The role of autophagy in colitis-associated colorectal cancer

In silico and animal studies on the anti-cancer mechanisms of Shaoyao Decoction against colitis-associated colorectal cancer

ETHNOPHARMACOLOGICAL RELEVANCE

It is well known that Shaoyao Decoction (SYD), as a commonly used formula of traditional Chinese medicine (TCM), has a beneficial effect on the treatment of ulcerative colitis (UC). It is found that SYD can also prevent colitis-associated colorectal cancer (CAC). However, its potential anti-cancer mechanism is still waiting to be revealed.

AIM OF THE STUDY

The aim of this study is to investigate the underlying mechanisms of SYD in inhibiting CAC through silico analysis as well as animal experiment validation.

MATERIALS AND METHODS

The primary active compounds, potential therapeutic targets and intervening signaling pathways, which SYD might inhibit the CAC process were predicted by network pharmacology analysis combined with our previous research result of high performance liquid chromatography (HPLC). We attempted to validate the acquired hub targets from molecular docking combined with the Gene Expression Profiling Interactive Analysis (GEPIA), the Human Protein Atlas (HPA), and the cBioPortal database comprehensively. Subsequently, an animal model of CAC mice induced by azoxymethane (AOM) and dextran sulfate sodium (DSS) was constructed and treated with SYD for 14 weeks, and tumor-related physical indicators were evaluated after sacrificed. In addition, samples of colon tissues were obtained for histologic and protein level studies to verify the predicted mechanism.

RESULTS

We obtained 166 active ingredients of SYD and predicted 148 potential targets through network pharmacology analysis, among which quercetin, berberine, kaempferol, wogonin and naringenin were selected as core drug ingredients, and TP53, AKT1, CASP3, PTGS2 and CCND1 were identified and included into the range of core targets. GO and KEGG analyses suggested that the PI3K-Akt signaling pathway might hold a crucial role in CAC prevention and treatment by promoting apoptosis and inhibiting tumor proliferation. In the animal experiment, both SYD and SASP treatments improved the inflammatory condition and pathological damage of the colon tissues in mice. After treatments with SYD and SASP, it was found that decreases of Cyclin D1 and Survivin expression levels and increases of p53 and Cleaved caspase-3 expression levels could be mediated by decreasing the phosphorylation levels of PI3K and Akt proteins in the colon tissues of mice.

CONCLUSION

The results of our study provide supports that SYD effectively inhibits CAC based on modulating PI3K-Akt signaling pathway to suppress tumor proliferation process as well as to promote tumor apoptosis process.

Molecular Mechanisms and Clinical Aspects of Colitis-Associated Cancer in Ulcerative Colitis

Inflammatory bowel diseases have long been recognized as entities with a higher risk of colorectal cancer. An increasing amount of information has been published regarding ulcerative colitis-associated colorectal cancer and its unique mechanisms in recent decades, as ulcerative colitis constitutes a chronic process characterized by cycles of activity and remission of unpredictable durations and intensities; cumulative genomic alterations occur during active disease and mucosal healing, resulting in a special sequence of events different to the events associated with sporadic colorectal cancer. The recognition of the core differences between sporadic colorectal cancer and colitis-associated cancer is of great importance to understand and guide the directions in which new research could be performed, and how it could be applied to current clinical scenarios. A DSS/AOM murine model has allowed for a better understanding of the pathogenic mechanisms in colitis-associated cancer, as it is currently the closest model to this unique scenario. In this review, we provide a summary of the main molecular mechanisms and the clinical aspects of colitis-associated cancer in ulcerative colitis.

Navigating therapeutic prospects by modulating autophagy in colorectal cancer

Colorectal cancer (CRC) remains a leading cause of death globally despite the improvements in cancer treatment. Autophagy is an evolutionarily conserved lysosomal-dependent degradation pathway that is critical in maintaining cellular homeostasis. However, in cancer, autophagy may have conflicting functions in preventing early tumour formation versus the maintenance of advanced-stage tumours. Defective autophagy has a broad and dynamic effect not just on cancer cells, but also on the tumour microenvironment which influences tumour progression and response to treatment. To add to the layer of complexity, somatic mutations in CRC including tumour protein p53 (TP53), v-raf murine sarcoma viral oncogene homolog B1 (BRAF), Kirsten rat sarcoma viral oncogene homolog (KRAS), and phosphatase and tensin homolog (PTEN) can render chemoresistance by promoting a pro-survival advantage through autophagy. Recent studies have also reported autophagy-related cell deaths that are distinct from classical autophagy by employing parts of the autophagic machinery, which impacts strategies for autophagy regulation in cancer therapy. This review discusses the molecular processes of autophagy in the evolution of CRC and its role in the tumour microenvironment, as well as prospective therapeutic methods based on autophagy suppression or promotion. It also highlights clinical trials using autophagy modulators for treating CRC, underscoring the importance of autophagy regulation in CRC therapy.

Involvement of autophagy and gut dysbiosis in ambient particulate matter-induced colonic inflammation

Ambient fine particulate matter (PM2.5), a vital environmental toxicant, not only adversely affects the cardiovascular and respiratory systems but also potentially exhibits an association with intestinal inflammation and colorectal cancer (CRC). The underlying molecular mechanisms of PM2.5 impacts on CRC are still unclear. In this study, we utilized collected ambient PM2.5 and standard reference material SRM2786 to investigate the toxic effects on the colon through in vivo chronic exposure mouse and in vitro cell culture models. We employed a chronic mouse exposure model to clarify the colonic injury and gut microbiome biomarkers. Prolonged exposure to PM2.5 via oropharyngeal aspiration led to a significant rise in colonic epithelial proliferation and reduced colon length in mice. It triggered characteristics indicative of gut microbiota dysbiosis linked to inflammatory bowel disease. The gut microbiome alternations may serve as a biomarker indicating the colonic health impacts of PM2.5 exposure. PM2.5 and SRM2786-induced cytotoxicity manifested as autophagy dysregulation-mediated abnormal proliferation, IL-8 production, p62/SQSTM1 accumulation, and lysosomal membrane damage in human colon cells WiDr and Caco-2. Both PM2.5 and SRM2786 exposures led to the accumulation of p62/SQSTM1 and compromised lysosomal membrane integrity, showing impaired autophagic flux in WiDr and Caco-2 cells. Finally, we examined the correlations between atmospheric PM2.5 data and biomarkers of colonic inflammation in human population. The serum level of IL-8 was significantly correlated with regional anthropogenic pollutants. In conclusion, our findings elucidate that ambient PM2.5 exhibits adverse effects on colon health manifested as inflammation, aberrant proliferation, and gut dysbiosis, potentially mediated through autophagy dysregulation, thereby highlighting the importance of further research on the impact of environmental pollutants on gastrointestinal health.

Therapeutic potential of Pien Tze Huang in colitis-associated colorectal cancer: mechanistic insights from a mouse model

BACKGROUND

Pien Tze Huang (PZH), a traditional Chinese medicine formulation, is recognized for its therapeutic effect on colitis and colorectal cancer. However, its protective role and underlying mechanism in colitis-associated colorectal cancer (CAC) remain to be elucidated.

METHODS

A CAC mouse model was established using AOM/DSS. Twenty mice were randomly divided into four groups (n = 5/group): Control, PZH, AOM/DSS, and AOM/DSS + PZH groups. Mice in the PZH and AOM/DSS + PZH group were orally administered PZH (250 mg/kg/d) from the first day of experiment, while the control and AOM/DSS group received an equivalent volume of distilled water. Parameters such as body weight, disease activity index (DAI), colon weight, colon length, colon histomorphology, intestinal tumor formation, serum concentrations of pro-inflammatory cytokines, proliferation and apoptosis in colon tissue were assessed. RNA sequencing was employed to identify the differentially expressed transcripts (DETs) in colonic tissues and related signaling pathways. Wnt/β-Catenin Pathway-Related genes in colon tissue were detected by QPCR and immunohistochemistry (IHC).

RESULTS

PZH significantly attenuated AOM/DSS-induced weight loss, DAI elevation, colonic weight gain, colon shortening, histological damage, and intestinal tumor formation in mice. PZH also notably decreased serum concentration of IL-6, IL-1β, and TNF-α. Furthermore, PZH inhibited cell proliferation and promote apoptosis in tumor tissues. RNA-seq and KEGG analysis revealed key pathways influenced by PZH, including Wnt/β-catenin signaling pathway. IHC staining confirmed that PZH suppressed the expression of β-catenin, cyclin D1 and c-Myc in colonic tissues.

CONCLUSIONS

PZH ameliorates AOM/DSS-induced CAC in mice by suppressing the activation of Wnt/β-catenin signaling pathway.

Inflammasomes Are Influenced by Epigenetic and Autophagy Mechanisms in Colorectal Cancer Signaling

Inflammasomes contribute to colorectal cancer signaling by primarily inducing inflammation in the surrounding tumor microenvironment. Its role in inflammation is receiving increasing attention, as inflammation has a protumor effect in addition to inducing tissue damage. The inflammasome's function is complex and controlled by several layers of regulation. Epigenetic processes impact the functioning or manifestation of genes that are involved in the control of inflammasomes or the subsequent signaling cascades. Researchers have intensively studied the significance of epigenetic mechanisms in regulation, as they encompass several potential therapeutic targets. The regulatory interactions between the inflammasome and autophagy are intricate, exhibiting both advantageous and harmful consequences. The regulatory aspects between the two entities also encompass several therapeutic targets. The relationship between the activation of the inflammasome, autophagy, and epigenetic alterations in CRC is complex and involves several interrelated pathways. This article provides a brief summary of the newest studies on how epigenetics and autophagy control the inflammasome, with a special focus on their role in colorectal cancer. Based on the latest findings, we also provide an overview of the latest therapeutic ideas for this complex network.

Studies on the mechanism of local and extra-intestinal tissue manifestations in AOM-DSS-induced carcinogenesis in BALB/c mice: role of PARP-1, NLRP3, and autophagy

Colitis-associated colorectal cancer (CACC) is one of the devastating complications of long-term inflammatory bowel disease and is associated with substantial morbidity and mortality. Combination of azoxymethane (AOM) and dextran sulfate sodium (DSS) has been extensively used for inflammation-mediated colon tumor development due to its reproducibility, potency, histological and molecular changes, and resemblance to human CACC. In the tumor microenvironment and extra-intestinal tissues, PARP-1, NLRP3 inflammasome, and autophagy's biological functions are complicated and encompass intricate interactions between these molecular components. The focus of the present investigation is to determine the colonic and extra-intestinal tissue damage induced by AOM-DSS and related molecular mechanisms. Azoxymethane (10 mg/kg, i.p.; single injection) followed by DSS (3 cycles, 7 days per cycle) over a period of 10 weeks induced colitis-associated colon cancer in male BALB/c mice. By initiating carcinogenesis with a single injection of azoxymethane (AOM) and then establishing inflammation with dextran sulfate sodium (DSS), a two-stage murine model for CACC was developed. Biochemical parameters, ELISA, histopathological and immunohistochemical analysis, and western blotting have been performed to evaluate the colonic, hepatic, testicular and pancreatic damage. In addition, the AOM/DSS-induced damage has been assessed by analyzing the expression of a variety of molecular targets, including proliferating cell nuclear antigen (PCNA), interleukin-10 (IL-10), AMP-activated protein kinase (AMPK), poly (ADP-ribose) polymerase-1 (PARP-1), cysteine-associated protein kinase-1 (caspase-1), NLR family pyrin domain containing 3 (NLRP3), beclin-1, and interleukin-1β (IL-1β). Present findings revealed that AOM/DSS developed tumors in colon tissue followed by extra-intestinal hepatic, testicular, and pancreatic damages.

Ameliorative effect of bound polyphenols in mung bean coat dietary fiber on DSS-induced ulcerative colitis in mice: the intestinal barrier and intestinal flora

The consumption of dietary fiber is beneficial for gut health, but the role of bound polyphenols in dietary fiber has lacked systematic study. The aim of this study is to evaluate the ameliorative effect of mung bean coat dietary fiber (MDF) on DSS-induced ulcerative colitis in mice in the presence and absence of bound polyphenols. Compared to polyphenol-removed MDF (PR-MDF), MDF and formulated-MDF (F-MDF,backfilling polyphenols by the amount of extracted from MDF into PR-MDF) alleviated symptoms such as weight loss and colonic injury in mice with colitis, effectively reduced excessive inflammatory responses, and the bound polyphenols restored the integrity of the intestinal barrier by promoting the expression of tight junction proteins. Additionally, bound polyphenols restored the expression of autophagy-related proteins (mTOR, beclin-1, Atg5 and Atg7) and inhibited the excessive expression of apoptotic-related proteins (Bax, caspase-9, and caspase-3). Furthermore, bound polyphenols could ameliorate the dysregulation of the intestinal microbiota by increasing the abundance of beneficial bacteria and inhibiting the abundance of harmful bacteria. Thus, it can be concluded that the presence of bound polyphenols in MDF plays a key role in the alleviation of DSS-induced ulcerative colitis.

Role of protein degradation systems in colorectal cancer

Protein degradation is essential for maintaining protein homeostasis. The ubiquitin‒proteasome system (UPS) and autophagy-lysosome system are the two primary pathways responsible for protein degradation and directly related to cell survival. In malignant tumors, the UPS plays a critical role in managing the excessive protein load caused by cancer cells hyperproliferation. In this review, we provide a comprehensive overview of the dual roles played by the UPS and autolysosome system in colorectal cancer (CRC), elucidating their impact on the initiation and progression of this disease while also highlighting their compensatory relationship. Simultaneously targeting both protein degradation pathways offers new promise for enhancing treatment efficacy against CRC. Additionally, apoptosis is closely linked to ubiquitination and autophagy, and caspases degrade proteins. A thorough comprehension of the interplay between various protein degradation pathways is highly important for clarifying the mechanism underlying the onset and progression of CRC.

New sights of immunometabolism and agent progress in colitis associated colorectal cancer

Colitis associated colorectal cancer is a disease with a high incidence and complex course that develops from chronic inflammation and deteriorates after various immune responses and inflammation-induced attacks. Colitis associated colorectal cancer has the characteristics of both immune diseases and cancer, and the similarity of treatment models contributes to the similar treatment dilemma. Immunometabolism contributes to the basis of life and is the core of many immune diseases. Manipulating metabolic signal transduction can be an effective way to control the immune process, which is expected to become a new target for colitis associated colorectal cancer therapy. Immune cells participate in the whole process of colitis associated colorectal cancer development by transforming their functional condition via changing their metabolic ways, such as glucose, lipid, and amino acid metabolism. The same immune and metabolic processes may play different roles in inflammation, dysplasia, and carcinoma, so anti-inflammation agents, immunomodulators, and agents targeting special metabolism should be used in combination to prevent and inhibit the development of colitis associated colorectal cancer.

Kinase Signaling in Colitis-Associated Colon Cancer and Inflammatory Bowel Disease

Colorectal cancer is a known complication of chronic inflammation of the colon ("colitis-associated colon cancer"). Inflammatory bowel disease (IBD) is a chronic inflammatory disorder of the gastrointestinal tract. Patients with IBD are at increased risk of colon cancer compared to the general population. Kinase signaling pathways play critical roles in both the inflammation and regulating cellular processes such as proliferation and survival that contribute to cancer development. Here we review the interplay of kinase signaling pathways (mitogen-activated protein kinases, cyclin-dependent kinases, autophagy-activated kinases, JAK-STAT, and other kinases) and their effects on colitis-associated colon cancer. We also discuss the role of JAK-STAT signaling in the pathogenesis of IBD and the therapeutic landscape of JAK inhibitors for the treatment of IBD.

Differential Gene Expression of Checkpoint Markers and Cancer Markers in Mouse Models of Spontaneous Chronic Colitis

The presence of checkpoint markers in cancer cells aids in immune escape. The identification of checkpoint markers and early cancer markers is of utmost importance to gain clarity regarding the relationship between colitis and progressive inflammation leading to cancer. Herein, the gene expression levels of checkpoint makers, cancer-related pathways, and cancer genes in colon tissues of mouse models of chronic colitis (Winnie and Winnie-Prolapse mice) using next-generation sequencing are determined. Winnie mice are a result of a Muc2 missense mutation. The identification of such genes and their subsequent expression and role at the protein level would enable novel markers for the early diagnosis of cancer in IBD patients. The differentially expressed genes in the colonic transcriptome were analysed based on the Kyoto Encyclopedia of Genes and Genomes pathway. The expression of several oncogenes is associated with the severity of IBD, with Winnie-Prolapse mice expressing a large number of key genes associated with development of cancer. This research presents a number of new targets to evaluate for the development of biomarkers and therapeutics.

Atomic vacancies-engineered ultrathin trimetallic nanozyme with anti-inflammation and antitumor performances for intestinal disease treatment

Colitis-associated colorectal cancer, which represents a highly aggressive subtypes of colorectal cancer, requires concurrent antitumor and anti-inflammation therapies in clinic. Herein, we successfully engineered Ru38Pd34Ni28 ultrathin trimetallic nanosheets (TMNSs) by introducing diverse transition metal atoms into the structure of RuPd nanosheets. Density functional theory (DFT) calculations reveal that the elaborate introduction of transition metal Ru and Ni facilitates the formation of Ru-O and Ni-O bonds on the surface of TMNSs for efficient reactive oxygen species (ROS) and reactive nitrogen species (RNS) scavenging, respectively. Moreover, the engineered abundant atomic vacancies on their surface conspicuously improve the performance in eliminating reactive oxygen and nitrogen species (RONS). The designed TMNSs act as a multi-metallic nanocatalyst with RONS elimination performance for chronic colitis treatment by relieving inflammation, as well as photothermal conversion capability for colon cancer therapy by inducing hyperthermia effect. Profiting from the excellent RONS scavenging activities, TMNSs can down-regulate the expression levels of the pro-inflammatory factors, thereby leading to prominent therapeutic efficacy against dextran sulfate sodium-induced colitis. Benefiting from the high photothermal performance, TMNSs cause significant suppression of CT-26 tumors without obvious recurrence. This work provides a distinct paradigm to design multi-metallic nanozymes for colon disease treatment by elaborate introduction of transition metal atoms and engineering of atomic vacancies.

Different Roles of Apoptosis and Autophagy in the Development of Human Colorectal Cancer

Colorectal cancer (CRC) remains a major life-threatening malignancy, despite numerous therapeutic and screening attempts. Apoptosis and autophagy are two processes that share common signaling pathways, are linked by functional relationships and have similar protein components. During the development of cancer, the two processes can trigger simultaneously in the same cell, causing, in some cases, an inhibition of autophagy by apoptosis or apoptosis by autophagy. Malignant cells that have accumulated genetic alterations can take advantage of any alterations in the apoptotic process and as a result, progress easily in the cancerous transformation. Autophagy often plays a suppressive role during the initial stages of carcinogenicity, while in the later stages of cancer development it can play a promoting role. It is extremely important to determine the regulation of this duality of autophagy in the development of CRC and to identify the molecules involved, as well as the signals and the mechanisms behind it. All the reported experimental results indicate that, while the antagonistic effects of autophagy and apoptosis occur in an adverse environment characterized by deprivation of oxygen and nutrients, leading to the formation and development of CRC, the effects of promotion and collaboration usually involve an auxiliary role of autophagy compared to apoptosis. In this review, we elucidate the different roles of autophagy and apoptosis in human CRC development.

MicroRNA-31 induced by Fusobacterium nucleatum infection promotes colorectal cancer tumorigenesis

Persistent Fusobacterium nucleatum infection is associated with the development of human colorectal cancer (CRC) and promotes tumorigenicity, but the underlying mechanisms remain unclear. Here, we reported that F. nucleatum promoted the tumorigenicity of CRC, which was associated with F. nucleatum-induced microRNA-31 (miR-31) expression in CRC tissues and cells. F. nucleatum infection inhibited autophagic flux by miR-31 through inhibiting syntaxin-12 (STX12) and was associated with the increased intracellular survival of F. nucleatum. Overexpression of miR-31 in CRC cells promoted their tumorigenicity by targeting eukaryotic initiation factor 4F-binding protein 1/2 (eIF4EBP1/2), whereas miR-31 knockout mice were resistant to the formation of colorectal tumors. In conclusion, F. nucleatum, miR-31, and STX12 form a closed loop in the autophagy pathway, and continuous F. nucleatum-induced miR-31 expression promotes the tumorigenicity of CRC cells by targeting eIF4EBP1/2. These findings reveal miR-31 as a potential diagnostic biomarker and therapeutic target in CRC patients with F. nucleatum infection.

Artificial neural network model- and response surface methodology-based optimization of Atractylodis Macrocephalae Rhizoma polysaccharide extraction, kinetic modelling and structural characterization

Atractylodis Macrocephalae Rhizoma (AMR) is the dried rhizome of Atractylodes macrocephala Koidz, which is widely used in the development of health products. AMR contains a large number of polysaccharides, but at present there are fewer applications for these polysaccharides. In this study, the effects of different extraction methods on the Atractylodis Macrocephalae Rhizoma polysaccharide (AMRP) yield were investigated, and the conditions for ultrasound-assisted extraction were optimized by response surface methodology (RSM) and three neural network models (BP neural network, GA-BP neural network and ACO-GA-BP neural network). The best conditions were a liquid-to-solid ratio of 17 mL/g, ultrasonic power of 400 W, extraction temperature of 72 °C, and extraction time of 40 min, which yielded 31.31% AMRP. The kinetic equation of AMRP was determined and compared with the results predicted by three neural network models. It was finally determined that the extraction conditions, kinetic processes and kinetic equation predicted by the GA-ACO-BP neural network were optimal. In addition, AMRP was characterized using SEM, FTIR, HPLC, UV, XRD, and NMR, and the structural study revealed that AMRP has a rough exterior and a porous interior; moreover, it contains high levels of glucose (5.07%), arabinose (0.80%), and galactose (0.74%). AMRP has three crystal structures, consisting of two β-type monosaccharides and one α-type monosaccharide. Additionally, the effectiveness of AMRP as an antioxidant was demonstrated in an in vitro experiment.

The "Self-eating" of cancer-associated fibroblast: A potential target for cancer

Autophagy helps maintain energy homeostasis and protect cells from stress effects by selectively removing misfolded/polyubiquitylated proteins, lipids, and damaged mitochondria. Cancer-associated fibroblasts (CAFs) are cellular components of tumor microenvironment (TME). Autophagy in CAFs inhibits tumor development in the early stages; however, it has a tumor-promoting effect in advanced stages. In this review, we aimed to summarize the modulators responsible for the induction of autophagy in CAFs, such as hypoxia, nutrient deprivation, mitochondrial stress, and endoplasmic reticulum stress. In addition, we aimed to present autophagy-related signaling pathways in CAFs, and role of autophagy in CAF activation, tumor progression, tumor immune microenvironment. Autophagy in CAFs may be an emerging target for tumor therapy. In summary, autophagy in CAFs is regulated by a variety of modulators and can reshape tumor immune microenvironment, affecting tumor progression and treatment.

Autophagy and the Insulin-like Growth Factor (IGF) System in Colonic Cells: Implications for Colorectal Neoplasia

Colorectal cancer (CRC) is one of the most common human malignancies worldwide. Along with apoptosis and inflammation, autophagy is one of three important mechanisms in CRC. The presence of autophagy/mitophagy in most normal mature intestinal epithelial cells has been confirmed, where it has mainly protective functions against reactive oxygen species (ROS)-induced DNA and protein damage. Autophagy regulates cell proliferation, metabolism, differentiation, secretion of mucins and/or anti-microbial peptides. Abnormal autophagy in intestinal epithelial cells leads to dysbiosis, a decline in local immunity and a decrease in cell secretory function. The insulin-like growth factor (IGF) signaling pathway plays an important role in colorectal carcinogenesis. This is evidenced by the biological activities of IGFs (IGF-1 and IGF-2), IGF-1 receptor type 1 (IGF-1R) and IGF-binding proteins (IGF BPs), which have been reported to regulate cell survival, proliferation, differentiation and apoptosis. Defects in autophagy are found in patients with metabolic syndrome (MetS), inflammatory bowel diseases (IBD) and CRC. In neoplastic cells, the IGF system modulates the autophagy process bidirectionally. In the current era of improving CRC therapies, it seems important to investigate the exact mechanisms not only of apoptosis, but also of autophagy in different populations of tumor microenvironment (TME) cells. The role of the IGF system in autophagy in normal as well as transformed colorectal cells still seems poorly understood. Hence, the aim of the review was to summarize the latest knowledge on the role of the IGF system in the molecular mechanisms of autophagy in the normal colon mucosa and in CRC, taking into account the cellular heterogeneity of the colonic and rectal epithelium.

Mexican Colorectal Cancer Research Consortium (MEX-CCRC): Etiology, Diagnosis/Prognosis, and Innovative Therapies

In 2013, recognizing that Colorectal Cancer (CRC) is the second leading cause of death by cancer worldwide and that it was a neglected disease increasing rapidly in Mexico, the community of researchers at the Biomedicine Research Unit of the Facultad de Estudios Superiores Iztacala from the Universidad Nacional Autónoma de México (UNAM) established an intramural consortium that involves a multidisciplinary group of researchers, technicians, and postgraduate students to contribute to the understanding of this pathology in Mexico. This article is about the work developed by the Mexican Colorectal Cancer Research Consortium (MEX-CCRC): how the Consortium was created, its members, and its short- and long-term goals. Moreover, it is a narrative of the accomplishments of this project. Finally, we reflect on possible strategies against CRC in Mexico and contrast all the data presented with another international strategy to prevent and treat CRC. We believe that the Consortium's characteristics must be maintained to initiate a national strategy, and the reported data could be useful to establish future collaborations with other countries in Latin America and the world.

Discovery and mechanism studies of a novel ATG4B inhibitor Ebselen by drug repurposing and its anti-colorectal cancer effects in mice

Cysteine protease ATG4B, a key autophagy protein, is an attractive target for colorectal cancer therapy. However, ATG4B inhibitors with higher efficiency, safety, and clear mechanism are still limited. In this study, we discovered ATG4B inhibitors based on the FDA-approved drug library through FRET-based high-throughput screening and gel-based analysis. Among the nine hits, compound Ebselen showed the most potent ATG4B inhibitory activity (IC₅₀ = 189 nM) and exhibited controllable selectivity and structural optimizable possibility against ATG4A and caspases. We then performed mass spectrometry assay and cysteine mutations to confirm that Ebselen could covalently bind to ATG4B at Cys74. Moreover, Cys292 and Cys361 instead of Cys74 are responsible for the redox-oligomerization and efficient activity inhibition of ATG4B. Ultimately through cell culture and mouse xenograft tumor models, we established the impact of Ebselen on autophagy and tumor suppression via ATG4B inhibition other than apoptosis. These results suggest that old drug Ebselen as an ATG4B inhibitor through oxidative modification may be repurposed as a promising anti-colorectal cancer drug.

Molecular and cellular pathways in colorectal cancer: apoptosis, autophagy and inflammation as key players

BACKGROUND

Colorectal carcinogenesis (CRC) is one of the most aggressive forms of cancer, particularly in developing countries. It accounts for the second and third-highest reason for cancer-induced lethality in women and men respectively. CRC involves genetic and epigenetic modifications in colonic epithelium, leading to colon adenocarcinoma. The current review highlights the pathogenic mechanisms and multifactorial etiology of CRC, influenced by apoptosis, inflammation, and autophagy pathways.

METHODS

We have carried out a selective literature review on mechanisms contributing to the pathogenesis of CRC.

RESULTS

Resistance to senescence and apoptosis of the mesenchymal cells, which play a key role in intestinal organogenesis, morphogenesis and homeostasis, appears important for sporadic CRC. Additionally, inflammation-associated tumorigenesis is a key incident in CRC, supported by immune disruptors, adaptive and innate immune traits, environmental factors, etc. involving oxidative stress, DNA damage and epigenetic modulations. The self-digesting mechanism, autophagy, also plays a twin role in CRC through the participation of LC3/LC3-II, Beclin-1, ATG5, other autophagy proteins, and Inflammatory Bowel Disease (IBD) susceptibility genes. It facilitates the promotion of effective surveillance pathways and stimulates the generation of malignant tumor cells. The autophagy and apoptotic pathways undergo synergistic or antagonistic interactions in CRC and bear a critical association with IBD that results from the pro-neoplastic effects of persistent intestinal inflammation. Conversely, pro-inflammatory factors stimulate tumor growth and angiogenesis and inhibit apoptosis, suppressing anti-tumor activities.

CONCLUSION

Hence, research attempts for the development of potential therapies for CRC are in progress, primarily based on combinatorial approaches targeting apoptosis, inflammation, and autophagy.

The role of autophagy in colorectal cancer: Impact on pathogenesis and implications in therapy

Colorectal cancer (CRC) is considered as a global major cause of cancer death. Surgical resection is the main line of treatment; however, chemo-, radiotherapy and other adjuvant agents are crucial to achieve good outcomes. The tumor microenvironment (TME) is a well-recognized key player in CRC progression, yet the processes linking the cancer cells to its TME are not fully delineated. Autophagy is one of such processes, with a controversial role in the pathogenesis of CRC, with its intricate links to many pathological factors and processes. Autophagy may apparently play conflicting roles in carcinogenesis, but the precise mechanisms determining the overall direction of the process seem to depend on the context. Additionally, it has been established that autophagy has a remarkable effect on the endothelial cells in the TME, the key substrate for angiogenesis that supports tumor metastasis. Favorable response to immunotherapy occurs only in a specific subpopulation of CRC patients, namely the microsatellite instability-high (MSI-H). In view of such limitations of immunotherapy in CRC, modulation of autophagy represents a potential adjuvant strategy to enhance the effect of those relatively safe agents on wider CRC molecular subtypes. In this review, we discussed the molecular control of autophagy in CRC and how autophagy affects different processes and mechanisms that shape the TME. We explored how autophagy contributes to CRC initiation and progression, and how it interacts with tumor immunity, hypoxia, and oxidative stress. The crosstalk between autophagy and the TME in CRC was extensively dissected. Finally, we reported the clinical efforts and challenges in combining autophagy modulators with various cancer-targeted agents to improve CRC patients’ survival and restrain cancer growth.

Chang qing formula ameliorates colitis-associated colorectal cancer via suppressing IL-17/NF-κB/STAT3 pathway in mice as revealed by network pharmacology study

Colitis-associated colorectal cancer (CAC) is a specific type of colorectal cancer (CRC) with high mortality and morbidity, the chronic inflammation in the intestinal mucosal is the characteristic of CAC. Chang Qing formula (CQF) is a Chinese herbal formula used clinically for the treatment of CAC with remarkable clinical efficacy, but its mechanism remains unclear. In the present work, Combined network pharmacology and transcriptomics were used to analyze the potential active ingredients and elucidate molecular mechanism of CQF in treating CAC. Firstly, the constituents migrating to blood of CQF were analyzed and identified by UPLC-Q-TOF-MS/MS, and core genes and pathways were screened by network pharmacology analysis. Encyclopedia of Genes and Genomes (KEGG) analysis showed that the IL-17 signaling pathway involved in CAC may be closely associated with the potential mechanismof action of CQF. Subsequently, the results from animal studies indicated that CQF profoundly reduced tumor numbers and tumor size in AOM/DSS mice. The RNA-seq data was analysed utilizing Ingenuity Pathway Analysis (IPA), and the results supported the idea that CQF exerts a tumour-suppressive effect via the IL-17 signalling pathway. Further studies demonstrated that CQF significantly reduced IL-17A levels, which in turn inhibited NF-κB/IL-6/STAT3 signaling cascade, suppressed MMP9 expression and promoted tumor cell apoptosis. In conclusion, the current study demonstrated that CQF remarkably improved inflammatory tumor microenvironment, and hindered the transformation of inflammation into cancer. These findings may help to design future strategies for the treatment of CAC.

Autophagy: A Versatile Player in the Progression of Colorectal Cancer and Drug Resistance

Colorectal cancer (CRC) is among the topmost malignancies for both genders. Despite the high incidence rate and advances in diagnostic tools, treatment in many cases is still ineffective. Most cancerous lesions in CRC begin as benign, followed by the development of invasive forms and metastases. The development of CRC has been linked to defects in autophagy, which plays both a pro-and anti-tumor role and is mainly context-dependent. Autophagy suppression could enhance apoptosis via p53 activation, or autophagy also promotes tumor progression by maintaining tumor growth and increasing resistance to chemotherapy. Autophagy promotes the invasion and metastasis of CRC cells via increased epithelial-mesenchymal transition (EMT). Moreover, dysbiosis of gut microbiota upregulated autophagy and metastasis markers. Autophagy responses may also modulate the tumor microenvironment (TME) via regulating the differentiation process of several innate immune cells. Treatments that promote tumor cell death by stimulating or inhibiting autophagy could be beneficial if used as an adjunct treatment, but the precise role of various autophagy-modulating drugs in CRC patients is needed to be explored. In this article, we present an overview of the autophagy process and its role in the pathogenesis and therapeutic resistance of CRC. Also, we focused on the current understanding of the role of the EMT and TME, including its relation to gut microbiota and immune cells, in autophagic manipulation of CRC. We believe that there is a potential link between autophagy, TME, EMT, and drug resistance, suggesting that further studies are needed to explore this aspect.

A Quassinoid Diterpenoid Eurycomanone from Eurycoma longifolia Jack Exerts Anti-Cancer Effect through Autophagy Inhibition

Eurycomanone (EN) is one of the representative quassinoid diterpenoids from roots of Eurycoma longifolia Jack, a natural medicine that is widely distributed in Southeast Asia. Previous studies showed that EN induces cancer cell apoptosis and exhibits anti-cancer activity, but the molecular mechanism of EN against cancer has still not been elucidated. In this study, we examined the regulatory effect of EN on autophagy to reveal the mechanism of EN-mediated colon cancer growth inhibition. First, we found that EN is able to inhibit colon cancer cell proliferation and colony formation. The angiogenesis level in cancer cells was inhibited as well. Next, the treatment of EN led to the suppression of autophagy, which was characterized by the downregulation of the LC3-II level and the formation of GFP-LC3 puncta under EN treatment in colon cancer. Moreover, we revealed that the mTOR signaling pathway was activated by EN in a time- and concentration-dependent manner. Finally, autophagy induction protected colon cancer cells from EN treatment, suggesting that autophagy improves cell survival. Taken together, our findings revealed the mechanism of EN against colon cancer through inhibiting autophagy and angiogenesis in colon cancer, supporting that the autophagy inhibitor EN could be developed to be a novel anti-cancer agent.

Gamma-mangostin isolated from garcinia mangostana suppresses colon carcinogenesis and stemness by downregulating the GSK3β/β-catenin/CDK6 cancer stem pathway

BACKGROUND

Despite advances in chemotherapies and targeted drugs, colorectal cancer (CRC) remains challenging to treat due to drug resistance. Emerging evidence indicates that cancer-associated fibroblasts (CAFs) facilitate the generation of cancer stem-like cells (CSCs) and drug resistance. Glycogen synthase kinase-3 (GSK) associated signaling pathways have been implicated in the generation of CSCs and represent a target for therapeutics development.

HYPOTHESIS

Gamma-mangostin (gMG) isolated from Garcinia mangostana was evaluated for its ability to downregulate GSK3β-associated signaling in CRC cells and overcome CAF-induced 5-fluorouracil resistance and CSC generation.

METHODS

Bioinformatics analysis, in silico molecular docking, in vitro assays, including cell viability tests, colony- and tumor sphere-formation assays, transwell migration assays, ELISA, SDS-PAGE, Western blotting, miR expression, qPCR, and flow cytometry, as well as in vivo mouse xenograft models were used to evaluate the antitumor effects of gMG.

RESULTS

Bioinformatics analyses indicated that GSK3β/CDK6/β-catenin mRNA signature was significantly higher in colon cancer patients. Additional algorithms predicted a higher miR-26b level was associated with significantly higher survival in CRC patients and GSK3β and CDK6 as targets of miR-26b-5p. To validate these findings in vitro, we showed that CAF-cocultured CRC cells expressed an increased expression of GSK3β, β-catenin, CDK6, and NF-κB. Therapeutically, we demonstrated that gMG treatment suppressed GSK3β-associated signaling pathways while concomitantly increased the miR-26b-5p level. Using a xenograft mouse model of CAFs cocultured HCT116 tumorspheres, we showed that gMG treatment reduced tumor growth and overcame CAF-induced 5-fluorouracil resistance.

CONCLUSIONS

Pharmacological intervention with gMG suppressed CRC carcinogenesis and stemness via downregulating GSK3/β-catenin/CDK6 and upregulating the miR-26b-5p tumor suppressor. Thus, gMG represents a potential new CRC therapeutic agent and warrants further investigation.

Decreased phosphorylation facilitates the degradation of the endogenous protective molecule c-Ski in vascular smooth muscle cells

The dysfunction of vascular smooth muscle cells (VSMCs) is critical for atherosclerosis (AS) progression. Autophagy is indispensable during phenotypic switching and proliferation of VSMCs, contribute to AS development. Cellular Sloan-Kettering Institute (c-Ski), the repressor of TGF-β signaling, is involved in diverse physiological and pathological processes. We previously defined c-Ski also as an endogenous protective molecule against AS via inhibiting abnormal proliferation and autophagy of VSMCs. However, the endogenous level of c-Ski in VSMCs is markedly decreased during the progression of AS, so that the protective effect is drastically weakened. Elucidating the molecular mechanisms is key to the understanding of AS development and treatment. We determined that oxidized low-density lipoprotein (ox-LDL) and platelet-derived growth factor (PDGF) directly induced the degradation of c-Ski protein, closely associated with reducing its phosphorylation. Serine₃₈₃ (S383) was identified as the crucial phosphorylation site for stabilizing protein expression and nuclear location of c-Ski, which was responsible for its transcriptional suppression of autophagy-related genes. Decreased S383 phosphorylation facilitated nuclear export and degradation of c-Ski, thereby lessened its inhibitory effect on induction of autophagy genes. These findings provide a novel view of c-Ski modification and function modulation under some vascular injury factors, which point to a new potential therapeutic strategy by targeting c-Ski.

Autophagy and Ubiquitination as Two Major Players in Colorectal Cancer: A Review on Recent Patents

BACKGROUND

As one of the most commonly diagnosed cancers among men and women, Colorectal Cancer (CRC) leads to high rates of morbidity and mortality across the globe. Recent anti- CRC therapies are now targeting specific signaling pathways involved in colorectal carcinogenesis. Ubiquitin Proteasome System (UPS) and autophagy are two main protein quality control systems, which play major roles in the carcinogenesis of colorectal cancer. A balanced function of these two pathways is necessary for the regulation of cell proliferation and cell death.

OBJECTIVE

In this systematic review, we discuss the available evidence regarding the roles of autophagy and ubiquitination in progression and inhibition of CRC.

METHODS

The search terms "colorectal cancer" or "colon cancer" or "colorectal carcinoma" or "colon carcinoma" in combination with "ubiquitin proteasome" and "autophagy" were searched in PubMed, Web of Science, and Scopus databases, and also Google Patents (https://patents.google .com) from January 2000 to Feb 2020.

RESULTS

The most important factors involved in UPS and autophagy have been investigated. There are many important factors involved in UPS and autophagy but this systematic review shows the studies that have mostly focused on the role of ATG, 20s proteasome and mTOR in CRC, and the more important factors such as ATG8, FIP200, and TIGAR factors that are effective in the regulation of autophagy in CRC cells have not been yet investigated.

CONCLUSION

The most important factors involved in UPS and autophagy such as ATG, 20s proteasome and mTOR, ATG8, FIP200, and TIGAR can be considered in drug therapy for controlling or activating autophagy.

Transcriptome analysis of potential candidate genes and molecular pathways in colitis-associated colorectal cancer of Mkp-1-deficient mice

BACKGROUND

The nuclear phosphatase mitogen-activate protein kinase phosphatase-1 (MKP-1) is a key negative regulator of the innate immune response through the regulation of the biosynthesis of proinflammatory cytokines. In colorectal cancer (CRC), which is induced mainly by chronic inflammation, Mkp-1 overexpression was found in addition to disturbances in Mkp-1 functions, which may play a role in cancer development in different types of tumors. However, the potential molecular mechanisms by which Mkp-1 influences CRC development is not clear. Here, we performed global gene expression profiling of Mkp-1 KO mice using RNA sequencing (RNA-seq) to explore the role of Mkp-1 in CRC progression using transcriptome analysis.

METHODS

Azoxymethane/dextran sodium sulfate (AOM/DSS) mouse models were used to examine the most dramatic molecular and signaling changes that occur during different phases of CRC development in wild-type mice and Mkp-1 KO mice. Comprehensive bioinformatics analyses were used to elucidate the molecular processes regulated by Mkp-1. Differentially expressed genes (DEGs) were identified and functionally analyzed by Gene Ontology (GO), Kyoto Enrichment of Genes and Genomes (KEGG). Then, protein-protein interaction (PPI) network analysis was conducted using the STRING database and Cytoscape software.

RESULTS

Persistent DEGs were different in adenoma and carcinoma stage (238 & 251, respectively) and in WT and MKp-1 KO mice (221& 196, respectively). Mkp-1 KO modulated key molecular processes typically activated in cancer, in particular, cell adhesion, ion transport, extracellular matrix organization, response to drug, response to hypoxia, and response to toxic substance. It was obvious that these pathways are closely associated with cancer development and metastasis. From the PPI network analyses, nine hub genes associated with CRC were identified.

CONCLUSION

These findings suggest that MKp-1 and its hub genes may play a critical role in cancer development, prognosis, and determining treatment outcomes. We provide clues to build a potential link between Mkp-1 and colitis-associated tumorigenesis and identify areas requiring further investigation.

Lysosome Depletion-Triggered Autophagy Impairment in Progressive Kidney Injury

Background

Macroautophagy (autophagy) is a cellular recycling process involving the destruction of damaged organelles and proteins in intracellular lysosomes for efficient nutrient reuse.

Summary

Impairment of the autophagy-lysosome pathway is tightly associated with multiple kidney diseases, such as diabetic nephropathy, proteinuric kidney disease, acute kidney injury, crystalline nephropathy, and drug- and heavy metal-induced renal injury. The impairment in the process of autophagic clearance may induce injury in renal intrinsic cells by activating the inflammasome, inducing cell cycle arrest, and cell death. The lysosome depletion may be a key mechanism triggering this process. In this review, we discuss this pathway and summarize the protective mechanisms for restoration of lysosome function and autophagic flux via the endosomal sorting complex required for transport (ESCRT) machinery, lysophagy, and transcription factor EB-mediated lysosome biogenesis.

Key Message

Further exploring mechanisms of ESCRT, lysophagy, and lysosome biogenesis may provide novel therapy strategies for the management of kidney diseases.

Autophagy Induction by Trichodermic Acid Attenuates Endoplasmic Reticulum Stress-Mediated Apoptosis in Colon Cancer Cells

Colorectal cancer (CRC) is the third leading malignant tumor in the world, which has high morbidity and mortality. In this study we found that trichodermic acid (TDA), a secondary metabolite isolated from the plant endophytic fungus Penicillium ochrochloronthe with a variety of biological and pharmacological activities, exhibited the antitumor effects on colorectal cancer cells in vitro and in vivo. Our results showed that TDA inhibited the proliferation of colon cancer cells in a dose-dependent manner. TDA induces sustained endoplasmic reticulum stress, which triggers apoptosis through IRE1α/XBP1 and PERK/ATF4/CHOP pathways. In addition, we found that TDA mediated endoplasmic reticulum stress also induces autophagy as a protective mechanism. Moreover, combined treatment of TDA with autophagy inhibitors significantly enhanced its anticancer effect. In conclusion, our results indicated that TDA can induce ER stress and autophagy mediated apoptosis, suggesting that targeting ER stress and autophagy may be an effective strategy for the treatment of CRC.

Exogenous H2S Protects Colon Cells in Ulcerative Colitis by Inhibiting NLRP3 and Activating Autophagy

Hydrogen sulfide (H₂S) has been reported to participate in intestinal mucosal defense and repair. However, the precise regulatory mechanisms of H₂S in ulcerative colitis (UC) remain unclear. We explored the effects of sodium hydrosulfide (NaHS), a donor of H₂S, in dextran sulfate sodium (DSS)-induced colitis in rats. The pathologic features were determined by analyzing the hematoxylin and eosin-stained samples. Interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), and myeloperoxidase (MPO) levels were determined using ELISA. The presence of cystathionine-γ-lyase (CSE) and light chain 3B (LC3B) were determined using immunohistochemical and immunofluorescence (IF) approaches, respectively. Next, we investigated the effects of NaHS in lipopolysaccharide (LPS)-stimulated human colonic smooth muscle cells (H2940). The level of reactive oxygen species (ROS) was determined using IF. NOD-like receptor 3 (NLRP3) and CSE were detected using western blot and quantitative real-time polymerase chain reaction. Autophagy was determined using western blot, IF, and electron microscopy. NaHS treatment considerably diminished colitis-induced histological injury and proinflammatory cytokine expressions. MPO, CSE, and H₂S were downregulated, whereas LC3B was upregulated after NaHS administration in colitic rats. NaHS remarkably attenuated the levels of ROS, CSE, and NLRP3 in LPS-stimulated cells and enhanced autophagy, as was revealed by increased LC3-II-to-LC3-I ratio, elevated LC3, and decreased p62. Importantly, NaHS promoted autophagosome formation in LPS-treated cells. Exogenous H₂S ameliorates intestinal injury by downregulating inflammation and activation of autophagy, suggesting the potential of NaHS as a therapeutic agent for UC.

Characteristics of Lymphoma in Patients with Inflammatory Bowel Disease: A Systematic Review

BACKGROUND

Lymphoma is a dreaded complication of inflammatory bowel diseases [IBD]. Knowledge about lymphoma in patients with IBD is limited to epidemiological data and the description of risk factors. We performed a systematic review to describe the clinical characteristics and prognosis of lymphoma in patients with IBD.

METHODS

Electronic databases were searched up to June 1, 2020. All published clinical characteristics of lymphoma occurring in patients with IBD were collected.

RESULTS

Eleven studies were included. A total of 589 lymphomas were described in patients with IBD. As seen in de novo lymphoma, non-Hodgkin's lymphoma [NHL] was the most common histological subtype [83.9%]. Diffuse large B-cell lymphoma [DLBCL] and follicular lymphoma were the most well-represented NHL in patients with IBD [30% and 13% respectively]. Two main differences were observed in comparison with de novo lymphoma: primary intestinal lymphoma [PIL] represented a large proportion of lymphoma in patients with IBD [22-75%] whereas mucosa-associated lymphoid tissue [MALT] lymphoma was under-represented. Epstein-Barr virus [EBV]-positive status was observed in a large proportion of tumours [44-75%]. Survival data of lymphoma in patients with IBD were similar to those of de novo lymphoma.

DISCUSSION

This systematic review first highlights that PIL [especially DLBCL subtype] is significantly more frequent in patients with IBD and represents the most common entity. Conversely, MALT lymphoma is extremely rare in the IBD population. However, the overall quality of the evidence is low. Further studies are required to better define lymphoma characteristics in patients with IBD.

Taraxasterol acetate targets RNF31 to inhibit RNF31/p53 axis-driven cell proliferation in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer worldwide. Several studies have suggested that taraxasterol acetate (TA) can inhibit the growth of tumor cells. However, to date, it remains unclear how TA inhibits cell growth and how RNF31 functions as an oncogene. We examined the expression of RNF31 in CRC tissue samples via immunohistochemistry and elucidated the function of RNF31 in CRC cells by constructing a cell model with RNF31 depletion. A cycloheximide (CHX)-chase analysis and immunofluorescence assays were conducted to demonstrate that TA can promote RNF31 degradation by activating autophagy. We used the PharmMapper website to predict targets of TA and identified RNF31. CHX-chase experiments showed that TA could facilitate RNF31 degradation, which was inhibited by the administration of chloroquine. Immunofluorescence assays showed that RNF31 protein was colocalized with LC3I/II and p62, suggesting that TA promoted RNF31 degradation by activating autophagy. We also found that CRC patients with RNF31 overexpression had poorer survival than those with low RNF31 expression. The results of the CHX-chase experiment showed that depletion of RNF31 alleviated p53 degradation, which was inhibited by MG132. A series of co-immunoprecipitation (Co-IP) assays revealed that RNF31 interacts with p53 and promotes p53 ubiquitination and degradation. A Co-IP assay performed with a truncated RNF31 plasmid showed that the PUB domain interacts with p53. Moreover, the PUB domain is the key structure in the induction of p53 ubiquitination. Our findings reveal a key role of RNF31 in CRC cell growth and indicate a mechanism through which TA inhibits cell growth.

Two Faces of Autophagy in the Struggle against Cancer

Autophagy can play a double role in cancerogenesis: it can either inhibit further development of the disease or protect cells, causing stimulation of tumour growth. This phenomenon is called "autophagy paradox", and is characterised by the features that the autophagy process provides the necessary substrates for biosynthesis to meet the cell's energy needs, and that the over-programmed activity of this process can lead to cell death through apoptosis. The fight against cancer is a difficult process due to high levels of resistance to chemotherapy and radiotherapy. More and more research is indicating that autophagy may play a very important role in the development of resistance by protecting cancer cells, which is why autophagy in cancer therapy can act as a "double-edged sword". This paper attempts to analyse the influence of autophagy and cancer stem cells on tumour development, and to compare new therapeutic strategies based on the modulation of these processes.

Identification and Validation of a Prognostic Model Based on Three Autophagy-Related Genes in Hepatocellular Carcinoma

Background

Accumulating studies have demonstrated that autophagy plays an important role in hepatocellular carcinoma (HCC). We aimed to construct a prognostic model based on autophagy-related genes (ARGs) to predict the survival of HCC patients.

Methods

Differentially expressed ARGs were identified based on the expression data from The Cancer Genome Atlas and ARGs of the Human Autophagy Database. Univariate Cox regression analysis was used to identify the prognosis-related ARGs. Multivariate Cox regression analysis was performed to construct the prognostic model. Receiver operating characteristic (ROC), Kaplan-Meier curve, and multivariate Cox regression analyses were performed to test the prognostic value of the model. The prognostic value of the model was further confirmed by an independent data cohort obtained from the International Cancer Genome Consortium (ICGC) database.

Results

A total of 34 prognosis-related ARGs were selected from 62 differentially expressed ARGs identified in HCC compared with noncancer tissues. After analysis, a novel prognostic model based on ARGs (PRKCD, BIRC5, and ATIC) was constructed. The risk score divided patients into high- or low-risk groups, which had significantly different survival rates. Multivariate Cox analysis indicated that the risk score was an independent risk factor for survival of HCC after adjusting for other conventional clinical parameters. ROC analysis showed that the predictive value of this model was better than that of other conventional clinical parameters. Moreover, the prognostic value of the model was further confirmed in an independent cohort from ICGC patients.

Conclusion

The prognosis-related ARGs could provide new perspectives on HCC, and the model should be helpful for predicting the prognosis of HCC patients.

The Effects of Autophagy-Related Genes and lncRNAs in Therapy and Prognosis of Colorectal Cancer

Cellular autophagy plays an important role in the occurrence and development of colorectal cancer (CRC). Whether autophagy-related genes and lncRNAs can be used as ideal markers in CRC is still controversial. The purpose of this study is to identify novel treatment and prognosis markers of CRC. We downloaded transcription and clinical data of CRC from the GEO (GSE40967, GSE12954, GSE17536) and TCGA database, screened for differentially autophagy-related genes (DEAGs) and lncRNAs, constructed prognostic model, and analyzed its relationship with immune infiltration. TCGA and GEO datasets (GSE12954 and GSE17536) were used to validate the effect of the model. Oncomine database and Human Protein Atlas verified the expression of DEAGs. We obtained a total of 151 DEAGs in three verification sets collaboratively. Then we constructed a risk prognostic model through Lasso regression to obtain 15 prognostic DEAGs from the training set and verified the risk prognostic model in three verification sets. The low-risk group survived longer than the high-risk group. Age, gender, pathological stage, and TNM stage were related to the prognostic risk of CRC. On the other hand, BRAF status, RFS event, and tumor location are considered as most significant risk factors of CRC in the training set. Furthermore, we found that the immune score of the low-risk group was higher. The content of CD8 + T cells, active NK cells, macrophages M0, macrophages M1, and active dendritic cells was noted more in the high-risk group. The content of plasma cells, resting memory CD4 + T cells, resting NK cells, resting mast cells, and neutrophil cells was higher in the low-risk group. After all, the Oncomine database and immunohistochemistry verified that the expression level of most key autophagy-related genes was consistent with the results that we found. In addition, we obtained six lncRNAs co-expressed with DEAGs from the training set and found that the survival time was longer in the low-risk group. This finding was verified in the verification set and showed same trend to the results mentioned above. In the final analysis, these results indicate that autophagy-related genes and lncRNAs can be used as prognostic and therapeutic markers for CRC.

DNA Sensing in the Innate Immune Response

The innate immune system recognizes conserved pathogen-associated molecular patterns and produces inflammatory cytokines that direct downstream immune responses. The inappropriate localization of DNA within the cell cytosol or endosomal compartments indicates that a cell may either be infected by a DNA virus or bacterium, or has problems with its own nuclear integrity. This DNA is sensed by certain receptors that mediate cytokine production and, in some cases, initiate an inflammatory and lytic form of cell death called pyroptosis. Dysregulation of these DNA-sensing pathways is thought to contribute to autoimmune diseases and the development of cancer. In this review, we will discuss the DNA sensors Toll-like receptor 9 (TLR9), cyclic GMP-AMP synthase (cGAS), stimulator of interferon genes (STING), absent in melanoma 2 (AIM2), and interferon gamma-inducible 16 (IFI16), their ligands, and their physiological significance. We will also examine the less-well-understood DEAH- and DEAD-box helicases DHX9, DHX36, DDX41, and RNA polymerase III, each of which may play an important role in DNA-mediated innate immunity.

Jervine exhibits anticancer effects on nasopharyngeal carcinoma through promoting autophagic apoptosis via the blockage of Hedgehog signaling

Nasopharyngeal carcinoma (NPC) is a malignant tumor originating from the superior mucosal epithelium of the nasopharynx. However, effective therapies for NPC are still required. Reducing Hedgehog signaling pathway has been shown to suppress tumor growth. In this study, we attempted to explore whether Jervine (JV), an inhibitor of Hedgehog signaling, had anti-cancer effects on NPC, and the underlying mechanisms. Our findings showed that JV treatments markedly reduced the proliferation of NPC cells in a dose- and time-dependent manner. Cell cycle arrest in G2/M phase was significantly enhanced by JV, along with evident DNA damage. Moreover, JV treatment effectively induced apoptosis in NPC cells through improving Caspase-3 activation. Furthermore, ROS production and mitochondrial impairments were detected in JV-incubated NPC cells with elevated releases of Cyto-c from mitochondria. JV also dramatically triggered autophagy through blocking AKT/mTOR and increasing AMPK signaling pathways. Intriguingly, we showed that JV-induced apoptosis was mainly via an autophagy-dependent manner. In addition, the expression levels of SHH, PTCH1, SMO and GLI1 were markedly suppressed in NPC cells, demonstrating the hindered Hedgehog signaling. Importantly, we found that JV-induced apoptosis and autophagy were closely associated with the blockage of Hedgehog signaling. Our in vivo studies confirmed the anti-cancer effects of JV on NPC through inducing autophagy, as evidenced by the markedly reduced tumor growth rate and weight without side effects and toxicity. Taken together, JV may be a promising and effective agent for human NPC treatment through repressing Hedgehog signaling pathway and inducing autophagic cell death.

VEGF knockdown enhances radiosensitivity of nasopharyngeal carcinoma by inhibiting autophagy through the activation of mTOR pathway

Vascular endothelial growth factor (VEGF) is an important pro-angiogenic factor. VEGF was reported to promote the occurrence of autophagy, which enhanced the radioresistance of tumors. The purpose of this study was to investigate the influence of VEGF silencing on the radiosensitivity of nasopharyngeal carcinoma (NPC) cells and the underlying mechanisms. The radiosensitivity of NPC cells after VEGF silencing was detected by cell counting kit 8 (CCK-8) and clonogenic assay, while cell cycle and apoptosis were detected by flow cytometry. The processes of DNA damage, repair and autophagy were examined by immunofluorescence and western blotting. The interaction between VEGF and mTOR was confirmed by western blotting and co-immunoprecipitation studies. The effect of VEGF on radiosensitivity of NPC cells was investigated in vivo using a xenograft model. Furthermore, immunohistochemistry and TUNEL assays were used to verify the relationship between autophagy and radiosensitivity in NPC after VEGF depletion. Downregulation of VEGF significantly inhibited cell proliferation and induced apoptosis of NPC cells after radiotherapy in vitro and in vivo. In addition, VEGF knockdown not only decreased autophagy level, but also delayed the DNA damage repair in NPC cells after irradiation. Mechanistically, silencing VEGF suppressed autophagy through activation of the mTOR pathway. VEGF depletion increased radiosensitivity of NPC cells by suppressing autophagy via activation of the mTOR pathway.

Chloroquine against malaria, cancers and viral diseases

Quinoline (QN) derivatives are often used for the prophylaxis and treatment of malaria. Chloroquine (CQ), a protonated, weakly basic drug, exerts its antimalarial effect mainly by increasing pH and accumulating in the food vacuole of the parasites. Repurposing CQ is an emerging strategy for new indications. Given the inhibition of autophagy and its immunomodulatory action, CQ shows positive efficacy against cancer and viral diseases, including Coronavirus 2019 (COVID-19). Here, we review the underlying mechanisms behind the antimalarial, anticancer and antiviral effects of CQ. We also discuss the clinical evidence for the use of CQ and hydroxychloroquine (HCQ) against COVID-19.

A Scaffold-Free 3-D Co-Culture Mimics the Major Features of the Reverse Warburg Effect In Vitro

Most tumors consume large amounts of glucose. Concepts to explain the mechanisms that mediate the achievement of this metabolic need have proposed a switch of the tumor mass to aerobic glycolysis. Depending on whether primarily tumor or stroma cells undergo such a commutation, the terms ‘Warburg effect’ or ‘reverse Warburg effect’ were coined to describe the underlying biological phenomena. However, current in vitro systems relying on 2-D culture, single cell-type spheroids, or basal-membrane extract (BME/Matrigel)-containing 3-D structures do not thoroughly reflect these processes. Here, we aimed to establish a BME/Matrigel-free 3-D microarray cancer model to recapitulate the metabolic interplay between cancer and stromal cells that allows mechanistic analyses and drug testing. Human HT-29 colon cancer and CCD-1137Sk fibroblast cells were used in mono- and co-cultures as 2-D monolayers, spheroids, and in a cell-chip format. Metabolic patterns were studied with immunofluorescence and confocal microscopy. In chip-based co-cultures, HT-29 cells showed facilitated 3-D growth and increased levels of hexokinase-2, TP53-induced glycolysis and apoptosis regulator (TIGAR), lactate dehydrogenase, and: translocase of outer mitochondrial membrane 20 (TOMM20), when compared with HT-29 mono-cultures. Fibroblasts co-cultured with HT-29 cells expressed higher levels of mono-carboxylate transporter 4, hexokinase-2, microtubule-associated proteins 1A/1B light chain 3, and ubiquitin-binding protein p62 than in fibroblast mono-cultures, in both 2-D cultures and chips. Tetramethylrhodamin-methylester (TMRM) live-cell imaging of chip co-cultures revealed a higher mitochondrial potential in cancer cells than in fibroblasts. The findings demonstrate a crosstalk between cancer cells and fibroblasts that affects cellular growth and metabolism. Chip-based 3-D co-cultures of cancer cells and fibroblasts mimicked features of the reverse Warburg effect.

A Nucleotide Analog Prevents Colitis-Associated Cancer via Beta-Catenin Independently of Inflammation and Autophagy

BACKGROUND & AIMS

Chronic bowel inflammation increases the risk of colon cancer; colitis-associated cancer (CAC). Thiopurine treatments are associated with a reduction in dysplasia and CAC in inflammatory bowel disease (IBD). Abnormal Wnt/β-catenin signalling is characteristic of >90% of colorectal cancers. Immunosuppression by thiopurines is via Rac1 GTPase, which also affects Wnt/β-catenin signalling. Autophagy is implicated in colonic tumors, and topical delivery of the thiopurine thioguanine (TG) is known to alleviate colitis and augment autophagy. This study investigated the effects of TG in a murine model of CAC and potential mechanisms.

METHODS

Colonic dysplasia was induced by exposure to azoxymethane (AOM) and dextran sodium sulfate (DSS) in wild-type (WT) mice and mice harboring intestinal epithelial cell-specific deletion of autophagy related 7 gene (Atg7^ΔIEC). TG or vehicle was administered intrarectally, and the effect on tumor burden and β-catenin activity was assessed. The mechanisms of action of TG were investigated in vitro and in vivo.

RESULTS

TG ameliorated DSS colitis in wild-type but not Atg7^ΔIEC mice, demonstrating that anti-inflammatory effects of locally delivered TG are autophagy-dependent. However, TG inhibited CAC in both wild-type and Atg7^ΔIEC mice. This was associated with decreased β-catenin activation/nuclear translocation demonstrating that TG's inhibition of tumorigenesis occurred independently of anti-inflammatory and pro-autophagic actions. These results were confirmed in cell lines, and the dependency on Rac1 GTPase was demonstrated by siRNA knockdown and overexpression of constitutively active Rac1.

CONCLUSIONS

Our findings provide evidence for a new mechanism that could be exploited to improve CAC chemoprophylactic approaches.

Mief1 augments thyroid cell dysfunction and apoptosis through inhibiting AMPK-PTEN signaling pathway

Objective: Inflammation-mediated thyroid cell dysfunction and apoptosis increases the like-hood of hypothyroidism.Aim: Our aim in the present study is to explore the role of mitochondrial elongation factor 1 (Mief1) in thyroid cell dysfunction induced by TNFα.Materials and methods: Different doses of TNFα were used to incubate with thyroid cells in vitro. The survival rate, apoptotic index and proliferation capacity of thyroid cells were measured. Cellular energy metabolism and endoplasmic reticulum function related to protein synthesis were detected.Results: In response to TNFα treatment, the levels of Mief1 were increased, coinciding with a drop in the viability of thyroid cells in vitro. Loss of Mief1 attenuates TNFα-induced cell death through reducing the ratio of cell apoptosis. Further, we found that Mief1 deletion reversed cell energy metabolism and this effect was attributable to mitochondrial protection. Mief1 knockdown sustained mitochondrial membrane potential and reduced mitochondrial ROS overproduction. In addition, Mief1 knockdown also reduced endoplasmic reticulum stress, as evidenced by decreased levels of Chop and Caspase-12. Finally, our data verified that TNFα treatment inhibited the activity of AMPK-PTEN pathway whereas Mief1 deletion reversed the activity of AMPK and thus promoted the upregulation of PTEN. However, inhibition of AMPK-PTEN pathways could abolish the beneficial effects exerted by Mief1 deletion on thyroid cells damage and dysfunction.Conclusions: Altogether, our data indicate that immune abnormality-mediated thyroid cell dysfunction and death are alleviated by Mief1 deletion possible driven through reversing the activity of AMPK-PTEN pathways.

Expression and clinical significance of p62 protein in colon cancer

p62 is a multifunctional protein involved in multiple cellular processes including proliferation, drug sensitivity and autophagy-associated cancer cell growth. However, the role of p62 in colon cancer remains controversial. Here we investigated the expression of p62 protein in colon cancer and its clinical significance.Patients with colon adenocarcinoma who underwent resection at the Third Affiliated Teaching Hospital of Xinjiang Medical University (Affiliated Cancer Hospital) were retrospectively analyzed. The expression of p62 protein in tumor tissues and adjacent normal tissues was detected by immunohistochemistry and western-blotting. Real-time quantitative polymerase chain reaction was used to detect the expression level of p62 messenger ribonucleic acid in specimens. Progression-free survival (PFS) and overall survival (OS) were assessed using Kaplan-Meier method and the log-rank test.A total of 85 colon cancer patients were enrolled, including 55 (64.71%) patients with high p62 expression, and 30 (35.29%) patients with low p62 expression. The transcription and expression level of p62 in colon cancer tissues were higher than those in adjacent normal tissues (P < .01). High expression of p62 was an independent risk factor for the poor prognosis (PFS and OS) of colon cancer.p62 may be a potential indicator of determining the progression and prognosis evaluation of colon cancer.

Long Noncoding RNA (lncRNA)-Mediated Competing Endogenous RNA Networks Provide Novel Potential Biomarkers and Therapeutic Targets for Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer and has a high metastasis and reoccurrence rate. Long noncoding RNAs (lncRNAs) play an important role in CRC growth and metastasis. Recent studies revealed that lncRNAs participate in CRC progression by coordinating with microRNAs (miRNAs) and protein-coding mRNAs. LncRNAs function as competitive endogenous RNAs (ceRNAs) by competitively occupying the shared binding sequences of miRNAs, thus sequestering the miRNAs and changing the expression of their downstream target genes. Such ceRNA networks formed by lncRNA/miRNA/mRNA interactions have been found in a broad spectrum of biological processes in CRC, including liver metastasis, epithelial to mesenchymal transition (EMT), inflammation formation, and chemo-/radioresistance. In this review, we summarize typical paradigms of lncRNA-associated ceRNA networks, which are involved in the underlying molecular mechanisms of CRC initiation and progression. We comprehensively discuss the competitive crosstalk among RNA transcripts and the novel targets for CRC prognosis and therapy.

Functions and Implications of Autophagy in Colon Cancer

Autophagy is an essential function to breakdown cellular proteins and organelles to recycle for new nutrient building blocks. In colorectal cancer, the importance of autophagy is becoming widely recognized as it demonstrates both pro- and anti-tumorigenic functions. In colon cancer, cell autonomous and non-autonomous roles for autophagy are essential in growth and progression. However, the mechanisms downstream of autophagy (to reduce or enhance tumor growth) are not well known. Additionally, the signals that activate and coordinate autophagy for tumor cell growth and survival are not clear. Here, we highlight the context- and cargo-dependent role of autophagy in proliferation, cell death, and cargo breakdown.