CQ sensitizes human pancreatic cancer cells to gemcitabine through the lysosomal apoptotic pathway via reactive oxygen species

TH301 Emerges as a Novel Anti-Oncogenic Agent for Human Pancreatic Cancer Cells: The Dispensable Roles of p53, CRY2 and BMAL1 in TH301-Induced CDKN1A/p21CIP1/WAF1 Upregulation

Background: Pancreatic Ductal Adeno-Carcinoma (PDAC) is a highly aggressive cancer, with limited treatment options. Disruption of the circadian clock, which regulates key cellular processes, has been implicated in PDAC initiation and progression. Hence, targeting circadian clock components may offer new therapeutic opportunities for the disease. This study investigates the cytopathic effects of TH301, a novel CRY2 stabilizer, on PDAC cells, aiming to evaluate its potential as a novel therapeutic agent. Methods: PDAC cell lines (AsPC-1, BxPC-3 and PANC-1) were treated with TH301, and cell viability, cell cycle progression, apoptosis, autophagy, circadian gene, and protein expression profiles were analyzed, using MTT assay, flow cytometry, Western blotting, and RT-qPCR technologies. Results: TH301 proved to significantly decrease cell viability and to induce cell cycle arrest at the G1-phase across all PDAC cell lines herein examined, especially the AsPC-1 and BxPC-3 ones. It caused dose-dependent apoptosis and autophagy, and it synergized with Chloroquine and Oxaliplatin to enhance anti-oncogenicity. The remarkable induction of p21 by TH301 was shown to follow clock- and p53-independent patterns, thereby indicating the critical engagement of alternative mechanisms. Conclusions: TH301 demonstrates significant anti-cancer activities in PDAC cells, thus serving as a promising new therapeutic agent, which can also synergize with approved treatment schemes by targeting pathways beyond circadian clock regulation. Altogether, TH301 likely opens new therapeutic windows for the successful management of pancreatic cancer in clinical practice.

Triphenylphosphonium-Conjugated Palmitic Acid for Mitochondrial Targeting of Pancreatic Cancer Cells: Proteomic and Molecular Evidence

Pancreatic ductal adenocarcinoma (PDAC)'s resistance to therapies is mainly attributed to pancreatic cancer stem cells (PCSCs). Mitochondria-impairing agents can be used to hamper PCSC propagation and reduce PDAC progression. Therefore, to develop an efficient vector for delivering drugs to the mitochondria, we synthesized tris(3,5-dimethylphenyl)phosphonium-conjugated palmitic acid. Triphenylphosphonium (TPP) is a lipophilic cationic moiety that promotes the accumulation of conjugated agents in the mitochondrion. Palmitic acid (PA), the most common saturated fatty acid, has pro-apoptotic activity in different types of cancer cells. TPP-PA was prepared by the reaction of 16-bromopalmitic acid with TPP, and its structure was characterized by 1H and 13C NMR and HRMS. We compared the proteomes of TPP-PA-treated and untreated PDAC cells and PCSCs, identifying dysregulated proteins and pathways. Furthermore, assessments of mitochondrial membrane potential, intracellular ROS, cardiolipin content and lipid peroxidation, ER stress, and autophagy markers provided information on the mechanism of action of TPP-PA. The findings showed that TPP-PA reduces PDAC cell proliferation through mitochondrial disruption that leads to increased ROS, activation of ER stress, and autophagy. Hence, TPP-PA might offer a new approach for eliminating both the primary population of cancer cells and PCSCs, which highlights the promise of TPP-derived compounds as anticancer agents for PDAC.

CDK12 inhibition upregulates ATG7 triggering autophagy via AKT/FOXO3 pathway and enhances anti-PD-1 efficacy in colorectal cancer

As the world's fourth most deadly cancer, colorectal cancer (CRC) still needed the novel therapeutic drugs and target urgently. Although cyclin-dependent kinase 12 (CDK12) has been shown to be implicated in the malignancy of several types of cancer, its functional role and mechanism in CRC remain largely unknown. Here, we found that suppression of CDK12 inhibited tumor growth in CRC by inducing apoptosis. And CDK12 inhibition triggered autophagy by upregulating autophagy related gene 7 (ATG7) expression. Inhibition of autophagy by ATG7 knockdown and chloroquine (CQ) further decreased cell viability induced by CDK12 inhibition. Further mechanism exploration showed that CDK12 interacted with protein kinase B (AKT) regulated autophagy via AKT/forkhead box O3 (AKT/FOXO3) pathway. FOXO3 transcriptionally upregulated ATG7 expression and autophagy when CDK12 inhibition in CRC. Level of CDK12 and p-FOXO3/FOXO3 ratio were correlated with survival in CRC patients. Moreover, CDK12 inhibition improved the efficacy of anti-programmed cell death 1(PD-1) therapy in CRC murine models by enhancing CD8 + T cells infiltration. Thus, our study founded that CDK12 inhibition upregulates ATG7 triggering autophagy via AKT/FOXO3 pathway and enhances anti-PD-1 efficacy in CRC. We revealed the roles of CDK12/FOXO3/ATG7 in regulating CRC progression, suggesting potential biomarkers and therapeutic target for CRC.

Unveiling the mechanisms and challenges of cancer drug resistance

Cancer treatment faces many hurdles and resistance is one among them. Anti-cancer treatment strategies are evolving due to innate and acquired resistance capacity, governed by genetic, epigenetic, proteomic, metabolic, or microenvironmental cues that ultimately enable selected cancer cells to survive and progress under unfavorable conditions. Although the mechanism of drug resistance is being widely studied to generate new target-based drugs with better potency than existing ones. However, due to the broader flexibility in acquired drug resistance, advanced therapeutic options with better efficacy need to be explored. Combination therapy is an alternative with a better success rate though the risk of amplified side effects is commonplace. Moreover, recent groundbreaking precision immune therapy is one of the ways to overcome drug resistance and has revolutionized anticancer therapy to a greater extent with the only limitation of being individual-specific and needs further attention. This review will focus on the challenges and strategies opted by cancer cells to withstand the current therapies at the molecular level and also highlights the emerging therapeutic options -like immunological, and stem cell-based options that may prove to have better potential to challenge the existing problem of therapy resistance. Video Abstract.

IPIAD- an augmentation regimen added to standard treatment of pancreatic ductal adenocarcinoma using already-marketed repurposed drugs irbesartan, pyrimethamine, itraconazole, azithromycin, and dapsone

This short note presents the data and rationale for adding five generic non-oncology drugs from general medical practice to gemcitabine, nab-paclitaxel, a current standard cytotoxic chemotherapy of pancreatic ductal adenocarcinoma. The regimen, called IPIAD, uses an angiotensin receptor blocker (ARB) irbesartan indicated for treating hypertension, an old antimicrobial drug pyrimethamine indicated for treating toxoplasmosis or malaria, an old antifungal drug itraconazole, an old broad spectrum antibiotic azithromycin and an old antibiotic dapsone. In reviewing selected growth driving systems active in pancreatic ductal adenocarcinoma then comparing these with detailed data on ancillary attributes of the IPIAD drugs, one can predict clinical benefit and slowing growth of pancreatic ductal adenocarcinoma by this augmentation regimen.

ISG15 Promotes Progression and Gemcitabine Resistance of Pancreatic Cancer Cells Through ATG7

Chemoresistance is an obstacle of improving pancreatic cancer (PC) prognosis. However, the biological function of ISG15 in PC and whether it correlates with the resistance to chemotherapy are still unknown. Here, we aimed to reveal the clinical significance of ISG15 in PC and its regulatory mechanism in cancer progression and resistance to therapy. The level of ISG15, a protein involved in post-translational modifications, is elevated in PC tissues. Clinically, higher ISG15 expression correlates with higher PC grades, stronger resistance to treatment and poorer prognosis. Moreover, ISG15 promotes the proliferation, migration, invasion, colony formation of PC cells and resistance to Gemcitabine, a classic chemotherapeutics for PC, both in vitro and in vivo. ISG15 promotes progression and resistance to therapy in PC cells by binding to ATG7, reducing its degradation, and thereby leading to enhanced autophagy in PC cells. ISG15 may be used as both a potential diagnosis marker and sensitizer for chemotherapeutics such as Gemcitabine during PC intervention.

The role of redox-mediated lysosomal dysfunction and therapeutic strategies

Redox homeostasis refers to the dynamic equilibrium between oxidant and reducing agent in the body which plays a crucial role in maintaining normal physiological activities of the body. The imbalance of redox homeostasis can lead to the development of various human diseases. Lysosomes regulate the degradation of cellular proteins and play an important role in influencing cell function and fate, and lysosomal dysfunction is closely associated with the development of various diseases. In addition, several studies have shown that redox homeostasis plays a direct or indirect role in regulating lysosomes. Therefore, this paper systematically reviews the role and mechanisms of redox homeostasis in the regulation of lysosomal function. Therapeutic strategies based on the regulation of redox exerted to disrupt or restore lysosomal function are further discussed. Uncovering the role of redox in the regulation of lysosomes helps to point new directions for the treatment of many human diseases.

Comparison of Tumour-Specific Phenotypes in Human Primary and Expandable Pancreatic Cancer Cell Lines

There is an ongoing need for patient-specific chemotherapy for pancreatic cancer. Tumour cells isolated from human tissues can be used to predict patients' response to chemotherapy. However, the isolation and maintenance of pancreatic cancer cells is challenging because these cells become highly vulnerable after losing the tumour microenvironment. Therefore, we investigated whether the cells retained their original characteristics after lentiviral transfection and expansion. Three human primary pancreatic cancer cell lines were lentivirally transduced to create expandable (Ex) cells which were then compared with primary (Pri) cells. No obvious differences in the morphology or epithelial-mesenchymal transition (EMT) were observed between the primary and expandable cell lines. The two expandable cell lines showed higher proliferation rates in the 2D and 3D models. All three expandable cell lines showed attenuated migratory ability. Differences in gene expression between primary and expandable cell lines were then compared using RNA-Seq data. Potential target drugs were predicted by differentially expressed genes (DEGs), and differentially expressed pathways (DEPs) related to tumour-specific characteristics such as proliferation, migration, EMT, drug resistance, and reactive oxygen species (ROS) were investigated using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. We found that the two expandable cell lines expressed similar chemosensitivity and redox-regulatory capability to gemcitabine and oxaliplatin in the 2D model as compared to their counterparts. In conclusion, we successfully generated expandable primary pancreatic cancer cell lines using lentiviral transduction. These expandable cells not only retain some tumour-specific biological traits of primary cells but also show an ongoing proliferative capacity, thereby yielding sufficient material for drug response assays, which may provide a patient-specific platform for chemotherapy drug screening.

Gemcitabine promotes autophagy and lysosomal function through ERK- and TFEB-dependent mechanisms

Gemcitabine is a first-line treatment agent for pancreatic ductal adenocarcinoma (PDAC). Contributing to its cytotoxicity, this chemotherapeutic agent is primarily a DNA replication inhibitor that also induces DNA damage. However, its therapeutic effects are limited owing to chemoresistance. Evidence in the literature points to a role for autophagy in restricting the efficacy of gemcitabine. Autophagy is a catabolic process in which intracellular components are delivered to degradative organelles lysosomes. Interfering with this process sensitizes PDAC cells to gemcitabine. It is consequently inferred that autophagy and lysosomal function need to be tightly regulated to maintain homeostasis and provide resistance to environmental stress, such as those imposed by chemotherapeutic drugs. However, the mechanism(s) through which gemcitabine promotes autophagy remains elusive, and the impact of gemcitabine on lysosomal function remains largely unexplored. Therefore, we applied complementary approaches to define the mechanisms triggered by gemcitabine that support autophagy and lysosome function. We found that gemcitabine elicited ERK-dependent autophagy in PDAC cells, but did not stimulate ERK activity or autophagy in non-tumoral human pancreatic epithelial cells. Gemcitabine also promoted transcription factor EB (TFEB)-dependent lysosomal function in PDAC cells. Indeed, treating PDAC cells with gemcitabine caused expansion of the lysosomal network, as revealed by Lysosome associated membrane protein-1 (LAMP1) and LysoTracker staining. More specific approaches have shown that gemcitabine promotes the activity of cathepsin B (CTSB), a cysteine protease playing an active role in lysosomal degradation. We showed that lysosomal function induced by gemcitabine depends on TFEB, the master regulator of autophagy and lysosomal biogenesis. Interfering with TFEB function considerably limited the clonogenic growth of PDAC cells and hindered the capacity of TFEB-depleted PDAC cells to develop orthotopic tumors.

The key role of microRNA-766 in the cancer development

Cancer is caused by defects in coding and non-coding RNAs. In addition, duplicated biological pathways diminish the efficacy of mono target cancer drugs. MicroRNAs (miRNAs) are short, endogenous, non-coding RNAs that regulate many target genes and play a crucial role in physiological processes such as cell division, differentiation, cell cycle, proliferation, and apoptosis, which are frequently disrupted in diseases such as cancer. MiR-766, one of the most adaptable and highly conserved microRNAs, is notably overexpressed in several diseases, including malignant tumors. Variations in miR-766 expression are linked to various pathological and physiological processes. Additionally, miR-766 promotes therapeutic resistance pathways in various types of tumors. Here, we present and discuss evidence implicating miR-766 in the development of cancer and treatment resistance. In addition, we discuss the potential applications of miR-766 as a therapeutic cancer target, diagnostic biomarker, and prognostic indicator. This may shed light on the development of novel therapeutic strategies for cancer therapy.

Effective combinations of anti-cancer and targeted drugs for pancreatic cancer treatment

Pancreatic cancer is highly aggressive and lethal. Due to the lack of effective methods for detecting the disease at an early stage, pancreatic cancer is frequently diagnosed late. Gemcitabine has been the standard chemotherapy drug for patients with pancreatic cancer for over 20 years, but its anti-tumor effect is limited. Therefore, FOLFIRINOX (leucovorin, fluorouracil, irinotecan, oxaliplatin) as well as combination therapies using gemcitabine and conventional agents, such as cisplatin and capecitabine, has also been administered; however, these have not resulted in complete remission. Therefore, there is a need to develop novel and effective therapies for pancreatic cancer. Recently, some studies have reported that combinations of gemcitabine and targeted drugs have had significant anti-tumor effects on pancreatic cancer cells. As gemcitabine induced DNA damage response, the proteins related to DNA damage response can be suitable additional targets for novel gemcitabine-based combination therapy. Furthermore, KRAS/ RAF/MEK/ERK signaling triggered by oncogenic mutated KRAS and autophagy are frequently activated in pancreatic cancer. Therefore, these characteristics of pancreatic cancer are potential targets for developing effective novel therapies.

In this minireview, combinations of gemcitabine and targeted drugs to these characteristics, combinations of targeted drugs, combinations of natural products and anti-cancer agents, including gemcitabine, and combinations among natural products are discussed.

Autophagy: A Key Player in Pancreatic Cancer Progression and a Potential Drug Target

Pancreatic cancer is known to have the lowest survival outcomes among all major cancers, and unfortunately, this has only been marginally improved over last four decades. The innate characteristics of pancreatic cancer include an aggressive and fast-growing nature from powerful driver mutations, a highly defensive tumor microenvironment and the upregulation of advantageous survival pathways such as autophagy. Autophagy involves targeted degradation of proteins and organelles to provide a secondary source of cellular supplies to maintain cell growth. Elevated autophagic activity in pancreatic cancer is recognized as a major survival pathway as it provides a plethora of support for tumors by supplying vital resources, maintaining tumour survival under the stressful microenvironment and promoting other pathways involved in tumour progression and metastasis. The combination of these features is unique to pancreatic cancer and present significant resistance to chemotherapeutic strategies, thus, indicating a need for further investigation into therapies targeting this crucial pathway. This review will outline the autophagy pathway and its regulation, in addition to the genetic landscape and tumor microenvironment that contribute to pancreatic cancer severity. Moreover, this review will also discuss the mechanisms of novel therapeutic strategies that inhibit autophagy and how they could be used to suppress tumor progression.

Autophagy-associated circRNA circATG7 facilitates autophagy and promotes pancreatic cancer progression

Dysregulation of autophagy and circular RNAs (circRNAs) are involved in the pancreatic cancer (PC) progression. However, the regulatory network between circRNAs, autophagy, and PC progression remains unknown. Herein, we demonstrated that autophagy-associated circRNA circ-autophagy related 7 (circATG7) was elevated in PC tissues compared to adjacent tissues, and in PC cells treated with EBSS and hypoxia. circATG7 expression was positively associated with tumor diameter and lymph node invasion in patients with PC. circATG7 overexpression promoted PC cell proliferation, mobility, and autophagy in vitro, while circATG7 knockdown induced the opposite effects. ATG7 inhibition attenuated the effects of circATG7 on the biological functions of PC cells. CircATG7 is located in the cell cytoplasm and nucleus. Cytoplasmic circATG7 sponged miR-766-5p and decreased its expression, and increased the expression of ATG7, a target gene of miR-766-5p. Nuclear circATG7 acted as a scaffold to increase the interaction between the human antigen R protein and ATG7 mRNA and enhanced ATG mRNA stability. Furthermore, we demonstrated that circATG7 regulates PC cell proliferation and metastasis in vivo via ATG7-dependent autophagy. In conclusion, our results demonstrated that circATG7 accelerates PC progression via miR-766-5p/ATG7 and that HUR/ATG7 depends on autophagic flux. Thus, circATG7 may be a potential therapeutic target for PC.

The new role of riluzole in the treatment of pancreatic cancer through the apoptosis and autophagy pathways

Pancreatic cancer is always diagnosed at an advanced stage. Hence, chemotherapy becomes the best choice for patients. Therefore, new anticancer drugs for pancreatic cancer are needed. Riluzole (RIL) is mainly used to treat amyotrophic lateral sclerosis clinically, but many previous studies have shown that RIL could inhibit tumors. However, no report has explored the association between RIL and pancreatic cancer. To validate this association, we performed this study. Our data showed that RIL could induce cytotoxicity, block the cell cycle, and inhibit clone formation, apoptosis, and migration in pancreatic cancer cells. Moreover, we demonstrated that RIL could suppress autophagy. However, more experiments will be needed to validate the reliability of our conclusions. In summary, our data suggest that RIL might provide clues for the development of a treatment for human pancreatic cancer in the future.

Drug Repurposing, an Attractive Strategy in Pancreatic Cancer Treatment: Preclinical and Clinical Updates

Pancreatic cancer (PC) is one of the deadliest malignancies worldwide, since patients rarely display symptoms until an advanced and unresectable stage of the disease. Current chemotherapy options are unsatisfactory and there is an urgent need for more effective and less toxic drugs to improve the dismal PC therapy. Repurposing of non-oncology drugs in PC treatment represents a very promising therapeutic option and different compounds are currently being considered as candidates for repurposing in the treatment of this tumor. In this review, we provide an update on some of the most promising FDA-approved, non-oncology, repurposed drug candidates that show prominent clinical and preclinical data in pancreatic cancer. We also focus on proposed mechanisms of action and known molecular targets that they modulate in PC. Furthermore, we provide an explorative bioinformatic analysis, which suggests that some of the PC repurposed drug candidates have additional, unexplored, oncology-relevant targets. Finally, we discuss recent developments regarding the immunomodulatory role displayed by some of these drugs, which may expand their potential application in synergy with approved anticancer immunomodulatory agents that are mostly ineffective as single agents in PC.

The role of anlotinib-mediated EGFR blockade in a positive feedback loop of CXCL11-EGF-EGFR signalling in anaplastic thyroid cancer angiogenesis

BACKGROUND

Hypoxia-induced angiogenesis functions importantly in anaplastic thyroid cancer (ATC) progression. However, the therapeutic potential of broad-spectrum anti-angiogenic agent remains undefined. Anlotinib conventionally targets VEGFR, FGFR and PDGFR. Here, a novel role of anlotinib on ATC angiogenesis was illustrated.

METHODS

Molecular expressions were established via tissue microarray. Multiple assays (tubule formation, 3D sprouting and chicken chorioallantoic membrane model) were used for angiogenic evaluation. Panels of molecular screening were achieved by antibody and PCR arrays. The loop binding motif of EGFR for homology modelling was prepared using Maestro.

RESULTS

Anlotinib could dose- and time-dependently inhibit cell viability under normoxia and hypoxia and could repress hypoxia-activated angiogenesis more efficiently in vitro and in vivo. CXCL11 and phospho-EGFR were hypoxia-upregulated with a positive correlation. The cancer-endothelium crosstalk could be mediated by the positive CXCL11-EGF-EGFR feedback loop, which could be blocked by anlotinib directly targeting EGFR via a dual mechanism by simultaneous inhibitory effects on cancer and endothelial cells. The AKT-mTOR pathway was involved in this regulatory network.

CONCLUSIONS

The newly identified CXCL11-EGF-EGFR signalling provided mechanistic insight into the interaction between cancer and endothelial cells under hypoxia, and EGFR was a novel target. Anlotinib may be the encouraging therapeutic candidate in ATC.

Combination Chemotherapy with Cisplatin and Chloroquine: Effect of Encapsulation in Micelles Formed by Self-Assembling Hybrid Dendritic-Linear-Dendritic Block Copolymers

Clinical outcomes of conventional drug combinations are not ideal due to high toxicity to healthy tissues. Cisplatin (CDDP) is the standard component for many cancer treatments, yet its principal dose-limiting side effect is nephrotoxicity. Thus, CDDP is commonly used in combination with other drugs, such as the autophagy inhibitor chloroquine (CQ), to enhance tumor cell killing efficacy and prevent the development of chemoresistance. In addition, nanocarrier-based drug delivery systems can overcome chemotherapy limitations, decreasing side effects and increasing tumor accumulation. The aim of this study was to evaluate the toxicity of CQ and CDDP against tumor and non-tumor cells when used in a combined treatment. For this purpose, two types of micelles based on Pluronic^® F127 hybrid dendritic–linear–dendritic block copolymers (HDLDBCs) modified with polyester or poly(esteramide) dendrons derived from 2,2′-bis(hydroxymethyl)propionic acid (HDLDBC-bMPA) or 2,2′-bis(glycyloxymethyl)propionic acid (HDLDBC-bGMPA) were explored as delivery nanocarriers. Our results indicated that the combined treatment with HDLDBC-bMPA(CQ) or HDLDBC-bGMPA(CQ) and CDDP increased cytotoxicity in tumor cells compared to the single treatment with CDDP. Encapsulations demonstrated less short-term cytotoxicity individually or when used in combination compared to the free drugs. However, and more importantly, a low degree of cytotoxicity against non-tumor cells was maintained, even when drugs were given simultaneously.

Suppression of lysosomal acid alpha-glucosidase impacts the modulation of transcription factor EB translocation in pancreatic cancer

Lysosomal degradation plays a crucial role in the metabolism of biological macromolecules supplied by autophagy. The regulation of the autophagy‐lysosome system, which contributes to intracellular homeostasis, chemoresistance, and tumor progression, has recently been revealed as a promising therapeutic approach for pancreatic cancer (PC). However, the details of lysosomal catabolic function in PC cells have not been fully elucidated. In this study, we show evidence that suppression of acid alpha‐glucosidase (GAA), one of the lysosomal enzymes, improves chemosensitivity and exerts apoptotic effects on PC cells through the disturbance of expression of the transcription factor EB. The levels of lysosomal enzyme were elevated by gemcitabine in PC cells. In particular, the levels of GAA were responsive to gemcitabine in a dose–dependent and time–dependent manner. Small interfering RNA against the GAA gene (siGAA) suppressed cell proliferation and promoted apoptosis in gemcitabine‐treated PC cells. In untreated PC cells, we observed accumulation of depolarized mitochondria. Gene therapy using adenoviral vectors carrying shRNA against the GAA gene increased the number of apoptotic cells and decreased the tumor growth in xenograft model mice. These results indicate that GAA is one of the key targets to improve the efficacy of gemcitabine and develop novel therapies for PC.

Overcoming Chemoresistance: Altering pH of Cellular Compartments by Chloroquine and Hydroxychloroquine

Resistance to the anti-cancer effects of chemotherapeutic agents (chemoresistance) is a major issue for people living with cancer and their providers. A diverse set of cellular and inter-organellar signaling changes have been implicated in chemoresistance, but it is still unclear what processes lead to chemoresistance and effective strategies to overcome chemoresistance are lacking. The anti-malaria drugs, chloroquine (CQ) and its derivative hydroxychloroquine (HCQ) are being used for the treatment of various cancers and CQ and HCQ are used in combination with chemotherapeutic drugs to enhance their anti-cancer effects. The widely accepted anti-cancer effect of CQ and HCQ is their ability to inhibit autophagic flux. As diprotic weak bases, CQ and HCQ preferentially accumulate in acidic organelles and neutralize their luminal pH. In addition, CQ and HCQ acidify the cytosolic and extracellular environments; processes implicated in tumorigenesis and cancer. Thus, the anti-cancer effects of CQ and HCQ extend beyond autophagy inhibition. The present review summarizes effects of CQ, HCQ and proton pump inhibitors on pH of various cellular compartments and discuss potential mechanisms underlying their pH-dependent anti-cancer effects. The mechanisms considered here include their ability to de-acidify lysosomes and inhibit autophagosome lysosome fusion, to de-acidify Golgi apparatus and secretory vesicles thus affecting secretion, and to acidify cytoplasm thus disturbing aerobic metabolism. Further, we review the ability of these agents to prevent chemotherapeutic drugs from accumulating in acidic organelles and altering their cytosolic concentrations.

2‑Hydroxypropyl‑β‑cyclodextrin blocks autophagy flux and triggers caspase‑8‑mediated apoptotic cascades in HepG2 cells

The cyclodextrin derivative, 2‑Hydroxypropyl-β‑cyclodextrin (HPβCD), from the cyclodextrin family is widely used as a drug carrier and offers promising strategies for treating neurodegenerative diseases and atherosclerosis regression. However, its side effects are not fully understood. Therefore, the aim of the present study was to investigate the possible adverse effects of relatively high concentrations of HPβCD on hepatocytes. It was found that a high dose (20 mM) of HPβCD treatment significantly inhibited the AKT/mTOR pathway and disrupted infusion of autophagosomes and lysosomes, which rapidly led to massive autophagosome accumulation in HepG2 cells. The autophagosomal membrane serves as a platform for caspase‑8 oligomerization, which is considered as the key step for its self‑activation. Using flow cytometry and TUNEL assay, increased apoptosis of HepG2 cells treated with a high dose HPβCD (20 mM) for 48 h was observed. In addition, western blotting results demonstrated that the expression of cleaved‑caspase‑8 was positively associated with microtubule‑associated protein 1 light chain 3 BII expression, which is an indicator of autophagosome level in the cytoplasm. Therefore, the present study provided novel evidence that HPβCD might be a potential risk contributing to the pathophysiological process of hepatic diseases, especially in an autophagy‑deficient state.

Pharmacological Advances of Chloroquine and Hydroxychloroquine: From Antimalarials to Investigative Therapies in COVID-19

During the coronavirus disease 2019 (COVID-19) pandemic, numerous existing chemicals have been screened for antiviral potential against the emerging coronavirus severe acute respiratory syndrome coronavirus 2. Chloroquine and hydroxychloroquine, after exhibiting potent in vitro efficacy, have gained tremendous attention. Both therapeutics are derivatives of natural alkaloid quinine and were first synthesized to treat malaria. Thereafter, the pharmaceutical applications of the agents have expanded to many new areas. In this article, the medicinal history and pharmacological activities of chloroquine and hydroxychloroquine are summarized. Antimalarial, anti-inflammatory, antitumor, antiviral properties, and therapeutic potential in the emerging viral infection COVID-19 are discussed. Pharmacokinetics, adverse effects, and toxicities are reviewed.

Oxidative damage of lysosomes in regulated cell death systems: Pathophysiology and pharmacologic interventions

Lysosomes are small specialized organelles containing a variety of different hydrolase enzymes that are responsible for degradation of all macromolecules, entering the cells through the endosomal system or originated from the internal sources. This allows for transport and recycling of nutrients and internalization of surface proteins for antigen presentation as well as maintaining cellular homeostasis. Lysosomes are also important storage compartments for metal ions and nutrients. The integrity of lysosomal membrane is central to maintaining their normal function, but like other cellular membranes, lysosomal membrane is subject to damage mediated by reactive oxygen species. This results in spillage of lysosomal enzymes into the cytoplasm, leading to proteolytic damage to cellular systems and organelles. Several forms of lysosomal dependent cell death have been identified in diseases. Examination of these events are important for finding treatment strategies relevant to cancer or neurodegenerative diseases as well as autoimmune deficiencies. In this review, we have examined the current literature on involvement of lysosomes in induction of programed cell death and have provided an extensive list of therapeutic approaches that can modulate cell death. Exploitation of these mechanisms can lead to novel therapies for cancer and neurodegenerative diseases.

Inhibition of autophagy by chloroquine enhances the antitumor activity of gemcitabine for gallbladder cancer

Gemcitabine (GEM), as an anti-metabolic nucleoside analog, has been shown to have anticancer effects in various tumors, but its chemotherapy resistance is still an important factor leading to poor prognosis of cancer patient. A large number of studies in recent years have shown that autophagy plays an important role in the chemotherapy sensitivity of many tumors, including pancreatic, non-small cell lung, and bladder cancer. However, whether GEM causes autophagy in gallbladder cancer (GBC) and whether it is related to chemotherapy resistance is unknown. In the present study, we demonstrated that GEM induced apoptosis and protective autophagy in GBC cells, which may be related to the AKT/mTOR signaling pathway, and GEM in combination with autophagy inhibitor chloroquine can strengthen the cytotoxic effect of GEM on GBC in vitro and in vivo. These findings showed that both autophagy and AKT/mTOR signals were engaged in GBC cell death evoked by GEM, GBC patients might benefit from this new treatment strategy, and molecular targeted treatment in combination with autophagy inhibitors shows promise as a treatment improvement.

Phosphoinositide specific phospholipase Cγ1 inhibition-driven autophagy caused cell death in human lung adenocarcinoma A549 cells in vivo and in vitro

Our previous studies indicated that phosphoinositide specific phospholipase Cγ1 (PLCγ1) was involved in autophagy induction in colon and hepatic carcinoma cells. However, whether and how PLCγ1 regulation in human lung adenocarcinoma is linked to autophagy remains unclear. Here, we assessed the protein expression of PLCγ1 in human lung adenocarcinoma tissue using immunohistochemistry assay and the relationship between PLCG1 and autophagy in The Cancer Genome Atlas Network (TCGA) using Spearman correlation analysis and GSEA software. Furthermore, the interaction between PLCγ1 and autophagy-related signal molecules was investigated in human lung adenocarcinoma A549 cells treated with different inhibitors or transduction with lentivirus-mediated PLCγ1 gene short-hairpin RNA (shRNA) vectors using MTT, clonogenicity, Transwell migration, RT-PCR, Caspase-3, mitochondrial transmembrane potential, and western blotting assays, as well as transmission electron microscope technique. Additionally, the effect of shRNA/PLCγ1 alone or combined with autophagic activator Lithium Chloride (LiCl) on tumor growth and metastasis was measured using immunohistochemistry and assays in A549 xenograft nude mouse model. The results showed that increased PLCγ1 expression occurred frequently in human lung adenocarcinoma tissue with higher grades of T in TNM staging classification. PLCγ1 significantly enriched in autophagic process and regulation, which negatively regulating autophagy was enriched in higher expression of PLCγ1. PLCγ1 inhibition partially reduced cell proliferation and migration of A549 cells, with an increased autophagic flux involving alterations of AMPKα, mTOR, and ERK levels. However, PLCγ1 inhibition-driven autophagy led to cell death without depending on Caspase-3 and RIP1. Additionally, the abrogation of PLCγ1 signaling by shRNA and combination with autophagic activator LiCl could efficaciously suppress tumor growth and metastasis in A549 xenograft nude mice, in combination with a decrease in P62 level. These findings collectively suggest that reduction of cell proliferation and migration by PLCγ1 inhibition could be partially attributed to PLCγ1 inhibition-driven autophagic cell death (ACD). It highlights the potential role of a combination between targeting PLCγ1 and autophagy pathway in anti-tumor therapy, which may be an efficacious new strategy to overcome the autophagy addition of tumor and acquired resistance to current therapy.

Molecular Mechanisms Underlying Autophagy-Mediated Treatment Resistance in Cancer

Despite advances in diagnostic tools and therapeutic options, treatment resistance remains a challenge for many cancer patients. Recent studies have found evidence that autophagy, a cellular pathway that delivers cytoplasmic components to lysosomes for degradation and recycling, contributes to treatment resistance in different cancer types. A role for autophagy in resistance to chemotherapies and targeted therapies has been described based largely on associations with various signaling pathways, including MAPK and PI3K/AKT signaling. However, our current understanding of the molecular mechanisms underlying the role of autophagy in facilitating treatment resistance remains limited. Here we provide a comprehensive summary of the evidence linking autophagy to major signaling pathways in the context of treatment resistance and tumor progression, and then highlight recently emerged molecular mechanisms underlying autophagy and the p62/KEAP1/NRF2 and FOXO3A/PUMA axes in chemoresistance.

Chicoric acid (CA) induces autophagy in gastric cancer through promoting endoplasmic reticulum (ER) stress regulated by AMPK

Gastric cancer is one of the most common cancers leading to tumor-related deaths worldwide. Chicoric acid (CA) exhibits a variety of protective effects in different diseases. However, its role in regulating tumor progression has not been reported. Autophagy, as a conserved catabolic process, sustains cellular homoeostasis responding to stress to modulate cell fate. In the study, the effects of CA on gastric cancer were investigated. The results indicated that CA treatment markedly reduced the cell viability and induced apoptosis in gastric cancer cells, and prevented tumor growth in an established xenograft gastric cancer model. Furthermore, CA exposure significantly induced autophagy both in gastric cancer cells and tumor samples, as evidenced by the up-regulated expression of LC3II. Moreover, phosphorylated AMP-activated protein kinase (AMPK) and p70S6 kinase (p70s6k) expression were obviously promoted by CA in vitro and in vivo. Importantly, blocking AMPK activation abrogated CA-induced expression of LC3II in gastric cancer cells. In addition, endoplasmic reticulum (ER) stress in tumor samples or cells was markedly induced by CA treatment through promoting the expression of associated signals such as Parkin, protein kinase RNA-like ER kinase (PERK), activating transcription factors 4 (ATF4) and ATF6. Importantly, these effects were abolished by the inhibition of AMPK signaling. Collectively, our findings indicated that CA prevents human gastric cancer progression by inducing autophagy partly through the activation of AMPK, and represents an effective therapeutic strategy against gastric cancer development.

Lobaplatin-Induced Apoptosis Requires p53-Mediated p38MAPK Activation Through ROS Generation in Non-Small-Cell Lung Cancer

Platinum-based chemotherapy is recommended as the first-line treatment regimen for patients with advanced non-small-cell lung cancer (NSCLC). Lobaplatin (LBP), a third-generation platinum anti-neoplastic agent, has shown an improved efficacy. This study is aimed to investigate the mechanisms of LBP-induced apoptosis in the A549 p53 wild-type cell line. The Cell Counting Kit-8 assay (CCK-8), flow cytometry (FCM), Western blot, xenograft tumor models, terminal deoxynucleotide transferase dUTP nick end labeling (TUNEL), and RNA interference were used in this study. Our results showed that the proliferation of A549 cells could be inhibited by LBP. At lower concentrations, LBP triggered cell cycle arrest at the G1 phase in A549 cells. LBP could also induce apoptosis of A549 cells. LBP also increased the expression of PARP and Bax and the cleavage of caspase-3, caspase-8, and caspase-9 and reduced Bcl-2 expression. In vivo experiment confirmed that LBP could inhibit tumor growth in the A549 xenograft models and induce apoptosis. Apoptosis of A549 cells was decreased after transfected with p53 shRNA or treated with reactive oxygen species inhibitor NAC and p38MAPK inhibitor SB203580, suggesting that the p53/ROS/p38MAPK pathway appeared to mediate the LBP-induced apoptosis of A549 cells. Our data demonstrate that LBP could be a promising candidate for the treatment of NSCLC with wild-type p53.

EGFR TKIs impair lysosome-dependent degradation of SQSTM1 to compromise the effectiveness in lung cancer

Tyrosine kinase inhibitors for epidermal growth factor receptor (EGFR TKIs) greatly improved clinical outcomes of patients with non-small cell lung cancer (NSCLC). Unfortunately, primary and acquired resistance limits their clinical benefits. To overcome such resistance, new generations of EGFR TKIs have been developed by targeting newly identified mutations in EGFR. However, much less effort has been put into alternative strategies, such as targeting the intrinsic protective responses to EGFR TKIs. In this study, we found that EGFR TKIs, including gefitinib and AZD9291, impaired lysosome-dependent degradation of SQSTM1, thus compromising their anti-cancer efficiency. By accumulating in the lysosome lumen, gefitinib and AZD9291 attenuated lysosomal acidification and impaired autolysosomal degradation of SQSTM1 owing to their intrinsic alkalinity. As a result, SQSTM1 protein was stabilized in response to gefitinib and AZD9291 treatment and conferred EGFR TKI resistance. Depleting SQSTM1 significantly increased the sensitivity of NSCLC cells to gefitinib and AZD9291 both in vitro and in vivo. Furthermore, a chemically modified gefitinib analog lacking alkalinity displayed stronger inhibitory effects on NSCLC cells. Therefore, targeting accumulated SQSTM1 or chemically modified EGFR TKIs may represent new strategies to increase the effectiveness of EGFR targeted therapy.

Lysosome inhibition sensitizes pancreatic cancer to replication stress by aspartate depletion

Functional lysosomes mediate autophagy and macropinocytosis for nutrient acquisition. Pancreatic ductal adenocarcinoma (PDAC) tumors exhibit high basal lysosomal activity, and inhibition of lysosome function suppresses PDAC cell proliferation and tumor growth. However, the codependencies induced by lysosomal inhibition in PDAC have not been systematically explored. We performed a comprehensive pharmacological inhibition screen of the protein kinome and found that replication stress response (RSR) inhibitors were synthetically lethal with chloroquine (CQ) in PDAC cells. CQ treatment reduced de novo nucleotide biosynthesis and induced replication stress. We found that CQ treatment caused mitochondrial dysfunction and depletion of aspartate, an essential precursor for de novo nucleotide synthesis, as an underlying mechanism. Supplementation with aspartate partially rescued the phenotypes induced by CQ. The synergy of CQ and the RSR inhibitor VE-822 was comprehensively validated in both 2D and 3D cultures of PDAC cell lines, a heterotypic spheroid culture with cancer-associated fibroblasts, and in vivo xenograft and syngeneic PDAC mouse models. These results indicate a codependency on functional lysosomes and RSR in PDAC and support the translational potential of the combination of CQ and RSR inhibitors.

Fisetin induces autophagy in pancreatic cancer cells via endoplasmic reticulum stress- and mitochondrial stress-dependent pathways

Pancreatic cancer is one of the most aggressive tumors and patients have poor survival rates. Fisetin, a natural flavonoid, was recently reported to have antitumor effects in various cancer models. Autophagy is a conserved catabolic process that maintains cellular homoeostasis in response to stress, and together with apoptosis, determines cell fate. Herein, we examined the effect of fisetin on pancreatic cancer. We reveal that fisetin inhibits PANC-1 cell proliferation using a real-time cell analysis system. Moreover, the in vivo antitumor effect of fisetin was verified in pancreatic cancer using a luciferase-expressing murine xenograft pancreatic cancer model. We found that the AMPK/mTOR signaling pathway was enhanced after fisetin treatment; however, autophagy was not diminished by adding the AMPK inhibitor compound C. Thus, we hypothesized that an another autophagy regulating pathway existed. RNA-seq analysis revealed that the unfolded protein response pathway, which is activated by ER stress, was enriched. We also found that the stress-induced transcription factor p8 was increased in fisetin-treated PANC-1 cells, and that fisetin-induced autophagy was blocked by silencing p8. We revealed that p8-dependent autophagy was AMPK-independent, and that p8 regulated ATF6, ATF4, and PERK in response to ER stress via p53/PKC-α-mediated signaling. Furthermore, mitophagy was associated with Parkin and PINK1 in response to mitochondrial stress. Interestingly, ATF4 and ATF6 were increased in cells treated with fisetin and compound C. Moreover, inhibiting the AMPK/mTOR pathway with compound C may upregulate p8-dependent autophagy. Thus, there may be crosstalk between the AMPK/mTOR and p8-dependent pathways.

Oral Dysbiosis in Pancreatic Cancer and Liver Cirrhosis: A Review of the Literature

The human body is naturally colonized by a huge number of different commensal microbial species, in a relatively stable equilibrium. When this microbial community undergoes dysbiosis at any part of the body, it interacts with the innate immune system and results in a poor health status, locally or systemically. Research studies show that bacteria are capable of significantly influencing specific cells of the immune system, resulting in many diseases, including a neoplastic response. Amongst the multiple different types of diseases, pancreatic cancer and liver cirrhosis were significantly considered in this paper, as they are major fatal diseases. Recently, these two diseases were shown to be associated with increased or decreased numbers of certain oral bacterial species. These findings open the way for a broader perception and more specific investigative studies, to better understand the possible future treatment and prevention. This review aims to describe the correlation between oral dysbiosis and both pancreatic cancer and liver cirrhotic diseases, as well as demonstrating the possible diagnostic and treatment modalities, relying on the oral microbiota, itself, as prospective, simple, applicable non-invasive approaches to patients, by focusing on the state of the art. PubMed was electronically searched, using the following key words: "oral microbiota" and "pancreatic cancer" (PC), "liver cirrhosis", "systemic involvement", and "inflammatory mediators". Oral dysbiosis is a common problem related to poor oral or systemic health conditions. Oral pathogens can disseminate to distant body organs via the local, oral blood circulation, or pass through the gastrointestinal tract and enter into the systemic circulation. Once oral pathogens reach an organ, they modify the immune response and stimulate the release of the inflammatory mediators, this results in a disease. Recent studies have reported a correlation between oral dysbiosis and the increased risk of pancreatic and liver diseases and provided evidence of the presence of oral pathogens in diseased organs. The profound impact that microbial communities have on human health, provides a wide domain towards precisely investigating and clearly understanding the mechanism of many diseases, including cancer. Oral microbiota is an essential contributor to health status and imbalance in this community was correlated to oral and systemic diseases. The presence of elevated numbers of certain oral bacteria, particularly P. gingivalis, as well as elevated levels of blood serum antibodies, against this bacterial species, was associated with a higher risk of pancreatic cancer and liver cirrhosis incidence. Attempts are increasingly directed towards investigating the composition of oral microbiome as a simple diagnostic approach in multiple diseases, including pancreatic and liver pathosis. Moreover, treatment efforts are concerned in the recruitment of microbiota, for remedial purposes of the aforementioned and other different diseases. Further investigation is required to confirm and clarify the role of oral microbiota in enhancing pancreatic and liver diseases. Improving the treatment modalities requires an exertion of more effort, especially, concerning the microbiome engineering and oral microbiota transplantation.

Improving Encapsulation of Hydrophilic Chloroquine Diphosphate into Biodegradable Nanoparticles: A Promising Approach against Herpes Virus Simplex-1 Infection

Chloroquine diphosphate (CQ) is a hydrophilic drug with low entrapment efficiency in hydrophobic nanoparticles (NP). Herpes simplex virus type 1 (HSV-1) is an enveloped double-stranded DNA virus worldwide known as a common human pathogen. This study aims to develop chloroquine-loaded poly(lactic acid) (PLA) nanoparticles (CQ-NP) to improve the chloroquine anti- HSV-1 efficacy. CQ-NP were successfully prepared using a modified emulsification-solvent evaporation method. Physicochemical properties of the NP were monitored using dynamic light scattering, atomic force microscopy, drug loading efficiency, and drug release studies. Spherical nanoparticles were produced with modal diameter of <300 nm, zeta potential of −20 mv and encapsulation efficiency of 64.1%. In vitro assays of CQ-NP performed in Vero E6 cells, using the MTT-assay, revealed different cytotoxicity levels. Blank nanoparticles (B-NP) were biocompatible. Finally, the antiviral activity tested by the plaque reduction assay revealed greater efficacy for CQ-NP compared to CQ at concentrations equal to or lower than 20 µg mL⁻¹ (p < 0.001). On the other hand, the B-NP had no antiviral activity. The CQ-NP has shown feasible properties and great potential to improve the antiviral activity of drugs.

Targeting autophagy enhances apatinib-induced apoptosis via endoplasmic reticulum stress for human colorectal cancer

Apatinib, a novel tyrosine kinase inhibitor (TKI), has been confirmed for its efficacy and safety in the treatment of advanced gastric carcinoma and some other solid tumors. However, the direct functional mechanisms of tumor lethality mediated by apatinib have not yet been fully characterized, and the precise mechanisms of drug resistance are largely unknown. Here, in this study, we demonstrated that apatinib could induce both apoptosis and autophagy in human colorectal cancer (CRC) via a mechanism that involved endoplasmic reticulum (ER) stress. Moreover, activation of the IRE1α pathway from apatinib-induced ER stress is responsible for the induction of autophagy; however, blocking autophagy could enhance the apoptosis in apatinib-treated human CRC cell lines. Furthermore, the combination of apatinib with autophagy inhibitor chloroquine (CQ) tends to have the most significant anti-tumor effect of CRC both in vitro and in vivo. Overall, our data show that because apatinib treatment could induce ER stress-related apoptosis and protective autophagy in human CRC cell lines, targeting autophagy is a promising therapeutic strategy to relieve apatinib drug resistance in CRC.