Diplatin, a Novel and Low-Toxicity Anti-Lung Cancer Platinum Complex, Activation of Cell Death in Tumors via a ROS/JNK/p53-Dependent Pathway, and a Low Rate of Acquired Treatment Resistance

Ursolic acid, an inhibitor of TMEM16A, co-loaded with cisplatin in hydrogel drug delivery system for multi-targeted therapy of lung cancer

The efficacy of single chemotherapy drugs in cancer treatment is often limited. Combining administration targeting multiple targets has emerged as an effective strategy to improve cancer treatment. Ursolic acid, a triterpenoid compound in various natural foods, was identified as a novel inhibitor of lung cancer specific target TMEM16A. The IC50 of ursolic acid on the whole-cell current of TMEM16A was 13.85 ± 1.64 μM. Molecular dynamics simulations and site-directed mutagenesis experiments indicated the binding sites of ursolic acid on TMEM16A as L381, R535, E623, and C625. Ursolic acid significantly inhibited the proliferation and migration of LA795 cells, while promoting cancer cell apoptosis. Mechanistic studies revealed that ursolic acid inhibited lung cancer through the MAPK and EMT pathways, and induced DNA and membrane damage. Next, a degradable and self-repairing hydrogel drug-loading system was designed to enhance the targeting effect of the ursolic acid and cisplatin drug combination. In vivo experiments showed that the hydrogel-loaded ursolic acid and cisplatin enhanced the antitumor activity and reduced the toxicity. This study presents a novel approach of multi-target combination therapy using ursolic acid and cisplatin, combined with the targeted delivery capability of the hydrogel system, which significantly improves the therapeutic efficacy in lung cancer.

c-Jun N-terminal kinase signaling in cellular senescence

Cellular senescence leads to decreased tissue regeneration and inflammation and is associated with diabetes, neurodegenerative diseases, and tumorigenesis. However, the mechanisms of cellular senescence are not fully understood. Emerging evidence has indicated that c-Jun N-terminal kinase (JNK) signaling is involved in the regulation of cellular senescence. JNK can downregulate hypoxia inducible factor-1α to accelerate hypoxia-induced neuronal cell senescence. The activation of JNK inhibits mTOR activity and triggers autophagy, which promotes cellular senescence. JNK can upregulate the expression of p53 and Bcl-2 and accelerates cancer cell senescence; however, this signaling also mediates the expression of amphiregulin and PD-LI to achieve cancer cell immune evasion and prevents their senescence. The activation of JNK further triggers forkhead box O expression and its target gene Jafrac1 to extend the lifespan of Drosophila. JNK can also upregulate the expression of DNA repair protein poly ADP-ribose polymerase 1 and heat shock protein to delay cellular senescence. This review discusses recent advances in understanding the function of JNK signaling in cellular senescence and includes a comprehensive analysis of the molecular mechanisms underlying JNK-mediated senescence evasion and oncogene-induced cellular senescence. We also summarize the research progress in anti-aging agents that target JNK signaling. This study will contribute to a better understanding of the molecular targets of cellular senescence and provides insights into anti-aging, which may be used to develop drugs for the treatment of aging-related diseases.

Targeting of G-protein coupled receptor 40 alleviates airway hyperresponsiveness through RhoA/ROCK1 signaling pathway in obese asthmatic mice

Obesity increases the severity of airway hyperresponsiveness (AHR) in individuals with asthma, but the mechanism is not well elucidated. G-protein coupled receptor 40 (GPR40) has been found to induce airway smooth muscle contraction after activated by long-chain fatty acids (LC-FFAs), suggesting a close correlation between GPR40 and AHR in obese. In this study, C57BL/6 mice were fed a high-fat diet (HFD) to induce obesity with or without ovalbumin (OVA) sensitization, the regulatory effects of GPR40 on AHR, inflammatory cells infiltration, and the expression of Th1/Th2 cytokines were evaluated by using a small-molecule antagonist of GPR40, DC260126. We found that the free fatty acids (FFAs) level and GPR40 expression were greatly elevated in the pulmonary tissues of obese asthmatic mice. DC260126 greatly reduced methacholine-induced AHR, ameliorated pulmonary pathological changes and decreased inflammatory cell infiltration in the airways in obese asthma. In addition, DC260126 could down-regulate the levels of Th2 cytokines (IL-4, IL-5, and IL-13) and pro-inflammatory cytokines (IL-1β, TNF-α), but elevated Th1 cytokine (IFN-γ) expression. In vitro, DC260126 could remarkedly reduce oleic acid (OA)-induced cell proliferation and migration in HASM cells. Mechanistically, the effects that DC260126 alleviated obese asthma was correlated with the down-regulation of GTP-RhoA and Rho-associated coiled-coil-forming protein kinase 1 (ROCK1). Herein, we proved that targeting of GPR40 with its antagonist helped to mitigate multiple parameters of obese asthma effectively.

Reactive Oxygen Species and Long Non-Coding RNAs, an Unexpected Crossroad in Cancer Cells

Long non-coding RNAs (lncRNA) have recently been identified as key regulators of oxidative stress in several malignancies. The level of reactive oxygen species (ROS) must be constantly regulated to maintain cancer cell proliferation and chemoresistance and to prevent apoptosis. This review will discuss how lncRNAs alter the ROS level in cancer cells. We will first describe the role of lncRNAs in the nuclear factor like 2 (Nrf-2) coordinated antioxidant response of cancer cells. Secondly, we show how lncRNAs can promote the Warburg effect in cancer cells, thus shifting the cancer cell’s “building blocks” towards molecules important in oxidative stress regulation. Lastly, we explain the role that lncRNAs play in ROS-induced cancer cell apoptosis and proliferation.

Regulated cell death (RCD) in cancer: key pathways and targeted therapies

Regulated cell death (RCD), also well-known as programmed cell death (PCD), refers to the form of cell death that can be regulated by a variety of biomacromolecules, which is distinctive from accidental cell death (ACD). Accumulating evidence has revealed that RCD subroutines are the key features of tumorigenesis, which may ultimately lead to the establishment of different potential therapeutic strategies. Hitherto, targeting the subroutines of RCD with pharmacological small-molecule compounds has been emerging as a promising therapeutic avenue, which has rapidly progressed in many types of human cancers. Thus, in this review, we focus on summarizing not only the key apoptotic and autophagy-dependent cell death signaling pathways, but the crucial pathways of other RCD subroutines, including necroptosis, pyroptosis, ferroptosis, parthanatos, entosis, NETosis and lysosome-dependent cell death (LCD) in cancer. Moreover, we further discuss the current situation of several small-molecule compounds targeting the different RCD subroutines to improve cancer treatment, such as single-target, dual or multiple-target small-molecule compounds, drug combinations, and some new emerging therapeutic strategies that would together shed new light on future directions to attack cancer cell vulnerabilities with small-molecule drugs targeting RCD for therapeutic purposes.

LCS-1 inhibition of superoxide dismutase 1 induces ROS-dependent death of glioma cells and degradates PARP and BRCA1

Gliomas are characterized by high morbidity and mortality, and have only slightly increased survival with recent considerable improvements for treatment. An innovative therapeutic strategy had been developed via inducing ROS-dependent cell death by targeting antioxidant proteins. In this study, we found that glioma tissues expressed high levels of superoxide dismutase 1 (SOD1). The expression of SOD1 was upregulated in glioma grade III and V tissues compared with that in normal brain tissues or glioma grade I tissues. U251 and U87 glioma cells expressed high levels of SOD1, low levels of SOD2 and very low levels of SOD3. LCS-1, an inhibitor of SOD1, increased the expression SOD1 at both mRNA and protein levels slightly but significantly. As expected, LCS-1 caused ROS production in a dose- and time-dependent manner. SOD1 inhibition also induced the gene expression of HO-1, GCLC, GCLM and NQO1 which are targeting genes of nuclear factor erythroid 2-related factor 2, suggesting the activation of ROS signal pathway. Importantly, LCS-1 induced death of U251 and U87 cells dose- and time-dependently. The cell death was reversed by the pretreatment of cells with ROS scavenges NAC or GSH. Furthermore, LCS-1 decreased the growth of xenograft tumors formed by U87 glioma cells in nude mice. Mechanistically, the inhibition of P53, caspases did not reverse LCS-1-induced cell death, indicating the failure of these molecules involving in cell death. Moreover, we found that LCS-1 treatment induced the degradation of both PARP and BRCA1 simultaneously, suggesting that LCS-1-induced cell death may be associated with the failure of DNA damage repair. Taking together, these results suggest that the degradation of both PARP and BRCA1 may contribute to cell death induced by SOD1 inhibition, and SOD1 may be a target for glioma therapy.

Synthesis, crystal structure, and in vitro evaluation of the anticancer activity of new Pt (Pd) complexes with 1-[(dimethylamino)methyl]-2-naphthol ligand

The synthesis of new Pt(II) and Pd(II) complexes with 1-aminomethyl-2-naphtol ligands has been first performed. The adducts of [PtCl4]2- and [PdCl4]2- anions with the 1-aminomethyl-2-naphtol NH cation were synthesized. The structure for four Pt (Pd)-containing compounds was investigated using X-ray diffraction. The obtained compounds were examined for in vitro cytotoxic activity against Jurkat and K562 human leukemia cells, lymphoma U937cells, A2780 and the cisplatin-resistant A2780cis lines of human ovarian cancer, and normal fibroblasts. Study of induction of apoptosis and the effect of new palladium and platinum complexes on the cell cycle was carried out. The cells showed a higher sensitivity to Pt(II) compounds than to Pd(II) ones. All the synthesized metal complexes show much more antitumor activity compared with a platinum-containing cisplatin drug.

Shp2 regulates PM2.5-induced airway epithelial barrier dysfunction by modulating ERK1/2 signaling pathway

The impact of fine particulate matter (PM2.5) on public health has received increasing attention. Through various biochemical mechanisms, PM2.5 alters the normal structure and function of the airway epithelium, causing epithelial barrier dysfunction. Src homology domain 2-containing protein tyrosine phosphatase 2 (Shp2) has been implicated in various respiratory diseases; however, its role in PM2.5-induced epithelial barrier dysfunction remains unclear. Herein, we assessed the regulatory effects of Shp2 on PM2.5-mediated epithelial barrier function and tight junction (TJ) protein expression in both mice and human pulmonary epithelial (16HBE) cells. We observed that Shp2 levels were upregulated and claudin-4 levels were downregulated after PM2.5 stimulation in vivo and in vitro. Mice were exposed to PM2.5 to induce acute lung injury, and disrupted epithelial barrier function, with decreased transepithelial electrical resistance (TER) and increased paracellular flux that was observed in 16HBE cells. In contrast, the selective inhibition or knockdown of Shp2 retained airway epithelial barrier function and reversed claudin-4 downregulation that triggered by PM2.5, and these effects may occur through the ERK1/2 MAPK signaling pathway. These data highlight an important role of Shp2 in PM2.5-induced airway epithelial barrier dysfunction and suggest a possible new course of therapy for PM2.5-induced respiratory diseases.

A Novel Biological Activity of the STAT3 Inhibitor Stattic in Inhibiting Glutathione Reductase and Suppressing the Tumorigenicity of Human Cervical Cancer Cells via a ROS-Dependent Pathway

Introduction

Glutathione reductase (GSR) provides reduced glutathione (GSH) to maintain redox homeostasis. Inhibition of GSR disrupts this balance, resulting in cell damage, which benefits cancer therapy. However, the effect of GSR inhibition on the tumorigenicity of human cervical cancer is not fully understood.

Materials and Methods

Tissue microarray analysis was employed to determine GSR expression in cervical cancer tissues by immunohistochemical staining. Cell death was measured with PI/FITC-annexin V staining. mRNA levels were measured via quantitative RT-PCR. Protein expression was measured by Western blotting and flow cytometry. STAT3 deletion was performed with CRISPR/Cas9 technology. GSR knockdown was achieved by RNA interference. Reactive oxygen species (ROS) levels were measured by DCF staining. GSR enzymatic activity was measured with a GSR assay kit. The effect of GSR inhibition on the growth of tumors formed by cervical cancer cells was investigated using a xenograft model.

Results

The expression of GSR was increased in human cervical cancer tissues, as shown by immunohistochemical staining. GSR knockdown by RNA interference in human cervical cancer cell lines resulted in cell death, suggesting the ability of GSR to maintain cancer cell survival. The STAT3 inhibitor 6-nitrobenzo[b]thiophene 1,1-dioxide (Stattic) also inhibited the enzymatic activity of GSR and induced the death of cervical cancer cells. More importantly, Stattic decreased the growth of xenograft tumors formed by cervical cancer cells in nude mice. Mechanistically, tumor cell death induced by Stattic-mediated GSR inhibition was ROS-dependent, since the ROS scavengers GSH and N-acetyl cysteine (NAC) reversed the effect of Stattic. In contrast, pharmacological and molecular inhibition of STAT3 did not induce the death of cervical cancer cells, suggesting a STAT3-independent activity of Stattic.

Conclusion

Stattic inhibits the enzymatic activity of GSR and induces STAT3-independent but ROS-dependent death of cervical cancer cells, suggesting its potential application as a therapeutic agent for human cervical cancers.

Doxycycline Induces Apoptosis of Brucella Suis S2 Strain-Infected HMC3 Microglial Cells by Activating Calreticulin-Dependent JNK/p53 Signaling Pathway

Neurobrucellosis is a chronic complication of human brucellosis that is caused by the presence of Brucella spp in the central nervous system (CNS) and the inflammation play a key role on the pathogenesis. Doxycycline (Dox) is a widely used antibiotic that induces apoptosis of bacteria-infected cells. However, the mechanisms of Brucella inhibition of microglial apoptosis and Dox induction of apoptosis are still poorly understood. In this study, we found that Brucella suis S2 strain (B. suis S2) increased calreticulin (CALR) protein levels and inhbited HMC3 cell apoptosis. Hence, we constructed two HMC3 cell line variants, one with stable overexpression (HMC3-CALR) and one with low expression of CALR (HMC3-sh-CALR). CALR was found to decrease levels of p-JNK and p-p53 proteins, as well as suppress apoptosis in HMC3 cells. These findings suggest that CALR suppresses apoptosis by inhibiting the JNK/p53 signaling pathway. Next, we treated HMC3, HMC3-CALR and HMC3-sh-CALR cell lines with B. suis S2 or Dox. Our results demonstrate that B. suis S2 restrains the JNK/p53 signaling pathway to inhibit HMC3 cell apoptosis via increasing CALR protein expression, while Dox plays the opposite role. Finally, we treated B. suis S2-infected HMC3 cells with Dox. Our results confirm that Dox induces JNK/p53-dependent apoptosis in B. suis S2-infected HMC3 cells through inhibition of CALR protein expression. Taken together, these results reveal that CALR and the JNK/p53 signaling pathway may serve as novel therapeutic targets for treatment of neurobrucellosis.

Three-Dimensional Ex Vivo Culture for Drug Responses of Patient-Derived Gastric Cancer Tissue

Gastric cancer (GC) is one of the most common malignancies with high mortality and substantial morbidity. Although the traditional treatment strategies for GC revolve around surgery, radiotherapy, and chemotherapy, none have been able to optimally treat most affected patients. To improve clinical outcomes and overcome potential GC resistance, we established a three-dimensional (3D) culturing platform that accurately predicts drug responses in a time- and cost-effective manner. We collected tumor tissues from patients following surgeries and cultured them for 3 days using our protocol. We first evaluated cell proliferation, viability, and apoptosis using the following markers: Ki67 and cleaved caspase 3 (Cas3). We demonstrated that cell viability was maintained for 72 h in culture and that the tumor microenvironments and vascular integrities of the tissues were intact throughout the culture period. We then administered chemotherapeutics to assess drug responses and found differential sensitivity across different patient-derived tissues, enabling us to determine individualized medication plans. Overall, our study validated this rapid, cost-effective, scalable, and reproducible protocol for GC tissue culture that can be employed for drug response assessments. Our 3D culture platform paves a new way for personalized medication in GC and other tumors and can greatly impact future oncological research.

The flavonoid 6-hydroxyflavone prevention of cisplatin-induced nephrotoxicity

In this study, the flavonoid, 6-hydroxyflavone was investigated for its renal protective activity in the cisplatin rat model of nephrotoxicity. Male Sprague-Dawley rats weighing 200-250 g were included in the study. 6-Hydroxyflavone was daily administered at 25 and 50 mg/kg (i.p.), while ascorbic acid was used as a positive control and injected (i.p.) at 50 mg/kg for 15 days. The nephrotoxicity was evoked with a single cisplatin injection at 7.5 mg/kg on the tenth day of treatment. The renal function and levels of oxidative stress markers were assessed. Each tissue slide of different groups was observed under a compound microscope attached with a digital camera. Cisplatin significantly decreased the overall body weight with an increase in serum creatinine and urea and production of severe histopathological and oxidative stress in the kidneys. The daily treatment with 6-hydroxyflavone significantly attenuated the cisplatin associated detrimental changes in the body weight, and serum levels of creatinine and urea at both 25 mg/kg (P<0.05) and 50 mg/kg (P<0.01). The 6-hydroxyflavone treatment also preserved the renal histoarchitecture from the toxicological influence of cisplatin as evident from a significant reduction in the severity of histopathological changes in the renal tissues. Moreover, 6-hydroxyflavone also reduced the cisplatin-induced lipid peroxidation and corrected the renal antioxidant status. A similar protective effect was observed with the positive control, ascorbic acid (50 mg/kg). These findings show that the flavonoid 6-hydroxyflavone has potential nephroprotective properties and can be used for the management of chemotherapy associated renal disturbances.

Diplatin, a novel water-soluble platinum complex, inhibits lung cancer growth via augmentation of Fas-mediated apoptosis

Platinum drugs, such as cisplatin (DDP) and carboplatin (CBP), are the main drugs for the treatment of lung cancer, but their practical clinical application is limited by severe toxicity and acquired drug resistance. Our previous study has indicated that diplatin, [2-(4-(diethyl-amino)butyl)malonate-O,O']-[(1R,2R)-cyclohexane-1,2-diamine N,N'] platinum (II) phosphate, a novel water-soluble platinum complex, could overcome DDP-resistant cells and was less toxic than comparable platinum drugs. In the present study, the effects and mechanisms of diplatin were further evaluated for its development as a novel anti-lung cancer platinum drug. Here, we found diplatin down-regulated the viability of H460 and LTEP-A-2 cells in a dose-dependent manner. Nude mice administrated with diplatin (30-120 mg/kg) via tail vein injection dose-dependently inhibited the growth of H460 and LTEP-A-2 xenograft tumors, whose action mainly correlated with the induction of tumor apoptosis. Particularly, the exposure of lung cancer cells or xenograft tumors to diplatin resulted in elevated Fas level, and knockdown of Fas ameliorated diplatin-induced cells apoptosis. Overall, we suggest that diplatin has potent anti-tumor activity, which probably acts through Fas-mediated signaling pathway.