Exercise accelerates recruitment of CD8+ T cell to promotes anti-tumor immunity in lung cancer via epinephrine

BACKGROUND AND PURPOSE

In recent years, there has been extensive research on the role of exercise as an adjunctive therapy for cancer. However, the potential mechanisms underlying the anti-tumor therapy of exercise in lung cancer remain to be fully elucidated. As such, our study aims to confirm whether exercise-induced elevation of epinephrine can accelerate CD8+ T cell recruitment through modulation of chemokines and thus ultimately inhibit tumor progression.

METHOD

C57BL/6 mice were subcutaneously inoculated with Lewis lung cancer cells (LLCs) to establish a subcutaneous tumor model. The tumor mice were randomly divided into different groups to performed a moderate-intensity exercise program on a treadmill for 5 consecutive days a week, 45 min a day. The blood samples and tumor tissues were collected after exercise for IHC, RT-qPCR, ELISA and Western blot. In addition, another group of mice received daily epinephrine treatment for two weeks (0.05 mg/mL, 200 µL i.p.) (EPI, n = 8) to replicate the effects of exercise on tumors in vivo. Lewis lung cancer cells were treated with different concentrations of epinephrine (0, 5, 10, 20 µM) to detect the effect of epinephrine on chemokine levels via ELISA and RT-qPCR.

RESULTS

This study reveals that both pre- and post-cancer exercise effectively impede the tumor progression. Exercise led to an increase in EPI levels and the infiltration of CD8+ T cell into the lung tumor. Exercise-induced elevation of EPI is involved in the regulation of Ccl5 and Cxcl10 levels further leading to enhanced CD8+ T cell infiltration and ultimately inhibiting tumor progression.

CONCLUSION

Exercise training enhance the anti-tumor immunity of lung cancer individuals. These findings will provide valuable insights for the future application of exercise therapy in clinical practice.

Angiotensin II type-2 receptor signaling facilitates liver injury repair and regeneration via inactivation of Hippo pathway

The angiotensin II type 2 receptor (AT2R) is a well-established component of the renin-angiotensin system and is known to counteract classical activation of this system and protect against organ damage. Pharmacological activation of the AT2R has significant therapeutic benefits, including vasodilation, natriuresis, anti-inflammatory activity, and improved insulin sensitivity. However, the precise biological functions of the AT2R in maintaining homeostasis in liver tissue remain largely unexplored. In this study, we found that the AT2R facilitates liver repair and regeneration following acute injury by deactivating Hippo signaling and that interleukin-6 transcriptionally upregulates expression of the AT2R in hepatocytes through STAT3 acting as a transcription activator binding to promoter regions of the AT2R. Subsequently, elevated AT2R levels activate downstream signaling via heterotrimeric G protein Gα12/13-coupled signals to induce Yap activity, thereby contributing to repair and regeneration processes in the liver. Conversely, a deficiency in the AT2R attenuates regeneration of the liver while increasing susceptibility to acetaminophen-induced liver injury. Administration of an AT2R agonist significantly enhances the repair and regeneration capacity of injured liver tissue. Our findings suggest that the AT2R acts as an upstream regulator in the Hippo pathway and is a potential target in the treatment of liver damage.

[Purification and characterization of L-amino acid oxidase from Agkistrodon halys pallas venom]

L-amino acid oxidase (LAO, EC 1.4.3.2) is widely found in snake venoms and is thought to contribute to the toxicity in envenoming. By using of Sephadex G-150, DEAE-Sepharose CL-6B and FPLC Superose 12 chromatography, a protein with L-amino acid oxidase activity was purified and characterized from Agkistrodon haly Pallas venom. Its molecular mass was 57 kD as determined by SDS-PAGE analysis under both reducing and non-reducing conditions, and its pI was about 4.9. The protein catalysed the stereospecific oxidative deamination of L-amino acid substrate. It inhibited the platelet aggregation induced by ADP and collagen dose-dependently, even at low concentrations of 0.2 micromol/L and 0.08 micromol/L, respectively. The LAO had antibacterial effect to E.coli K12D31, and the effective concentration was as low as 0.03 g/L. Furthermore, the LAO showed cytotoxicity in crystal violet assay and apoptosis-inducing activity in the A549 cells. After 24h treatment with 5 mg/L LAO, the typical DNA fragmentation pattern of apoptotic cells was observed by using of agrose gel electrophoresis.

Propranolol increases phosphatidic acid level via activation of phospholipase D

AIM

To investigate the propranolol-induced phospholipase D (PLD) activity, its contribution to the increase in the level of phosphatidic acid, and the role of protein kinase C (PKC) in this event.

METHODS

A combination of [3H]-myristate labeling, transphosphatidylation reaction, lipid extraction, and thin layer chromatography was used to measure the PLD activity. PKC inhibitors and prolonged phorbol-12-myristate-13-acetate (PMA) treatment were used to study the involvement of PKC in propranolol-induced PLD activation. Immunoblotting was used to detect the intracellular levels of PKC.

RESULTS

Treatment of A-549 cells with propranolol in the presence of butanol, resulted in the rapid activation of PLD. Propranolol induced the formation of phosphatidylbutanol (PBut), a unique product of PLD, at the expense of phosphatidic acid (PA) formation. Pretreatment of cells with PKC inhibitors Ro-31-8220, staurosporine, and rottlerin increased the propranolol-induced PLD. Down-regulation of PKC by prolonged treatment of cells with PMA also potentiated the propranolol-induced PLD activity.

CONCLUSION

Propranolol induces rapid activation of PLD activity, which results in the increase in intracellular level of PA. The data also indicate that propranolol-induced PLD activity could be negatively regulated by PKC.

The involvement of p38 MAPK in transforming growth factor beta1-induced apoptosis in murine hepatocytes

We reported in this manuscript that TGF-beta1 induces apoptosis in AML12 murine hepatocytes, which is associated with the activation of p38 MAPK signaling pathway. SB202190, a specific inhibitor of p38 MAPK, strongly inhibited the TGF-beta1-induced apoptosis and PAI-1 promoter activity. Treatment of cells with TGF-beta1 activates p38. Furthermore, over-expression of dominant negative mutant p38 also reduced the TGF-beta1-induced apoptosis. The data indicate that the activation of p38 is involved in TGF-beta1-mediated gene expression and apoptosis.

Cycloheximide blocks TGF-beta1-induced apoptosis in murine hepatocytes

AIM

To study the mechanism of transforming growth factor beta1-induced apoptosis in cultured hepatocytes.

METHODS

DNA fragmentation and fluorescent microscopy were used to characterize cell apoptosis. Crystal violet staining was used to assess cell viability. Immunoblotting was used to detect Tak1, p53, and Bax. Dual luciferase assay was used to determine TGF-beta1-induced gene expression. Thin layer chromatography was used to examine ceramide level in AML12 cells.

RESULTS

In response to TGF-beta1 treatment, AML12 cells exhibited typical chang es, which was characteristic of apoptosis, such as condensation of chromatin, disintegration of nuclei, and DNA fragmentation. TGF-beta1-induced apoptosis in AML12 cells was completely blocked in the presence of cycloheximide. The inhibitory effect of cycloheximide was accompanied with down-regulation of Tak1 expression and TGF-beta1-induced PAI-1 expression. TGF-beta1 induced p53 expression but not Bax. No increase of ceramide was observed in TGF-beta1-induced apoptosis.

CONCLUSION

TGF-beta1-induced apoptosis requires TGF-beta1-induced gene expression.

Regulation of phospholipase D activity and ceramide production in daunorubicin-induced apoptosis in A-431 cells

We demonstrated here that daunorubicin induced apoptosis in A-431 cells, a human epidermoid carcinoma cell line. Treatment of cells with daunorubicin induced chromatin condensation, nuclear fragmentation, internucleosomal DNA degradation, and the proteolytic cleavage of PKC-delta and poly(ADP-ribose) polymerase in A-431 cells. Daunorubicin, as well as sphingomyelinase (SMase) and the exogenous cell-permeable ceramide analogue C(2)-ceramide, inhibited phospholipase D activity stimulated by phorbol 12-myristate 13-acetate or epidermal growth factor (EGF). Like ceramide, daunorubicin also decreased EGF-induced diacylglycerol generation. However, no increase in ceramide level was observed in daunorubicin-induced apoptosis in A-431 cells. Moreover, treatment of A-431 cells with exogenous cell-permeable C(2)-ceramide or SMase did not induce apoptosis. These results indicate that daunorubicin induces apoptosis in A-431 cells via a mechanism that does not involve increased ceramide formation.

Activation of phospholipase D activity in transforming growth factor-beta-induced cell growth inhibition

Cells regulate phospholipase D (PLD) activity in response to numerous extracellular signals. Here, we investigated the involvement of PLD activity in transforming growth factor-beta (TGF-beta1)-mediated growth inhibition of epithelial cells. TGF-beta1 inhibits the growth of MDCK, Mv1Lu, and A-549 cells. In the presence of 0.4% butanol, TGF-beta1 induces an increase in the formation of phosphatidylbutanol, a unique product catalyzed by PLD. TGF-beta1 also induces an increase in phosphatidic acid (PA) level in A-549 and MDCK cells. TGF-beta1 induces an increase in the levels of DAG labeled with [3H]-myristic acid in A-549 and MDCK cells but not in Mv1Lu cells. No increase of DAG was observed in cells prelabeled with [3H]-arachidonic acid. The data presented suggest that PLD activation is involved in the TGF-beta1-induced cell growth inhibition.