The Dual Role of the NFATc2/galectin-9 Axis in Modulating Tumor-Initiating Cell Phenotypes and Immune Suppression in Lung Adenocarcinoma.

Tumor-initiating cells (TICs) resilience and an immunosuppressive microenvironment are aggressive oncogenic phenotypes that contribute to unsatisfactory long-term outcomes in lung adenocarcinoma (LUAD) patients. The molecular mechanisms mediating the interaction between TICs and immune tolerance have not been elucidated. The role of Galectin-9 in oncogenesis and immunosuppressive microenvironment is still unknown. This study explored the potential role of galectin-9 in TIC regulation and immune modulation in LUAD. The results show that galectin-9 supports TIC properties in LUAD. Co-culture of patient-derived organoids and matched peripheral blood mononuclear cells showed that tumor-secreted galectin-9 suppressed T cell cytotoxicity and induced regulatory T cells (Tregs). Clinically, galectin-9 is upregulated in human LUAD. High expression of galectin-9 predicted poor recurrence-free survival and correlated with high levels of Treg infiltration. LGALS9, the gene encoding galectin-9, is found to be transcriptionally regulated by the nuclear factor of activated T cells 2 (NFATc2), a previously reported TIC regulator, via in silico prediction and luciferase reporter assays. Overall, the results suggest that the NFATc2/galectin-9 axis plays a dual role in TIC regulation and immune suppression.

NHE7 upregulation potentiates the uptake of small extracellular vesicles by enhancing maturation of macropinosomes in hepatocellular carcinoma.

BACKGROUND: Small extracellular vesicles (sEVs) mediate intercellular communication that contributes to hepatocellular carcinoma (HCC) progression via multifaceted pathways. The success of cell entry determines the effect of sEV on recipient cells. Here, we aimed to delineate the mechanisms underlying the uptake of sEV in HCC. METHODS: Macropinocytosis was examined by the ability of cells to internalize dextran and sEV. Macropinocytosis was analyzed in Na(+)/H(+) exchanger 7 (NHE7)-knockdown and -overexpressing cells. The properties of cells were studied using functional assays. pH biosensor was used to evaluate the intracellular and endosomal pH. The expression of NHE7 in patients' liver tissues was examined by immunofluorescent staining. Inducible silencing of NHE7 in established tumors was performed to reveal the therapeutic potential of targeting NHE7. RESULTS: The data revealed that macropinocytosis controlled the internalization of sEVs and their oncogenic effect on recipient cells. It was found that metastatic HCC cells exhibited the highest efficiency of sEV uptake relative to normal liver cells and non-metastatic HCC cells. Attenuation of macropinocytic activity by 5-(N-ethyl-N-isopropyl)-amiloride (EIPA) limited the entry of sEVs and compromised cell aggressiveness. Mechanistically, we delineated that high level of NHE7, a sodium-hydrogen exchanger, alkalized intracellular pH and acidized endosomal pH, leading to the maturation of macropinosomes. Inducible inhibition of NHE7 in established tumors developed in mice delayed tumor development and suppressed lung metastasis. Clinically, NHE7 expression was upregulated and linked to dismal prognosis of HCC. CONCLUSIONS: This study advances the understanding that NHE7 enhances sEV uptake by macropinocytosis to promote the malignant properties of HCC cells. Inhibition of sEV uptake via macropinocytosis can be exploited as a treatment alone or in combination with conventional therapeutic approaches for HCC.

Small Extracellular Vesicle-Derived vWF Induces a Positive Feedback Loop between Tumor and Endothelial Cells to Promote Angiogenesis and Metastasis in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is a hypervascular malignancy by which its growth and dissemination are largely driven by the modulation of tumor-derived small extracellular vesicles (sEVs). Proteomic profiling of circulating sEVs of control individuals and HCC patients identifies von Willibrand factor (vWF) to be upregulated progressively along HCC stages. Elevated sEV-vWF levels are found in a larger cohort of HCC-sEV samples and metastatic HCC cell lines compared to their respective normal counterparts. Circulating sEVs of late-stage HCC patients markedly augment angiogenesis, tumor-endothelial adhesion, pulmonary vascular leakiness, and metastasis, which are significantly compromised by anti-vWF antibody. The role of vWF is further corroborated by the enhanced promoting effect of sEVs collected from vWF-overexpressing cells. sEV-vWF modulates endothelial cells through an elevated level of vascular endothelial growth factor A (VEGF-A) and fibroblast growth factor 2 (FGF2). Mechanistically, secreted FGF2 elicits a positive feedback response in HCC via the FGFR4/ERK1 signaling pathway. The co-administration of anti-vWF antibody or FGFR inhibitor significantly improves the treatment outcome of sorafenib in a patient-derived xenograft mouse model. This study reveals mutual stimulation between HCC and endothelial cells by tumor-derived sEVs and endothelial angiogenic factors, facilitating angiogenesis and metastasis. It also provides insights into a new therapeutic strategy involving blocking tumor-endothelial intercellular communication.

Targeting GSTP1 as Therapeutic Strategy against Lung Adenocarcinoma Stemness and Resistance to Tyrosine Kinase Inhibitors.

Glutathione S-transferase pi (GSTP1), a phase II detoxification enzyme, is known to be overexpressed and mediates chemotherapeutic resistance in lung cancer. However, whether GSTP1 supports cancer stem cells (CSCs) and the underlying mechanisms in lung adenocarcinoma (LUAD) remain largely unknown. This study unveiled that GSTP1 is upregulated in lung CSCs and supports tumor self-renewal, metastasis, and resistance to targeted tyrosine kinase inhibitors of LUAD both in vitro and in vivo. Mechanistically, CaMK2A (calcium/calmodulin-dependent protein kinase 2 isoform A)/NRF2 (nuclear factor erythroid 2-related factor 2)/GSTP1 is uncovered as a regulatory axis under hypoxia. CaMK2A increased GSTP1 expression through phosphorylating the Sersine558 residue of NRF2 and promoting its nuclear translocation, a novel mechanism for NRF2 activation apart from conventional oxidization-dependent activation. Upregulation of GSTP1 in turn suppressed reactive oxygen species levels and supported CSC phenotypes. Clinically, GSTP1 analyzed by immunohistochemistry is upregulated in a proportion of LUAD and serves as a prognostic marker for survival. Using patient-derived organoids from an ALK-translocated LUAD, the therapeutic potential of a specific GSTP1 inhibitor ezatiostat in combination treatment with the ALK inhibitor crizotinib is demonstrated. This study demonstrates GSTP1 to be a promising therapeutic target for long-term control of LUAD through targeting CSCs.

CAMK2A supported tumor initiating cells of lung adenocarcinoma by upregulating SOX2 through EZH2 phosphorylation.

Tumor initiating cells (TIC) of lung cancer are mainly induced by stress-related plasticity. Calcium/Calmodulin dependent protein kinase II alpha (CAMK2A) is a key calcium signaling molecule activated by exogenous and endogenous stimuli with effects on multiple cell functions but little is known about its role on TIC. In human lung adenocarcinomas (AD), CAMK2A was aberrantly activated in a proportion of cases and was an independent risk factor predicting shorter survivals. Functionally, CAMK2A enhanced TIC phenotypes in vitro and in vivo. CAMK2A regulated SOX2 expression by reducing H3K27me3 and EZH2 occupancy at SOX2 regulatory regions, leading to its epigenetic de-repression with functional consequences. Further, CAMK2A caused kinase-dependent phosphorylation of EZH2 at T487 with suppression of EZH2 activity. Together, the data demonstrated the CAMK2A-EZH2-SOX2 axis on TIC regulation. This study provided phenotypic and mechanistic evidence for the TIC supportive role of CAMK2A, implicating a novel predictive and therapeutic target for lung cancer.

MRP4 sustains Wnt/ß-catenin signaling for pregnancy, endometriosis and endometrial cancer.

Rationale: Abnormal Wnt/ß-catenin signaling in the endometrium can lead to both embryo implantation failure and severe pathogenic changes of the endometrium such as endometrial cancer and endometriosis. However, how Wnt/ß-catenin signaling is regulated in the endometrium remains elusive. We explored possible regulation of Wnt/ß-catenin signaling by multi-drug resistance protein 4 (MRP4), a potential target in cancer chemotherapy, and investigated the mechanism. Methods: Knockdown of MRP4 was performed in human endometrial cells in vitro or in a mouse embryo-implantation model in vivo. Immunoprecipitation, immunoblotting and immunofluorescence were used to assess protein interaction and stability. Wnt/ß-catenin signaling was assessed by TOPflash reporter assay and quantitative PCR array. Normal and endometriotic human endometrial tissues were examined. Data from human microarray or RNAseq databases of more than 100 participants with endometriosis, endometrial cancer or IVF were analyzed. In vitro and in vivo tumorigenesis was performed. Results: MRP4-knockdown, but not its transporter-function-inhibition, accelerates ß-catenin degradation in human endometrial cells. MRP4 and ß-catenin are co-localized and co-immunoprecipitated in mouse and human endometrium. MRP4-knockdown in mouse uterus reduces ß-catenin levels, downregulates a series of Wnt/ß-catenin target genes and impairs embryo implantation, which are all reversed by blocking ß-catenin degradation. Analysis of human endometrial biopsy samples and available databases reveals significant and positive correlations of MRP4 with ß-catenin and Wnt/ß-catenin target genes in the receptive endometrium in IVF, ectopic endometriotic lesions and endometrial cancers. Knockdown of MRP4 also inhibits in vitro and in vivo endometrial tumorigenesis. Conclusion: A previously undefined role of MRP4 in stabilizing ß-catenin to sustain Wnt/ß-catenin signaling in endometrial cells is revealed for both embryo implantation and endometrial disorders, suggesting MRP4 as a theranostic target for endometrial diseases associated with Wnt/ß-catenin signaling abnormality.

NFATc2 enhances tumor-initiating phenotypes through the NFATc2/SOX2/ALDH axis in lung adenocarcinoma.

Tumor-initiating cells (TIC) are dynamic cancer cell subsets that display enhanced tumor functions and resilience to treatment but the mechanism of TIC induction or maintenance in lung cancer is not fully understood. In this study, we show the calcium pathway transcription factor NFATc2 is a novel regulator of lung TIC phenotypes, including tumorspheres, cell motility, tumorigenesis, as well as in vitro and in vivo responses to chemotherapy and targeted therapy. In human lung cancers, high NFATc2 expression predicted poor tumor differentiation, adverse recurrence-free and cancer-specific overall survivals. Mechanistic investigations identified NFATc2 response elements in the 3' enhancer region of SOX2, and NFATc2/SOX2 coupling upregulates ALDH1A1 by binding to its 5' enhancer. Through this axis, oxidative stress induced by cancer drug treatment is attenuated, leading to increased resistance in a mutation-independent manner. Targeting this axis provides a novel approach for the long-term treatment of lung cancer through TIC elimination.

bba, a synthetic derivative of 23-hydroxybutulinic acid, reverses multidrug resistance by inhibiting the efflux activity of MRP7 (ABCC10).

Natural products are frequently used for adjuvant chemotherapy in cancer treatment. 23-O-(1,4'-bipiperidine-1-carbonyl) betulinic acid (BBA) is a synthetic derivative of 23-hydroxybutulinic acid (23-HBA), which is a natural pentacyclic triterpene and the major active constituent of the root of Pulsatillachinensis. We previously reported that BBA could reverse P-glycoprotein (P-gp/ABCB1)-mediated multidrug resistance (MDR). In the present study, we investigated whether BBA has the potential to reverse multidrug resistance protein 7 (MRP7/ABCC10)-mediated MDR. We found that BBA concentration-dependently enhanced the sensitivity of MRP7-transfected HEK293 cells to paclitaxel, docetaxel and vinblastine. Accumulation and efflux experiments demonstrated that BBA increased the intracellular accumulation of [(3)H]-paclitaxel by inhibiting the efflux of [(3)H]-paclitaxel from HEK293/MRP7 cells. In addition, immunoblotting and immunofluorescence analyses indicated no significant alteration of MRP7 protein expression and localization in plasma membranes after treatment with BBA. These results demonstrate that BBA reverses MRP7-mediated MDR through blocking the drug efflux function of MRP7 without affecting the intracellular ATP levels. Our findings suggest that BBA has the potential to be used in combination with conventional chemotherapeutic agents to augment the response to chemotherapy.

Nilotinib potentiates anticancer drug sensitivity in murine ABCB1-, ABCG2-, and ABCC10-multidrug resistance xenograft models.

A panel of clinically used tyrosine kinase inhibitors were compared and nilotinib was found to most potently sensitize specific anticancer agents by blocking the functions of ABCB1/P-glycoprotein, ABCG2/BCRP and ABCC10/MRP7 transporters involved in multi-drug resistance. Nilotinib appreciably enhanced the antitumor response of (1) paclitaxel in the ABCB1- and novel ABCC10-xenograft models, and (2) doxorubicin in a novel ABCG2-xenograft model. With no apparent toxicity observed in the above models, nilotinib attenuated tumor growth synergistically and increased paclitaxel concentrations in ABCB1-overexpressing tumors. The beneficial actions of nilotinib warrant consideration as viable combinations in the clinic with agents that suffer from MDR-mediated insensitivity.

BBA, a derivative of 23-hydroxybetulinic acid, potently reverses ABCB1-mediated drug resistance in vitro and in vivo.

23-O-(1,4'-Bipiperidine-1-carbonyl)betulinic acid (BBA), a synthetic derivative of 23-hydroxybetulinic acid (23-HBA), shows a reversal effect on multidrug resistance (MDR) in our preliminary screening. Overexpression of ATP-binding cassette (ABC) transporters such as ABCB1, ABCG2, and ABCC1 has been reported in recent studies to be a major factor contributing to MDR. Our study results showed that BBA enhanced the cytotoxicity of ABCB1 substrates and increased the accumulation of doxorubicin or rhodamine123 in ABCB1 overexpressing cells, but had no effect on non ABCB1 substrate, such as cisplatin; what's more, BBA slightly reversed ABCG2-mediated resistance to SN-38, but did not affect the ABCC1-mediated MDR. Further studies on the mechanism indicated that BBA did not alter the expression of ABCB1 at mRNA or protein levels, but affected the ABCB1 ATPase activity by stimulating the basal activity at lower concentrations and inhibiting the activity at higher concentrations. In addition, BBA inhibited the verapamil-stimulated ABCB1 ATPase activity and the photolabeling of ABCB1 with [(125)I] iodoarylazidoprazosin in a concentration-dependent manner, indicating that BBA directly interacts with ABCB1. The docking study confirmed this notion that BBA could bind to the drug binding site(s) on ABCB1, but its binding position was only partially overlapping with that of verapamil or iodoarylazidoprazosin. Importantly, BBA increased the inhibitory effect of paclitaxel in ABCB1 overexpressing KB-C2 cell xenografts in nude mice. Taken together, our findings suggest that BBA can reverse ABCB1-mediated MDR by inhibiting its efflux function of ABCB1, which supports the development of BBA as a novel potential MDR reversal agent used in the clinic.

PDE5 inhibitors, sildenafil and vardenafil, reverse multidrug resistance by inhibiting the efflux function of multidrug resistance protein 7 (ATP-binding Cassette C10) transporter.

Phosphodiesterase type 5 (PDE5) inhibitors are widely used in the treatment of male erectile dysfunction and pulmonary hypertension. Recently, several groups have evaluated the ability of PDE5 inhibitors for their anticancer activities. Previously, we had shown that sildenafil, vardenafil and tadalafil could reverse P-glycoprotein (ATP-binding cassette B1)-mediated MDR. In the present study, we determined whether these PDE5 inhibitors have the potential to reverse multidrug resistance protein 7 (MRP7; ATP-binding cassette C10)-mediated MDR. We found that sildenafil and vardenafil dose-dependently enhanced the sensitivity of MRP7-transfected HEK293 cells to paclitaxel, docetaxel and vinblastine, while tadalafil had only a minimal effect. Accumulation and efflux experiments demonstrated that sildenafil and vardenafil increased the intracellular accumulation of [(3)H]-paclitaxel by inhibiting the efflux of [(3 H]-paclitaxel in HEK/MRP7 cells. In addition, immunoblot and immunofluorescence analyses indicated that no significant alterations of MRP7 protein expression and localization in plasma membranes were found after treatment with sildenafil, vardenafil or tadalafil. These results demonstrate that sildenafil and vardenafil reverse MRP7-mediated a MDR through inhibition of the drug efflux function of MRP7. Our findings indicate a potentially novel use of PDE5 inhibitors as an adjuvant chemotherapeutic agent in clinical practice.

GW583340 and GW2974, human EGFR and HER-2 inhibitors, reverse ABCG2- and ABCB1-mediated drug resistance.

The overexpression of ATP binding cassette (ABC) transporters often leads to the development of multidrug resistance (MDR) and results in a suboptimal response to chemotherapy. Previously, we reported that lapatinib (GW572016), a human epidermal growth factor receptor (EGFR) and HER-2 tyrosine kinase inhibitor (TKI), significantly reverses MDR in cancer cells by blocking the efflux function of ABC subfamily B member 1 (ABCB1) and ABC subfamily G member 2 (ABCG2). In the present study, we conducted in vitro experiments to evaluate if GW583340 and GW2974, structural analogues of lapatinib, could reverse ABCB1- and ABCG2-mediated MDR. Our results showed that GW583340 and GW2974 significantly sensitized ABCB1 and ABCG2 overexpressing MDR cells to their anticancer substrates. GW583340 and GW2974 significantly increased the intracellular accumulation of [(3)H]-paclitaxel in ABCB1 overexpressing cells and [(3)H]-mitoxantrone in ABCG2 overexpressing cells respectively. In addition, GW583340 and GW2974 significantly inhibited ABCG2-mediated transport of methotrexate in ABCG2 overexpressing membrane vesicles. There was no significant change in the expression levels of ABCB1 and ABCG2 in the cell lines exposed to 5µM of either GW583340 or GW2974 for 3 days. In addition, a docking model predicted the binding conformation of GW583340 and GW2974 to be within the transmembrane region of homology modeled human ABCB1 and ABCG2. We conclude that GW583340 and GW2974, at clinically achievable plasma concentrations, reverse ABCB1- and ABCG2-mediated MDR by blocking the drug efflux function of these transporters. These findings may be useful in developing combination therapy for cancer treatment with EGFR TKIs.

[Effects of atorvastatin on plasma hypersensitive C-reactive protein and interleukin-6 in patients with acute cerebral infarction].

OBJECTIVE: To observe the effects of different doses of atorvastatin on the plasma hypersensitive C-reactive protein (hsCRP) and interleukin-6 (IL-6) in patients with acute cerebral infarction. METHODS: 131 patients with acute cerebral infarction, 73 males and 58 females, aged 63 +/- 11, were randomly divided into 3 groups: Group A (n = 47), with basal treatment; Group B (n = 42), atorvastatin 10 mg was added every night; and Group C (n = 42), atorvastatin 20 mg was added every night. Before the treatment and 7 and 14 days after the treatment the plasma levels of hsCRP and IL-6, fasting plasma levels of lipid, such as total cholesterol (TC) and low density lipoprotein-C (LDL-C), liver functions, such as aspartate aminotransferase (ALT) and alanine transaminase (ALT), creatine kinase (CK), urea nitrogen, were detected. Neurological function deficit was determined. The survival condition was surveyed 6 months after. RESULTS: (1) The TC and LDL-C decreased after treatment in the 3 groups with significant differences between Group A and Group C, Group B and Group C, and Group B and Group C (all P < 0.05). (2) The plasma level of hsCRP decreased by 9.1%, 33.9%, and 30.1% respectively 7 days after treatment in Groups A, B, and C with significant differences between Groups A and B and between Groups A and C (both P < 0.05), however, without significant difference between Group B and Group C. The level of hsCRP decreased by 34.3%, 56.0%, and 52.9% respectively 14 days after treatment in the 3 groups with significant differences between Groups A and B and between Groups A and C (both P < 0.05), however, without significant difference between Group B and Group C. (3) The level of IL-6 decreased 7 and 14 days after treatment in all 3 groups, however, without significant differences between any 2 groups (all P > 0.05). (4) The decrease of hsCRP and decrease of IL-6 were not correlated with the percentage of TC decrease (both P > 0.05) in Group B. The decrease of hsCRP was not correlated with the changes of blood lipids in Group C. (5) Both the plasma hsCRP and IL-6 before treatment were positively correlated with the infection volume and neurological function score (all P < 0.01). CONCLUSION: Atorvastatin has an anti-inflammatory action benefiting the alleviation of secondary inflammatory damaged in acute cerebral infarction that is independent of lipid lowering.

[Effects of long-term replacement therapy of compound nylestriol tablet or low-dose 17 beta-estradiol on the expression of nerve growth factor in OVX rat hippocampal formation].

OBJECTIVE: To determine the effects of long-term estrogen deficiency and replacement therapy of compound nylestriol tablet or low-dose 17 beta-estradiol on the expression of nerve growth factor (NGF) in rat hippocampal formation. METHODS: Fifty 7 month-old female Sprague-Dawley rats were randomly divided into 5 groups: normal control, sham operated (SHAM), ovariectomized (OVX), OVX plus 17 beta-estradiol (OVX/ERT), and OVX plus compound nylestriol tablet (OVX/NL) groups. Immunohistochemistry of NGF was used to quantitatively determine the levels of expression of NGF using cell counting and imaging system in ovariectomized rat hippocampal formation. RESULTS: The number and optical density of NGF-positive neurons of all hippocampal subregions and dentate gyrus in OVX rats were obviously lower than those of the normal control, SHAM, OVX/NL, and OVX/ERT rats. CONCLUSION: Long-term estrogen deficiency can lead to a decrease of NGF expression in hippocampal formation, while the replacement of low-dose 17 beta-estradiol or compound nylestriol tablet can equally preserve the expression of NGF to a normal level, showing a neurotrophic effect of estrogen.

Divergent effects of retinoic acids on the expression of ERalpha and 17beta-hydroxysteroid dehydrogenase type 2 in endometrial carcinoma cells (RL 95-2).

The effects of E2 are dependent on ERs and local E2 concentration in target cells. Modulation of intracellular E2 concentration involves the action of 17beta-hydroxysteroid dehydrogenase (17HSD) type 2, the enzyme converting E2 to estrone. In the present study, the influence of RAs on the growth of endometrial cancer cell line RL 95-2 as well as the expression of ERs and 17HSD type 2 have been investigated. It was found that RAs repress the growth of RL 95-2 cells, which express all subtypes of RXR and RAR, as examined by RT-PCR. Also, quantitative RT-PCR analysis showed that both ERalpha and ERbeta are present in RL 95-2 cells, and Western blot assay further revealed that ERalpha expression was decreased by all trans-RA treatment. In contrast, RAs induced 17HSD type 2 mRNA expression in a dose- and time-dependent fashion. This stimulatory effect was also detected at the level of in vivo oxidative 17HSD activity in cultured cells. On the other hand, the abundance of 17HSD type 2 mRNA was not altered by RAs in cultured normal epithelial cells isolated from human early- and late-secretory endometrium. The data indicate that RAs have an inhibitory effect on the growth of RL 95-2 cells and a cross-talk with the estrogen pathway in estrogen-responsive endometrial cancer cells.