eEF2 kinase mediated autophagy as a potential therapeutic target for paclitaxel-resistant triple-negative breast cancer

PPP2CA Inhibition Promotes Ferroptosis Sensitivity Through AMPK/SCD1 Pathway in Colorectal Cancer

PURPOSE

Colorectal cancer (CRC) is a very common malignancy of the digestive system. Despite a variety of treatments including surgery, chemotherapeutic and targeted drugs, the prognosis for patients with CRC is still unsatisfactory and the mortality remains high. Protein phosphorylation plays an essential role in tumorigenesis and progression and is also crucial for protein to act with proper functions. Ferroptosis is found widely involved in various diseases especially tumors as a newly identified programmed cell death.

METHODS

In our study, we aimed at PPP2CA as a prospective target which may play a crucial role in CRC progression. In one hand, knockdown of PPP2CA significantly enhanced the malignant phenotype in HCT116. In the other hand, knockdown of PPP2CA significantly enhanced Erastin-induced ferroptosis as well.

RESULTS

Specifically, knockdown of PPP2CA in HCT116 significantly increased the relative level of malondialdehyde (MDA), reactive oxygen species (ROS) and Fe2+, and decreased GSH/GSSG ratio after the treatment of certain concentration of Erastin. Besides, we found that the inhibition of PPP2CA further led to the suppression of SCD1 expression in CRC cells in a AMPK-dependent way.

CONCLUSION

Ultimately, we conclude that PPP2CA may regulate Erastin-induced ferroptosis through AMPK/SCD1 signaling pathway.

Emerging Futuristic Targeted Therapeutics: A Comprising Study Towards a New Era for the Management of TNBC

Triple-negative breast cancer is characterized by high lethality attributed to factors such as chemoresistance, transcriptomic, and genomic heterogeneity, leading to a poor prognosis and limiting available targeted treatment options. While the identification of molecular targets remains pivotal for therapy involving chemo drugs, the current challenge lies in the poor response rates, low survival rates, and frequent relapses. Despite various clinical investigations exploring molecular targeted therapies in conjunction with conventional chemo treatment, the outcomes have been less than optimal. The critical need for more effective therapies underscores the urgency to discover potent novel treatments, including molecular and immune targets, as well as emerging strategies. This review provides a comprehensive analysis of conventional treatment approaches and explores emerging molecular and immune-targeted therapeutics, elucidating their mechanisms to address the existing obstacles for a more effective management of triple-negative breast cancer.

ANXA2 (annexin A2) is crucial to ATG7-mediated autophagy, leading to tumor aggressiveness in triple-negative breast cancer cells

Triple-negative breast cancer (TNBC) is associated with a poor prognosis and metastatic growth. TNBC cells frequently undergo macroautophagy/autophagy, contributing to tumor progression and chemotherapeutic resistance. ANXA2 (annexin A2), a potential therapeutic target for TNBC, has been reported to stimulate autophagy. In this study, we investigated the role of ANXA2 in autophagic processes in TNBC cells. TNBC patients exhibited high levels of ANXA2, which correlated with poor outcomes. ANXA2 increased LC3B-II levels following bafilomycin A1 treatment and enhanced autophagic flux in TNBC cells. Notably, ANXA2 upregulated the phosphorylation of HSF1 (heat shock transcription factor 1), resulting in the transcriptional activation of ATG7 (autophagy related 7). The mechanistic target of rapamycin kinase complex 2 (MTORC2) played an important role in ANXA2-mediated ATG7 transcription by HSF1. MTORC2 did not affect the mRNA level of ANXA2, but it was involved in the protein stability of ANXA2. HSPA (heat shock protein family A (Hsp70)) was a potential interacting protein with ANXA2, which may protect ANXA2 from lysosomal proteolysis. ANXA2 knockdown significantly increased sensitivity to doxorubicin, the first-line chemotherapeutic regimen for TNBC treatment, suggesting that the inhibition of autophagy by ANXA2 knockdown may overcome doxorubicin resistance. In a TNBC xenograft mouse model, we demonstrated that ANXA2 knockdown combined with doxorubicin administration significantly inhibited tumor growth compared to doxorubicin treatment alone, offering a promising avenue to enhance the effectiveness of chemotherapy. In summary, our study elucidated the molecular mechanism by which ANXA2 modulates autophagy, suggesting a potential therapeutic approach for TNBC treatment.Abbreviation: ATG: autophagy related; ChIP: chromatin-immunoprecipitation; HBSS: Hanks' balanced salt solution; HSF1: heat shock transcription factor 1; MTOR: mechanistic target of rapamycin kinase; TNBC: triple-negative breast cancer; TFEB: transcription factor EB; TFE3: transcription factor binding to IGHM enhancer 3.

Surface Proteome of Extracellular Vesicles and Correlation Analysis Reveal Breast Cancer Biomarkers

Breast cancer (BC) is the second most frequently diagnosed cancer and accounts for approximately 25% of new cancer cases in Canadian women. Using biomarkers as a less-invasive BC diagnostic method is currently under investigation but is not ready for practical application in clinical settings. During the last decade, extracellular vesicles (EVs) have emerged as a promising source of biomarkers because they contain cancer-derived proteins, RNAs, and metabolites. In this study, EV proteins from small EVs (sEVs) and medium EVs (mEVs) were isolated from BC MDA-MB-231 and MCF7 and non-cancerous breast epithelial MCF10A cell lines and then analyzed by two approaches: global proteomic analysis and enrichment of EV surface proteins by Sulfo-NHS-SS-Biotin labeling. From the first approach, proteomic profiling identified 2459 proteins, which were subjected to comparative analysis and correlation network analysis. Twelve potential biomarker proteins were identified based on cell line-specific expression and filtered by their predicted co-localization with known EV marker proteins, CD63, CD9, and CD81. This approach resulted in the identification of 11 proteins, four of which were further investigated by Western blot analysis. The presence of transmembrane serine protease matriptase (ST14), claudin-3 (CLDN3), and integrin alpha-7 (ITGA7) in each cell line was validated by Western blot, revealing that ST14 and CLDN3 may be further explored as potential EV biomarkers for BC. The surface labeling approach enriched proteins that were not identified using the first approach. Ten potential BC biomarkers (Glutathione S-transferase P1 (GSTP1), Elongation factor 2 (EEF2), DEAD/H box RNA helicase (DDX10), progesterone receptor (PGR), Ras-related C3 botulinum toxin substrate 2 (RAC2), Disintegrin and metalloproteinase domain-containing protein 10 (ADAM10), Aconitase 2 (ACO2), UTP20 small subunit processome component (UTP20), NEDD4 binding protein 2 (N4BP2), Programmed cell death 6 (PDCD6)) were selected from surface proteins commonly identified from MDA-MB-231 and MCF7, but not identified in MCF10A EVs. In total, 846 surface proteins were identified from the second approach, of which 11 were already known as BC markers. This study supports the proposition that Evs are a rich source of known and novel biomarkers that may be used for non-invasive detection of BC. Furthermore, the presented datasets could be further explored for the identification of potential biomarkers in BC.

HIF-1α Contributes to Hypoxia-induced VSMC Proliferation and Migration by Regulating Autophagy in Type A Aortic Dissection

Type A aortic dissection (AD) is a catastrophic cardiovascular disease. Hypoxia-inducible factor-1α (HIF-1α) and autophagy are reported to be upregulated in the AD specimens. However, the interaction between HIF-1α and autophagy in the pathogenesis of AD remains to be explored. HIF-1α and LC3 levels are evaluated in 10 AD and 10 normal aortic specimens. MDC staining, autophagic vacuoles, and autophagic flux are detected in human aortic smooth muscle cells (HASMCs) under hypoxia treatment. CCK-8, transwell, and wound healing assay are used to identify proliferation and migration under hypoxia treatment. Furthermore, 3-MA is used to inhibit autophagy in hypoxia-treated HASMCs. This study reveals that AD tissues highly express HIF-1α and the LC3. Autophagy is induced under hypoxia in a time-dependent manner, and autophagy is positively related to HIF-1α in HASMCs. Moreover, the proliferation and migration of HASMCs are enhanced by hypoxia, whereas the knockdown of HIF-1α attenuates this effect. Additionally, inhibiting autophagy with 3-MA ameliorates hypoxia-induced proliferation and migration of HASMCs. In summary, the above results indicate that HIF-1α facilitates HASMC proliferation and migration by upregulating autophagy in a hypoxic microenvironment. Thus, inhibition of autophagy may be a novel therapeutic target for the prevention and treatment of AD.

Rottlerin and genistein inhibit neuroblastoma cell proliferation and invasion through EF2K suppression and related protein pathways

Neuroblastoma is one of the most common solid tumors in children younger than 1 year of age, with poor prognosis and survival rates. Therefore, novel molecular targets and therapeutic strategies are needed to prolong patient survival. For this purpose, we investigated the effects of rottlerin and genistein separately and in combination on neuroblastoma cells (SH-SY5Y, Kelly). First, the effects of rottlerin and genistein were investigated on cell proliferation. Different rottlerin (1-50 µM) and genistein (5-150 µM) doses were used as experimental groups compared to the control (DMSO/vehicle). The IC50 dose was found to be 5 µM for rottlerin and 30 µM for genistein (P < 0.0001). Other analyses, such as colony formation assays, annexin V/propidium iodide staining, matrigel invasion assays, and Western blot analysis, were performed with these doses and their combinations. To assess statistical significance, statistical analysis was conducted using the one-way ANOVA with the post hoc Tukey test. Our results showed that IC50 doses of rottlerin and genistein induced a significant reduction in cell proliferation, colony formation, and invasion in neuroblastoma cells (P < 0.0001). The combination of these doses increased the levels of inhibition of cell proliferation and invasion while decreasing the level of apoptosis (P 0.0001). Furthermore, these agents caused G1-cell cycle arrest in these cells. Our western blot data showed that rottlerin and genistein treatments markedly inhibit elongation factor 2 kinase (EF2K) and other pro-tumorigenic, metastatic proteins in neuroblastoma cells. These agents probably showed their anti-proliferative, anti-metastatic, and pro-apoptotic effects through EF2K downregulation. Our results suggested that rottlerin and genistein have inhibitory effects on cancer cell proliferation, invasion, and cell cycle and induce apoptosis in both cell lines. Combined treatment with rottlerin and genistein may be a viable approach and beneficial to neuroblastoma patients as the combined effect significantly suppresses the above-mentioned pathways.

Analysis of differential membrane proteins related to matrix stiffness-mediated metformin resistance in hepatocellular carcinoma cells

BACKGROUND

Our previous work shows that increased matrix stiffness not only alters malignant characteristics of hepatocellular carcinoma (HCC) cells, but also attenuates metformin efficacy in treating HCC cells. Here, we identified differential membrane proteins related to matrix stiffness-mediated metformin resistance for better understand therapeutic resistance of metformin in HCC.

METHODS

Differential membrane proteins in HCC cells grown on different stiffness substrates before and after metformin intervention were screened and identified using isobaric tags for relative and absolute quantification (iTRAQ) labeling coupled with the liquid chromatography-tandem mass spectrometry (LC-MS/MS), then bioinformatic analysis were applied to determine candidate membrane protein and their possible signaling pathway.

RESULTS

A total of 5159 proteins were identified and 354 differential membrane proteins and membrane associated proteins, which might be associated with matrix stiffness-mediated metformin resistance were discovered. Then 94 candidate membrane proteins including 21 up-regulated protein molecules and 73 down-regulated protein molecules were further obtained. Some of them such as Annexin A2 (ANXA2), Filamin-A (FLNA), Moesin (MSN), Myosin-9 (MYH9), Elongation factor 2 (eEF2), and Tax1 binding Protein 3 (TAX1BP3) were selected for further validation. Their expressions were all downregulated in HCC cells grown on different stiffness substrates after metformin intervention. More importantly, the degree of decrease was obviously weakened on the higher stiffness substrate compared with that on the lower stiffness substrate, indicating that these candidate membrane proteins might contribute to matrix stiffness-mediated metformin resistance in HCC.

CONCLUSIONS

There was an obvious change in membrane proteins in matrix stiffness-mediated metformin resistance in HCC cells. Six candidate membrane proteins may reflect the response of HCC cells under high stiffness stimulation to metformin intervention, which deserve to be investigated in the future.

Targeting lncRNA DDIT4-AS1 Sensitizes Triple Negative Breast Cancer to Chemotherapy via Suppressing of Autophagy

In this study, it is found that the lncRNA, DNA damage inducible transcript 4 antisense RNA1 (DDIT4-AS1), is highly expressed in triple-negative breast cancer (TNBC) cell lines and tissues due to H3K27 acetylation in the promoter region, and promotes the proliferation, migration, and invasion of TNBC cells via activating autophagy. Mechanistically, it is shown that DDIT4-AS1 induces autophagy by stabilizing DDIT4 mRNA via recruiting the RNA binding protein AUF1 and promoting the interaction between DDIT4 mRNA and AUF1, thereby inhibiting mTOR signaling pathway. Furthermore, silencing of DDIT4-AS1 enhances the sensitivity of TNBC cells to chemotherapeutic agents such as paclitaxel both in vitro and in vivo. Using a self-activatable siRNA/drug core-shell nanoparticle system, which effectively deliver both DDIT4-AS1 siRNA and paclitaxel to the tumor-bearing mice, a significantly enhanced antitumor activity is achieved. Importantly, the codelivery nanoparticles exert a stronger antitumor effect on breast cancer patient-derived organoids. These findings indicate that lncRNA DDIT4-AS1-mediated activation of autophagy promotes progression and chemoresistance of TNBC, and targeting of DDIT4-AS1 may be exploited as a new therapeutic approach to enhancing the efficacy of chemotherapy against TNBC.

Towards dual function of autophagy in breast cancer: A potent regulator of tumor progression and therapy response

As a devastating disease, breast cancer has been responsible for decrease in life expectancy of females and its morbidity and mortality are high. Breast cancer is the most common tumor in females and its treatment has been based on employment of surgical resection, chemotherapy and radiotherapy. The changes in biological behavior of breast tumor relies on genomic and epigenetic mutations and depletions as well as dysregulation of molecular mechanisms that autophagy is among them. Autophagy function can be oncogenic in increasing tumorigenesis, and when it has pro-death function, it causes reduction in viability of tumor cells. The carcinogenic function of autophagy in breast tumor is an impediment towards effective therapy of patients, as it can cause drug resistance and radio-resistance. The important hallmarks of breast tumor such as glucose metabolism, proliferation, apoptosis and metastasis can be regulated by autophagy. Oncogenic autophagy can inhibit apoptosis, while it promotes stemness of breast tumor. Moreover, autophagy demonstrates interaction with tumor microenvironment components such as macrophages and its level can be regulated by anti-tumor compounds in breast tumor therapy. The reasons of considering autophagy in breast cancer therapy is its pleiotropic function, dual role (pro-survival and pro-death) and crosstalk with important molecular mechanisms such as apoptosis. Moreover, current review provides a pre-clinical and clinical evaluation of autophagy in breast tumor.

A pan-cancer-bioinformatic-based literature review of TRPM7 in cancers

TRPM7, a divalent cation-selective channel with kinase domains, has been widely reported to potentially affect cancers. In this study, we conducted multiple bioinformatic analyses based on open databases and reviewed articles that provided evidence for the effects of TRPM7 on cancers. The purposes of this paper are 1) to provide a pan-cancer overview of TRPM7 in cancers; 2) to summarize evidence of TRPM7 effects on cancers; 3) to identify potential future studies of TRPM7 in cancer. Bioinformatics analysis revealed that no cancer-related TRPM7 mutation was found. TRPM7 is aberrantly expressed in most cancer types but the cancer-noncancer expression pattern varies across cancer types. TRPM7 was not associated with survival, TMB, or cancer stemness in most cancer types. TRPM7 affected drug sensitivity and tumor immunity in some cancer types. The in vitro evidence, preclinical in vivo evidence, and clinical evidence for TRPM7 effects on cancers as well as TRPM7 kinase substrate and TRPM7-targeting drugs associated with cancers were summarized to facilitate comparison. We matched the bioinformatics evidence to literature evidence, thereby unveiling potential avenues for future investigation of TRPM7 in cancers. We believe that this paper will help orient research toward important and relevant aspects of the role of TRPM7 in cancers.

Mechanisms of cancer cell death induction by paclitaxel: an updated review

Chemoresistance of cancer cells is a major problem in treating cancer. Knowledge of how cancer cells may die or resist cancer drugs is critical to providing certain strategies to overcome tumour resistance to treatment. Paclitaxel is known as a chemotherapy drug that can suppress the proliferation of cancer cells by inducing cell cycle arrest and induction of mitotic catastrophe. However, today, it is well known that paclitaxel can induce multiple kinds of cell death in cancers. Besides the induction of mitotic catastrophe that occurs during mitosis, paclitaxel has been shown to induce the expression of several pro-apoptosis mediators. It also can modulate the activity of anti-apoptosis mediators. However, certain cell-killing mechanisms such as senescence and autophagy can increase resistance to paclitaxel. This review focuses on the mechanisms of cell death, including apoptosis, mitotic catastrophe, senescence, autophagic cell death, pyroptosis, etc., following paclitaxel treatment. In addition, mechanisms of resistance to cell death due to exposure to paclitaxel and the use of combinations to overcome drug resistance will be discussed.

Increased eEF2K Promotes Glycolysis and Aggressive Behaviors of Fibroblast-Like Synoviocytes in Rheumatoid Arthritis

Objective

Aggressive phenotype and abnormal glycolytic metabolism of fibroblast-like synoviocytes (FLSs) are essential to joint inflammation and damage in rheumatoid arthritis (RA). Eukaryotic elongation factor-2 kinase (eEF2K) is a negative regulator of protein synthesis and has been shown to play an important role in regulating various cellular processes and promoting glycolysis in tumor cells. However, the role of eEF2K in regulating the pathogenic FLS behaviors is unknown.

Methods

A specific inhibitor of eEF2K, NH125, and siRNA were used to evaluate the role of eEF2K on RA FLSs in vitro. Collagen-induced arthritis (CIA) mice were used to evaluate the in vivo effect of eEF2K. Cell migration, invasion of RA FLSs were assessed by transwell or wound healing assays. Relative changes of cytokines were analyzed by quantitative real-time PCR, western blot and ELISA.

Results

Herein, we found an increased expression of eEF2K in synovial tissues and FLSs of RA patients. eEF2K knockdown by siRNA or treatment with NH125, an inhibitor of eEF2K, significantly reduced inflammation, migration/invasion, glucose uptake and lactate productions. eEF2K knockdown suppressed TNF-α-induced activation of NF-κB and AKT pathways in RA FLSs. Lactate reversed the inhibitory effect of eEF2K knockdown on inflammation and migration of RA FLSs. Moreover, lactate was also involved in eEF2K-mediated activation of NF-κB and AKT. NH125 treatment attenuated the severity of arthritis in collagen-induced arthritis mice.

Conclusion

eEF2K inhibition suppressed glycolysis and aggressive behaviors of RA FLS, which indicated that targeting eEF2K may be a new strategy for the treatment of RA.

Autophagy: A promising target for triple negative breast cancers

Triple negative breast cancer (TNBC) is the most aggressive type of breast cancers which constitutes about 15% of all breast cancer cases and characterized by negative expression of hormonal receptors and human epidermal growth factor receptor 2 (HER2). Thus, endocrine and HER2 targeted therapies are not effective toward TNBCs, and they mainly rely on chemotherapy and surgery for treatment. Despite recent advances in chemotherapy, 40% of TNBC patients develop a metastatic relapse and recurrence. Therefore, understanding the molecular profile of TNBC is warranted to identify targets that can be selected for the development of a new and effective therapeutic approach. Autophagy is an internal defensive mechanism that allows the cells to survive under different stressors. It has been well known that autophagy exerts a crucial role in cancer progression. The critical role of autophagy in TNBC progression is emerging in recent years. This review will discuss autophagic pathway, how autophagy affects TNBC progression and recent therapeutic approaches that can target autophagy as a new treatment modality.

eEF2K as a novel metastatic and prognostic biomarker in gastric cancer patients

BACKGROUND

Although eukaryotic elongation factor 2 kinase (eEF2K) has been reported to be a potential oncogenic factor in many human cancers, its usefulness as a clinical prognostic biomarker for gastric cancer has not been investigated.

METHODS

In this study, data about 540 patients with stomach adenocarcinoma (STAD) were analyzed from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) databases to determine the expression of eEF2K. Immunohistochemistry (IHC), western blots, and real-time polymerase chain reaction (RT-PCR) were also performed to determine the clinical significance of eEF2K expression in 96 postoperative patients with gastric cancer. Among the 96 patients, 36 had low expression of eEF2K and 60 had high expression.

RESULTS

Analysis of the TCGA and GEO datasets revealed that eEF2K expression was significantly higher in the STAD tissue samples than in the non-tumorous gastric tissues. IHC, western blots, and RT-PCR confirmed these findings. The high expression level of eEF2K was found to be related to the presence of lymph node metastasis (p = 0.002). Moreover, multivariate analysis showed that eEF2K was an independent indicator of prognosis for overall survival (OS) (hazard ratio [HR] = 1.72, 95% confidence interval [CI] = 1.06-2.79; p = 0.03) and disease-free survival (DFS) (HR = 1.66, 95% CI = 0.997-2.765; p = 0.052) in patients with surgically resected STAD.

CONCLUSION

Collectively, our findings suggest that eEF2K is a clinical indicator of metastatic and prognostic significance for STAD survival and could serve as a potential therapeutic target.

Isorhamnetin Promotes MKN-45 Gastric Cancer Cell Apoptosis by Inhibiting PI3K-Mediated Adaptive Autophagy in a Hypoxic Environment

A tumor-related hypoxic microenvironment can promote the proliferation of gastric cancer cells, and hypoxic-induced autophagy is the main mechanism of protection against hypoxia in gastric cancer cells. Isorhamnetin (ISO) is a chemical substance derived from plants, mainly from the sea buckthorn. Previous studies have shown that ISO has antitumor effects, but the effects of ISO against gastric cancer in a hypoxic environment are still unknown. In this study, we investigated the effects of ISO against gastric cancer in a hypoxic environment and the mechanisms underlying ISO-induced gastric cancer cell death. The results show that ISO targeted PI3K and blocked the PI3K-AKT-mTOR signaling pathway, significantly inhibiting gastric cancer cell autophagy in a hypoxic environment, inhibiting cell proliferation, decreasing mitochondrial membrane potential, and promoting mitochondria-mediated apoptosis. ISO, a functional food component, is a promising candidate for the treatment of gastric cancer.

Epigenetics of Triple-negative breast cancer via natural compounds

Triple-negative breast cancer (TNBC) is a highly resistant, lethal, and metastatic sub-division of breast carcinoma, characterized by the deficiency of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). In women, TNBC shows a higher aggressive behavior with poor patient prognosis and a higher recurrence rate during reproductive age. TNBC is defined by the presence of epithelial-to-mesenchymal-transition (EMT), which shows a significant role in cancer progression. At the epigenetic level, TNBC is characterized by epigenetic signatures, such as DNA methylation, histone remodeling, and a host of miRNA, MiR-193, LncRNA, HIF-2α, eEF2K, LIN9/NEK2, IMP3, LISCH7/TGF-β1, GD3s and KLK12 mediated regulation. These modifications either are silenced or activate the necessary genes that are prevalent in TNBC. The review is based on epigenetic mediated mechanistic changes in TNBC. Furthermore, Thymoquinone (TQ), Regorafenib, Fangjihuangqi decoction, Saikosaponin A, and Huaier, etc., are potent antitumor natural compounds extensively reported in the literature. Further, the review emphasizes the role of these natural compounds in TNBC and their possible epigenetic targets, which can be utilized as a potential therapeutic strategy in treatment of TNBC.

Inhibiting Eukaryotic Elongation Factor 2 Kinase: An Update on Pharmacological Small-Molecule Compounds in Cancer

Eukaryotic elongation factor 2 kinase (eEF2K), a member of the atypical protein kinase family of alpha-kinases, is well-known as a negative regulator of protein synthesis by phosphorylating eEF2. Notably, eEF2K functions as a key regulator of several cellular processes, leading to tumorigenesis. To date, some small-molecule compounds have been reported as potential eEF2K inhibitors in cancer drug discovery. However, an ideal targeted drug design still faces huge challenges. Alternatively, other design strategies, such as repurposed drugs, dual-target drugs, and drug combination strategies, provide insights into the improvement of cancer treatment. Here, we summarize the crucial eEF2K-modulating pathways in cancer, including AMPK, REDD1, and Src. Moreover, we discuss the inhibition of eEF2K with single-target inhibitors, repurposed drugs, dual-target inhibitors, drug combination strategies, and other emerging technologies for therapeutic purposes. Together, these inspiring findings provide insights into a promising strategy for inhibiting eEF2K with small-molecule compounds to improve potential cancer therapy.

Prognosis and Characterization of Immune Microenvironment in Acute Myeloid Leukemia Through Identification of an Autophagy-Related Signature

Acute myeloid leukemia (AML) is one of the most common hematopoietic malignancies that has an unfavorable outcome and a high rate of relapse. Autophagy plays a vital role in the development of and therapeutic responses to leukemia. This study identifies a potential autophagy-related signature to monitor the prognoses of patients of AML. Transcriptomic profiles of AML patients (GSE37642) with the relevant clinical information were downloaded from Gene Expression Omnibus (GEO) as the training set while TCGA-AML and GSE12417 were used as validation cohorts. Univariate regression analyses and multivariate stepwise Cox regression analysis were respectively applied to identify the autophagy-related signature. The univariate Cox regression analysis identified 32 autophagy-related genes (ARGs) that were significantly associated with the overall survival (OS) of the patients, and were mainly rich in signaling pathways for autophagy, p53, AMPK, and TNF. A prognostic signature that comprised eight ARGs (BAG3, CALCOCO2, CAMKK2, CANX, DAPK1, P4HB, TSC2, and ULK1) and had good predictive capacity was established by LASSO–Cox stepwise regression analysis. High-risk patients were found to have significantly shorter OS than patients in low-risk group. The signature can be used as an independent prognostic predictor after adjusting for clinicopathological parameters, and was validated on two external AML sets. Differentially expressed genes analyzed in two groups were involved in inflammatory and immune signaling pathways. An analysis of tumor-infiltrating immune cells confirmed that high-risk patients had a strong immunosuppressive microenvironment. Potential druggable OS-related ARGs were then investigated through protein–drug interactions. This study provides a systematic analysis of ARGs and develops an OS-related prognostic predictor for AML patients. Further work is needed to verify its clinical utility and identify the underlying molecular mechanisms in AML.

Tumor mutation burden and JARID2 gene alteration are associated with short disease-free survival in locally advanced triple-negative breast cancer

Background

In locally advanced triple-negative breast cancer (TNBC), patients who did not achieve pathologic complete response (non-pCR) after neoadjuvant chemotherapy develop rapid tumor metastasis. Tumor mutation burden (TMB) is a potential biomarker of cancer therapy, though whether it is applicable to TNBC is still unclear.

Methods

A total of 14 non-pCR TNBC patients were enrolled, and tissue samples from radical operation were collected. Of these, 7 cases developed disease progression within 12 months after operation [short disease-free survival (short DFS)], while others showed longer DFS over 1 year (long DFS). Next generation sequencing (NGS) analysis targeting 422 cancer-related genes and in vitro studies were performed.

Results

A total of 72 mutations were detected within 14 patients, which ranged from 1 to 8 per patient with a median mutations number of 5. The median number of mutations in the short-DFS group was higher than that in the long-DFS group (6.0 vs. 4.3; P=0.094). Furthermore, 6 gene mutation types were detected, with missense mutations displayed in the majority (36/72, 50.0%). No correlation between mutation type and DFS was found. Among 422 cancer-related genes, alterations in 30 genes were detected. TP53 (12/14, 85.7%) was the most common mutation gene in the entire cohort. RB1 mutations significantly occurred in patients with high Ki-67 scores (P=0.013). Additionally, 4 mutations of PTPN13 (57.1%, 4/7) and 3 of JARID2 (42.9%, 3/7) were only detected in the short-DFS group, while patients with JARID2 mutation had a significantly shorter DFS period (P=0.026). Experiments in vitro confirmed that JARID2 gene was widely expressed in various breast cancer cell lines. Knockdown of JARID2 in MD-MBA-231 cells by small interfering RNA (siRNA) decreased the expression of E-cadherin, and increased the levels of vimentin, MMP7, and MMP9.

Conclusions

In non-pCR TNBC, JARID2 mutation and TMB elevated in patients with short-DFS, indicating the potential prognostic biomarkers and therapeutic molecular targets for locally advanced TNBC.

Metformin and oxyphotodynamic therapy as a novel treatment approach for triple-negative breast cancer

Background

Treatment for triple-negative breast cancer (TNBC) remains a significant challenge due to a lack of targeted therapies. While photodynamic therapy (PDT) has been utilized as a treatment approach for several types of cancer, oxyphotodynamic therapy (OPDT) is a novel method that improves treatment efficacy by increasing local oxygen concentration. Metformin (MET) has been demonstrated utility as an anti-tumor agent by acting through the adenosine monophosphate-activated protein kinase (AMPK) pathway. We hypothesized that MET in combination with heme, a byproduct of 5-aminolevulinic acid (ALA), may increase cytotoxicity for cancer treatment. This study aimed to investigate the synergistic effect of MET and ALA with PDT or OPDT on TNBC tumorigenic cells.

Methods

The treatment efficacy and phototoxicity of PDT or OPDT were determined using a cell viability assay. PDT/OPDT experiments were carried out in nine groups based on different combinations and concentrations of ALA and/or MET. To calculate the synergistic effect by compuSyn soft for different groups, cells were incubated with ALA and/or MET at the following concentrations (0, 0.25, 0.5,1, 2, 4, 8, 16, 24, and 32 mM). The fluorescence of ALA-induced protoporphyrin IX (PpIX) and MitoTracker Green were observed under a confocal microscope.

Results

The optimized therapeutic concentration ratio of ALA and MET was determined to be 1:1. The inhibition of cancer growth (IC₅₀) for each group was 14.03, 10.62, 7.71, 18.27, 22.09, 23.96, 4.57, 10.20, and 8.18 mM, respectively. The combination index (CI) values (fa =0.5) of the last three combination groups (groups 7, 8, and 9) were 0.44, 1.70, and 1.47, respectively. PpIX fluorescence intensity of group 9 (ALA-MET-OPDT group) remained the highest among all groups, indicating an enhanced therapeutic effect.

Conclusions

This study introduces OPDT as a novel anti-tumor therapy for TNBC. Furthermore, the combined use of ALA and MET had a synergistic anti-tumor effect in TNBC cells when combined with OPDT.

Downregulation of miR-182-5p inhibits the proliferation and invasion of triple-negative breast cancer cells through regulating TLR4/NF-κB pathway activity by targeting FBXW7

Background

To investigate the role of miR-182-5p in the proliferation and invasion of triple-negative breast cancer (TNBC) cells, as well as the underlying mechanism.

Methods

qRT-PCR was used to detect the level of miR-182-5p in tissues and cells. CCK-8 assay, flow cytometry, and Transwell assay were performed to detect cell proliferation, apoptosis rate, and invasion, respectively. Pearson correlation analysis was used to determine the correlation between miR-182-5p and its predicted target gene FBXW7, and the target of miR-182-5p was identified by dual-luciferase reporter gene assay. ELISA assay was used to examine the levels of cytokines in the culture supernatant of tumor cells. Western blot analysis was used to detect the expressions of FBXW7, TLR4, and NF-κB) pathways in tumor cells.

Results

In MDA-MB-231 and BT-549 cells, downregulation of miR-182-5p significantly inhibited cell proliferation and invasion and promoted tumor cell apoptosis. Pearson correlation analysis showed that miR-182-5p had a negative correlation with FBXW7. Dual-luciferase reporter gene assay showed that miR-182-5p could directly target FBXW7. Further studies showed that FBXW7 overexpression significantly inhibited cell proliferation and invasion and increased the apoptosis rate. Downregulation of miR-182-5p significantly reduced the levels of TNF-α, IL-1 β, IL-6, and IL-18 in the culture supernatant, and decreased the activity of TLR4/NF-κB pathway in tumor cells, while downregulation of FBXW7 significantly inhibited the effect of miR-182-5p on tumor cells.

Conclusions

Downregulation of miR-182-5p inhibits TLR4/NF-κB pathway activity by increasing FBXW7 expression, thereby suppressing the proliferation and invasion of TNBC cells.

Curcumol enhances the anti-tumor effects of metformin via suppressing epithelial-mesenchymal transition in triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) is a severe disease with a high mortality rate. Metformin has been found to possess anti-tumor properties. Curcumol, an active ingredient extracted from curcuma, exerts the protective effect in TNBC cells through inducing apoptosis. However, the effects of curcumol combined with metformin on the treatment of TNBC have yet to be fully established.

Methods

TNBC cells MDA-MB-231 and MDA-MB-468 cells were used in the study. TNBC cells were treated with curcumol and metformin alone or treated with curcumol combined with metformin. Cell viability was determined using Cell Counting Kit-8 (CCK-8) assay. Cell apoptosis was detected using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The levels of proteins were measured using Western blot. Wound healing assay and Transwell invasion assays were used to determine cell migration and invasion ability, respectively. A xenograft model was established to investigate the tumor growth ability. Immunohistochemistry was performed to determine the expression of Ki-67 and Vascular endothelial growth factor (VEGF).

Results

In the study, the administration of curcumol alone had no significant effects on the TNBC cells. However, the anti-proliferation, anti-metastasis, and anti-epithelial-mesenchymal transition (EMT) effects of metformin were enhanced by the addition of curcumol. Further, curcumol reversed TNBC cell proliferation, migration, invasion, and EMT induced by rucaparib, and enhanced the effect of metformin on rucaparib-induced TNBC cells. The combination of curcumol and metformin also suppressed tumor growth, EMT marker expression, and the activation of Wnt2/β-Catenin signaling during in vivo experiments.

Conclusions

The combination of curcumol and metformin enhances the anti-tumor effects of metformin on TNBC via inhibiting EMT. Curcumol combined with metformin may hold promise as a therapeutic strategy for TNBC.

Triclosan induces ROS-dependent cell death and autophagy in A375 melanoma cells

Melanoma is a common type of cutaneous tumor, but current drug treatments do not satisfy clinical practice requirements. At present, mitochondrial uncoupling is an effective antitumor treatment. Triclosan, a common antimicrobial, also acts as a mitochondrial uncoupler. The aims of the present study were to investigate the effects of triclosan on melanoma cells and the underlying mechanisms. Mitochondrial membrane potential (MMP), mitochondrial morphology, mitochondrial reactive oxygen species (mito-ROS), intracellular superoxide anion and [Ca²⁺]_i were measured using confocal microscopy. It was found that triclosan application was associated with decreased A375 cell viability in a dose- and time-dependent manner and these effects may have cell specificity. Furthermore, triclosan induced MMP depolarization, ATP content decrease, mito-ROS and [Ca²⁺]_i level increases, excessive mitochondrial fission, AMP-activated protein kinase (AMPK) activation and STAT3 inhibition. Moreover, these aforementioned effects were reversed by acetylcysteine treatment. Triclosan acute treatment also induced mitochondrial swelling, which was reversed after AMPK-knockdown associated with [Ca²⁺]_i overload. Cell death was caused by STAT3 inhibition but not AMPK activation. Moreover, triclosan induced autophagy via the ROS/AMPK/p62/microtubule-associated protein 1A/1B-light chain 3 (LC3) signaling pathway, which may serve a role in feedback protection. Collectively, the present results suggested that triclosan increased mito-ROS production in melanoma cells, following induced cell death via the STAT3/Bcl-2 pathway and autophagy via the AMPK/p62/LC3 pathway.

The effect of low frequency and low intensity ultrasound combined with microbubbles on the sonoporation efficiency of MDA-MB-231 cells

Background

Ultrasound can produce certain biophysical effects including thermal and non-thermal effects on cells. Sonoporation, the most widely studied non-thermal biological effect of ultrasound, is considered to be the basis for new therapeutic applications. Ultrasound irradiation can increase the permeability of cell membranes through sonoporous effect, which makes molecules like those of drugs, protein, and DNA that normally cannot pass through the cell membranes be able to enter cells. Considering the poor therapeutic effect and poor prognosis of triple negative breast cancer, we aimed to explore the experimental conditions and find the optimal parameters to improve the therapeutic efficacy of chemotherapeutic drugs for MDA-MB-231 cells.

Methods

By establishing an experimental and control group, our study investigated the effect of low frequency and low intensity ultrasound combined with microbubbles on MDA-MB-231 cell membrane permeability at different times. We conducted factorial cross-design and set 3 levels of ultrasound intensity: 230, 300, and 370 mW/cm²; 3 levels of irradiation time: 1, 2, and 3 minutes; and 6 levels of microbubble doses: 0, 0.2, 0.4, 0.6, 0.8, and 1 mL.

Results

Results show that ultrasound intensity, time of irradiation, and microbubbles concentration are not only related to but also have interactive effects on the sonoporation efficiency of MDA-MB-231 cells, with the rank order being sound intensity, irradiation time, and microbubble concentration. The average positive rates (%) of FD4 staining in sound intensities of 230, 300, and 370 mW/cm² levels were 1.20±0.71, 13.80±5.86, and 10.71±4.36, respectively; and in irradiated times of 1, 2, and 3 min they were 7.54±5.95, 9.74±8.42, and 8.59±5.80, respectively. When the microbubbles increased according to the gradient of 0, 0.2, 0.4, 0.6, 0.8, and 1 mL, the positive rates (%) of FD4 staining were 7.32±5.89, 9.26±7.39, 8.31±5.67, 10.12±8.42, 8.67±7.23, and 7.72±6.24.

Conclusions

In our study, the optimal parameters of the sonoporous effect for MDA-MB-231 cells were 300 mW/cm² of ultrasound intensity, 2 minutes of irradiation time, and 20% microbubbles concentration.