Imiquimod-induced ROS production disrupts the balance of mitochondrial dynamics and increases mitophagy in skin cancer cells

TLR7-Induced Mitochondrial Reactive Oxygen Species Production in Monocyte-derived Dendritic Cells Drives IL-12-Dependent NK Cell Activation and Enhances Antitumor Immunity

Dendritic cell (DC)-based vaccines are promising immunotherapies for cancer. Although DC-based therapies are known to activate tumor-specific T cells, the interplay between DCs and NK cells in this setting is not fully understood. In this study, we demonstrated a novel TLR7/ mitochondrial reactive oxygen species (mROS)/IL-12 axis that drives potent NK cell responses against tumors. We showed that TLR7 activation by imiquimod in peripheral blood monocyte-derived CD11c+ DCs triggered mROS production, leading to enhanced IL-12 secretion and subsequent NK cell activation, as evidenced by increased IFN-γ production and tumor cell cytotoxicity. Notably, mROS neutralization abrogates NK cell-mediated tumor cell lysis, and TLR7-mediated DC activation of NK cells occurs independently of MyD88, suggesting involvement of the noncanonical NF-κB pathway. Our findings provide a rationale for targeting the TLR7/mROS/IL-12 axis to enhance the efficacy of DC-based cancer immunotherapy.

The Protective Effects of Mcl-1 on Mitochondrial Damage and Oxidative Stress in Imiquimod-Induced Cancer Cell Death

Mitochondria, vital organelles that generate ATP, determine cell fate. Dysfunctional and damaged mitochondria are fragmented and removed through mitophagy, a mitochondrial quality control mechanism. The FDA-approved drug IMQ, a synthetic agonist of Toll-like receptor 7, exhibits antitumor activity against various skin malignancies. We previously reported that IMQ promptly reduced the level of the antiapoptotic Mcl-1 protein and that Mcl-1 overexpression attenuated IMQ-triggered apoptosis in skin cancer cells. Furthermore, IMQ profoundly disrupted mitochondrial function, promoted mitochondrial fragmentation, induced mitophagy, and caused cell death by generating high levels of ROS. However, whether Mcl-1 protects mitochondria from IMQ treatment is still unknown. In this study, we demonstrated that Mcl-1 overexpression induced resistance to IMQ-induced apoptosis and reduced both IMQ-induced ROS generation and oxidative stress in cancer cells. Mcl-1 overexpression maintained mitochondrial function and integrity and prevented mitophagy in IMQ-treated cancer cells. Furthermore, IL-6 protected against IMQ-induced apoptosis by increasing Mcl-1 expression and attenuating IMQ-induced mitochondrial fragmentation. Mcl-1 overexpression ameliorates IMQ-induced ROS generation and mitochondrial fragmentation, thereby increasing mitochondrial stability and ultimately attenuating IMQ-induced cell death. Investigating the roles of Mcl-1 in mitochondria is a potential strategy for cancer therapy development.

Lindqvist-type Polyoxometalates Act as Anti-breast Cancer Drugs via Mitophagy-induced Apoptosis

OBJECTIVE

Lindqvist-type polyoxometalates (POMs) exhibit potential antitumor activities. This study aimed to examine the effects of Lindqvist-type POMs against breast cancer and the underlying mechanism.

METHODS

Using different cancer cell lines, the present study evaluated the antitumor activities of POM analogues that were modified at the body skeleton based on molybdenum-vanadium-centered negative oxygen ion polycondensations with different side strains. Cell colony formation assay, autophagy detection, mitochondrial observation, qRT-PCR, Western blotting, and animal model were used to evaluate the antitumor activities of POMs against breast cancer cells and the related mechanism.

RESULTS

MO-4, a Lindqvist-type POM linking a proline at its side strain, was selected for subsequent experiments due to its low half maximal inhibitory concentration in the inhibition of proliferation of breast cancer cells. It was found that MO-4 induced the apoptosis of multiple types of breast cancer cells. Mechanistically, MO-4 activated intracellular mitophagy by elevating mitochondrial reactive oxygen species (ROS) levels and resulting in apoptosis. In vivo, breast tumor growth and distant metastasis were significantly reduced following MO-4 treatment.

CONCLUSION

Collectively, the results of the present study demonstrated that the novel Lindqvist-type POM MO-4 may exhibit potential in the treatment of breast cancer.

Obeticholic Acid Inhibit Mitochondria Dysfunction Via Regulating ERK1/2-DRP Pathway to Exert Protective Effect on Lipopolysaccharide-Induced Myocardial Injury

Farnesoid X receptor (FXR) plays critical regulatory roles in cardiovascular physiology/pathology. However, the role of FXR agonist obeticholic acid (OCA) in sepsis-associated myocardial injury and underlying mechanisms remain unclear. C57BL/6J mice are treated with OCA before lipopolysaccharide (LPS) administration. The histopathology of the heart and assessment of FXR expression and mitochondria function are performed. To explore the underlying mechanisms, H9c2 cells, and primary cardiomyocytes are pre-treated with OCA before LPS treatment, and extracellular signal-regulated protein kinase (ERK) inhibitor PD98059 is used. LPS-induced myocardial injury in mice is significantly improved by OCA pretreatment. Mechanistically, OCA pretreatment decreased reactive oxygen species (ROS) levels and blocked the loss of mitochondrial membrane potential (ΔΨm) in cardiomyocytes. The expression of glutathione peroxidase 1 (GPX1), superoxide dismutase 1 (SOD1), superoxide dismutase 2 (SOD2), and nuclear factor erythroid 2-related factor 2 (NRF-2) increased in the case of OCA pretreatment. In addition, OCA improved mitochondria respiratory chain with increasing Complex I expression and decreasing cytochrome C (Cyt-C) diffusion. Moreover, OCA pretreatment inhibited LPS-induced mitochondria dysfunction via suppressing ERK1/2-DRP signaling pathway. FXR agonist OCA inhibits LPS-induced mitochondria dysfunction via suppressing ERK1/2-DRP signaling pathway to protect mice against LPS-induced myocardial injury.

Aging and homeostasis of the hypodermis in the age-related deterioration of skin function

Adipose tissues in the hypodermis, the crucial stem cell reservoir in the skin and the endocrine organ for the maintenance of skin homeostasis undergo significant changes during skin aging. Dermal white adipose tissue (dWAT) has recently been recognized as an important organ for both non-metabolic and metabolic health in skin regeneration and rejuvenation. Defective differentiation, adipogenesis, improper adipocytokine production, and immunological dissonance dysfunction in dWAT lead to age-associated clinical changes. Here, we review age-related alterations in dWAT across levels, emphasizing the mechanisms underlying the regulation of aging. We also discuss the pathogenic changes involved in age-related fat dysfunction and the unfavorable consequences of accelerated skin aging, such as chronic inflammaging, immunosenescence, delayed wound healing, and fibrosis. Research has shown that adipose aging is an early initiation event and a potential target for extending longevity. We believe that adipose tissues play an essential role in aging and form a potential therapeutic target for the treatment of age-related skin diseases. Further research is needed to improve our understanding of this phenomenon.

Huang Lian Jie Du Decoction enhances the anti-tumor efficacy of immune checkpoint inhibitors by activating TLR7/8 signalling in melanoma

BACKGROUND

The clinical application of immune checkpoint inhibitors (ICIs) is limited by their drug resistance, necessitating the development of ICI sensitizers to improve cancer immunotherapy outcomes. Huang Lian Jie Du Decoction (HLJD, Oren-gedoku-to in Japanese, Hwangryunhaedok-tang in Korean), a famous traditional Chinese medicinal prescription, has exhibited potential in the field of cancer treatment. This study aims to investigate the impact of HLJD on the efficacy of ICIs in melanoma and elucidate the underlying mechanisms.

METHODS

The potential synergistic effects of HLJD and ICIs were investigated on the tumor-bearing mice model of B16F10 melanoma, and the tumor infiltration of immune cells was tested by flow cytometry. The differential gene expression in tumors between HLJD and ICIs group and ICIs alone group were analyzed by RNA-seq. The effects of HLJD on oxidative stress, TLR7/8, and type I interferons (IFN-Is) signaling were further validated by immunofluorescence, PCR array, and immunochemistry in tumor tissue.

RESULTS

HLJD enhanced the anti-tumor effect of ICIs, significantly inhibited tumor growth, and prolonged the survival duration in melanoma. HLJD increased the tumor infiltration of anti-tumor immune cells, especially DCs, CD4+ T cells and CD8+T cells. Mechanically, HLJD activated the oxidative stress and TLR7/8 signaling pathway and IFN-Is-related genes in tumors.

CONCLUSIONS

HLJD enhanced the therapeutic benefits of ICIs in melanoma, through increasing reactive oxygen species (ROS), promoting the TLR7/8 pathway, and activating IFN-Is signaling, which in turn activated DCs and T cells.

Quercetin promotes ATG5-mediating autophagy-dependent ferroptosis in gastric cancer

Quercetin has been documented to possess a multitude of pharmacological effects, encompassing antioxidant, antiviral, antimicrobial, and anti-inflammatory properties. Nevertheless, the exact molecular mechanisms responsible for the anti-tumor properties of quercetin remain to be fully explicated. To this end, quercetin was administered to gastric cancer cells (in vitro) AGS and MKN45, as well as BALB/c mice (in vivo). The proliferation ability of cells was evaluated using cholecystokinin octapeptide (CCK-8) and colony formation assays. The evaluation of ferroptosis involved the measurement of iron, malondialdehyde (MDA), and lipid reactive oxygen species. Autophagy and apoptosis were evaluated using immunofluorescence staining, western blotting, and flow cytometry analysis. Our findings indicate that quercetin significantly inhibited cell viability and tumor volume compared to the control group. Additionally, quercetin was found to decrease glutathione (GSH), malondialdehyde, and reactive oxygen species (ROS) levels while suppressing beclin1 and LC3B levels in cancer cells. Remarkably, the utilization of siATG5 was found to reverse all the aforementioned effects of quercetin. Ultimately, the effects of quercetin on gastric cancer were validated. In summary, our findings provide evidence that quercetin facilitates autophagy-mediated ferroptosis in gastric cancer.

A Comprehensive Review of Various Therapeutic Strategies for the Management of Skin Cancer

Skin cancer (SC) poses a global threat to the healthcare system and is expected to increase significantly over the next two decades if not diagnosed at an early stage. Early diagnosis is crucial for successful treatment, as the disease becomes more challenging to cure as it progresses. However, identifying new drugs, achieving clinical success, and overcoming drug resistance remain significant challenges. To overcome these obstacles and provide effective treatment, it is crucial to understand the causes of skin cancer, how cells grow and divide, factors that affect cell growth, and how drug resistance occurs. In this review, we have explained various therapeutic approaches for SC treatment via ligands, targeted photosensitizers, natural and synthetic drugs for the treatment of SC, an epigenetic approach for management of melanoma, photodynamic therapy, and targeted therapy for BRAF-mutated melanoma. This article also provides a detailed summary of the various natural drugs that are effective in managing melanoma and reducing the occurrence of skin cancer at early stages and focuses on the current status and future prospects of various therapies available for the management of skin cancer.

ZnO nanomaterials target mitochondrial apoptosis and mitochondrial autophagy pathways in cancer cells

In recent years, the application of engineering nanomaterials has significantly contributed to the development of various biomedical fields. Zinc oxide nanomaterials (ZnO NMts) have gained wide popularity due to their biocompatibility, unique physical and chemical properties, stability, and cost-effectiveness for large-scale production. They have emerged as potential materials for anticancer applications. This article provides a comprehensive review of the synthesis methods of ZnO NMts and highlights the advantages of combining ZnO NMts with anticancer drugs as a nano platform for cancer treatment. Additionally, the article briefly explains the mechanism of action of ZnO NMts in tumor cells, focusing on the mitochondrial pathways that target cell apoptosis and autophagy. It is observed that these pathways are primarily influenced by reactive oxygen species generated through oxidative stress. The article discusses the promising prospects of ZnO NMts combined with anticancer drugs in the field of cancer medicine and emphasizes the need for further in-depth research on the mitochondrial apoptosis and mitochondrial autophagy pathways.

Low-dose imiquimod induces melanogenesis in melanoma cells through an ROS-mediated pathway

BACKGROUND

Melanogenesis is the process of melanin maturation which not only protects skin from UV radiation but also plays an important role in antigenicity of melanomas. Imiquimod (IMQ) is a toll-like receptor 7 (TLR7) agonist that exhibits antiviral and anticancer activity.

OBJECTIVE

To explore whether IMQ could induce melanogenesis in melanoma cells.

METHODS

The mouse melanoma cell line B16F10, the mouse immortalized melanocyte Melan-A, and human melanoma cell lines MNT-1, C32 and A375 were utilized in this study. The pigmented level was observed by the centrifuged cell pellet. The intracellular and extracellular melanin levels were examined in the absorbance in NaOH-extracted cell lysate and cell-cultured medium, respectively. The expression of melanogenesis related proteins was examined by immunoblotting. The intracellular cyclic AMP amount was evaluated by the cAMP Glo assay kit. The activity of phosphodiesterase 4B (PDE4B) was investigated by CREB reporter assay with overexpressed PDE4B or not.

RESULTS

We demonstrated that a low dose of IMQ could trigger melanogenesis in B16F10 cells. IMQ induced microphthalmia-associated transcription factor (MITF) nuclear translocation, upregulated the expression of melanogenesis-related proteins, increased tyrosinase (TYR) activity, and led to pigmentation in B16F10 cells. Next, we found that IMQ-induced melanogenesis was activated by excessive intracellular cAMP accumulation, which was regulated through IMQ-mediated PDE4B inhibition. Finally, IMQ-induced ROS production was found to be involved in melanogenesis by its control of PDE4B activity.

CONCLUSIONS

Low dose of IMQ could activate melanogenesis through the ROS/PDE4B/PKA pathway in melanoma cells.

Chaihu Shugan San promotes gastric motility in rats with functional dyspepsia by regulating Drp-1-mediated ICC mitophagy

CONTEXT

Chaihu Shugan San (CHSGS) was effective in the treatment of functional dyspepsia (FD).

OBJECTIVE

To investigate the mechanism of CHSGS in FD through dynamin-related protein 1 (Drp-1)-mediated interstitial cells of cajal (ICC) mitophagy.

MATERIALS AND METHODS

Forty Sprague-Dawley (SD) rats were randomly divided into control, model, mdivi-1, mdivi-1 + CHSGS and CHSGS groups. Tail-clamping stimulation was used to establish the FD model. Mdivi-1 + CHSGS and CHSGS groups were given CHSGS aqueous solution (4.8 g/kg) by gavage twice a day. Mdivi-1 (25 mg/kg) was injected intraperitoneally once every other week for 4 w. Mitochondrial damage was observed by corresponding kits and related protein expressions were assessed by Immunofluorescence and (or) Western Blot.

RESULTS

Compared with the mean value of the control group, superoxide dismutase (SOD) and citrate synthase (CS) in the model group were decreased by 11% and 35%; malondialdehyde (MDA) and reactive oxygen species (ROS) were increased by 1.2- and 2.8-times; ckit fluorescence and protein expressions were decreased by 85% and 51%, co-localization expression of LC3 and voltage dependent anion channel 1 (VDAC1), Drp-1 and translocase of the outer mitochondrial membrane 20 (Tom20) were increased by 10.1- and 5.4-times; protein expressions of Drp-1, Beclin-1, and LC3 were increased by 0.5-, 1.4-, and 2.5-times whereas p62 was decreased by 43%. After mdivi-1 and (or) CHSGS intervention, the above situation has been improved.

DISCUSSION AND CONCLUSION

CHSGS could improve mitochondrial damage and promote gastric motility in FD rats by regulating Drp-1-mediated ICC mitophagy.

Topical Calcipotriol Plus Imiquimod Immunotherapy for Nonkeratinocyte Skin Cancers

Nonkeratinocyte cutaneous malignancies, including breast cancer cutaneous metastasis and melanoma in situ, are often poor surgical candidates. Imiquimod (IMQ), a toll-like receptor 7 agonist that activates innate immunity in the skin, is used to treat these cutaneous malignancies. However, IMQ's modest effect on the activation of adaptive immunity limits its efficacy as a monotherapy. In this study, we demonstrate that topical TSLP cytokine inducers-calcipotriol and retinoic acid-synergize with IMQ to activate CD4+ T-cell immunity against nonkeratinocyte cutaneous malignancies. Topical calcipotriol plus IMQ treatment reduced breast tumor growth compared with calcipotriol or IMQ alone (P < 0.0001). Calcipotriol plus IMQ-mediated tumor suppression was associated with significant infiltration of CD4+ effector T cells in the tumor microenvironment. Notably, topical calcipotriol plus IMQ immunotherapy enabled immune checkpoint blockade therapy to effectively control immunologically cold breast tumors, which was associated with induction of CD4+ T-cell immunity. Topical treatment with calcipotriol plus IMQ and retinoic acid plus IMQ also blocked subcutaneous melanoma growth. These findings highlight the synergistic effect of topical TSLP induction in combination with innate immune cell activation as an effective immunotherapy for malignancies affecting the skin.

Recent advances in treating female genital human papillomavirus related neoplasms with topical imiquimod

Human papillomavirus (HPV) encompasses a group of viruses that infect the skin and mucous membranes. In the presence of certain factors, persistent infection with high-risk HPVs can trigger a process of neoplastic transformation. Imiquimod is a topical agent that acts as a Toll-like receptor 7/8 agonist, stimulating the innate and adaptive immune system to exert antitumor and antiviral effects. It has been approved for the treatment of various skin conditions, however, its efficacy and safety in the management of HPV-related-neoplasms of the lower genital tract, such as vulvar, vaginal, and cervical neoplasia, are still under investigation. This review summarizes the current evidence on the use of imiquimod for the treatment of HPV-induced lesions of the female lower genital tract, focusing on its indications, mechanisms of action, outcomes, and predictors of response.

Adjusted vascular contractility relies on integrity of progranulin pathway: Insights into mitochondrial function

Objective

Cardiovascular disease (CVD) is a global health crisis and a leading cause of mortality. The intricate interplay between vascular contractility and mitochondrial function is central to CVD pathogenesis. The progranulin gene (GRN) encodes glycoprotein progranulin (PGRN), a ubiquitous molecule with known anti-inflammatory property. However, the role of PGRN in CVD remains enigmatic. In this study, we sought to dissect the significance of PGRN in the regulation vascular contractility and investigate the interface between PGRN and mitochondrial quality.

Method

Our investigation utilized aortae from male and female C57BL6/J wild-type (PGRN+/+) and B6(Cg)-Grntm1.1Aidi/J (PGRN-/-) mice, encompassing wire myograph assays to assess vascular contractility and primary aortic vascular smooth muscle cells (VSMCs) for mechanistic insights.

Results

Our results showed suppression of contractile activity in PGRN-/- VSMCs and aorta, followed by reduced α-smooth muscle actin expression. Mechanistically, PGRN deficiency impaired mitochondrial oxygen consumption rate (OCR), complex I activity, mitochondrial turnover, and mitochondrial redox signaling, while restoration of PGRN levels in aortae from PGRN-/- mice via lentivirus delivery ameliorated contractility and boosted OCR. In addition, VSMC overexpressing PGRN displayed higher mitochondrial respiration and complex I activity accompanied by cellular hypercontractility. Furthermore, increased PGRN triggered lysosome biogenesis by regulating transcription factor EB and accelerated mitophagy flux in VSMC, while treatment with spermidine, an autophagy inducer, improved mitochondrial phenotype and enhanced vascular contractility. Finally, angiotensin II failed to induce vascular contractility in PGRN-/- suggesting a key role of PGRN to maintain the vascular tone.

Conclusion

Our findings suggest that PGRN preserves the vascular contractility via regulating mitophagy flux, mitochondrial complex I activity, and redox signaling. Therefore, loss of PGRN function appears as a pivotal risk factor in CVD development.

Synthesis, characterization, molecular docking, RNA-sequence and anticancer efficacy evaluation in vitro of ruthenium(II) complexes on B16 cells

In recent years, the studies of the ruthenium(II) complexes on anticancer activity have been paid great attention, many Ru(II) complexes possess high anticancer efficiency. In this paper, three ligands CPIP (2-(4-chlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline), DCPIP (2-(3,4-dichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline), TCPIP (2-(2,3,5-trichlorophenyl)-1H-imidazo[4,5-f][1,10]phenanthroline) and their three ruthenium (II) complexes [Ru(dip)2(CPIP)](PF6)2 (1, dip = 4,7-diphenyl-1,10-phenanthroline), [Ru(dip)2(DCPIP)](PF6)2 (2) and [Ru(dip)2(TCPIP)](PF6)2 (3) were synthesized and characterized. 3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide (MTT) assay was used to investigate in vitro cytotoxicity of complexes against various cancer cells. The results showed that complexes 1-3 exhibited pronounced cytotoxic effect on B16 cells with low IC50 values of 7.2 ± 0.1, 11.7 ± 0.6 and 1.2 ± 0.2 μM, respectively. The 3D model demonstrated that the complexes can validly prevent the cell proliferation. Apoptosis determined using Annexin V-FITC/PI double staining revealed that complexes 1-3 can effectively induce apoptosis in B16 cells. The intracellular localization of 1-3 in the mitochondria, the levels of intracellular reactive oxygen species (ROS), the opening of mitochondrial permeability transition pore as well as the decline of mitochondrial membrane potential were investigated, which demonstrated that the complexes 1-3 led to apoptosis via a ROS-mediated mitochondrial dysfunction pathway. The RNA-sequence indicated that the complexes upregulate the expression of 74 genes and downregulate the expression of 81 genes. The molecular docking showed that the complexes interact with the proteins through hydrogen bond, π-cation and π-π interaction. The results show that ruthenium(II) complexes 1, 2 and 3 can block tumor cell growth and induce cell death through autophagy and ROS-mediated mitochondrial dysfunction pathways.

The worsening of skeletal muscle atrophy induced by immobilization at the early stage of remobilization correlates with BNIP3-dependent mitophagy

BACKGROUND

Recent studies have shown that immobilization enhances reactive oxygen species (ROS) production and mitophagy activity in atrophic skeletal muscle. However, there are relatively few studies examining the biological changes and underlying mechanisms of skeletal muscle during remobilization. In this study, we aimed to investigate the effects of remobilization on skeletal muscle and explore the role of BNIP3-dependent mitophagy in this process.

METHODS

Thirty rats were randomly divided into six groups based on immobilization and remobilization time: control (C), immobilization for two weeks (I-2w), and remobilization for one day (R-1d), three days (R-3d), seven days (R-7d), and two weeks (R-2w). At the end of the experimental period, the rectus femoris muscles were removed and weighed, and the measurements were expressed as the ratio of muscle wet weight to body weight (MWW/BW). Sirius Red staining was performed to calculate the values of cross-sectional area (CSA) of rectus femoris. Oxidative fluorescent dihydroethidium was used to evaluate the production of ROS, and the levels of superoxide dismutase (SOD) were also detected. The morphological changes of mitochondria and the formation of mitophagosomes in rectus femoris were examined and evaluated by transmission electron microscope. Immunofluorescence was employed to detect the co-localization of BNIP3 and LC3B, while Western blot analysis was performed to quantify the levels of proteins associated with mitophagy and mitochondrial biogenesis. The total ATP content of the rectus femoris was determined to assess mitochondrial function.

RESULTS

Within the first three days of remobilization, the rats demonstrated decreased MWW/BW, CSA, and ATP concentration, along with increased ROS production and HIF-1α protein levels in the rectus femoris. Results also indicated that remobilization triggered BNIP3-dependent mitophagy, supported by the accumulation of mitophagosomes, the degradation of mitochondrial proteins (including HSP60 and COX IV), the elevation of BNIP3-dependent mitophagy protein markers (including BNIP3, LC3B-II/LC3B-I, and Beclin-1), and the accumulation of puncta representing co-localization of BNIP3 with LC3B. Additionally, PGC-1α, which is involved in the regulation of mitochondrial biogenesis, was upregulated within the first seven days of remobilization to counteract this adverse effect.

CONCLUSION

Our findings suggested that BNIP3-denpendent mitophagy was sustained activated at the early stages of remobilization, and it might contribute to the worsening of skeletal muscle atrophy.

Imiquimod as Local Immunotherapy in the Management of Premalignant Cutaneous Conditions and Skin Cancer

Cutaneous cancers are, by far, the most common malignant neoplasms of the human being. Due to the great array of clinical conditions, their worldwide increasing incidence and the steady ageing of the population, non-invasive treatments modalities that show a good clinical response, a proper benefit-risk ratio and cosmetic results are becoming increasingly important in the clinical setting. Imiquimod is a topically applied immunomodulator which is often used in the management of several premalignant and malignant cutaneous disorders. This article is a review of the current literature on its mechanism of action, pharmacokinetics, and therapeutical effects.

Activation of TLR7-mediated autophagy increases epileptic susceptibility via reduced KIF5A-dependent GABAA receptor transport in a murine model

The pathophysiological mechanisms underlying epileptogenesis are poorly understood but are considered to actively involve an imbalance between excitatory and inhibitory synaptic transmission. Excessive activation of autophagy, a cellular pathway that leads to the removal of proteins, is known to aggravate the disease. Toll-like receptor (TLR) 7 is an innate immune receptor that regulates autophagy in infectious and noninfectious diseases. However, the relationship between TLR7, autophagy, and synaptic transmission during epileptogenesis remains unclear. We found that TLR7 was activated in neurons in the early stage of epileptogenesis. TLR7 knockout significantly suppressed seizure susceptibility and neuronal excitability. Furthermore, activation of TLR7 induced autophagy and decreased the expression of kinesin family member 5 A (KIF5A), which influenced interactions with γ-aminobutyric acid type A receptor (GABAAR)-associated protein and GABAARβ2/3, thus producing abnormal GABAAR-mediated postsynaptic transmission. Our results indicated that TLR7 is an important factor in regulating epileptogenesis, suggesting a possible therapeutic target for epilepsy.

Methods to Evaluate Changes in Mitochondrial Structure and Function in Cancer

Mitochondria are regulators of key cellular processes, including energy production and redox homeostasis. Mitochondrial dysfunction is associated with various human diseases, including cancer. Importantly, both structural and functional changes can alter mitochondrial function. Morphologic and quantifiable changes in mitochondria can affect their function and contribute to disease. Structural mitochondrial changes include alterations in cristae morphology, mitochondrial DNA integrity and quantity, and dynamics, such as fission and fusion. Functional parameters related to mitochondrial biology include the production of reactive oxygen species, bioenergetic capacity, calcium retention, and membrane potential. Although these parameters can occur independently of one another, changes in mitochondrial structure and function are often interrelated. Thus, evaluating changes in both mitochondrial structure and function is crucial to understanding the molecular events involved in disease onset and progression. This review focuses on the relationship between alterations in mitochondrial structure and function and cancer, with a particular emphasis on gynecologic malignancies. Selecting methods with tractable parameters may be critical to identifying and targeting mitochondria-related therapeutic options. Methods to measure changes in mitochondrial structure and function, with the associated benefits and limitations, are summarized.

High uric acid aggravates apoptosis of lung epithelial cells induced by cigarette smoke extract through downregulating PRDX2 in chronic obstructive pulmonary disease

Cigarette smoke exposure is the major cause of chronic obstructive pulmonary disease (COPD). Cigarette smoke heightens the elevation of reactive oxygen species (ROS) and thus leads to apoptosis. Hyperuricemia has been considered as a risk factor for COPD. However, the underlying mechanism for this aggravating effect remains unclear. The current study sought to examine the role of high uric acid (HUA) in COPD using cigarette smoke extract (CSE) exposed murine lung epithelial (MLE-12) cells. Our data showed that CSE induced the increase of ROS, mitochondrial dynamics disorder, and apoptosis, while HUA treatment aggravated the effects of CSE. Further studies suggested that HUA decreased the expression of antioxidant enzyme-peroxiredoxin-2 (PRDX2). Overexpression of PRDX2 inhibited excessive ROS generation, mitochondrial dynamics disorder, and apoptosis induced by HUA. Knockdown of PRDX2 by small interfering RNA (siRNA) promoted ROS generation, mitochondrial dynamics disorder, and apoptosis in MLE-12 cells treated with HUA. However, antioxidant N-acetylcysteine (NAC) reversed the effects of PRDX2-siRNA on MLE-12 cells. In conclusion, HUA aggravated CSE-induced cellular ROS levels and led to ROS-dependent mitochondrial dynamics disorder and apoptosis in MLE-12 cells through downregulating PRDX2.

PINK1/Parkin pathway-mediated mitophagy by AS-IV to explore the molecular mechanism of muscle cell damage

BACKGROUND

Functional disorders of mitochondria are closely related to muscle diseases. Many studies have also shown that oxidative stress can stimulate the production of a large number of reactive oxygen species (ROS), which have various adverse effects on mitochondria and can damage muscle cells.

PURPOSE

In this study, based on our previous research, we focused on the PINK1/Parkin pathway to explore the mechanism by which AS-IV alleviates muscle injury by inhibiting excessive mitophagy.

METHODS

L6 myoblasts were treated with AS-IV after stimulation with hydrogen peroxide (H₂O₂) and carbonyl cyanide m-chlorophenylhydrazone (CCCP). Then, we detected the related indices of oxidative stress and mitophagy by different methods. A PINK1 knockdown cell line was established by lentiviral infection to obtain further evidence that AS-IV reduces mitochondrial damage through PINK1/Parkin.

RESULTS

After mitochondrial damage, the expression of malondialdehyde (MDA) and intracellular ROS in L6 myoblasts significantly increased, while the expression of superoxide dismutase (SOD) and ATP decreased. The mRNA and protein expression levels of Tom20 and Tim23 were decreased, while those of VDAC1 were increased. PINK1, Parkin, and LC3 II mRNA and protein expression increased, and P62 mRNA and protein expression decreased·H₂O₂ combined with CCCP strongly activated the mitophagy pathway and impaired mitochondrial function. However, abnormal expression of these factors could be reversed after treatment with AS-IV, and excessive mitochondrial autophagy could also be reversed, thus restoring the regulatory function of mitochondria. However, AS-IV-adjusted function was resisted after PINK1 knockdown.

CONCLUSION

AS-IV is a potential drug for myasthenia gravis (MG), and its treatment mechanism is related to mediating mitophagy and restoring mitochondrial function through the PINK1/Parkin pathway.

Long-term blue light exposure impairs mitochondrial dynamics in the retina in light-induced retinal degeneration in vivo and in vitro

Long-term light exposure, especially in the spectrum of blue light, frequently causes excessive oxidative stress in dry age-related macular degeneration (AMD). Here, to gain insight into the underlying mechanism, we focused on mitochondrial dynamics alterations under long-term exposure to blue light in mouse and retinal cells. Six-month-old C57BL/6 mice were exposed to blue light (450 nm, 800 lx) for 2 weeks. The phenotypic changes in the retina were assayed using haematoxylin-eosin staining and transmission electron microscopy. Long-term blue light exposure significantly thinned each retinal layer in mice, induced retinal apoptosis and impaired retinal mitochondria. A retinal pigment epithelial cell line (ARPE-19) was used to verify the phototoxicity of blue light. Flow cytometry, immunofluorescence and MitoSox Red probe experiments confirmed that more total and mitochondria-specific ROS were generated in the blue light group than in the control group. Mito-Tracker Green probe showed fragmented mitochondrial morphology. The western blotting results indicated a significant increase in DRP1, OMA1, and BAX and a decrease in OPA1 and Bcl-2. In conclusion, long-term exposure to blue light damaged the retinas of mice, especially the ONL and RPE cells. There was destruction and dysfunction of mitochondria in RPE cells in vivo and in vitro. Mitochondrial dynamics were disrupted with characteristics of fusion-related obstruction after blue-light irradiation.

Long-term Copper Exposure Induces Mitochondrial Dynamics Disorder and Mitophagy in the Cerebrum of Pigs

Copper (Cu) is an essential trace element for growth and development in most organisms. However, environmental exposure to high doses of Cu can damage multiple organs. To investigate the underlying mechanism of Cu toxicity on mitochondrial dynamics and mitophagy in the cerebrum of pigs, 60 30-day-old pigs were randomly divided into three groups and treated with different contents of anhydrous Cu sulfate in the diets (Cu 10 mg/kg, control group; Cu 125 mg/kg, group I; Cu 250 mg/kg, group II) for 80 days. The Cu levels and histological changes in the cerebrum were measured. Moreover, the protein and mRNA expression levels related to mitophagy and mitochondrial dynamics were determined. The results showed that the contents of Cu were increased in the cerebrum with increasing dietary Cu. Vacuolar degeneration was found in group I and group II compared to the control group. Additionally, the protein and mRNA expression levels of PINK1, Parkin, and Drp1 and the protein level of LC3-II were remarkably upregulated with increasing levels of dietary Cu. Nevertheless, the protein and mRNA expression levels of MFN1 and MFN2 and the mRNA expression of P62 were obviously downregulated in a Cu dose-dependent manner. Overall, these results suggested that excess Cu could trigger mitochondrial dynamics disorder and mitophagy in the pig cerebrum, which provided a novel insight into Cu-induced toxicology.

cRGD-targeted gold-based nanoparticles overcome EGFR-TKI resistance of NSCLC via low-temperature photothermal therapy combined with sonodynamic therapy

Epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) is a first-line targeted drug for the treatment of advanced non-small cell lung cancer (NSCLC) in clinical practice, but EGFR-TKI-acquired resistance limits its therapeutic effect. To address this challenge, a novel multifunctional gold-based targeted nanoparticle-based drug delivery system is fabricated. The gold-based nanoparticle is loaded with the EGFR-TKI (gefitinib) and IR780, and the surface-modified gold nanoshell layer has a photothermal effect for thermally triggered drug release. Finally, the unique binding of cyclic arginine-glycine-aspartic acid (cRGD) to the α_vβ₃ receptor ensured that the nanoparticle (cRGD-GIPG) targeted transport into drug-resistant NSCLC cells was functional. Due to the sonodynamic properties of IR780, ultrasound (US) irradiation promoted reactive oxygen species (ROS) generation, while low-temperature photothermal therapy (PTT) not only promoted the release of drug, but also further enhanced the cytotoxic effects of ROS. In turn, it blocked the activation of TGF-β/PDLIM5/SMAD resistance pathway and induced apoptosis of drug-resistant cells through mitochondrial apoptosis, enabling the treatment of EGFR-TKI-resistant NSCLC. The low-temperature PTT combined with sonodynamic therapy (SDT) by cRGD-GIPG thus shows potent anticancer activity against EGFR-TKI-resistant NSCLC cells in vitro and in vivo. The present work provides a valuable strategy for highly targeted and EGFR-TKI-resistant reversal therapy in NSCLC.

Non-coding RNAs regulate mitochondrial dynamics in the development of gastric cancer

Gastric cancer (GC) is a malignant cancer that reduces life expectancy worldwide. Although treatment strategies have improved, patients with GC still have poor prognoses. Hence, it is necessary to understand the molecular mechanisms of GC and to find new therapeutic targets. Mitochondrial dynamics and mitochondrial dysfunction are associated with cancer cell growth and progression. Numerous studies have reported that non-coding RNAs (ncRNAs) can participate in the occurrence and development of GC by regulating mitochondrial dynamics. Elucidating the crosstalk between ncRNAs and mitochondria would be helpful in preventing and treating GC. Herein, we review and summarize the functions of oncogenes and tumor suppressors in suppressing ncRNAs and regulating mitochondrial dynamics in GC tumor growth, proliferation, invasion and metastasis. This review provides new insights into the pathogenesis of and intervention for GC.

Corilagin Restrains NLRP3 Inflammasome Activation and Pyroptosis through the ROS/TXNIP/NLRP3 Pathway to Prevent Inflammation

Corilagin, a gallotannin, shows excellent antioxidant and anti-inflammatory effects. The NLRP3 inflammasome dysfunction has been implicated in a variety of inflammation diseases. However, it remains unclear how corilagin regulates the NLRP3 inflammasome to relieve gouty arthritis. In this study, bone marrow-derived macrophages (BMDMs) were pretreated with lipopolysaccharide (LPS) and then incubated with NLRP3 inflammasome agonists, such as adenine nucleoside triphosphate (ATP), nigericin, and monosodium urate (MSU) crystals. The MSU crystals were intra-articular injected to induce acute gouty arthritis. Here we showed that corilagin reduced lactate dehydrogenase (LDH) secretion and the proportion of propidium iodide- (PI-)stained cells. Corilagin suppressed the expression of N-terminal of the pyroptosis executive protein gasdermin D (GSDMD-NT). Corilagin restricted caspase-1 p20 and interleukin (IL)-1β release. Meanwhile, corilagin attenuated ASC oligomerization and speck formation. Our findings confirmed that corilagin diminished NLRP3 inflammasome activation and macrophage pyroptosis. We further discovered that corilagin limited the mitochondrial reactive oxygen species (ROS) production and prevented the interaction between TXNIP and NLRP3, but ROS activator imiquimod could antagonize the inhibitory function of corilagin on NLRP3 inflammasome and macrophage pyroptosis. Additionally, corilagin ameliorated MSU crystals induced joint swelling, inhibited IL-1β production, and abated macrophage and neutrophil migration into the joint capsule. Collectively, these results demonstrated that corilagin suppressed the ROS/TXNIP/NLRP3 pathway to repress inflammasome activation and pyroptosis and suggest its potential antioxidative role in alleviating NLRP3-dependent gouty arthritis.

Imiquimod-induced ROS production causes lysosomal membrane permeabilization and activates caspase-8-mediated apoptosis in skin cancer cells

BACKGROUND

Lysosomal cell death is induced by lysosomal membrane permeabilization (LMP) and the subsequent release of lysosomal proteolytic enzymes, including cathepsins (CTSs), which results in mitochondrial dysfunction and apoptosis. Imiquimod (IMQ), a synthetic TLR7 ligand, has both antiviral and antitumor activity against various skin malignancies in clinical treatment. Previously, we demonstrated IMQ not only caused lysosomal dysfunction but also triggered lysosome biogenesis to achieve lysosomal adaptation in cancer cells.

OBJECTIVE

To determine whether lysosomes are involved in IMQ-induced apoptosis.

METHODS

The human skin cancer cell lines BCC, A375 and mouse melanoma cell line B16F10 were used in all experiments. Cell death was determined by the Cell Counting Kit-8 (CCK-8) assay and DNA content assay. Protein expression was determined by immunoblotting. Caspase-8 activity was assessed using a fluorescence caspase-8 kit and determined by flow cytometry and confocal microscopy.

RESULTS

IMQ not only induced lysosome damage but also abrogated lysosome function in skin cancer cells. IMQ-induced caspase-8 activation contributed to the processes of lysosomal cell death. Moreover, the use of ROS scavengers significantly abolished caspase-8 activation and inhibited IMQ-induced LMP. Additionally, pharmacological inhibition of CTSD not only abrogated caspase-8 activation but also rescued IMQ-induced cell death. Finally, lysosome-alkalizing agents enhanced the cytotoxicity of IMQ in vitro and in vivo.

CONCLUSIONS

IMQ-induced ROS accumulation promotes LMP, releases CTSs into the cytosol, stimulates caspase-8 activation and finally causes lysosomal cell death. Lysosomal cell death and the CTSD/caspase-8 axis may play a crucial role in IMQ-induced cell death.

Ambient ozone exposure induces ROS related-mitophagy and pyroptosis via NLRP3 inflammasome activation in rat lung cells

OBJECTIVE

To study the regulatory relationship between ozone-induced mitophagy and pyroptosis in lung epithelial cells.

RESULTS

First, type I primary alveolar epithelial cells and male Wistar rats were treated with ozone at different dosages. The ATP content and mitochondrial membrane potential significantly decreased in type I primary alveolar epithelial cells. The mitophagy-related markers and PINK1/Parkin pathway-related proteins, and the co-localization of LC3, Parkin, and mitochondria in type I alveolar epithelial cells indicated that ozone exposure triggered mitophagy. On the other hand, the reactive oxygen species (ROS) inhibitor NAC could significantly alleviate mitophagy in epithelial cells. After treatment with the mitophagy inhibitor MDIVI-1, the levels of the NLRP3 inflammasome, cleaved caspase-1, and N-gasdermin D (N-GSDMD) significantly decreased in the cells. Altogether, these results indicated that mitophagy can be triggered by ozone exposure, and subsequently induces cell death mediated by the NLRP3 inflammasome. Finally, the overexpression and knockdown of NLRP3 confirmed this conclusion.

CONCLUSION

Ozone exposure induced oxidative damage, leading to mitochondrial structural and functional damage. Ozone-induced ROS triggered mitophagy through the activation of the PINK1/Parkin signaling pathway, then pyroptosis through activation of the NLRP3 inflammasome.

Oxidative Stress-Related lncRNAs Are Potential Biomarkers for Predicting Prognosis and Immune Responses in Patients With LUAD

Lung adenocarcinoma is increasingly harmful to society and individuals as cancer with an inferior prognosis and insensitive to chemotherapy. Previous studies have demonstrated that oxidative stress and lncRNAs play a vital role in many biological processes. Therefore, we explored the role of lncRNAs associated with oxidative stress in the prognosis and survival of LUAD patients. We examined the expression profiles of lncRNAs and oxidative stress genes in this study. A prognosis prediction model and a nomogram were built based on oxidative stress-related lncRNAs. Functional and drug sensitivity analyses were also performed depending on oxidative stress-related lncRNA signature. Moreover, we investigated the relationship between immune response and immunotherapy. The results showed that a risk scoring model based on 16 critical oxidative stress lncRNAs was able to distinguish the clinical status of LUAD and better predict the prognosis and survival. Additionally, the model demonstrated a close correlation with the tumor immune system, and these key lncRNAs also revealed the relationship between LUAD and chemotherapeutic drug sensitivity. Our work aims to provide new perspectives and new ideas for the treatment and management of LUAD.

Hesperadin suppresses pancreatic cancer through ATF4/GADD45A axis at nanomolar concentrations

Pancreatic cancer (PC) is a fatal disease with poor survival and limited therapeutic strategies. In this study, we identified Hesperadin as a potent anti-cancer compound against PC, from a high-throughput screening of a commercial chemical library associated with cell death. Hesperadin induced potent growth inhibition in PC cell lines and patient-derived tumor organoids in a dose- and time-dependent manner, with IC50 values in the nanomolar range. Cellular studies showed that Hesperadin caused mitochondria damage in PC cells, resulting in reactive oxygen species production, ER stress and apoptotic cell death. Transcriptomic analysis using RNA-sequencing data identified GADD45A as a potential target of Hesperadin. Mechanistic studies showed that Hesperadin could increase GADD45A expression in PC cells via ATF4, leading to apoptosis. Moreover, immunohistochemical staining of 92 PC patient samples demonstrated the correlation between ATF4 and GADD45A expression. PC xenograft studies demonstrated that Hesperadin could effectively inhibit the growth of PC cells in vivo. Together, these findings suggest that Hesperadin is a novel drug candidate for PC.

ROS antagonizes the protection of Parkin-mediated mitophagy against aluminum-induced liver inflammatory injury in mice

Aluminum (Al) is a food pollutant that has extensive deleterious effects on the liver. Our previous research proposed that E3 ubiquitin ligase PARK2 knockout (Parkin^-/-) could aggravate Al-induced liver damage by inhibiting mitophagy, during which the reactive oxygen species (ROS) content increases. Inhibition of mitophagy can activate inflammasome. But the link between Parkin-mediated mitophagy and liver inflammatory injury caused by Al, and the role of ROS in it remain unclear. In this study, we applied Al, Parkin^-/- and N-acetyl-L-cysteine (NAC) to act on C57BL/6N mice to investigate them. We found that Al could induce liver inflammatory injury and Parkin^-/- could aggravate it. Meanwhile, inhibition of ROS alleviated oxidative stress, mitochondrial damage, mitophagy and inflammatory injury caused by Al in Parkin^-/- mice liver. These results indicated that ROS antagonized the protection of Parkin-mediated mitophagy against Al-induced liver inflammatory damage in mice.

Targeting mitochondria in dermatological therapy: Beyond oxidative damage and skin aging

INTRODUCTION

The analysis of the role of the mitochondria in oxidative damage and skin aging is a significant aspect of dermatological research. Mitochondria generate most reactive oxygen species (ROS); however, excessive ROS are cytotoxic and DNA-damaging and promote (photo-)aging. ROS also possesses key physiological and regulatory functions and mitochondrial dysfunction is prominent in several skin diseases including skin cancers. Although many standard dermatotherapeutics modulate mitochondrial function, dermatological therapy rarely targets the mitochondria. Accordingly, there is a rationale for "mitochondrial dermatology"-based approaches to be applied to therapeutic research.

AREAS COVERED

This paper examines the functions of mitochondria in cutaneous physiology beyond energy (ATP) and ROS production. Keratinocyte differentiation and epidermal barrier maintenance, appendage morphogenesis and homeostasis, photoaging and skin cancer are considered. Based on related PubMed search results, the paper evaluates thyroid hormones, glucocorticoids, Vitamin D3 derivatives, retinoids, cannabinoid receptor agonists, PPARγ agonists, thyrotropin, and thyrotropin-releasing hormone as instructive lead compounds. Moreover, the mitochondrial protein MPZL3 as a promising new drug target for future "mitochondrial dermatology" is highlighted.

EXPERT OPINION

Future dermatological therapeutic research should have a mitochondrial medicine emphasis. Focusing on selected lead agents, protein targets, in silico drug design, and model diseases will fertilize a mito-centric approach.

Insights Into Mitochondrial Dynamics in Chlamydial Infection

Mitochondria are intracellular organelles that are instrumental in the creation of energy, metabolism, apoptosis, and intrinsic immunity. Mitochondria exhibit an extraordinarily high degree of flexibility, and are constantly undergoing dynamic fusion and fission changes. Chlamydia is an intracellular bacterium that causes serious health problems in both humans and animals. Due to a deficiency of multiple metabolic enzymes, these pathogenic bacteria are highly dependent on their eukaryotic host cells, resulting in a close link between Chlamydia infection and host cell mitochondria. Indeed, Chlamydia increase mitochondrial fusion by inhibiting the activation of dynein-related protein 1 (DRP1), which can regulate host cell metabolism for extra energy. Additionally, Chlamydia can inhibit mitochondrial fission by blocking DRP1 oligomerization, preventing host cell apoptosis. These mechanisms are critical for maintaining a favorable environment for reproduction and growth of Chlamydia. This review discusses the molecular mechanisms of mitochondrial fusion and fission, as well as the mechanisms by which Chlamydia infection alters the mitochondrial dynamics and the prospects of limiting chlamydial development by altering mitochondrial dynamics.

Activation of the STING-IRF3 pathway involved in psoriasis with diabetes mellitus

Psoriasis and type 2 diabetes mellitus (T2DM) share similar inflammatory pathways in their pathogenesis. The stimulator of interferon genes (STING)‐interferon regulatory factor 3 (IRF3) pathway has recently been shown to play an important role in immune and metabolic diseases. In this study, we investigated the activation of the STING‐IRF3 pathway in human immortalized keratinocytes (HaCaT) cells treated with palmitic acid (PA) and imiquimod (IMQ). Additionally, we detected the STING‐IRF3 pathway in diabetic mice with imiquimod (IMQ)‐induced psoriasis and assessed the potential of STING inhibitor C‐176. Furthermore, skin samples from patients with psoriasis and diabetes were collected for immunohistochemical analysis. The results indicated that the STING‐IRF3 pathway was activated in HaCaT cells. Moreover, the STING pathway was also found to be induced in the skin tissue of diabetic mice with psoriasis; the inflammatory responses were ameliorated by treatment with C‐176. In the skin tissue samples of patients with psoriasis and diabetes, immunohistochemistry showed that the expression levels of STING and phosphorylated IRF3 were also significantly increased. Thus, we conclude that the STING‐IRF3 pathway is involved in the inflammatory response in the manifestation of psoriasis with T2DM. Inhibition of the activation of the STING pathway can ameliorate the development of psoriasis in diabetes and could be targeted for the development of therapeutic agents for these conditions.

The multifaceted roles of mitochondria at the crossroads of cell life and death in cancer

Mitochondria are the cytoplasmic organelles mostly known as the "electric engine" of the cells; however, they also play pivotal roles in different biological processes, such as cell growth/apoptosis, Ca²⁺ and redox homeostasis, and cell stemness. In cancer cells, mitochondria undergo peculiar functional and structural dynamics involved in the survival/death fate of the cell. Cancer cells use glycolysis to support macromolecular biosynthesis and energy production ("Warburg effect"); however, mitochondrial OXPHOS has been shown to be still active during carcinogenesis and even exacerbated in drug-resistant and stem cancer cells. This metabolic rewiring is associated with mutations in genes encoding mitochondrial metabolic enzymes ("oncometabolites"), alterations of ROS production and redox biology, and a fine-tuned balance between anti-/proapoptotic proteins. In cancer cells, mitochondria also experience dynamic alterations from the structural point of view undergoing coordinated cycles of biogenesis, fusion/fission and mitophagy, and physically communicating with the endoplasmic reticulum (ER), through the Ca²⁺ flux, at the MAM (mitochondria-associated membranes) levels. This review addresses the peculiar mitochondrial metabolic and structural dynamics occurring in cancer cells and their role in coordinating the balance between cell survival and death. The role of mitochondrial dynamics as effective biomarkers of tumor progression and promising targets for anticancer strategies is also discussed.

Current Strategies for Tumor Photodynamic Therapy Combined With Immunotherapy

Photodynamic therapy (PDT) is a low invasive antitumor therapy with fewer side effects. On the other hand, immunotherapy also has significant clinical applications in the treatment of cancer. Both therapies, on their own, have some limitations and are incapable of meeting the demands of the current cancer treatment. The efficacy of PDT and immunotherapy against tumor metastasis and tumor recurrence may be improved by combination strategies. In this review, we discussed the possibility that PDT could be used to activate immune responses by inducing immunogenic cell death or generating cancer vaccines. Furthermore, we explored the latest advances in PDT antitumor therapy in combination with some immunotherapy such as immune adjuvants, inhibitors of immune suppression, and immune checkpoint blockade.

Early redox homeostasis disruption contributes to the differential cytotoxicity of imiquimod on transformed and normal endothelial cells

The off-label use of imiquimod (IQ) for hemangioma treatment has shown clinical benefits. We have previously reported a selective direct IQ-cytotoxic effect on transformed (H5V) vs. normal (1G11) endothelial cells (EC). In the present study, we investigated the mechanism underlying this selective cytotoxicity in terms of TLR7/8 receptor expression, NF-κB signalling and time-dependent modifications of oxidative stress parameters (ROS: reactive oxygen species, catalase and superoxide dismutase activities, GSH/GSSG and lipid peroxidation). TLR7/8 level was extremely low in both cell lines, and IQ did not upregulate TLR7/8 expression or activate NF-κB signalling. IQ significantly induced ROS in H5V after 2 h and strongly affected antioxidant defenses. After 12 h, enzyme activities were restored to baseline levels but a robust drop in GSH/GSSG persisted together with increased lipid peroxidation levels and a marked mitochondrial dysfunction. Although in normal IQ-treated EC some oxidative stress parameters were affected after 4 h, mitochondrial health and GSH/GSSG ratio remained notably unaffected after 12 h. Therefore, the early alterations (0-2 h) in transformed EC breached redox homeostasis as strongly as to enhance their susceptibility to IQ. This interesting facet of IQ as redox disruptor could broaden its therapeutic potential for other skin malignancies, alone or in adjuvant schemes.

Mitochondrial dynamics regulators: implications for therapeutic intervention in cancer

Regardless of the recent advances in therapeutic developments, cancer is still among the primary causes of death globally, indicating the need for alternative therapeutic strategies. Mitochondria, a dynamic organelle, continuously undergo the fusion and fission processes to meet cell requirements. The balanced fission and fusion processes, referred to as mitochondrial dynamics, coordinate mitochondrial shape, size, number, energy metabolism, cell cycle, mitophagy, and apoptosis. An imbalance between these opposing events alters mitochondWangrial dynamics, affects the overall mitochondrial shape, and deregulates mitochondrial function. Emerging evidence indicates that alteration of mitochondrial dynamics contributes to various aspects of tumorigenesis and cancer progression. Therefore, targeting the mitochondrial dynamics regulator could be a potential therapeutic approach for cancer treatment. This review will address the role of imbalanced mitochondrial dynamics in mitochondrial dysfunction during cancer progression. We will outline the clinical significance of mitochondrial dynamics regulators in various cancer types with recent updates in cancer stemness and chemoresistance and its therapeutic potential and clinical utility as a predictive biomarker.

Tumor Microenvironment-Activated Nanoparticles Loaded with an Iron-Carbonyl Complex for Chemodynamic Immunotherapy of Lung Metastasis of Melanoma In Vivo

In this work, a nanoplatform (FeCORM NPs) loaded with an iron-carbonyl complex was constructed. By exploiting chemodynamic therapy (CDT) and immunogenic cell death (ICD)-induced immunotherapy (IMT), the nanoparticles exhibited excellent efficacy against lung metastasis of melanoma in vivo. The iron-carbonyl compound of the nanomaterials could be initiated by both glutathione (GSH) and hydrogen peroxide (H₂O₂) to release CO and generate ferrous iron through ligand exchange and oxidative destruction pathways. The released CO caused mitochondria damage, whereas the generated ferrous iron led to oxidative stress via the Fenton reaction. On the other hand, the nanomaterials induced ICD-based IMT, which worked jointly with CDT to exhibit excellent effects against lung metastasis of melanoma through a mouse model. This work demonstrated how a nanoplatform, simple and stable but showing excellent efficacy against tumors, could be built using simple building blocks via a self-assembling approach. Importantly, the system took advantage of relatively high levels of GSH and H₂O₂ in tumors to initiate the therapeutic effects, which rendered the nanoplatform with a capability to differentiate normal cells from tumor cells. In principle, the system has great potential for future clinical applications, not only in the treatment of lung metastasis of melanoma but also in suppressing other types of tumors.

Regulation of mitochondrial dynamics in skin: role in pathophysiology

Skin is a dynamic interface between the external environment and internal organs. It has high turnover that allows the renewal of dead skin cells, thus maintaining a healthy skin homeostasis. Mitochondria fulfills all the energy needs for these cells. In addition, mitochondria are an active source of free radicals that have been determined as crucially important in skin health and disease. The common notion of limited role of mitochondria as merely the cellular powerhouse has drastically changed. Several extracellular stressors have proved to induce impairment in the dynamic properties of mitochondria such as fusion and fission, which further leads to an activation of selective autophagic response known as mitophagy. Altered mitochondrial dynamics have been lately associated with skin photodamage and cutaneous manifestations of several diseased states, thereby suggesting it to be an effective therapeutic target. This review summarizes the molecular mechanisms involved with impaired mitochondrial dynamics and its potential role in skin health and disease.

Biosynthesis of gold nanoparticles using Nigella sativa and Curtobacterium proimmune K3 and evaluation of their anticancer activity

In recent times, the development of functionalized nanoparticle methodology for biomedical applications has become a major challenge. In the present study, we prepared a novel gold nanoparticle (AuNP), named Curto-Cumin AuNP (CC-AuNP), using the biosynthetic process involving Nigella sativa (black cumin) seed extract and membrane vesicles isolated from the novel probiotic strain, Curtobacterium proimmune K3. Various spectrometric and microscopic analyses were performed to characterize the physicochemical properties of the nanoparticles. CC-AuNP exhibited significant cytotoxicity against human gastric adenocarcinoma (AGS) cells but not against normal cells. The toxic effects of the nanoparticles were associated with the excessive production of reactive oxygen species (ROS) in damaged mitochondria. Further, we investigated the molecular mechanisms underlying the cytotoxic effect of CC-AuNP. Results showed that except for B cell lymphoma 2 (Bcl-2), the intracellular apoptotic signaling molecules, such as p53, Bcl-associated X protein (Bax), and Caspase 9/Caspase 3 were significantly upregulated in AGS cells. ROS production and alterations in mitochondrial membrane potential were observed in AGS cells treated with CC-AuNP. The activation of autophagy flux-related biomarkers, such as LC3b/a, Beclin-1, p62, and Caspase 8, was confirmed by qPCR and western blotting. Autophagy pathway was suppressed in CC-AuNP-treated AGS cells and could not proceed further to the mature state. This was confirmed by the evaluation of both apoptosis and autophagy signaling pathways using autophagy-induced AGS cells treated with rapamycin, a well-studied autophagy activator. Overall, our results showed that CC-AuNP upregulates apoptotic signaling and suppresses the autophagy-related signaling pathway, and thus has potential as an anticancer agent. To our knowledge, the present study is the first to demonstrate that CC-AuNP may serve as novel therapeutic agent against gastric cancer. Furthermore, our study provides preliminary data which can be used to develop novel anticancer candidates and understand their anticancer mechanisms, and seems to be a good starting point for the development of alternative medications based on CC-AuNP.

Elucidating Role of Reactive Oxygen Species (ROS) in Cisplatin Chemotherapy: A Focus on Molecular Pathways and Possible Therapeutic Strategies

The failure of chemotherapy is a major challenge nowadays, and in order to ensure effective treatment of cancer patients, it is of great importance to reveal the molecular pathways and mechanisms involved in chemoresistance. Cisplatin (CP) is a platinum-containing drug with anti-tumor activity against different cancers in both pre-clinical and clinical studies. However, drug resistance has restricted its potential in the treatment of cancer patients. CP can promote levels of free radicals, particularly reactive oxygen species (ROS) to induce cell death. Due to the double-edged sword role of ROS in cancer as a pro-survival or pro-death mechanism, ROS can result in CP resistance. In the present review, association of ROS with CP sensitivity/resistance is discussed, and in particular, how molecular pathways, both upstream and downstream targets, can affect the response of cancer cells to CP chemotherapy. Furthermore, anti-tumor compounds, such as curcumin, emodin, chloroquine that regulate ROS and related molecular pathways in increasing CP sensitivity are described. Nanoparticles can provide co-delivery of CP with anti-tumor agents and by mediating photodynamic therapy, and induce ROS overgeneration to trigger CP sensitivity. Genetic tools, such as small interfering RNA (siRNA) can down-regulate molecular pathways such as HIF-1α and Nrf2 to promote ROS levels, leading to CP sensitivity. Considering the relationship between ROS and CP chemotherapy, and translating these findings to clinic can pave the way for effective treatment of cancer patients.

Mitochondrial Dynamics, ROS, and Cell Signaling: A Blended Overview

Mitochondria are key intracellular organelles involved not only in the metabolic state of the cell, but also in several cellular functions, such as proliferation, Calcium signaling, and lipid trafficking. Indeed, these organelles are characterized by continuous events of fission and fusion which contribute to the dynamic plasticity of their network, also strongly influenced by mitochondrial contacts with other subcellular organelles. Nevertheless, mitochondria release a major amount of reactive oxygen species (ROS) inside eukaryotic cells, which are reported to mediate a plethora of both physiological and pathological cellular functions, such as growth and proliferation, regulation of autophagy, apoptosis, and metastasis. Therefore, targeting mitochondrial ROS could be a promising strategy to overcome and hinder the development of diseases such as cancer, where malignant cells, possessing a higher amount of ROS with respect to healthy ones, could be specifically targeted by therapeutic treatments. In this review, we collected the ultimate findings on the blended interplay among mitochondrial shaping, mitochondrial ROS, and several signaling pathways, in order to contribute to the dissection of intracellular molecular mechanisms involved in the pathophysiology of eukaryotic cells, possibly improving future therapeutic approaches.

STAT3 Pathway in Gastric Cancer: Signaling, Therapeutic Targeting and Future Prospects

Molecular signaling pathways play a significant role in the regulation of biological mechanisms, and their abnormal expression can provide the conditions for cancer development. The signal transducer and activator of transcription 3 (STAT3) is a key member of the STAT proteins and its oncogene role in cancer has been shown. STAT3 is able to promote the proliferation and invasion of cancer cells and induces chemoresistance. Different downstream targets of STAT3 have been identified in cancer and it has also been shown that microRNA (miR), long non-coding RNA (lncRNA) and other molecular pathways are able to function as upstream mediators of STAT3 in cancer. In the present review, we focus on the role and regulation of STAT3 in gastric cancer (GC). miRs and lncRNAs are considered as potential upstream mediators of STAT3 and they are able to affect STAT3 expression in exerting their oncogene or onco-suppressor role in GC cells. Anti-tumor compounds suppress the STAT3 signaling pathway to restrict the proliferation and malignant behavior of GC cells. Other molecular pathways, such as sirtuin, stathmin and so on, can act as upstream mediators of STAT3 in GC. Notably, the components of the tumor microenvironment that are capable of targeting STAT3 in GC, such as fibroblasts and macrophages, are discussed in this review. Finally, we demonstrate that STAT3 can target oncogene factors to enhance the proliferation and metastasis of GC cells.