In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.

Guidelines for the use and interpretatoin of assays for monitoring autophagy

Oral squamous cell carcinoma is a challenging oncology problem.A reliable biomarker for metastasis or high-risk prognosis in oral cancer patients remains undefined.Using quantitative immunohistochemistry,we examined the expression of vimentin,E-cadherin,and beta-catenin in 83 oral squamous cell carcinoma patients,and the relationships between the expression of these markers and specific clinicopathological features were analysed.The high expression of vimentin was observed in 23 of 43(53%) tumours from patients who eventually developed a recurrent tumour and was associated with recurrence and death(P 0.001 and 0.001,respectively).The decreased expression of E-cadherin was observed in 36 of 43(84%) tumours from patients who eventually developed a recurrent tumour and was also associated with recurrence and death(P 0.001 and 0.001,respectively).Although no correlation between beta-catenin expression in whole-tumour sections and clinicopathological features was observed,decreased beta-catenin expression at the tumour invasive front was closely associated with recurrence and death(P=0.002 and 0.002,respectively).The expression of vimentin and that of E-cadherin were associated with survival and were independent prognostic factors in univariate and multivariate analyses.Our data show that the overexpression of vimentin was closely associated with recurrence and death in oral squamous cell carcinoma patients.The combination of the upregulation of vimentin and aberrant expression of E-cadherin/beta-catenin complexes at the tumour invasive front may provide a useful prognostic marker in oral squamous cell carcinoma.

Upregulation of vimentin and aberrant expression of E-cadherin/beta-catenin complex in oral squamous cell carcinomas:correlation with the clinicopathological features and patient outcome

Hypoxia is an integral component of the tumor microenvironment. Either as chronic or cycling hypoxia, it exerts a similar effect on cancer processes by activating hypoxia-inducible factor-1 (HIF-1) and nuclear factor (NF-κB), with cycling hypoxia showing a stronger proinflammatory influence. One of the systems affected by hypoxia is the CXC chemokine system. This paper reviews all available information on hypoxia-induced changes in the expression of all CXC chemokines (CXCL1, CXCL2, CXCL3, CXCL4, CXCL5, CXCL6, CXCL7, CXCL8 (IL-8), CXCL9, CXCL10, CXCL11, CXCL12 (SDF-1), CXCL13, CXCL14, CXCL15, CXCL16, CXCL17) as well as CXC chemokine receptors-CXCR1, CXCR2, CXCR3, CXCR4, CXCR5, CXCR6, CXCR7 and CXCR8. First, we present basic information on the effect of these chemoattractant cytokines on cancer processes. We then discuss the effect of hypoxia-induced changes on CXC chemokine expression on the angiogenesis, lymphangiogenesis and recruitment of various cells to the tumor niche, including myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), tumor-associated neutrophils (TANs), regulatory T cells (Tregs) and tumor-infiltrating lymphocytes (TILs). Finally, the review summarizes data on the use of drugs targeting the CXC chemokine system in cancer therapies.

The Effect of Hypoxia on the Expression of CXC Chemokines and CXC Chemokine Receptors-A Review of Literature.

Leveraging disulfiram to treat cancer: Mechanisms of action, delivery strategies, and treatment regimens

To circumvent the huge cost, long R&D time and the difficulty to identify the targets of new drugs, repurposing the ones that have been clinically approved has been considered as a viable strategy to treat different diseases. In the current study, we outlined the rationale for repurposing disulfiram (DSF, an old alcohol-aversion drug) to treat primary breast cancer and its metastases. Methods: To overcome a few shortcomings of the individual administration of DSF, such as the dependence on copper ions (Cu2+) and limited capability in selective targeting, we here artificially synthesized the active form of DSF, diethyldithiocarbamate (DTC)-Cu complex (CuET) for cancer therapeutics. To achieve a greater efficacy in vivo, smart nanomedicines were devised through a one-step self-assembly of three functional components including a chemically stable and biocompatible phase-change material (PCM), the robust anticancer drug (CuET) and a near-infrared (NIR) dye (DIR), namely CuET/DIR NPs. A number of in vitro assays were performed including the photothermal efficacy, light-triggered drug release behavior, nuclear localization, DNA damage and induction of apoptosis of CuET/DIR NPs and molecular mechanisms underlying CuET-induced repression on cancer metastatic behaviors. Meanwhile, the mice bearing 4T1-LG12-drived orthotopic tumors were employed to evaluate in vivo biodistribution and anti-tumor effect of CuET/DIR NPs. The intravenous injection model was employed to reflect the changes of the intrinsic metastatic propensity of 4T1-LG12 cells responding to CuET/DIR NPs. Results: The rationally designed nanomedicines have self-traceability for bioimaging, long blood circulation time for enhanced drug accumulation in the tumor site and photo-responsive release of the anticancer drugs. Moreover, our data unearthed that CuET/DIR nanomedicines behave like "Trojan horse" to transport CuET into the cytoplasm, realizing substantial intracellular accumulation. Upon NIR laser irradiation, massive CuET would be triggered to release from the nanomedicines and reach a high local concentration towards the nucleus, where the pro-apoptotic effects were conducted. Importantly, our CuET/DIR nanomedicines revealed a pronounced capability to leash breast cancer metastases through inhibition on EMT. Additionally, these nanomedicines showed great biocompatibility in animals. Conclusion: These combined data unearthed a remarkably enhanced tumor-killing efficacy of our CuET nanomedicines through nuclear targeting. This work may open a new research area of repurposing DSF as innovative therapeutic agents to treat breast cancer and its metastases.

Diethyldithiocarbamate-copper nanocomplex reinforces disulfiram chemotherapeutic efficacy through light-triggered nuclear targeting.

Objectives Bone mesenchymal stem cells (BMSCs) play critical roles in tumour microenvironment However, molecular mechanisms of how BMSCs to be recruited and effect subsequent tumour progression are poorly understood in oral squamous cell carcinoma (OSCC) Materials and methods The distribution of CXCL8 was detected by immunohistochemical staining in OSCC tissues The chemotaxis of conditioned media from different epithelial cells to BMSCs was examined by trans-well assay Real-time quantitative PCR (qPCR) and ELISA were used to detect the expression of related cytokines and chemokine receptors The migration of BMSCs was observed in BALB/c nude mice The roles of BMSCs in proliferation, migration and invasion of OSCC were detected by CCK-8, flow cytometry and trans-well assay Epithelial-mesenchymal transition (EMT)-related markers were analysed by qPCR and Western blot in vitro, and growth was evaluated in BALB/c nude mice using subcutaneously implanted OSCC in nude mouse model in vivo Results Using OSCC, we show CXCL8, secreted by OSCC, binds to exclusively CXCR2 in BMSCs to facilitate migration of BMSCs to OSCC TGF-β secreted by BMSCs subsequently induces EMT of OSCC to promote their proliferation, migration and infiltration We also showed that the Ras/Raf/Erk axis plays a critical role in tumour progression Conclusions Our results provide the molecular basis for BMSC recruitment into tumours, and how this process leads to tumour progression and leads us to develop a novel OSCC treatment target

https://onlinelibrary.wiley.com/doi/pdf/10.1111/cpr.12859

Bone mesenchymal stem cells are recruited via CXCL8‐CXCR2 and promote EMT through TGF‐β signal pathways in oral squamous carcinoma

Epithelial-mesenchymal transition (EMT) is involved in both physiological and pathological processes. EMT plays an essential role in the invasion, migration and metastasis of tumours. Autophagy has been shown to regulate EMT in a variety of cancers but not in head and neck squamous cell carcinoma (HNSCC). Herein, we investigated whether autophagy also regulates EMT in HNSCC. Analyses of clinical data from three public databases revealed that higher expression of fibronectin-1 (FN1) correlated with poorer prognosis and higher tumour pathological grade in HNSCC. Data from SCC-25 cells demonstrated that rapamycin and Earle's balanced salt solution (EBSS) promoted autophagy, leading to increased FN1 degradation, while 3-methyladenine (3-MA), bafilomycin A1 (Baf A1) and chloroquine (CQ) inhibited autophagy, leading to decreased FN1 degradation. On the other hand, autophagic flux was blocked in BECN1 mutant HNSCC Cal-27 cells, and rapamycin did not promote autophagy in Cal-27 cells; also in addition, FN1 degradation was inhibited. Further, we identified FN1 degradation through the lysosome-dependent degradation pathway using the proteasome inhibitor MG132. Data from immunoprecipitation assays also showed that p62/SQSTM1 participated as an autophagy adapter in the autophagy-lysosome pathway of FN1 degradation. Finally, data from immunoprecipitation assays demonstrated that the interaction between p62 and FN1 was abolished in p62 mutant MCF-7 and A2780 cell lines. These results indicate that autophagy significantly promotes the degradation of FN1. Collectively, our findings clearly suggest that FN1, as a marker of EMT, has adverse effects on HNSCC and elucidate the autophagy-lysosome degradation mechanism of FN1.

/pdf/regulation-of-fn1-degradation-by-the-p62-sqstm1-dependent-4bjfa7659z.pdf

Regulation of FN1 degradation by the p62/SQSTM1-dependent autophagy-lysosome pathway in HNSCC.

Purpose: Smad4 loss is highly related to poor prognosis and decreased patient survival in oral squamous cell carcinoma (OSCC), suggesting that agents that target both Smad4-mutated and Smad4 wild-type cells could treat OSCC more effectively. Disulfiram (Dsf) has anticancer activity through a variety of mechanisms, including inhibition of epithelial-mesenchymal transition (EMT). It remains unclear whether Dsf has the same effect on Smad4-mutated and Smad4 wild-type OSCC or not and what mechanism is involved. Methods: Effect of Dsf on TGFβ1-induced EMT in CAL27 (Smad4 mutation) and SCC25 (Smad4 wild-type) cells were evaluated through analyzing changes in morphology, expression of EMT markers, and migration and invasion of cells. The ERK-pathway inhibitor U0126 was used to confirm TGFβ-ERK-Snail pathway-mediated cell behavior. Dsf's effects on tumor growth and metastasis in vivo were examined through a subcutaneous xenograft mouse model and an intravenous tumor mouse model. Results: Dsf inhibited TGFβ1-induced EMT through suppression of morphological change, EMT-marker expression, and cell migration and invasion in both CAL27 and SCC25. Phosphorylation of ERK and expression of Snail were blocked by Dsf treatment. Like Dsf, U0126 had a similar effect on EMT of CAL27 and SCC25. Dsf also reduced tumor growth and metastasis in vivo, accompanied by decreased expression of EMT markers in tumors. Conclusion: These results indicated that Dsf inhibited EMT of OSCC in vitro and in vivo independently of Smad4 through suppression of the TGFβ-ERK-Snail pathway, suggesting the broad-spectrum anticancer potential of Dsf for clinical use against OSCC.

/pdf/disulfiram-inhibits-epithelial-mesenchymal-transition-3mp3ko0ely.pdf

Disulfiram inhibits epithelial-mesenchymal transition through TGFβ-ERK-Snail pathway independently of Smad4 to decrease oral squamous cell carcinoma metastasis.

Yumeng Chen

Papers

Bone mesenchymal stem cells are recruited via CXCL8‐CXCR2 and promote EMT through TGF‐β signal pathways in oral squamous carcinoma

Regulation of FN1 degradation by the p62/SQSTM1-dependent autophagy-lysosome pathway in HNSCC.

Disulfiram inhibits epithelial-mesenchymal transition through TGFβ-ERK-Snail pathway independently of Smad4 to decrease oral squamous cell carcinoma metastasis.

Modification of Metal-Organic Framework Nanoparticles Using Dental Pulp Mesenchymal Stem Cell Membranes to Target Oral Squamous Cell Carcinoma.

Correction: Regulation of FN1 degradation by p62/SQSTM1-dependent autophagy-lysosomal pathway in HNSCC.