Dual inhibition of Akt and ERK signaling induces cell senescence in triple-negative breast cancer

BI-2865, a pan-KRAS inhibitor, reverses the P-glycoprotein induced multidrug resistance in vitro and in vivo

BACKGROUND

Multidrug resistance (MDR) limits successful cancer chemotherapy. P-glycoprotein (P-gp), BCRP and MRP1 are the key triggers of MDR. Unfortunately, no MDR modulator was approved by FDA to date. Here, we will investigate the effect of BI-2865, a pan-KRAS inhibitor, on reversing MDR induced by P-gp, BCRP and MRP1 in vitro and in vivo, and its reversal mechanisms will be explored.

METHODS

The cytotoxicity of BI-2865 and its MDR removal effect in vitro were tested by MTT assays, and the corresponding reversal function in vivo was assessed through the P-gp mediated KBv200 xenografts in mice. BI-2865 induced alterations of drug discharge and reservation in cells were estimated by experiments of Flow cytometry with fluorescent doxorubicin, and the chemo-drug accumulation in xenografts' tumor were analyzed through LC-MS. Mechanisms of BI-2865 inhibiting P-gp substrate's efflux were analyzed through the vanadate-sensitive ATPase assay, [125I]-IAAP-photolabeling assay and computer molecular docking. The effects of BI-2865 on P-gp expression and KRAS-downstream signaling were detected via Western blotting, Flow cytometry and/or qRT-PCR. Subcellular localization of P-gp was visualized by Immunofluorescence.

RESULTS

We found BI-2865 notably fortified response of P-gp-driven MDR cancer cells to the administration of chemo-drugs including paclitaxel, vincristine and doxorubicin, while such an effect was not observed in their parental sensitive cells and BCRP or MRP1-driven MDR cells. Importantly, the mice vivo combination study has verified that BI-2865 effectively improved the anti-tumor action of paclitaxel without toxic injury. In mechanism, BI-2865 prompted doxorubicin accumulating in carcinoma cells by directly blocking the efflux function of P-gp, which more specifically, was achieved by BI-2865 competitively binding to the drug-binding sites of P-gp. What's more, at the effective MDR reversal concentrations, BI-2865 neither varied the expression and location of P-gp nor reduced its downstream AKT or ERK1/2 signaling activity.

CONCLUSIONS

This study uncovered a new application of BI-2865 as a MDR modulator, which might be used to effectively, safely and specifically improve chemotherapeutic efficacy in the clinical P-gp mediated MDR refractory cancers.

Natural bioactive compounds and FOXO3a in cancer therapeutics: An update

Forkhead box protein 3a (FOXO3a) is a transcription factor that regulates various downstream targets upon its activation, leading to the upregulation of tumor suppressor and apoptotic pathways. Hence, targeting FOXO3a is an emerging strategy for cancer prevention and treatment. Recently, Natural Bioactive Compounds (NBCs) have been used in drug discovery for treating various disorders including cancer. Notably, several NBCs have been shown as potent FOXO3a activators. NBCs upregulate FOXO3a expressions through PI3K/Akt, MEK/ERK, AMPK, and IκB signaling pathways. FOXO3a promotes its anticancer effects by upregulating the levels of its downstream targets, including Bim, FasL, and Bax, leading to apoptosis. This review focuses on the dysregulation of FOXO3a in carcinogenesis and explores the potent FOXO3a activating NBCs for cancer prevention and treatment. Additionally, the review evaluates the safety and efficacy of NBCs. Looking ahead, NBCs are anticipated to become a cost-effective, potent, and safer therapeutic option for cancer, making them a focal point of research in the field of cancer prevention and treatment.

Lactic acid promotes nucleus pulposus cell senescence and corresponding intervertebral disc degeneration via interacting with Akt

The accumulation of metabolites in the intervertebral disc is considered an important cause of intervertebral disc degeneration (IVDD). Lactic acid, which is a metabolite that is produced by cellular anaerobic glycolysis, has been proven to be closely associated with IVDD. However, little is known about the role of lactic acid in nucleus pulposus cells (NPCs) senescence and oxidative stress. The aim of this study was to investigate the effect of lactic acid on NPCs senescence and oxidative stress as well as the underlying mechanism. A puncture-induced disc degeneration (PIDD) model was established in rats. Metabolomics analysis revealed that lactic acid levels were significantly increased in degenerated intervertebral discs. Elimination of excessive lactic acid using a lactate oxidase (LOx)-overexpressing lentivirus alleviated the progression of IVDD. In vitro experiments showed that high concentrations of lactic acid could induce senescence and oxidative stress in NPCs. High-throughput RNA sequencing results and bioinformatic analysis demonstrated that the induction of NPCs senescence and oxidative stress by lactic acid may be related to the PI3K/Akt signaling pathway. Further study verified that high concentrations of lactic acid could induce NPCs senescence and oxidative stress by interacting with Akt and regulating its downstream Akt/p21/p27/cyclin D1 and Akt/Nrf2/HO-1 pathways. Utilizing molecular docking, site-directed mutation and microscale thermophoresis assays, we found that lactic acid could regulate Akt kinase activity by binding to the Lys39 and Leu52 residues in the PH domain of Akt. These results highlight the involvement of lactic acid in NPCs senescence and oxidative stress, and lactic acid may become a novel potential therapeutic target for the treatment of IVDD.

SHOC2 mediates the drug-resistance of triple-negative breast cancer cells to everolimus

Aberrant activation of the mTOR pathway is a characteristic alteration in triple-negative breast cancer, but the mTOR pathway inhibitor everolimus is not effective for the triple-negative breast cancer (TNBC) patients. Presently, we showed that the activation of ERK pathway was an important mechanism of resistance to everolimus in TNBC cells in this study. SHOC2, a key protein mediating the Ras-Raf-ERK pathway, could act as a scaffolding protein to facilitate the activation of the pathway by mediating the interaction of key components of the pathway. Our results showed that everolimus activated the Raf-ERK pathway by promoting the interaction between SHOC2 and c-Raf and that knockdown of SHOC2 significantly inhibited the Raf-ERK pathway induced by everolimus. We further demonstrated that SHOC2 expression levels were closely related to the sensitivity of TNBC cells to everolimus and that interference with SHOC2 expression in combination with everolimus had significant effects on the cell cycle progression and apoptosis in vitro experiments. Western blotting analysis showed that cell cycle regulators and apoptosis-related proteins were significantly altered by the combination treatment. Xenograft model also demonstrated that knockdown of SHOC2 significantly increased the sensitivity of tumor to everolimus in nude mice. In conclusion, our study showed that SHOC2 is a key factor in regulating the sensitivity of TNBC cells to everolimus and that combined therapy may be a more effective therapeutic approach for TNBC patients.

Intratumoral injection of norcantharidin liposome emulsion hybrid delivery system amplifies the cancer-fighting effects of oral sorafenib against hepatocellular carcinoma

Interventional therapies are increasingly used in clinical trials for hepatocellular carcinoma (HCC). Sorafenib is the front-line remedy for HCC, however, chemoresistance occurs immutably and affects the effectiveness of treatment. In a previous study, a norcantharidin liposome emulsion hybrid (NLEH) delivery system for HCC was developed. This study aims to examine the therapeutic effects of the combination of intratumoral injection of NLEH and sorafenib in treating HCC. Sorafenib combined with NLEH activated the apoptosis pathway by synergistically upregulating caspase-9, promoting cytotoxicity, apoptosis (64.57%), and G2/M cell cycle arrest (48.96%). Norcantharidin could alleviate sorafenib resistance by counteracting sorafenib-induced phosphorylation of Akt. Additionally, intratumoral injection of NLEH exhibited a sustained accumulation in the tumor within 24 h and didn't distribute to other major organs. Intratumoral injection of NLEH in combination with oral sorafenib displayed the most potent tumor growth inhibitory effect (77.91%) in vivo. H&E staining results and the indicators of the renal and liver function tests demonstrated the safety of this combination therapy. Overall, these results showed that intratumoral injection of NLEH in combination with oral sorafenib treatment represented a rational potential therapeutic option for HCC.

Quinoxalinone substituted pyrrolizine (4h)-induced dual inhibition of AKT and ERK instigates apoptosis in breast and colorectal cancer by modulating mitochondrial membrane potential

AKT and ERK 1/2 play a pivotal role in cancer cell survival, proliferation, migration, and angiogenesis. Therefore, AKT and ERK 1/2 are considered crucial targets for cancer intervention. In this study, we envisaged the role of AKT and ERK signaling in apoptosis regulation in presence of compound 4h, a novel synthetic derivative of quinoxalinone substituted spiropyrrolizines exhibiting substantial antiproliferative activity in various cancer cell lines. Structurally 4h is a spiropyrrolizine derivative. Molecular docking analysis revealed that compound 4h shows strong binding affinity with AKT-1 (-9.5 kcal/mol) and ERK2 (-9.0 kcal/mol) via binding at allosteric sites of AKT and active site of ERK2. The implications of 4h binding with these two survival kinases resulted in the obstruction for ATP binding, hence, hampering their phosphorylation dependent activation. We demonstrate that 4h mediated apoptotic induction via disruption in the mitochondrial membrane potential of MCF-7 and HCT-116 cells and 4h-mediated inhibition of survival pathways occurred in a wild type PTEN background and is diminished in PTEN-/- cells. In 4T1 mammary carcinoma model, 4h exhibited pronounced reduction in the tumor size and tumor volume at significantly low doses. Besides, 4h reached the highest plasma concentration of 5.8 μM within a period of 1 h in mice model intraperitoneally. Furthermore, 4h showed acceptable clearance with an adequate elimination half-life and satisfactory pharmacokinetic behaviour, thus proclaiming as a potential lead molecule against breast and colorectal cancer by specifically inhibiting simultaneously AKT and ERK1/2 kinases.

10-Gingerol Enhances the Effect of Taxol in Triple-Negative Breast Cancer via Targeting ADRB2 Signaling

Purpose

Although paclitaxel is widely used in cancer treatment, severe side effects and drug resistance limit its clinical use. 10-gingerol (10-G) is a natural compound isolated from ginger, which displays anti-inflammatory, antioxidant, and antiproliferative properties. However, the chemotherapy-sensitization effect of 10-G on triple-negative breast cancer (TNBC) has not been fully clarified. This study is aimed at investigating the effect of 10-G on the paclitaxel sensitivity in TNBC, and its underlying mechanism.

Methods

The study was determined through in vitro and in vivo experiments. Cell viability and proliferation were detected by cell counting kit 8 (CCK-8) and colony formation. To detect cell apoptosis, flow cytometry and TUNEL were used. The expression of proteins was detected by Western blotting and immunohistochemistry. The molecular docking and gene knockout were corroborated by interactions between 10-G and adrenoceptor Beta 2 (ADRB2). The body weight of mice, histopathology and organs (kidney and spleen) coefficients were used to monitor the drug toxicities.

Results

In vitro, 10-G increased the sensitivity of TNBC cells to paclitaxel, and could synergistically promote the apoptosis of TNBC cells induced by paclitaxel. In combination with molecular docking and lentivirus knockdown studies, ADRB2 was identified as a 10-G binding protein. 10-G inhibited ADRB2 by binding to the active site of ADRB2. Knockdown of ADRB2 reduces the proliferation activity of TNBC cells but also attenuates the sensitizing effects of 10-G to paclitaxel. Western blotting and immunohistochemistry showed that 10-G played an anti-proliferation and chemotherapy-sensitizing role by inhibiting the ADRB2/ERK signal. Toxicity evaluation showed that 10-G would not increase hepatorenal toxicity with paclitaxel.

Conclusion

This data suggests that 10-G may be used as a new chemotherapeutic synergist in combination with paclitaxel to enhance anticancer activity. The potential value of ADRB2 as a target for improving chemotherapy sensitivity was also emphasized.

Review targeted drug delivery systems for norcantharidin in cancer therapy

Norcantharidin (NCTD) is a demethylated derivative of cantharidin (CTD), the main anticancer active ingredient isolated from traditional Chinese medicine Mylabris. NCTD has been approved by the State Food and Drug Administration for the treatment of various solid tumors, especially liver cancer. Although NCTD greatly reduces the toxicity of CTD, there is still a certain degree of urinary toxicity and organ toxicity, and the poor solubility, short half-life, fast metabolism, as well as high venous irritation and weak tumor targeting ability limit its widespread application in the clinic. To reduce its toxicity and improve its efficacy, design of targeted drug delivery systems based on biomaterials and nanomaterials is one of the most feasible strategies. Therefore, this review focused on the studies of targeted drug delivery systems combined with NCTD in recent years, including passive and active targeted drug delivery systems, and physicochemical targeted drug delivery systems for improving drug bioavailability and enhancing its efficacy, as well as increasing drug targeting ability and reducing its adverse effects.

Graphical Abstract

Norbornene and Related Structures as Scaffolds in the Search for New Cancer Treatments

The norbornene scaffold has arisen as a promising structure in medicinal chemistry due to its possible therapeutic application in cancer treatment. The development of norbornene-based derivatives as potential chemotherapeutic agents is attracting significant attention. Here, we report an unprecedented review on the recent advances of investigations into the antitumoral efficacy of different compounds, including the abovementioned bicyclic scaffold in their structure, in combination with chemotherapeutic agents or forming metal complexes. The impact that structural modifications to these bicyclic compounds have on the antitumoral properties and the mechanisms by which these norbornene derivatives act are discussed in this review. In addition, the use of norbornene, and its related compounds, encapsulation in nanosystems for its use in cancer therapies is here detailed.

FAM83A promotes the progression and metastasis of human pancreatic neuroendocrine tumors by inducing the epithelial-mesenchymal transition via the PI3K/AKT and ERK pathways

PURPOSE

Family with sequence similarity 83, member A (FAM83A) has been reported to play an important role in cancer progression and metastasis. The purpose of this study was to clarify the role and mechanism of FAM83A in pancreatic neuroendocrine tumors (PanNETs).

METHODS

PanNET specimens and adjacent nontumor pancreatic tissues obtained from 68 patients who underwent curative surgery for PanNETs were assessed for FAM83A expression using immunochemical staining. The relationships between FAM83A expression, clinicopathological parameters and prognosis were statistically analyzed. PanNET cell lines were used to study the role of FAM83A in the progression and metastasis of PanNETs in vitro and in vivo.

RESULTS

FAM83A was overexpressed in PanNET specimens compared with adjacent nontumor tissues. Furthermore, FAM83A expression was closely associated with lymph node metastasis (P = 0.02), perineural invasion (P = 0.001), WHO classification (P = 0.039), AJCC stage (P = 0.01) and shorter disease-free survival in patients with PanNETs (P < 0.001). FAM83A overexpression effectively promoted PanNET cell proliferation, migration, invasion and growth both in vitro and in vivo, whereas FAM83A inhibition exerted the opposite effects. Subsequent mechanistic investigations revealed that FAM83A promotes the progression and metastasis of PanNETs by inducing epithelial-mesenchymal transition (EMT) via the PI3K/AKT and ERK pathways.

CONCLUSIONS

FAM83A plays an important role in the progression and metastasis of PanNET by inducing the EMT via the activation of the ERK and PI3K/AKT pathways and may serve as a valuable molecular target in PanNET treatment.

Adagrasib, a KRAS G12C inhibitor, reverses the multidrug resistance mediated by ABCB1 in vitro and in vivo

Background

Multidrug resistance (MDR) is a complex phenomenon that frequently leads to chemotherapy failure during cancer treatment. The overexpression of ATP-binding cassette (ABC) transporters represents the major mechanism contributing to MDR. To date, no effective MDR modulator has been applied in clinic. Adagrasib (MRTX849), a specific inhibitor targeting KRAS G12C mutant, is currently under investigation in clinical trials for the treatment of non-small cell lung cancer (NSCLC). This study focused on investigating the circumvention of MDR by MRTX849.

Methods

The cytotoxicity and MDR reversal effect of MRTX849 were assessed by MTT assay. Drug accumulation and drug efflux were evaluated by flow cytometry. The MDR reversal by MRTX849 in vivo was investigated in two ABCB1-overexpressing tumor xenograft models in nude mice. The interaction between MRTX849 and ABCB1 substrate binding sites was studied by the [125I]-IAAP-photoaffinity labeling assay. The vanadate-sensitive ATPase assay was performed to identify whether MRTX849 would change ABCB1 ATPase activity. The effect of MRTX849 on expression of ABCB1 and PI3K/AKT signaling molecules was examined by flow cytometry, Western blot and Quantitative Real-time PCR analyses.

Results

MRTX849 was shown to enhance the anticancer efficacy of ABCB1 substrate drugs in the transporter-overexpressing cells both in vitro and in vivo. The MDR reversal effect was specific against ABCB1 because no similar effect was observed in the parental sensitive cells or in ABCG2-mediated MDR cells. Mechanistically, MRTX849 increased the cellular accumulation of ABCB1 substrates including doxorubicin (Dox) and rhodamine 123 (Rho123) in ABCB1-overexpressing MDR cells by suppressing ABCB1 efflux activity. Additionally, MRTX849 stimulated ABCB1 ATPase activity and competed with [125I]-IAAP for photolabeling of ABCB1 in a concentration-dependent manner. However, MRTX849 did not alter ABCB1 expression or phosphorylation of AKT/ERK at the effective MDR reversal drug concentrations.

Conclusions

In summary, MRTX849 was found to overcome ABCB1-mediated MDR both in vitro and in vivo by specifically attenuating ABCB1 efflux activity in drug-resistant cancer cells. Further studies are warranted to translate the combination of MRTX849 and conventional chemotherapy to clinical application for circumvention of MDR.

Cromolyn chitosan nanoparticles reverse the DNA methylation of RASSF1A and p16 genes and mitigate DNMT1 and METTL3 expression in breast cancer cell line and tumor xenograft model in mice

BACKGROUND

Developing epigenetic drugs for breast cancer (BC) remains a novel therapeutic approach. Cromolyn is a mast cell stabilizer emerging as an anticancer drug; its encapsulation in chitosan nanoparticles (CSNPs) improves its effect and bioavailability. However, its effect on DNA and RNA methylation machineries has not been previously tackled.

METHODS

The possible anticancer effect of cromolyn CSNPs and its potential as an epigenetic drug was investigated in vitro using MCF-7 human BC cell line and in vivo using Ehrlich ascites carcinoma-xenograft model in mice symbolizing murine mammary adenocarcinoma. Mice were injected with a single dose of Ehrlich ascites carcinoma cells subcutaneously for the induction of tumor mass, and then randomized into three groups: control, cromolyn CSNPs (equivalent to 5 mg cromolyn/kg, i.p.) and plain CSNPs twice/week for 2 weeks.

RESULTS

Cromolyn CSNPs showed prominent anticancer effect in MCF-7 cells by reducing the cell viability percent and enhancing DNA damage in the comet assay demonstrating its apoptotic actions. Mechanistically, cromolyn CSNPs influenced potential epigenetic processes through mitigating DNA methyltransferase 1 (DNMT1) expression, reversing the hypermethylation pattern of the tumor suppressor RASSF1A and p16 genes and attenuating the expression of the RNA N⁶-methyladenosine writer, methyltransferase-like 3 (METTL3). Cromolyn CSNPs diminished ERK1/2 phosphorylation, a possible arm influencing DNMT1 expression. In vivo, cromolyn CSNPs lessened the tumor volume and halted DNMT1 and METTL3 expression in Ehrlich carcinoma mice.

CONCLUSIONS

Cromolyn CSNPs have the premise as an epigenetic drug through inhibiting ERK1/2 phosphorylation/DNMT1/DNA methylation and possibly impacting the RNA methylation machinery via mitigating METTL3 expression.

Bioactive constituents of animal-derived traditional Chinese medicinal materials for breast cancer: opportunities and challenges

Breast cancer is globally the most common invasive cancer in women and remains one of the leading causes of cancer-related deaths. Surgery, radiotherapy, chemotherapy, immunotherapy, and endocrine therapy are currently the main treatments for this cancer type. However, some breast cancer patients are prone to drug resistance related to chemotherapy or immunotherapy, resulting in limited treatment efficacy. Consequently, traditional Chinese medicinal materials (TCMMs) as natural products have become an attractive source of novel drugs. In this review, we summarized the current knowledge on the active components of animal-derived TCMMs, including Ophiocordycepssinensis-derived cordycepin, the aqueous and ethanolic extracts of O.sinensis, norcantharidin (NCTD), Chansu, bee venom, deer antlers, Ostreagigas, and scorpion venom, with reference to marked anti-breast cancer effects due to regulating cell cycle arrest, proliferation, apoptosis, metastasis, and drug resistance. In future studies, the underlying mechanisms for the antitumor effects of these components need to be further investigated by utilizing multi-omics technologies. Furthermore, large-scale clinical trials are necessary to validate the efficacy of bioactive constituents alone or in combination with chemotherapeutic drugs for breast cancer treatment.

Blocking STAT3 signaling augments MEK/ERK inhibitor efficacy in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the world's leading causes of death, and its primary clinical therapy relies on surgical resection, chemotherapy, radiotherapy, and chemoradiotherapy. Although the genomic features and clinical significance of ESCC have been identified, the outcomes of targeted therapies are still unsatisfactory. Here, we demonstrate that mitogen-activated protein kinase (MAPK) signaling is highly activated and associated with poor prognosis in patients with ESCC. Mitogen-activated protein kinase kinase (MEK) inhibitors efficiently blocked the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) in ESCC, while signal transducer and activator of transcription 3 (STAT3) signaling was rapidly activated. Combined STAT3 inhibition prevented the emergence of resistance and enhanced MEK inhibitor-induced cell cycle arrest and senescence in vitro and in vivo. Mechanistic studies revealed that the suppressor of cytokine signaling 3 (SOCS3) was downregulated, resulting in an increase in STAT3 phosphorylation in MEK-inhibited cells. Furthermore, chromatin immunoprecipitation showed that ELK1, which was activated by MEK/ERK signaling, induced SOCS3 transcription. These data suggest that the development of combined MEK and STAT3 inhibition could be a useful strategy in ESCC targeted therapy.

Rapamycin and trametinib: a rational combination for treatment of NSCLC

Mammalian target of rapamycin (mTOR) is one of the most commonly activated pathways in human cancers, including lung cancer. Targeting mTOR with molecule inhibitors is considered as a useful therapeutic strategy. However, the results obtained from the clinical trials with the inhibitors so far have not met the original expectations, largely because of the drug resistance. Thus, combined or multiple drug therapy can bring about more favorable clinical outcomes. Here, we found that activation of ERK pathway was responsible for rapamycin drug resistance in non-small-cell lung cancer (NSCLC) cells. Accordingly, rapamycin-resistant NSCLC cells were more sensitive to ERK inhibitor (ERKi), trametinib, and in turn, trametinib-resistant NSCLC cells were also susceptible to rapamycin. Combining rapamycin with trametinib led to a potent synergistic antitumor efficacy, which induced G1-phase cycle arrest and apoptosis. In addition, rapamycin synergized with another ERKi, MEK162, and in turn, trametinib synergized with other mTORi, Torin1 and OSI-027. Mechanistically, rapamycin in combination with trametinib resulted in a greater decrease of phosphorylation of AKT, ERK, mTOR and 4EBP1. In xenograft mouse model, co-administration of rapamycin and trametinib caused a substantial suppression in tumor growth without obvious drug toxicity. Overall, our study identifies a reasonable combined strategy for treatment of NSCLC.

Discovery of 8,9-seco-ent-Kaurane Diterpenoids as Potential Leads for the Treatment of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is a lethal malignancy without safe and effective therapeutic drugs. In this study, the anti-TNBC bioassay-guided isolation of the medicinal plant Croton kongensis followed by the structural modification led to the construction of a small ent-kaurane diterpenoid library (1-25). With subsequent biological screening, 20 highly potent compounds (IC₅₀s < 3 μM) were identified. Among them, 8,9-seco-ent-kaurane 6 displayed comparable activity (IC₅₀s ∼ 80 nM) to doxorubicin but with better selectivity. The analysis of structure-activity relationships suggested that the cleavage of the C8-C9 bond and the presence of α,β-unsaturated ketone moiety were essential for the activity. The mechanistic study revealed that 6 induced apoptosis, autophagy, and metastasis suppression in TNBC cells via inhibition of Akt. In vivo, 6 significantly suppressed the TNBC tumor growth without causing side effects. All these results suggested that 6 may serve as a promising lead for the development of novel anti-TNBC agents in the future.

Combination Treatment With Inhibitors of ERK and Autophagy Enhances Antitumor Activity of Betulinic Acid in Non-small-Cell Lung Cancer In Vivo and In Vitro

Aberrant activation of the Ras-ERK signaling pathway drives many important cancer phenotypes, and several inhibitors targeting such pathways are under investigation and/or approved by the FDA as single- or multi-agent therapy for patients with melanoma and non-small-cell lung cancer (NSCLC). Here, we show that betulinic acid (BA), a natural pentacyclic triterpenoid, inhibits cell proliferation, and induces apoptosis and protective autophagy in NSCLC cells. Thus, the cancer cell killing activity of BA is enhanced by autophagy inhibition. Mitogen-activated protein kinases, and especially ERK that facilitates cancer cell survival, are also activated by BA treatment. As such, in the presence of ERK inhibitors (ERKi), lung cancer cells are much more sensitive to BA. However, the dual treatment of BA and ERKi results in increased protective autophagy and AKT phosphorylation. Accordingly, inhibition of AKT has a highly synergistic anticancer effect with co-treatment of BA and ERKi. Notably, autophagy inhibition by hydroxychloroquine (HCQ) increases the response of lung cancer cells to BA in combination with ERKi. In vivo, the three-drug combination (BA, ERKi, and HCQ), resulted in superior therapeutic efficacy than single or dual treatments in the xenograft mouse model. Thus, our study provides a combined therapy strategy that is a highly effective treatment for patients with NSCLC.

B7-H3 suppresses doxorubicin-induced senescence-like growth arrest in colorectal cancer through the AKT/TM4SF1/SIRT1 pathway

Emerging evidence suggests that cellular senescence induced by chemotherapy has been recognized as a new weapon for cancer therapy. This study aimed to research novel functions of B7-H3 in cellular senescence induced by a low dose of doxorubicin (DOX) in colorectal cancer (CRC). Here, our results demonstrated that B7-H3 knockdown promoted, while B7-H3 overexpression inhibited, DOX-induced cellular senescence. B7-H3 knockdown dramatically enhanced the growth arrest of CRC cells after low-dose DOX treatment, but B7-H3 overexpression had the opposite effect. By RNA-seq analysis and western blot, we showed that B7-H3 prevented cellular senescence and growth arrest through the AKT/TM4SF1/SIRT1 pathway. Blocking the AKT/TM4SF1/SIRT1 pathway dramatically reversed B7-H3-induced resistance to cellular senescence. More importantly, B7-H3 inhibited DOX-induced cellular senescence of CRC cells in vivo. Therefore, targeting B7-H3 or the B7-H3/AKT/TM4SF1/SIRT1 pathway might be a new strategy for promoting cellular senescence-like growth arrest during drug treatment in CRC.

Possibility of inducing tumor cell senescence during therapy

The treatment options for cancer include surgery, radiotherapy and chemotherapy. However, the traditional approach of high-dose chemotherapy brings tremendous toxic side effects to patients, as well as potentially causing drug resistance. Drug resistance affects cell proliferation, cell senescence and apoptosis. Cellular senescence refers to the process in which cells change from an active proliferative status to a growth-arrested status. There are multiple factors that regulate this process and cellular senescence is activated by various pathways. Senescent cells present specific characteristics, such as an increased cell volume, flattened cell body morphology, ceased cell division and the expression of β-galactosidase. Tumor senescence can be categorized into replicative senescence and premature senescence. Cellular senescence may inhibit the occurrence and development of tumors, serving as an innovative strategy for the treatment of cancer. The present review mainly focuses on senescent biomarkers, methods for the induction of cellular senescence and its possible application in the treatment of cancer.

Antitumor Effects of a Sesquiterpene Derivative from Marine Sponge in Human Breast Cancer Cells

In this study, the anti-proliferative effect of ilimaquinone, a sesquiterpene derivative from the marine sponge, in breast cancer cells was investigated. Ilimaquinone inhibited the proliferation of MCF-7 and MDA-MB-231 breast cancer cells with IC₅₀ values of 10.6 μM and 13.5 μM, respectively. Non-tumorigenic human breast epithelial cells were less sensitive to ilimaquinone than breast cancer cells. Flow cytometric and Western blot analysis showed that ilimaquinone induced S-phase arrest by modulating the expression of p-CDC-2 and p21. Ilimaquinone induces apoptosis, which is accompanied by multiple biological biomarkers, including the downregulation of Akt, ERK, and Bax, upregulation of p38, loss of mitochondrial membrane potential, increased reactive oxygen species generation, and induced autophagy. Collectively, these findings suggest that ilimaquinone causes cell cycle arrest as well as induces apoptosis and autophagy in breast cancer cells.

Small-Molecule Drug Discovery in Triple Negative Breast Cancer: Current Situation and Future Directions

Triple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, but an effective targeted therapy has not been well-established so far. Considering the lack of effective targets, where do we go next in the current TNBC drug development? A promising intervention for TNBC might lie in de novo small-molecule drugs that precisely target different molecular characteristics of TNBC. However, an ideal single-target drug discovery still faces a huge challenge. Alternatively, other new emerging strategies, such as dual-target drug, drug repurposing, and combination strategies, may provide new insight into the improvement of TNBC therapeutics. In this review, we focus on summarizing the current situation of a series of candidate small-molecule drugs in TNBC therapy, including single-target drugs, dual-target drugs, as well as drug repurposing and combination strategies that will together shed new light on the future directions targeting TNBC vulnerabilities with small-molecule drugs for future therapeutic purposes.

Thioridazine hydrochloride: an antipsychotic agent that inhibits tumor growth and lung metastasis in triple-negative breast cancer via inducing G0/G1 arrest and apoptosis

ABBREVIATIONS

CCK8: Cell Counting Kit-8; CDK: cyclin-dependent kinase; DRD2: dopamine D2 receptor; ERK1/2: extracellular signal-regulated kinase 1/2; GAPDH: glyceraldehyde 3-phosphate dehydrogenase; H&E: hematoxylin and eosin; MMP: membrane potential; NAC: N-acetyl-L-cysteine; PI: Propidium iodide; Rh123: rhodamine-123; ROS: reactive oxygen species; TBST: tris-buffered saline containing 0.1% Tween 20 TNBC: Triple-negative breast cancer; Thi-hyd: Thioridazine hydrochloride.

Senescence and adiponectin signaling - Studies in canine testis

BACKGROUND

The meaning of senescence for tissue physiological and pathological conditions is poorly known. Based on initial reports especially proteins and mechanisms that regulate this process are necessary to be determinate.

METHODS

The main aim of the study was to investigate the presence of senescent cells in canine testicular tissue (mixed breed testes; n = 60) in relation to adiponectin signaling. In detail, new information on the senescence cell number, as well as senescence and adiponectin signaling mechanisms in cryptorchid and germ cell tumor testes were provided with the use of immunohistochemical and colorimetric analyses.

RESULTS

Comparison of immunohistochemical results, in cryptorchid and tumor testes revealed increased number of senescent cells (p16 and γH2AX markers). Increased expression of adiponectin and adiponectin receptor 1, as well as extracellular signal-activated kinase (ERK1/2) in pathological testes were detected. In addition, decreased cholesterol and increased testosterone levels in tumor testis were found.

CONCLUSION

The present study is the first to demonstrate the presence as well as the differences that exist in senecent cell number in mixed breed dog testes with cryptorchidism and germ cell tumor. Altered expression of adiponectin signaling and ERK1/2 signaling pathways together with altered cholesterol and testosterone levels reflect important senescence role in disturbed functions of canine testis. Moreover, the application of studied here senescence regulating molecules for detection and prevention against pathologies of the male gonad should be furtherly considered.

The Premature Senescence in Breast Cancer Treatment Strategy

Cellular senescence is a permanent blockade of cell proliferation. In response to therapy-induced stress, cancer cells undergo apoptosis or premature senescence. In apoptosis-resistant cancer cells or at lower doses of anticancer drugs, therapy-induced stress leads to premature senescence. The role of this senescence in cancer treatment is discussable. First of all, the senescent cells lose the ability to proliferate, migrate, and invade. In addition, the senescent cells secrete a set of proteins (inflammatory cytokines, chemokines, growth factors) known as the senescence-associated secretory phenotype (SASP), which influences non-senescent normal cells and non-senescent cancer cells in the tumor microenvironment and triggers tumor promotion and recurrence. Recently, many studies have examined senescence induction through breast cancer therapy and potentially using this phenomenon to treat this cancer. This review summarizes the recent in vitro, in vivo, and clinical studies investigating senescence in breast cancer treatments. Senescence inductors, senolytics, as well as their action mechanism are discussed herein. Potential SASP-modulating treatment strategies are also described.

A novel 4-aminoquinazoline derivative, DHW-208, suppresses the growth of human breast cancer cells by targeting the PI3K/AKT/mTOR pathway

Breast cancer is one of the most frequent cancers among women worldwide. However, there is still no effective therapeutic strategy for advanced breast cancer that has metastasized. Aberrant activation of the PI3K/AKT/mTOR pathway is an essential step for the growth of human breast cancers. In our previous study, we designed and synthesized DHW-208 (2,4-difluoro-N-(5-(4-((1-(2-hydroxyethyl)-1H-pyrazol-4-yl)amino)quinazolin-6-yl)-2-methoxypyridin-3-yl)benzenesulfonamide) as a novel pan-PI3K inhibitor. This study aimed to assess the therapeutic efficacy of DHW-208 in breast cancer and investigate its underlying mechanism. We found that DHW-208 inhibited the growth, proliferation, migration, and invasion of breast cancer cells. Moreover, DHW-208 induced breast cancer cell apoptosis via the mitochondrial pathway and induced G0/G1 cell-cycle arrest. In vitro results show that DHW-208 is a dual inhibitor of PI3K and mTOR, and suppress the growth of human breast cancer cells by targeting the PI3K/AKT/mTOR pathway. Consistent with the in vitro results, in vivo studies demonstrated that DHW-208 elicits an antitumor effect by inhibiting the PI3K/AKT/mTOR-signaling pathway with a high degree of safety in breast cancer. Above all, we report for the first time that DHW-208 suppressed the growth of human breast cancer cells by inhibiting the PI3K/AKT/mTOR-signaling pathway both in vivo and in vitro. Our study may provide evidence for the use of DHW-208 as an effective, novel therapeutic candidate for the treatment of human breast cancers in clinical trials.

Insight into norcantharidin, a small-molecule synthetic compound with potential multi-target anticancer activities

Norcantharidin (NCTD) is a demethylated derivative of cantharidin, which is an anticancer active ingredient of traditional Chinese medicine, and is currently used clinically as a routine anti-cancer drug in China. Clarifying the anticancer effect and molecular mechanism of NCTD is critical for its clinical application. Here, we summarized the physiological, chemical, pharmacokinetic characteristics and clinical applications of NCTD. Besides, we mainly focus on its potential multi-target anticancer activities and underlying mechanisms, and discuss the problems existing in clinical application and scientific research of NCTD, so as to provide a potential anticancer therapeutic agent for human malignant tumors.

Strontium/Chitosan/Hydroxyapatite/Norcantharidin Composite That Inhibits Osteosarcoma and Promotes Osteogenesis In Vitro

Hydroxyapatite can deliver drugs, and its composite material is capable of repairing bone defects in tumors. This study was conducted to evaluate the effect of composite materials on tumor growth inhibition and bone growth induction. Composites containing drug delivery compounds were synthesized by coprecipitation and freeze-drying and then characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). In addition, the effect of hydroxyapatite nanoparticles (nano-SHAP) on proliferation of an osteosarcoma cell line (MG-63) and an osteoblast cell line (MC3T3-E1) was evaluated, and its mechanism was studied. The use of nano-SHAP alone did not affect the proliferation of normal cell lines. However, nanoparticles containing different amounts of norcantharidin in the composite materials and had different inhibitory effects on osteosarcoma and different effects on osteoblasts. And, with the increase of the content of norcantharidin, the antitumor performance of the composite has been enhanced. In summary, the nano-SHAP system developed in this study is a drug delivery material that can inhibit the growth of tumors and induce the proliferation of osteoblasts.

Dual Inhibition of Pirarubicin-Induced AKT and ERK Activations by Phenformin Sensitively Suppresses Bladder Cancer Growth

Activations of Akt or ERK pathway induced by clinical drugs promote therapeutic failure due to decrease of drug response, and no available strategies have been developed to solve these problems. In this study, we found that pirarubicin (THP), one important chemotherapeutic drug for treating bladder cancer intravesically, dramatically elevated phosphorylations of both Akt and Erk1/2 in addition to inducing DNA damage. MK2206 or AZD6244, representative Akt and Erk1/2 inhibitors, respectively, profoundly sensitized bladder cancer cells to THP treatment. Interestingly, we found that inhibition of a single arm of either Akt or Erk1/2 pathway would induce the increase of another arm, indicating the existence of the crosstalk between these two pathways. Thus, simultaneous suppression of both signals may be needed for increasing the sensitivity of THP. On the other hand, we revealed that phenformin efficiently inhibited both Akt and Erk1/2 phosphorylation in a dose-dependent manner. Furthermore, we demonstrated that phenformin, mimicking dual inhibitors, plays dramatically synergistic action with THP both in vitro and in vivo. Our findings suggest that combination therapy of THP with dual inhibitors may constitute a successful strategy for improving chemotherapy response.