Conflicting evidence for the role of JNK as a target in breast cancer cell proliferation: Comparisons between pharmacological inhibition and selective shRNA knockdown approaches

Empagliflozin treatment of cardiotoxicity: A comprehensive review of clinical, immunobiological, neuroimmune, and therapeutic implications

Cancer and cardiovascular disorders are known as the two main leading causes of mortality worldwide. Cardiotoxicity is a critical and common adverse effect of cancer-related chemotherapy. Chemotherapy-induced cardiotoxicity has been associated with various cancer treatments, such as anthracyclines, immune checkpoint inhibitors, and kinase inhibitors. Different methods have been reported for the management of chemotherapy-induced cardiotoxicity. In this regard, sodium-glucose cotransporter-2 inhibitors (SGLT2i), a class of antidiabetic agents, have recently been applied to manage heart failure patients. Further, SGLT2i drugs such as EMPA exert protective cardiac and systemic effects. Moreover, it can reduce inflammation through the mediation of major inflammatory components, such as Nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasomes, Adenosine 5'-monophosphate-activated protein kinase (AMPK), and c-Jun N-terminal kinase (JNK) pathways, Signal transducer and activator of transcription (STAT), and overall decreasing transcription of proinflammatory cytokines. The clinical outcome of EMPA administration is related to improving cardiovascular risk factors, including body weight, lipid profile, blood pressure, and arterial stiffness. Intriguingly, SGLT2 suppressors can regulate microglia-driven hyperinflammation affecting neurological and cardiovascular disorders. In this review, we discuss the protective effects of EMPA in chemotherapy-induced cardiotoxicity from molecular, immunological, and neuroimmunological aspects to preclinical and clinical outcomes.

PLZF and PLZF-MAPK10 can predict the prognosis of postoperative patients with hepatocellular carcinoma

OBJECTIVE

The current study aimed to explore the expression level of promyelocytic leukaemia zinc finger (PLZF) in hepatocellular carcinoma tissues and to investigate the value of detecting the expression levels of PLZF and mitogen-activated protein kinase 10 (MAPK10) on predicting prognosis.

METHODS

This study selected data from 53 patients with HCC who had undergone hepatectomy in our hospital. The expressions of PLZF and MAPK10 in tumor tissues and normal tissues were compared and related clinical factors were analyzed. The clinical data including patient's gender, age, hepatitis B virus infection (HBV), alpha-fetoprotein levels (AFP), tumor size, TNM stage (AJCC), cirrhosis, portal vein tumor thrombus (PVTT), bile duct tumor thrombus (BDTT), and OS (Overall survival) was collected.

RESULTS

We found that PLZF expression was significantly down-regulated in HCC samples compared with that in adjacent non-tumor tissues (P=0.001). The expression level of PLZF was correlated with patients' gender (P=0.046), tumor stage (P=0.039), and OS (P=0.015). Moreover, the expression level of PLZF-MAPK10 (P-M protein) was correlated with gender (P=0.000) and tumor stage (P=0.045). Multivariate analyses showed that microsatellite nodules, PLZF, and P-M protein were independent risk factors of HCC prognosis. Postoperative patients with a normal expression level of PLZF and MAPK10 have a longer overall survival than those with abnormal levels (P=0.039).

CONCLUSION

PLZF expression was significantly down-regulated in HCC tissues and itself and PLZF-MAPK10 were both independent prognostic factors for the OS of patients with HCC.

Empagliflozin and Doxorubicin Synergistically Inhibit the Survival of Triple-Negative Breast Cancer Cells via Interfering with the mTOR Pathway and Inhibition of Calmodulin: In Vitro and Molecular Docking Studies

Triple-negative breast cancers (TNBCs) comprise 10-15% of all breast cancers but with more resistance affinity against chemotherapeutics. Although doxorubicin (DOX) is the recommended first choice, it has observed cardiotoxicity together with apparent drug resistance. The anti-hyperglycemic drug, empagliflozin (EMP), was recently indicated to have in vitro anticancer potential together with its previously reported cardioprotective properties related to calmodulin inhibition. In this study, we carried out molecular docking studies which revealed the potential blocking of the calmodulin receptor by EMP through its binding with similar crucial amino acids compared to its cocrystallized inhibitor (AAA) as a proposed mechanism of action. Moreover, combination of DOX with EMP showed a slightly lower cytotoxic activity against the MDA-MB-231 cell line (IC₅₀ = 1.700 ± 0.121) compared to DOX alone (IC₅₀ = 1.230 ± 0.131), but it achieved a more characteristic arrest in the growth of cells by 4.67-fold more than DOX alone (with only 3.27-fold) in comparison to the control as determined by cell cycle analysis, and at the same time reached an increase in the total apoptosis percentage from 27.05- to 29.22-fold, compared to DOX alone as indicated by Annexin V-FITC apoptosis assay. Briefly, the aforementioned in vitro studies in addition to PCR of pro- and antiapoptotic genes (mTOR, p21, JNK, Bcl2, and MDR1) suggest the chemosensitization effect of EMP combination with DOX which can reduce the required therapeutic dose of DOX in TNBC and eventually will decrease its toxic side effects (especially cardiotoxicity), along with decreasing the chemoresistance of TNBC cells to DOX treatment.

The role of high fat diet in the regulation of MAP kinases activity in left ventricular fibrosis

It is well known that obesity contributes to the development of systemic inflammatory responses, which in turn may be involved in the process of interstitial fibrosis and left ventricular (LV) remodelling. Activation of pro-inflammatory factors such as transforming growth factor β (TGF-β) can directly stimulate mitogen-activated protein kinase (MAPK) p38 and JNK. The aim of the study was to evaluate the level of TGF-β and MAPK p38 and JNK in the LV in Sprague Dawley (SPRD) rats maintained on a high fat diet (HFD). The SPRD rats from 4 weeks of age were on a normal fat diet (NFD) or a HFD for 12 weeks (NFD-16-week-old rats, NFD 16-wk; or HFD-16-week-old rats, HFD 16-wk) or 16 weeks (NFD-20-week-old rats, NFD 20-wk; or HFD-20-week-old rats, HFD 20-wk). At the end of the experiment, blood and LV were collected from all rats for further analysis (biochemical, Real Time PCR and immunohistochemical analysis). TGF-β mRNA expression did not differ between the study groups of rats. However, p38 MAPK mRNA expression was significantly lower in the HFD 20-wk rats than in both the HFD 16-wk rats and the NFD 20-wk rats. c-jun mRNA expression was significantly higher in the HFD 16-wk rats than in the NFD 16-wk rats. There was significantly lower expression of c-jun mRNA in the HFD 20-wk rats and in the NFD 20-wk rats than in the HFD 16-wk rats and in the NFD 16-wk rats, respectively. TGF-β type II receptor (TβRII) protein demonstrated only cytoplasmic reactivity, while p38 MAPK protein and c-jun protein showed both nuclear and cytoplasmic reactivity. The results suggest that a high fat diet and in two time intervals significantly influence the expression of p38 MAPK and JNK in the LV. However, demonstrating their potential involvement in the processes of interstitial myocardial fibrosis and left ventricular remodeling requires further research.

Conflicting evidence for the role of JNK as a target in breast cancer cell proliferation: Comparisons between pharmacological inhibition and selective shRNA knockdown approaches

As a target, the JNK pathway has been implicated in roles including cell death, proliferation, and inflammation in variety of contexts which span cardiovascular disease, neurodegenerative pathologies, and cancer. JNK1 and JNK2 have recently been demonstrated to function independently, highlighting a new parameter in the study of the JNK pathway. In order for JNK1 and JNK2-specific roles to be defined, better tools need to be employed. Previous studies have relied upon the broad spectrum JNK inhibitor, SP600125, to characterize the role of JNK signaling in a number of cell lines, including the breast cancer cell line MCF-7. In line with previous literature, our study has demonstrated that SP600125 treatment inhibited c-Jun and JNK phosphorylation and MCF-7 proliferation. However, in addition to targeting JNK1, JNK2, and JNK3, SP600125 has been previously demonstrated to suppress the activity of a number of other serine/threonine kinases, making SP600125 an inadequate tool for JNK isoform-specific roles to be determined. In this study, lentiviral shRNA was employed to selectively knockdown JNK1, JNK2, and JNK1/2 in MCF-7 cells. Using this approach, JNK phosphorylation was fully inhibited following stable knockdown of respective JNK isoforms. Interestingly, despite suppression of JNK phosphorylation, MCF-7 cell proliferation, cell cycle progression, or cell death remained unaffected. These findings raise the question of whether JNK phosphorylation really is pivotal in MCF-7 cell growth and death or if suppression of these events is a result of one of the many off-targets cited for SP600125.