by activating autophagy via suppression of mammalian target of rapamycin (mTOR). Inhibition of autophagy using chloroquine could partially reverse the radiation enhancing effect of palbociclib. Lastly, the xenografted tumor experiment confirmed the radiosensitizing effect of palbociclib in ESCC in vivo.

CONCLUSION

Our results showed that palbociclib improved the radiosensitivity of ESCC in vivo and in vitro, and thus it may be a promising radiosensitization agent for the treatment of ESCC.

The Intricate Interplay between Cell Cycle Regulators and Autophagy in Cancer

Simple Summary

Autophagy is an intracellular catabolic program regulated by multiple external and internal cues. A large amount of evidence unraveled that cell-cycle regulators are crucial in its control. This review highlights the interplay between cell-cycle regulators, including cyclin-dependent kinase inhibitors, cyclin-dependent kinases, and E2F factors, in the control of autophagy all along the cell cycle. Beyond the intimate link between cell cycle and autophagy, this review opens therapeutic perspectives in modulating together these two aspects to block cancer progression.

Abstract

In the past decade, cell cycle regulators have extended their canonical role in cell cycle progression to the regulation of various cellular processes, including cellular metabolism. The regulation of metabolism is intimately connected with the function of autophagy, a catabolic process that promotes the efficient recycling of endogenous components from both extrinsic stress, e.g., nutrient deprivation, and intrinsic sub-lethal damage. Mediating cellular homeostasis and cytoprotection, autophagy is found to be dysregulated in numerous pathophysiological contexts, such as cancer. As an adaptative advantage, the upregulation of autophagy allows tumor cells to integrate stress signals, escaping multiple cell death mechanisms. Nevertheless, the precise role of autophagy during tumor development and progression remains highly context-dependent. Recently, multiple articles has suggested the importance of various cell cycle regulators in the modulation of autophagic processes. Here, we review the current clues indicating that cell-cycle regulators, including cyclin-dependent kinase inhibitors (CKIs), cyclin-dependent kinases (CDKs), and E2F transcription factors, are intrinsically linked to the regulation of autophagy. As an increasing number of studies highlight the importance of autophagy in cancer progression, we finally evoke new perspectives in therapeutic avenues that may include both cell cycle inhibitors and autophagy modulators to synergize antitumor efficacy.

Cyclin-Dependent Kinase Inhibitors and Their Therapeutic Potential in Colorectal Cancer Treatment

Cyclin-dependent kinases (CDKs) are key players in cell cycle regulation. So far, more than ten CDKs have been described. Their direct interaction with cyclins allow progression through G1 phase, transitions to S and G2 phase and finally through mitosis (M). While CDK activation is important in cell renewal, its aberrant expression can lead to the development of malignant tumor cells. Dysregulations in CDK pathways are often encountered in various types of cancer, including all gastrointestinal (GI) tract tumors. This prompted the development of CDK inhibitors as novel therapies for cancer. Currently, CDK inhibitors such as CDK4/6 inhibitors are used in pre-clinical studies for cancer treatment. In this review, we will focus on the therapeutic role of various CDK inhibitors in colorectal cancer, with a special focus on the CDK4/6 inhibitors.

Analyzing the scaffold diversity of cyclin-dependent kinase inhibitors and revisiting the clinical and preclinical pipeline

Kinases have gained an important place in the list of vital therapeutic targets because of their overwhelming clinical success in the last two decades. Among various clinically validated kinases, the cyclin-dependent kinases (CDK) are one of the extensively studied drug targets for clinical development. Food and Drug Administration has approved three CDK inhibitors for therapeutic use, and at least 27 inhibitors are under active clinical development. In the last decade, research and development in this area took a rapid pace, and thus the analysis of scaffold diversity is essential for future drug design. Available reviews lack the systematic study and discussion on the scaffold diversity of CDK inhibitors. Herein we have reviewed and critically analyzed the chemical diversity present in the preclinical and clinical pipeline of CDK inhibitors. Our analysis has shown that although several scaffolds represent CDK inhibitors, only the amino-pyrimidine is a well-represented scaffold. The three-nitrogen framework of amino-pyrimidine is a fundamental hinge-binding unit. Further, we have discussed the selectivity aspects among CDKs, the clinical trial dose-limiting toxicities, and highlighted the most advanced clinical candidates. We also discuss the changing paradigm towards selective inhibitors and an overview of ATP-binding pockets of all druggable CDKs. We carefully analyzed the clinical pipeline to unravel the candidates that are currently under active clinical development. In addition to the plenty of dual CDK4/6 inhibitors, there are many selective CDK7, CDK9, and CDK8/19 inhibitors in the clinical pipeline.

mTOR Activity and Autophagy in Senescent Cells, a Complex Partnership

Cellular senescence is a form of proliferative arrest triggered in response to a wide variety of stimuli and characterized by unique changes in cell morphology and function. Although unable to divide, senescent cells remain metabolically active and acquire the ability to produce and secrete bioactive molecules, some of which have recognized pro-inflammatory and/or pro-tumorigenic actions. As expected, this “senescence-associated secretory phenotype (SASP)” accounts for most of the non-cell-autonomous effects of senescent cells, which can be beneficial or detrimental for tissue homeostasis, depending on the context. It is now evident that many features linked to cellular senescence, including the SASP, reflect complex changes in the activities of mTOR and other metabolic pathways. Indeed, the available evidence indicates that mTOR-dependent signaling is required for the maintenance or implementation of different aspects of cellular senescence. Thus, depending on the cell type and biological context, inhibiting mTOR in cells undergoing senescence can reverse senescence, induce quiescence or cell death, or exacerbate some features of senescent cells while inhibiting others. Interestingly, autophagy—a highly regulated catabolic process—is also commonly upregulated in senescent cells. As mTOR activation leads to repression of autophagy in non-senescent cells (mTOR as an upstream regulator of autophagy), the upregulation of autophagy observed in senescent cells must take place in an mTOR-independent manner. Notably, there is evidence that autophagy provides free amino acids that feed the mTOR complex 1 (mTORC1), which in turn is required to initiate the synthesis of SASP components. Therefore, mTOR activation can follow the induction of autophagy in senescent cells (mTOR as a downstream effector of autophagy). These functional connections suggest the existence of autophagy regulatory pathways in senescent cells that differ from those activated in non-senescence contexts. We envision that untangling these functional connections will be key for the generation of combinatorial anti-cancer therapies involving pro-senescence drugs, mTOR inhibitors, and/or autophagy inhibitors.

Anti-cancer therapy with cyclin-dependent kinase inhibitors: impact and challenges

The introduction of cyclin-dependent kinase 4/6 inhibitors (CKIs) has marked a major development in the standard treatment of advanced breast cancer. Extensive preclinical, translational and clinical research efforts into CKI agents are ongoing, and clinical application of this class of systemic anti-cancer therapy is anticipated to expand beyond metastatic breast cancer treatment. Emerging evidence indicates that mechanisms by which CKI agents exert their therapeutic effect transcend their initially expected impacts on cell cycle control into the realms of cancer immunology and metabolism. The recent expansion in our understanding of the multifaceted impact of CKIs on tumour biology has the potential to improve clinical study design, therapeutic strategies and ultimately patient outcomes. This review contextualises the current status of CKI therapy by providing an overview of the original and emerging insights into mechanisms of action and the evidence behind their current routine use in breast cancer management. Recent preclinical and clinical studies into CKIs across tumour types are discussed, including a synthesis of the more than 300 clinical trials of CKI-combination treatments registered as of November 2020. Key challenges and opportunities anticipated in the 2020s are explored, including treatment resistance, combination therapy strategies and potential biomarker development.

Pharmacoinformatics and Preclinical Studies of NSC765690 and NSC765599, Potential STAT3/CDK2/4/6 Inhibitors with Antitumor Activities against NCI60 Human Tumor Cell Lines

Signal transducer and activator of transcription 3 (STAT3) is a transcriptional regulator of a number of biological processes including cell differentiation, proliferation, survival, and angiogenesis, while cyclin-dependent kinases (CDKs) are a critical regulator of cell cycle progression. These proteins appear to play central roles in angiogenesis and cell survival and are widely implicated in tumor progression. In this study, we used the well-characterized US National Cancer Institute 60 (NCI60) human tumor cell lines to screen the in vitro anti-cancer activities of our novel small molecule derivatives (NSC765690 and NSC765599) of salicylanilide. Furthermore, we used the DTP-COMPARE algorithm and in silico drug target prediction to identify the potential molecular targets, and finally, we used molecular docking to assess the interaction between the compounds and prominent potential targets. We found that NSC765690 and NSC765599 exhibited an anti-proliferative effect against the 60 panels of NCI human cancer cell lines, and dose-dependent cytotoxic preference for NSCLC, melanoma, renal, and breast cancer cell lines. Protein–ligand interactions studies revealed that NSC765690 and NSC765599 were favored ligands for STAT3/CDK2/4/6. Moreover, cyclization of the salicylanilide core scaffold of NSC765690 mediated its higher anti-cancer activities and had greater potential to interact with STAT3/CDK2/4/6 than did NSC765599 with an open-ring structure. NSC765690 and NSC765599 met the required safety and criteria of a good drug candidate, and are thus worthy of further in-vitro and in-vivo investigations in tumor-bearing mice to assess their full therapeutic efficacy.

Targeting Autophagy in Breast Cancer

Breast cancer is a heterogeneous disease consisting of different biological subtypes, with differences in terms of incidence, response to diverse treatments, risk of disease progression, and sites of metastases. In the last years, several molecular targets have emerged and new drugs, targeting PI3K/Akt/mTOR and cyclinD/CDK/pRb pathways and tumor microenvironment have been integrated into clinical practice. However, it is clear now that breast cancer is able to develop resistance to these drugs and the identification of the underlying molecular mechanisms is paramount to drive further drug development. Autophagy is a highly conserved homeostatic process that can be activated in response to antineoplastic agents as a cytoprotective mechanism. Inhibition of autophagy could enhance tumor cell death by diverse anti-cancer therapies, representing an attractive approach to control mechanisms of drug resistance. In this manuscript, we present a review of autophagy focusing on its interplay with targeted drugs used for breast cancer treatment.

Dissecting pharmacological effects of chloroquine in cancer treatment: interference with inflammatory signaling pathways

Chloroquines are 4-aminoquinoline-based drugs mainly used to treat malaria. At pharmacological concentrations, they have significant effects on tissue homeostasis, targeting diverse signaling pathways in mammalian cells. A key target pathway is autophagy, which regulates macromolecule turnover in the cell. In addition to affecting cellular metabolism and bioenergetic flow equilibrium, autophagy plays a pivotal role at the interface between inflammation and cancer progression. Chloroquines consequently have critical effects in tissue metabolic activity and importantly, in key functions of the immune system. In this article, we will review the work addressing the role of chloroquines in the homeostasis of mammalian tissue, and the potential strengths and weaknesses concerning their use in cancer therapy.

The immunoglobulin superfamily member 3 (IGSF3) promotes hepatocellular carcinoma progression through activation of the NF-κB pathway

Background

Patients with hepatocellular carcinoma (HCC) suffer from a high fatality rate, likely due to increased incidence of tumor relapse and metastasis. Understanding the molecular mechanisms that contribute to HCC development and progression is vital for the discovery of new treatment targets. This study aims to explore the expression profiles and functions of immunoglobulin superfamily member 3 (IGSF3) in HCC.

Methods

We evaluated IGSF3 levels in HCC and normal tissues using bioinformatics, western blot, quantitative real-time PCR (qRT-PCR), and immunohistochemistry. We also conducted proliferation assays, colony formation assays, flow cytometry, cell migration assay, cell invasion assay, qRT-PCR, and western blotting in HCC cell lines. Immunofluorescence and western blotting further used to study the IGSF3 pathway. A mouse xenograft model was utilized to examine the influence of IGSF3 on HCC growth in vivo.

Results

IGSF3 levels were higher in HCC tissues and cell lines. Silencing of IGSF3 via lentiviral vector system (LV) inhibited migration, invasion, and growth of HCC cell lines in vitro as well as tumor growth in vivo. Overexpression of IGSF3 promoted result in vitro. Importantly, we found that IGSF3 activates the NF-κB pathway to promote tumorigenic features in HCC cell lines.

Conclusions

We found that IGSF3 can be used as a novel biomarker for HCC detection. Moreover, IGSF3 elicits HCC progression by activating the NF-κB pathway. As such, our data provides potential options for therapeutic targets in patients with HCC.

Zinc finger of the cerebellum 5 promotes colorectal cancer cell proliferation and cell cycle progression through enhanced CDK1/CDC25c signaling

Introduction

Colorectal cancer (CRC), mostly caused by external or environmental factors, is the third most common and lethal cancer worldwide. Although a large number of investigations have been carried out to reveal the evolution of CRC, the underlying mechanisms of CRC remain unclear.

Material and methods

Expression of zinc finger of the cerebellum 5 (ZIC5) in CRC tissues and cell models was measured by qRT-PCR and IHC. Cell transfection was carried out for ZIC5 overexpression or knockdown. The MTT assay was applied to examine the capacity of glioma cell proliferation. Wound healing assay and tumor invasion assay were used to test the capacity of glioma cell migration and invasion respectively. Cell cycle analysis and western blot were used to verify the apoptosis rates of CRC cells upon ZIC5 overexpression or downregulation. A further tumor Xenograft study was used to examine the effects of ZIC5 on tumor malignancy in vivo.

Results

Cell models using HCT116 and SW620 cells were established to study the ZIC5 function upon ZIC5 overexpression of knockdown. Consistently, we discovered that ZIC5 also significantly increased in Chinese CRC patients. In addition, ZIC5 promoted CRC cell proliferation through increasing the proportion of cells maintained in the S phase. ZIC5 overexpression facilitated the capacity of CRC cell migration and invasion. Inhibition of ZIC5 mitigated such malignant effects.

Conclusions

Collectively, investigations of the ZIC5 in CRC provided a new insight into CRC diagnosis, treatment, prognosis and next-step translational therapeutic developments from bench to clinic.

Latest Overview of the Cyclin-Dependent Kinases 4/6 Inhibitors in Breast Cancer: The Past, the Present and the Future

Endocrine resistance in hormone receptor positive breast cancer patients urges us to develop novel approaches such as inhibitors of the cyclin-dependent kinases (CDK) 4/6 to reverse its resistance. Nowadays, three selective CDK4/6 inhibitors (Palbociclib, Ribociclib and Abemaciclib) are approved by Federal Drug Administration and the European Medicines Agency for the treatment of advanced and metastatic HR+/HER2- breast cancer. However, no consistent conclusion has been reached to its application in other types of breast cancer. Therefore, the purpose of our study was to overview the clinical trials about the beneficial effects of Palbociclib, Ribociclib and Abemaciclib in breast cancer with their tolerable adverse effects, and discuss their resistant mechanisms thus looking for useful biomarkers to predict the efficiency of the CDK4/6 inhibitors. The CDK4/6 inhibitors application after the support of preclinic and clinic data will be helpful to provide other alternatively suitable strategies for different types of breast cancer patients.

Selective Autophagy Regulates Cell Cycle in Cancer Therapy

Aberrant function of cell cycle regulators results in uncontrolled cell proliferation, making them attractive therapeutic targets in cancer treatment. Indeed, survival of many cancers exclusively relies on these proteins, and several specific inhibitors are in clinical use. Although the ubiquitin-proteasome system is responsible for the periodic quality control of cell cycle proteins during cell cycle progression, increasing evidence clearly demonstrates the intimate interaction between cell cycle regulation and selective autophagy, important homeostasis maintenance machinery. However, these studies have often led to divergent rather than unifying explanations due to complexity of the autophagy signaling network, the inconsistent functions between general autophagy and selective autophagy, and the different characteristics of autophagic substrates. In this review, we highlight current data illustrating the contradictory and important role of cell cycle proteins in regulating autophagy. We also focus on how selective autophagy acts as a central mechanism to maintain orderly DNA repair and genome integrity by degrading specific cell cycle proteins, regulating cell division, and promoting DNA damage repair. We further discuss the ways in which selective autophagy may impact the cell cycle regulators, since failure to appropriately remove these can interfere with cell death-related processes, including senescence and autophagy-related cell death. Imbalanced cell proliferation is typically utilized by cancer cells to acquire resistance. Finally, we discuss the possibility of a potent anticancer therapeutic strategy that targets selective autophagy or autophagy and cell cycle together.

Cyclin D1-CDK4 activity drives sensitivity to bortezomib in mantle cell lymphoma by blocking autophagy-mediated proteolysis of NOXA

BACKGROUND

Mantle cell lymphoma (MCL) is an aggressive B-non-Hodgkin lymphoma with generally poor outcome. MCL is characterized by an aberrantly high cyclin D1-driven CDK4 activity. New molecular targeted therapies such as inhibitors of the ubiquitin-proteasome system (UPS) have shown promising results in preclinical studies and MCL patients. Our previous research revealed stabilization of the short-lived pro-apoptotic NOXA as a critical determinant for sensitivity to these inhibitors. It is currently unclear how cyclin D1 overexpression and aberrant CDK4 activity affect NOXA stabilization and treatment efficacy of UPS inhibitors in MCL.

METHODS

The effect of cyclin D1-driven CDK4 activity on response of MCL cell lines and primary cells to proteasome inhibitor treatment was investigated using survival assays (Flow cytometry, AnnexinV/PI) and Western blot analysis of NOXA protein. Half-life of NOXA protein was determined by cycloheximide treatment and subsequent Western blot analysis. The role of autophagy was analyzed by LC3-II protein expression and autophagolysosome detection. Furthermore, silencing of autophagy-related genes was performed using siRNA and MCL cells were treated with autophagy inhibitors in combination with proteasome and CDK4 inhibition.

RESULTS

In this study, we show that proteasome inhibitor-mediated cell death in MCL depends on cyclin D1-driven CDK4 activity. Inhibition of cyclin D1/CDK4 activity significantly reduced proteasome inhibitor-mediated stabilization of NOXA protein, mainly driven by an autophagy-mediated proteolysis. Bortezomib-induced cell death was significantly potentiated by compounds that interfere with autophagosomal function. Combined treatment with bortezomib and autophagy inhibitors enhanced NOXA stability leading to super-induction of NOXA protein. In addition to established autophagy modulators, we identified the fatty acid synthase inhibitor orlistat to be an efficient autophagy inhibitor when used in combination with bortezomib. Accordingly, this combination synergistically induced apoptosis both in MCL cell lines and in patient samples.

CONCLUSION

Our data demonstrate that CDK4 activity in MCL is critical for NOXA stabilization upon treatment with UPS inhibitors allowing preferential induction of cell death in cyclin D transformed cells. Under UPS blocked conditions, autophagy appears as the critical regulator of NOXA induction. Therefore, inhibitors of autophagy are promising candidates to increase the activity of proteasome inhibitors in MCL.

Autophagy Inhibition in Pancreatic Adenocarcinoma

Although some progress has been made in recent years with the development of more effective chemotherapy regimens, new treatment approaches are needed to improve outcomes for patients with pancreatic adenocarcinoma. The cellular process of autophagy, a cell survival mechanism that allows cancer cells to survive the hazardous conditions of the tumor microenvironment and treatment, has emerged as a viable target in pancreatic cancer. We review the mechanism of autophagy, its role in pancreatic carcinogenesis, the preclinical and clinical evidence supporting targeting autophagy in patients with pancreatic adenocarcinoma, and areas of future investigation that hold promise for improving this treatment approach.