Autophagy is a delicate intracellular degradation process that occurs due to diverse stressful conditions, including the accumulation of damaged proteins and organelles as well as nutrient deprivation. The mechanism of autophagy is initiated by the creation of autophagosomes, which capture and encapsulate abnormal components. Afterward, autophagosomes assemble with lysosomes to recycle or remove degradative cargo. The regulation of autophagy has bipolar roles in cancer suppression and promotion in diverse cancers. Furthermore, autophagy modulates the features of tumorigenesis, cancer metastasis, cancer stem cells, and drug resistance against anticancer agents. Some autophagy regulators are used to modulate autophagy for anticancer therapy but the dual roles of autophagy limit their application in anticancer therapy, and present as the main reason for therapy failure. In this review, we summarize the mechanisms of autophagy, tumorigenesis, metastasis, cancer stem cells, and resistance against anticancer agents. Finally, we discuss whether targeting autophagy is a promising and effective therapeutic strategy in anticancer therapy.

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Colorectal cancer (CRC) is one of the leading causes of cancer-related death due to its aggressive metastasis in later stages. Although there is a growing interest in the tumorigenic role of cellular prion protein (PrPC) in the process of metastasis, the precise mechanism behind the cellular communication involving prion proteins remains poorly understood. This study found that hypoxic tumor microenvironment increased the PrPC-expressing exosomes from CRC, and these exosomes regulate the CRC cell behavior and tumor progression depending on the expression of PrPC. Hypoxic exosomes from CRC cells promoted sphere formation, the expression of tumor-inducing genes, migration, invasion, and tumor growth. Furthermore, these exosomes increased endothelial permeability, migration, invasion, and angiogenic cytokine secretion. These effects were associated with PrPC expression. Application of anti-PrPC antibody with 5-fluorouracil significantly suppressed the CRC progression in a murine xenograft model. Taken together, these findings indicate that PrP-expressing exosomes secreted by hypoxic CRC cells are a key factor in the tumorigenic CRC-to-CRC and CRC-to-endothelial cell communication. Significance: These findings suggest that inhibiting PrPC in hypoxic exosomes during chemotherapy may be an effective therapeutic strategy in colorectal cancer.

Novel series of chlorin e6-curcumin derivatives were designed and synthesized. All the synthesized compounds 16, 17, 18, and 19 were tested for their photodynamic treatment (PDT) efficacy against human pancreatic cancer cell lines: AsPC-1, MIA-PaCa-2, and PANC-1. The cellular uptake study was performed in the aforementioned cell lines using fluorescence-activated cell sorting (FACS). 17, among the synthesized compounds with IC50 values of 0.27, 0.42, and 0.21 µM against AsPC-1, MIA PaCa-2, and PANC-1 cell lines, respectively, demonstrated excellent cellular internalization capability and exhibited higher phototoxicity relative to the parent Ce6. The quantitative analyses using Annexin V-PI staining revealed that the 17-PDT-induced apoptosis was dose-dependent. In pancreatic cell lines, 17 reduced the expression of the anti-apoptotic protein, Bcl-2, and increased the pro-apoptotic protein, cytochrome C, which indicates the activation of intrinsic apoptosis, the primary cause of cancer cell death. Structure–activity relationship studies have shown that the incorporation of additional methyl ester moiety and conjugation to the enone moiety of curcumin enhances cellular uptake and PDT efficacy. Moreover, in vivo PDT testing in melanoma mouse models revealed that 17-PDT greatly reduced tumor growth. Therefore, 17 might be an effective photosensitizer for PDT anticancer therapy.

A biocatalytic system that could produce bioactive resveratrol poly-glucosides, using sucrose as a low-cost source of UDP-glucose donors and amylosucrase DgAS from Deinococcus geothermalis, was developed in this study. This system boasts several advantages, including the rapid and direct conversion of substrates to products, thermostability, regio-stereospecificity, and effectiveness, both in vitro and in vivo, at 40 °C. The results showed that the optimal reaction condition of the production of resveratrol glucosides was obtained by 2.0 µg/mL DgAS and 100 mM sucrose at pH 7.0, incubated at 40 °C for 5 h. With a success rate of around 97.0% in vitro and 95.0% in vivo in a short period of time, resveratrol-O-glucosides showed exciting outcomes in cosmetic applications, including antioxidant, anti-inflammatory, anti-aging, and whitening effects when tested with Raw 264.7, B16, and HS68 cell lines. DgAS is recognized as an important biocatalyst due to its high thermostability, effectiveness, and specificity among all known amylosucrases (ASases) in the production of poly-glucosides in a chain of polyphenols, such as resveratrol, making it an ideal candidate for industrial use in the cost-effective production of cosmetic items.