AMP- activated protein kinase (AMPK) promotes breast cancer stemness and drug resistance

Therapeutic delivery of siRNA for the management of breast cancer and triple-negative breast cancer

Breast cancer is the leading cause of cancer-related deaths among women globally. The difficulties with anticancer medications, such as ineffective targeting, larger doses, toxicity to healthy cells and side effects, have prompted attention to alternate approaches to address these difficulties. RNA interference by small interfering RNA (siRNA) is one such tactic. When compared with chemotherapy, siRNA has several advantages, including the ability to quickly modify and suppress the expression of the target gene and display superior efficacy and safety. However, there are known challenges and hurdles that limits their clinical translation. Decomposition by endonucleases, renal clearance, hydrophilicity, negative surface charge, short half-life and off-target effects of naked siRNA are obstacles that hinder the desired biological activity of naked siRNA. Nanoparticulate systems such as polymeric, lipid, lipid-polymeric, metallic, mesoporous silica nanoparticles and several other nanocarriers were used for effective delivery of siRNA and to knock down genes involved in breast cancer and triple-negative breast cancer. The focus of this review is to provide a comprehensive picture of various strategies utilized for delivering siRNA, such as combinatorial delivery, development of modified nanoparticles, smart nanocarriers and nanocarriers that target angiogenesis, cancer stem cells and metastasis of breast cancer.

Density Gradient Centrifugation Is an Effective Tool to Isolate Cancer Stem-like Cells from Hypoxic and Normoxia Triple-Negative Breast Cancer Models

Accumulating evidence has indicated that stemness-related genes are associated with the aggressiveness of triple-negative breast cancer (TNBC). Because no universal markers for breast CSCs are available, we applied the density gradient centrifugation method to enrich breast CSCs. We demonstrated that the density centrifugation method allows for the isolation of cancer stem cells (CSCs) from adherent and non-adherent MCF7 (Luminal A), MDA-MB-231 (TNBC) and MDA-MB-468 (TNBC) breast cancer cells. The current study shows that the CSCs' enriched fraction from Luminal A and TNBC cells have an increased capacity to grow anchorage-independently. CSCs from adherent TNBC are mainly characterized by metabolic plasticity, whereas CSCs from Luminal A have an increased mitochondrial capacity. Moreover, we found that non-adherent growth CSCs isolated from large mammospheres have a higher ability to grow anchorage-independently compared to CSCs isolated from small mammospheres. In CSCs, a metabolic shift towards glycolysis was observed due to the hypoxic environment of the large mammosphere. Using a bioinformatic analysis, we indicate that hypoxia HYOU1 gene overexpression is associated with the aggressiveness, metastasis and poor prognosis of TNBC. An in vitro study demonstrated that HYOU1 overexpression increases breast cancer cells' stemness and hyperactivates their metabolic activity. In conclusion, we show that density gradient centrifugation is a non-marker-based approach to isolate metabolically flexible (normoxia) CSCs and glycolytic (hypoxic) CSCs from aggressive TNBC.

Glucosyltriazole amphiphile treatment attenuates breast cancer by modulating the AMPK signaling

Breast cancer is the second most frequent cancer among women. Out of various subtypes, triple-negative breast cancers (TNBCs) account for 15% of breast cancers and exhibit more aggressive characteristics as well as a worse prognosis due to their proclivity for metastatic progression and limited therapeutic strategies. It has been demonstrated that AMP-activated protein kinase (AMPK) has context-specific protumorigenic implications in breast cancer cells. A set of glucosyltriazole amphiphiles, consisting of acetylated (9a-h) and unmodified sugar hydroxyl groups (10a-h), were synthesized and subjected to in vitro biological evaluation. Among them, 9h exhibited significant anticancer activity against MDA-MB-231, MCF-7, and 4T1 cell lines with IC50 values of 12.5, 15, and 12.55 μM, respectively. Further, compound 9h was evaluated for apoptosis and cell cycle analysis in in vitro models (using breast cancer cells) and antitumour activity in an in vivo model (orthotopic mouse model using 4T1 cells). Annexin-V assay results revealed that treatment with 9h caused 34% and 28% cell death at a concentration of 15 or 7.5 μM, respectively, while cell cycle analysis demonstrated that 9h arrested the cells at the G2/M or G1 phase in MCF-7, MDA-MB-231 and 4T1 cells, respectively. Further, in vivo, investigation showed that compound 9h exhibited equipotent as doxorubicin at 7.5 mg/kg, and superior efficacy than doxorubicin at 15 mg/kg. The mechanistic approach revealed that 9h showed potent anticancer activity in an in vivo orthotopic model (4T1 cells) partly by suppressing the AMPK activation. Therefore, modulating the AMPK activation could be a probable approach for targeting breast cancer and mitigating cancer progression.

Geneticin ameliorates pulmonary fibrosis by attenuating the TGF-β/Smad via modulating AMPK/SIRT1 signaling

AIM

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive condition with unknown aetiology that causes the lung parenchyma to scar incessantly, lowering the quality of life and hastening death. In this investigation, we studied the anti-fibrotic activity of Geneticin (a derivative of gentamycin) using in vitro and in vivo models.

MAIN METHODS

The TGF-β-mediated differentiation model was adopted to investigate (fibrotic marker's levels/expression) the anti-fibrotic activity of geneticin (GNC) in in-vitro scenarios (LL29 and DHLF cells). In vivo, the bleomycin (BLM)-induced pulmonary fibrosis model was employed by administering BLM intratracheally. Post 14 days of BLM administration, animals were treated with geneticin (6.25, 12.5, and 25 mg·kg-1) for another 14 days, and their therapeutic effect was investigated using a spectrum of techniques.

KEY FINDINGS

RTqPCR and western-blot results revealed that geneticin treatment significantly attenuated the TGF-β/BLM mediated fibrotic cascade of markers in both in-vitro and in-vivo models respectively. Further, the BLM-induced pulmonary fibrosis model revealed, that geneticin dose-dependently reduced the BLM-induced inflammatory cell infiltrations, and thickness of the alveoli walls, improved the structural distortion of the lung, and aided in improving the survival rate of the rats. Picrosirus and Masson's trichrome staining indicated that geneticin therapy reduced collagen deposition and, as a result, lung functional characteristics were improved as assessed by flexivent. Mechanistic studies have shown that geneticin reduced fibrosis by attenuating the TGF-β/Smad through modulating the AMPK/SIRT1 signaling.

SIGNIFICANCE

These findings suggest that geneticin may be a promising therapeutic agent for the treatment of pulmonary fibrosis in clinical settings.

Design and synthesis of Meldrum's acid based 7-azaindole anchored 1,2,3-triazole hybrids as anticancer agents

A series of Meldrum's acid, 7-azaindole and 1,2,3-triazole hybrids were synthesized and evaluated for their in vitro anticancer activity against five different cancer cell lines viz. MCF-7 (breast cancer), HeLa (cervical cancer), DU-145 (prostate cancer), HepG2 (liver cancer) and K562 (myelogenous leukemia cell). Among the series, compound 6b containing a 4-methyl substitution showed potent activity against HeLa cell line. Cell cycle analysis revealed that compound 6b induced cell cycle arrest at the G2/M phase and induced apoptosis. Apoptotic activity was further confirmed by Hoechst staining and Annexin V-FITC assay. Compound 6b has been found to exhibit higher activity in all four cell lines, with IC50 values of 6.67 ± 0.39 μM, 4.44 ± 0.32 μM, 12.38 ± 0.51 μM and 9.97 ± 0.25 μM against MCF-7, HeLa, DU-145 and HepG2 cell lines respectively. Compounds 6m (9.68 ± 0.10 μM) and 6n (9.52 ± 0.38 μM), which have dimethoxy and trimethoxy substitutions, respectively, have demonstrated significant anticancer activity against HeLa cells compared to the other cells. The molecular docking study of ligand 6b against the crystal structure of EGFR and Mcl-1 scored notable binding energy values and displayed important interactions like H-bond, π-cation and other hydrophobic interactions.

CD24 negativity reprograms mitochondrial metabolism to PPARα and NF-κB-driven fatty acid β-oxidation in triple-negative breast cancer

CD24 is a well-characterized breast cancer (BC) stem cell (BCSC) marker. Primary breast tumor cells having CD24-negativity together with CD44-positivity is known to maintain high metastatic potential. However, the functional role of CD24 gene in triple-negative BC (TNBC), an aggressive subtype of BC, is not well understood. While the significance of CD24 in regulating immune pathways is well recognized in previous studies, the significance of CD24 low expression in onco-signaling and metabolic rewiring is largely unknown. Using CD24 knock-down and over-expression TNBC models, our in vitro and in vivo analysis suggest that CD24 is a tumor suppressor in metastatic TNBC. Comprehensive in silico gene expression analysis of breast tumors followed by lipidomic and metabolomic analyses of CD24-modulated cells revealed that CD24 negativity induces mitochondrial oxidative phosphorylation and reprograms TNBC metabolism toward the fatty acid beta-oxidation (FAO) pathway. CD24 silencing activates PPARα-mediated regulation of FAO in TNBC cells. Further analysis using reverse-phase protein array and its validation using CD24-modulated TNBC cells and xenograft models nominated CD24-NF-κB-CPT1A signaling pathway as the central regulatory mechanism of CD24-mediated FAO activity. Overall, our study proposes a novel role of CD24 in metabolic reprogramming that can open new avenues for the treatment strategies for patients with metastatic TNBC.

Yohimbine ameliorates liver inflammation and fibrosis by regulating oxidative stress and Wnt/β-catenin pathway

BACKGROUND AND PURPOSE

Chronic liver injury, caused by various aetiologies, causes recurrent tissue damage, culminating in decreased liver regenerative ability and resulting in fibrosis followed by cirrhosis. In this study, the anti-fibrotic activity of Yohimbine hydrochloride (YHC) was investigated using various in vitro models and in vivo models.

METHODS

To assess the anti-inflammatory, antioxidant, and anti-fibrotic effects of YHC, lipopolysaccharide or TGF-β induced differentiation or lipid-induced oxidative-stress models were employed using HLECs, HSC-LX2, and HepG2 cells. Further, thioacetamide (TAA) induced hepatic inflammation/fibrosis models were utilized to validate the YHC's anti-fibrotic activity in rats.

RESULTS

Inflammation/differentiation experiments in HLECs and HSC-LX2 revealed that YHC treatment significantly (p < 0.001) mitigated the lipopolysaccharide or TGF-β induced upregulation of inflammatory and fibrotic markers expression respectively. In addition, YHC dose-dependently reduced the TGF-β induced migration and palmitic acid-induced oxidative stress in HepG2 cells. Further, TAA administration (5 weeks) in vivo rat model showed increased inflammatory marker levels/expression, oxidative stress, and pathological abnormalities. Additionally, TAA administration (9 weeks) elevated the fibrotic marker expression, collagen deposition in liver tissues, and shortened longevity in rats. Treatment with YHC dose-dependently mitigated the TAA-induced abnormalities in both inflammation and fibrosis models and improved the survival of the rats. Further mechanistic approaches revealed that TAA administration elevated the JNK, Wnt components and β-catenin expression in hepatic stellate cells and animal tissues. Further treatment with YHC significantly modulated the JNK/Wnt/β-catenin signaling. Moreover, the β-catenin nuclear translocation results showed that β-catenin levels were significantly elevated in the nuclear fraction of TAA control samples and reduced in YHC-treated samples.

CONCLUSION

Yohimbine treatment significantly improved inflammation and fibrosis by inhibiting differentiation, oxidative stress, and collagen deposition by partly modulating the JNK/Wnt/β-catenin pathway. These results might serve as a foundation for proposing yohimbine as a potential lead compound for liver fibrosis.

CAB39 promotes cisplatin resistance in bladder cancer via the LKB1-AMPK-LC3 pathway

Systemic therapy for muscle-invasive bladder cancer (BC) remains dominated by cisplatin-based chemotherapy. However, resistance to cisplatin therapy greatly limits long-term survival. Resistance to cisplatin-based chemotherapy still needs to be addressed. In this study, we established three cisplatin-resistant BC cell lines by multiple cisplatin pulse treatments. Interestingly, after exposure to cisplatin, all cisplatin-resistant cell lines showed lower reactive oxygen species (ROS) levels than the corresponding parental cell lines. Using proteomic analysis, we identified 35 proteins that were upregulated in cisplatin-resistant BC cells. By knocking down eleven of these genes, we found that after CAB39 knockdown, BC cisplatin-resistant cells were more sensitive to cisplatin. Overexpression of CAB39 had the opposite effect. Then, the knockdown of six genes downstream of CAB39 revealed that CAB39 promoted cisplatin resistance in BC through LKB1. Moreover, a key cause of cisplatin-induced cell death is damage to mitochondria and increased ROS levels. In our study, cisplatin-resistant cells exhibited higher autophagic flux and healthier mitochondrial status after cisplatin exposure. We demonstrated that the CAB39-LKB1-AMPK-LC3 pathway plays a critical role in enhancing autophagy to maintain the health of mitochondria and reduce ROS levels. In addition, the autophagy inhibitor chloroquine (CQ) can significantly enhance the killing effect of cisplatin on BC cells. Compared with gemcitabine plus cisplatin (GC), GC plus CQ significantly reduced tumor burden in vivo. In conclusion, our study shows that CAB39 counteracts the killing of cisplatin by enhancing the autophagy of BC cells to damaged mitochondria and other organelles to alleviate the damage of cells caused by harmful substances such as ROS.

Protective effect of β-glucan on Poly(I:C)-induced acute lung injury/inflammation: Therapeutic implications of viral infections in the respiratory system

AIMS

Acute lung inflammation, particularly acute respiratory distress syndrome (ARDS), is caused by a variety of pathogens including bacteria and viruses. β-Glucans have been reported to possess both anti-inflammatory and immunomodulatory properties. The current study evaluated the therapeutic effect of β-glucans on polyinosinic:polycytidylic acid (Poly(I:C)) induced lung inflammation in both hamster and mice models.

MAIN METHODS

Poly(I:C)-induced ALI/inflammation models were developed in hamsters (2.5 mg/kg) and mice (2 mg/kg) by delivering the Poly(I:C) intratracheally, and followed with and without β-glucan administration. After treatment, lung mechanics were assessed and lung tissues were isolated and analyzed for mRNA/protein expression, and histopathological examinations.

KEY FINDINGS

Poly(I:C) administration, caused a significant elevation of inflammatory marker's expression in lung tissues and showed abnormal lung mechanics in mice and hamsters. Interestingly, treatment with β-glucan significantly (p < 0.001) reversed the Poly(I:C)-induced inflammatory events and inflammatory markers expression in both mRNA (IL-6, IL-1β, TNF-α, CCL2 and CCL7) and protein levels (TNF-α, CD68, myeloperoxidase, neutrophil elastase, MUC-5Ac and iNOS). Lung functional assays revealed that β-glucan treatment significantly improved lung mechanics. Histopathological analysis showed that β-glucan treatment significantly attenuated the Poly(I:C) induced inflammatory cell infiltration, injury and goblet cell population in lung tissues. Consistent with these findings, β-glucan treatment markedly reduced the number of neutrophils and macrophages in lung tissues. Our findings further demonstrated that β-glucan could reduce inflammation by suppressing the MAPK pathway.

SIGNIFICANCE

These results suggested that β-glucan may attenuate the pathogenic effects of Poly(I:C)-induced ALI/ARDS via modulating the MAPK pathway, indicating β-glucan as a possible therapeutic agent for the treatment of viral-pulmonary inflammation/injury.

Synthesis and Characterization of a New Cationic Lipid: Efficient siRNA Delivery and Anticancer Activity of Survivin-siRNA Lipoplexes for the Treatment of Lung and Breast Cancers

Survivin has been shown to be widely expressed in most tumor cells, including lung and breast cancers. Due to limited siRNA delivery, it is more challenging to target survivin using knockdown-based techniques. Designing and developing new, bifunctional chemical molecules with both selective anti-proliferative activity and effective siRNA transfection capabilities by targeting a particular gene is important to treat aggressive tumors like triple-negative breast tumors (TNBC). The cationic lipids deliver small interfering RNA (siRNA) and also display inherent anti-cancer activities; therefore, cationic lipid therapies have become very popular for treating malignant cancers. In the current study, we attempted to synthesize a series of acid-containing cationic lipids, anthranilic acid-containing mef lipids, and indoleacetic acid-containing etodo lipids etc. Further, we elucidated their bi-functional activity for their anticancer activity and survivin siRNA-mediated anti-cancer activity. Our results showed that lipoplexes with siRNA-Etodo: Dotap (ED) and siRNA-Mef: Dotap (MD) exhibited homogeneous particle size and positive zeta potential. Further, biological investigations resulted in enhanced survivin siRNA delivery with high stability, improved transfection efficiency, and anti-cancer activity. Additionally, our findings showed that survivin siRNA lipoplexes (ED and MD) in A549 cells and 4T1 cells exhibited stronger survivin knockdown, enhanced apoptosis, and G1 or G2/M phase arrest in both cell types. In vivo results revealed that treatment with survivin complexed lipoplexes significantly reduced tumor growth and tumor weight compared to control. Thus, our novel quaternary amine-based liposome formulations are predicted to open up new possibilities in the development of a simple and widely utilized platform for siRNA delivery and anti-cancer activities.

A Triphenylphosphonium-Functionalized Delivery System for an ATM Kinase Inhibitor That Ameliorates Doxorubicin Resistance in Breast Carcinoma Mammospheres

The enzyme ataxia-telangiectasia mutated (ATM) kinase is a pluripotent signaling mediator which activates cellular responses to genotoxic and metabolic stress. It has been shown that ATM enables the growth of mammalian adenocarcinoma stem cells, and therefore the potential benefits in cancer chemotherapy of a number of ATM inhibitors, such as KU-55933 (KU), are currently being investigated. We assayed the effects of utilizing a triphenylphosphonium-functionalized nanocarrier delivery system for KU on breast cancer cells grown either as a monolayer or in three-dimensional mammospheres. We observed that the encapsulated KU was effective against chemotherapy-resistant mammospheres of breast cancer cells, while having comparably lower cytotoxicity against adherent cells grown as monolayers. We also noted that the encapsulated KU sensitized the mammospheres to the anthracycline drug doxorubicin significantly, while having only a weak effect on adherent breast cancer cells. Our results suggest that triphenylphosphonium-functionalized drug delivery systems that contain encapsulated KU, or compounds with a similar impact, are a useful addition to chemotherapeutic treatment schemes that target proliferating cancers.

Novel Anti-Cancer Products Targeting AMPK: Natural Herbal Medicine against Breast Cancer

Breast cancer is a common cancer in women worldwide. The existing clinical treatment strategies have been able to limit the progression of breast cancer and cancer metastasis, but abnormal metabolism, immunosuppression, and multidrug resistance involving multiple regulators remain the major challenges for the treatment of breast cancer. Adenosine 5'-monophosphate (AMP)-Activated Protein Kinase (AMPK) can regulate metabolic reprogramming and reverse the "Warburg effect" via multiple metabolic signaling pathways in breast cancer. Previous studies suggest that the activation of AMPK suppresses the growth and metastasis of breast cancer cells, as well as stimulating the responses of immune cells. However, some other reports claim that the development and poor prognosis of breast cancer are related to the overexpression and aberrant activation of AMPK. Thus, the role of AMPK in the progression of breast cancer is still controversial. In this review, we summarize the current understanding of AMPK, particularly the comprehensive bidirectional functions of AMPK in cancer progression; discuss the pharmacological activators of AMPK and some specific molecules, including the natural products (including berberine, curcumin, (-)-epigallocatechin-3-gallate, ginsenosides, and paclitaxel) that influence the efficacy of these activators in cancer therapy; and elaborate the role of AMPK as a potential therapeutic target for the treatment of breast cancer.

Selenium Yeast and Fish Oil Combination Diminishes Cancer Stem Cell Traits and Reverses Cisplatin Resistance in A549 Sphere Cells

Cisplatin is a prevalent chemotherapeutic agent used for non-small cell lung cancer (NSCLC) that is difficult to treat by targeted therapy, but the emergence of resistance severely limits its efficacy. Thus, an effective strategy to combat cisplatin resistance is required. This study demonstrated that, at clinically achievable concentrations, the combination of selenium yeast (Se-Y) and fish oil (FO) could synergistically induce the apoptosis of cancer stem cell (CSC)-like A549 NSCLC sphere cells, accompanied by a reversal of their resistance to cisplatin. Compared to parental A549 cells, sphere cells have higher cisplatin resistance and possess elevated CSC markers (CD133 and ABCG2), epithelial-mesenchymal transition markers (anexelekto (AXL), vimentin, and N-cadherin), and cytoprotective endoplasmic reticulum (ER) stress marker (glucose-regulated protein 78) and increased oncogenic drivers, such as yes-associated protein, transcriptional coactivator with PDZ-binding motif, β-catenin, and cyclooxygenase-2. In contrast, the proapoptotic ER stress marker CCAAT/enhancer-binding protein homologous protein and AMP-activated protein kinase (AMPK) activity were reduced in sphere cells. The Se-Y and FO combination synergistically counteracted the above molecular features of A549 sphere cells and diminished their elevated CSC-like side population. AMPK inhibition by compound C restored the side population proportion diminished by this nutrient combination. The results suggest that the Se-Y and FO combination can potentially improve the outcome of cisplatin-treated NSCLC with phenotypes such as A549 cells.