Single-cell analysis identifies PLK1 as a driver of immunosuppressive tumor microenvironment in LUAD.

PLK1 (Polo-like kinase 1) plays a critical role in the progression of lung adenocarcinoma (LUAD). Recent studies have unveiled that targeting PLK1 improves the efficacy of immunotherapy, highlighting its important role in the regulation of tumor immunity. Nevertheless, our understanding of the intricate interplay between PLK1 and the tumor microenvironment (TME) remains incomplete. Here, using genetically engineered mouse model and single-cell RNA-seq analysis, we report that PLK1 promotes an immunosuppressive TME in LUAD, characterized with enhanced M2 polarization of tumor associated macrophages (TAM) and dampened antigen presentation process. Mechanistically, elevated PLK1 coincides with increased secretion of CXCL2 cytokine, which promotes M2 polarization of TAM and diminishes expression of class II major histocompatibility complex (MHC-II) in professional antigen-presenting cells. Furthermore, PLK1 negatively regulates MHC-II expression in cancer cells, which has been shown to be associated with compromised tumor immunity and unfavorable patient outcomes. Taken together, our results reveal PLK1 as a novel modulator of TME in LUAD and provide possible therapeutic interventions.

Phosphorylation of AHR by PLK1 promotes metastasis of LUAD via DIO2-TH signaling.

Metastasis of lung adenocarcinoma (LUAD) is a major cause of death in patients. Aryl hydrocarbon receptor (AHR), an important transcription factor, is involved in the initiation and progression of lung cancer. Polo-like kinase 1 (PLK1), a serine/threonine kinase, acts as an oncogene promoting the malignancy of multiple cancer types. However, the interaction between these two factors and their significance in lung cancer remain to be determined. In this study, we demonstrate that PLK1 phosphorylates AHR at S489 in LUAD, leading to epithelial-mesenchymal transition (EMT) and metastatic events. RNA-seq analyses reveal that type 2 deiodinase (DIO2) is responsible for EMT and enhanced metastatic potential. DIO2 converts tetraiodothyronine (T4) to triiodothyronine (T3), activating thyroid hormone (TH) signaling. In vitro and in vivo experiments demonstrate that treatment with T3 or T4 promotes the metastasis of LUAD, whereas depletion of DIO2 or a deiodinase inhibitor disrupts this property. Taking together, our results identify the AHR phosphorylation by PLK1 and subsequent activation of DIO2-TH signaling as mechanisms leading to LUAD metastasis. These findings can inform possible therapeutic interventions for this event.

Diptoindonesin G antagonizes AR signaling and enhances the efficacy of antiandrogen therapy in prostate cancer.

BACKGROUND: The androgen receptor (AR) signaling pathway has been well demonstrated to play a crucial role in the development, progression, and drug resistance of prostate cancer. Although the current anti-androgen therapy could significantly benefit prostate cancer patients initially, the efficacy of the single drug usually lasts for a relatively short period, as drug resistance quickly emerges. METHODS: We have performed an unbiased bioinformatics analysis using the RNA-seq results in 22Rv1 cells to identify the cell response toward Dip G treatment. The RNA-seq results were validated by qRT-PCR. Protein levels were detected by western blot or staining. Cell viability was measured by Aquabluer and colony formation assay. RESULTS: Here, we identified that Diptoindonesin G (Dip G), a natural extracted compound, could promote the proteasome degradation of AR and polo-like kinase 1 (PLK1) through modulating the activation of CHIP E3 ligase. Administration of Dip G has shown a profound efficiency in the suppression of AR and PLK1, not only in androgen-dependent LNCaP cells but also in castration-resistant and enzalutamide-resistant cells in a CHIP-dependent manner. Through co-targeting the AR signaling, Dip G robustly improved the efficacy of HSP90 inhibitors and enzalutamide in both human prostate cancer cells and in vivo xenograft mouse model. CONCLUSIONS: Our results revealed that Dip G-mediated AR degradation would be a promising and valuable therapeutic strategy in the clinic.

Inhibition of the erythropoietin-producing receptor EPHB4 antagonizes androgen receptor overexpression and reduces enzalutamide resistance.

Prostate cancer (PCa) cells heavily rely on an active androgen receptor (AR) pathway for their survival. Enzalutamide (MDV3100) is a second-generation antiandrogenic drug that was approved by the Food and Drug Administration in 2012 to treat patients with castration-resistant prostate cancer (CRPC). However, emergence of resistance against this drug is inevitable, and it has been a major challenge to develop interventions that help manage enzalutamide-resistant CRPC. Erythropoietin-producing human hepatocellular (Eph) receptors are targeted by ephrin protein ligands and have a broad range of functions. Increasing evidence indicates that this signaling pathway plays an important role in tumorigenesis. Overexpression of EPH receptor B4 (EPHB4) has been observed in multiple types of cancer, being closely associated with proliferation, invasion, and metastasis of tumors. Here, using RNA-Seq analyses of clinical and preclinical samples, along with several biochemical and molecular methods, we report that enzalutamide-resistant PCa requires an active EPHB4 pathway that supports drug resistance of this tumor type. Using a small kinase inhibitor and RNAi-based gene silencing to disrupt EPHB4 activity, we found that these disruptions re-sensitize enzalutamide-resistant PCa to the drug both in vitro and in vivo Mechanistically, we found that EPHB4 stimulates the AR by inducing proto-oncogene c-Myc (c-Myc) expression. Taken together, these results provide critical insight into the mechanism of enzalutamide resistance in PCa, potentially offering a therapeutic avenue for enhancing the efficacy of enzalutamide to better manage this common malignancy.

NOTCH signaling is activated in and contributes to resistance in enzalutamide-resistant prostate cancer cells.

Prostate cancer is the second leading cause of cancer death among men in the United States. The androgen receptor (AR) antagonist enzalutamide is a Food and Drug Administration-approved drug for treatment of patients with late-stage prostate cancer and is currently under clinical study for early-stage prostate cancer treatment. After a short positive response period, tumors will develop drug resistance. In this study using RNA-Seq and bioinformatics analyses, we observed that NOTCH signaling is a deregulated pathway in enzalutamide-resistant cells. NOTCH2 and c-MYC gene expression positively correlated with AR expression in samples from patient with hormone refractory disease in which AR expression levels correspond to those typically observed in enzalutamide resistance. Cleaved NOTCH1, HES1 (Hes family BHLH transcription factor 1), and c-MYC protein expression levels are elevated in two enzalutamide-resistant cell lines, MR49F and C4-2R, indicating NOTCH signaling activation. Moreover, inhibition of the overexpressed ADAM metallopeptidase domain 10 (ADAM10) in the resistant cells induces an exclusive reduction in cleaved NOTCH1 expression. Furthermore, exposure of enzalutamide-resistant cells to both PF-03084014 and enzalutamide increased cell death, decreased colony formation ability, and resensitized cells to enzalutamide. Knockdown of NOTCH1 in C4-2R increased enzalutamide sensitivity by decreasing cell proliferation and increasing cleaved PARP expression. In a 22RV1 xenograft model, PF-03084014 and enzalutamide decreased tumor growth through reducing cell proliferation and increasing apoptosis. These results indicate that NOTCH1 signaling may contribute to enzalutamide resistance in prostate cancer, and inhibition of NOTCH signaling can resensitize resistant cells to enzalutamide.

Inhibition of cholesterol biosynthesis overcomes enzalutamide resistance in castration-resistant prostate cancer (CRPC).

Enzalutamide, a nonsteroidal second-generation antiandrogen, has been recently approved for the management of castration-resistant prostate cancer (CRPC). Although patients can benefit from enzalutamide at the beginning of this therapy, acquired enzalutamide resistance usually occurs within a short period. This motivated us to investigate the mechanism involved and possible approaches for overcoming enzalutamide resistance in CRPC. In the present study, we found that 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMGCR), a crucial enzyme in the mevalonate pathway for sterol biosynthesis, is elevated in enzalutamide-resistant prostate cancer cell lines. HMGCR knockdown could resensitize these cells to the drug, and HMGCR overexpression conferred resistance to it, suggesting that aberrant HMGCR expression is an important enzalutamide-resistance mechanism in prostate cancer cells. Furthermore, enzalutamide-resistant prostate cancer cells were more sensitive to statins, which are HMGCR inhibitors. Of note, a combination of simvastatin and enzalutamide significantly inhibited the growth of enzalutamide-resistant prostate cancer cells in vitro and tumors in vivo Mechanistically, simvastatin decreased protein levels of the androgen receptor (AR), which was further reduced in combination with enzalutamide. We observed that the decrease in AR may occur through simvastatin-mediated inhibition of the mTOR pathway, whose activation was associated with increased HMGCR and AR expression. These results indicate that simvastatin enhances the efficacy of enzalutamide-based therapy, highlighting the therapeutic potential of statins to overcome enzalutamide resistance in CRPC.

Increased expression of GATA zinc finger domain containing 1 through gene amplification promotes liver cancer by directly inducing phosphatase of regenerating liver 3.

We identified that GATA zinc finger domain containing 1 (GATAD1), a transcriptional factor, was significantly up-regulated in hepatocellular carcinoma (HCC) through gene amplification. We demonstrated the critical role, molecular mechanisms, and clinical implications of GATAD1 as a novel oncogenic factor in HCC. We found that GATAD1 protein was expressed in 76.6% of primary HCCs (85/111) but silenced in normal liver tissues. Gene amplification of GATAD1 was positively correlated with its overexpression in primary HCCs (R = 0.629, P < 0.0001). GATAD1 significantly increased cell proliferation, G1 -S cell cycle transition, and migration/invasion but suppressed apoptosis in liver cell lines and promoted tumor growth and lung metastasis in both xenograft and orthotopic mouse models. Mechanistically, GATAD1 induced the transcriptional expression of phosphatase of regenerating liver 3 (PRL3) by binding to its promoter identified by RNA sequencing and chromatin immunoprecipitation-PCR analyses. PRL3 played an oncogenic role in HCC. Knockdown of PRL3 blunted the tumorigenic effect of GATAD1. In addition, GATAD1 activated Akt signaling, evidenced by increased phosphorylation levels of total Akt, Akt1, Akt2, and Akt target glycogen synthase kinase 3ß, while knockdown of PRL3 abolished this effect of GATAD1. We further unveiled that PRL3 activated Akt signaling by dephosphorylating phosphatase and tensin homolog at tyrosine residue, thus reducing phosphatase and tensin homolog protein. The PRL3 inhibitor 5-[[5-bromo-2-[(2-bromophenyl)methoxy]phenyl]methylene]-2-thioxo-4-thiazolidinone significantly suppressed HCC growth by inhibiting Akt activation. Moreover, high GATAD1 nuclear protein expression was associated with poor survival of HCC patients as an independent prognostic factor. CONCLUSION: GATAD1 plays a pivotal oncogenic role in HCC by directly inducing PRL3 transcription to activate the Akt signaling pathway. GATAD1 may serve as an independent poor prognostic factor for HCC patients. (Hepatology 2018;67:2302-2319).

GESTATIONAL WEIGHT GAIN AS AN INDEPENDENT RISK FACTOR FOR MACROSOMIA IN WOMEN WITH INTERMEDIATE STATE GESTATIONAL BLOOD GLUCOSE.

Objective: Macrosomia is closely associated with gestational diabetes mellitus (GDM) but its relationship with maternal intermediate state gestational blood glucose (ISGBG; normal fasting blood glucose and 7.8 mmol/L <1 hour blood glucose [BG] <10 mmol/L or 6.7 mmol/L <2 hour BG <8.5 mmol/L) is unclear. Here, we analyzed the clinical characteristics and pregnancy outcomes and explored risk factors for macrosomia in women with ISGBG. Methods: A total of 847 women with normal glucose tolerance gestation, 330 with ISGBG, and 99 with GDM were included. Maternal and fetal clinical data were collected and 3-point BG following oral glucose tolerance test, fasting insulin, glycated hemoglobin, and blood lipids profile were measured. Results: The incidence rate of macrosomia among the neonates of women with ISGBG was as high as 10.9%. In the ISGBG group, prepregnancy body mass index (BMI), gestational weight gain (GWG) and the proportion of women with excessive GWG (eGWG) were significantly higher in women with macrosomia compared with those who delivered a normal weight neonate. In women with ISGBG, neonate weight was positively correlated with maternal prepregnancy weight (r = 0.183, P<.01), prepregnancy BMI (r = 0.135, P<.01), and GWG (r = 0.255, P<.01), and negatively correlated with high-density lipoprotein cholesterol (r = -0.172, P<.01). Nonetheless, only eGWG was an independent risk factor (odds ratio = 3.18, 95% confidence interval = 1.26 to 7.88, P<.05) for macrosomia. The risk of macrosomia in pregnant women with prepregnancy BMI <25 kg/m2 or BMI ≥25 kg/m2 and eGWG was 3.39 and 3.27 times, respectively. Conclusion: The incidence rate of macrosomia is increased in women with ISGBG and eGWG is the strongest independent risk factor. In order to reduce the risk for macrosomia, timely lifestyle intervention to promote appropriate weight gain during pregnancy deserves evaluation. Abbreviations: AUC = area under the curve; BG = blood glucose; 1 hour BG = 1 hour blood glucose after OGTT; 2 hour BG = 2 hour blood glucose after OGTT; BMI = body mass index; CI = confidence interval; eGWG = excessive gestational weight gain; FBG = fasting blood glucose; FINS = fasting insulin; GDM = gestational diabetes mellitus; HbA1c = glycated hemoglobin; HDL-C = high-density lipoprotein cholesterol; HOMA-IR = homeostasis model assessment of insulin resistance index; ISGBG = intermediate state gestation blood glucose; LDL-C = low-density lipoprotein cholesterol; Ln = natural logarithm; MLBW = mature low birth weight; NGTG = normal glucose tolerance gestation; OGTT = oral glucose tolerance test; OR = odds ratio; SD = standard deviation.

p15RS/RPRD1A (p15INK4b-related sequence/regulation of nuclear pre-mRNA domain-containing protein 1A) interacts with HDAC2 in inhibition of the Wnt/ß-catenin signaling pathway.

We previously reported that p15RS (p15INK4b-related sequence), a regulation of nuclear pre-mRNA domain containing protein, inhibited Wnt signaling by interrupting the formation of the ß-catenin·TCF4 complex. However, how p15RS functions as an intrinsic repressor to repress transcription remains unclear. In this study, we show that p15RS, through a specific interaction with HDAC2 (histone deacetylase 2), a deacetylase that regulates gene transcription, maintains histone H3 in a deacetylated state in the promoter region of Wnt-targeted genes where ß-catenin·TCF4 is bound. We observed that histone deacetylase inhibitors impair the ability of p15RS in inhibiting Wnt/ß-catenin signaling. Depletion of HDAC2 markedly disabled p15RS inhibition of Wnt/ß-catenin-mediated transcription. Interestingly, overexpression of p15RS decreases the level of acetylated histone H3 in the c-MYC promoter. Finally, we demonstrate that p15RS significantly enhances the association of HDAC2 and TCF4 and enhances the occupancy of HDAC2 to DNA, resulting in the deacetylation of histone H3 and the failure of ß-catenin interaction. We propose that p15RS acts as an intrinsic transcriptional repressor for Wnt/ß-catenin-mediated gene transcription at least partially through recruiting HDAC2 to occupy the promoter and maintaining deacetylated histone H3.

CREPT/RPRD1B, a recently identified novel protein highly expressed in tumors, enhances the ß-catenin·TCF4 transcriptional activity in response to Wnt signaling.

CREPT (cell cycle-related and expression elevated protein in tumor)/RPRD1B (regulation of nuclear pre-mRNA domain-containing protein 1B), highly expressed during tumorigenesis, was shown to enhance transcription of CCND1 and to promote cell proliferation by interacting with RNA polymerase II. However, which signaling pathway is involved in CREPT-mediated activation of gene transcription remains unclear. In this study, we reveal that CREPT participates in transcription of the Wnt/ß-catenin signaling activated genes through the ß-catenin and the TCF4 complex. Our results demonstrate that CREPT interacts with both ß-catenin and TCF4, and enhances the association of ß-catenin with TCF4, in response to Wnt stimulation. Furthermore, CREPT was shown to occupy at TCF4 binding sites (TBS) of the promoters of Wnt-targeted genes under Wnt stimulation. Interestingly, depletion of CREPT resulted in decreased occupancy of ß-catenin on TBS, and over-expression of CREPT enhances the activity of the ß-catenin·TCF4 complex to initiate transcription of Wnt target genes, which results in up-regulated cell proliferation and invasion. Our study suggests that CREPT acts as an activator to promote transcriptional activity of the ß-catenin·TCF4 complex in response to Wnt signaling.

Elevating PLK1 overcomes BETi resistance in prostate cancer via triggering BRD4 phosphorylation-dependent degradation in mitosis.

Bromodomain-containing protein 4 (BRD4) has emerged as a promising therapeutic target in prostate cancer (PCa). Understanding the mechanisms of BRD4 stability could enhance the clinical response to BRD4-targeted therapy. In this study, we report that BRD4 protein levels are significantly decreased during mitosis in a PLK1-dependent manner. Mechanistically, we show that BRD4 is primarily phosphorylated at T1186 by the CDK1/cyclin B complex, recruiting PLK1 to phosphorylate BRD4 at S24/S1100, which are recognized by the APC/CCdh1 complex for proteasome pathway degradation. We find that PLK1 overexpression lowers SPOP mutation-stabilized BRD4, consequently rendering PCa cells re-sensitized to BRD4 inhibitors. Intriguingly, we report that sequential treatment of docetaxel and JQ1 resulted in significant inhibition of PCa. Collectively, the results support that PLK1-phosphorylated BRD4 triggers its degradation at M phase. Sequential treatment of docetaxel and JQ1 overcomes BRD4 accumulation-associated bromodomain and extra-terminal inhibitor (BETi) resistance, which may shed light on the development of strategies to treat PCa.

A kinome-wide CRISPR screen identifies CK1α as a target to overcome enzalutamide resistance of prostate cancer.

Enzalutamide (ENZA), a second-generation androgen receptor antagonist, has significantly increased progression-free and overall survival of patients with metastatic prostate cancer (PCa). However, resistance remains a prominent obstacle in treatment. Utilizing a kinome-wide CRISPR-Cas9 knockout screen, we identified casein kinase 1α (CK1α) as a therapeutic target to overcome ENZA resistance. Depletion or pharmacologic inhibition of CK1α enhanced ENZA efficacy in ENZA-resistant cells and patient-derived xenografts. Mechanistically, CK1α phosphorylates the serine residue S1270 and modulates the protein abundance of ataxia telangiectasia mutated (ATM), a primary initiator of DNA double-strand break (DSB)-response signaling, which is compromised in ENZA-resistant cells and patients. Inhibition of CK1α stabilizes ATM, resulting in the restoration of DSB signaling, and thus increases ENZA-induced cell death and growth arrest. Our study details a therapeutic approach for ENZA-resistant PCa and characterizes a particular perspective for the function of CK1α in the regulation of DNA-damage response.

Single-cell analysis characterizes PLK1 as a catalyst of an immunosuppressive tumor microenvironment in LUAD.

PLK1 (Polo-like kinase 1) plays a critical role in the progression of lung adenocarcinoma (LUAD). Recent studies have unveiled that targeting PLK1 improves the efficacy of immunotherapy, highlighting its important role in the regulation of tumor immunity. Nevertheless, our understanding of the intricate interplay between PLK1 and the tumor microenvironment (TME) remains incomplete. Here, using genetically engineered mouse model and single-cell RNA-seq analysis, we report that PLK1 promotes an immunosuppressive TME in LUAD, characterized with enhanced M2 polarization of tumor associated macrophages (TAM) and dampened antigen presentation process. Mechanistically, elevated PLK1 coincides with increased secretion of CXCL2 cytokine, which promotes M2 polarization of TAM and diminishes expression of class II major histocompatibility complex (MHC-II) in professional antigen-presenting cells. Furthermore, PLK1 negatively regulates MHC-II expression in cancer cells, which has been shown to be associated with compromised tumor immunity and unfavorable patient outcomes. Taken together, our results reveal PLK1 as a novel modulator of TME in LUAD and provide possible therapeutic interventions.

Phosphorylation of AHR by PLK1 promotes metastasis of LUAD via DIO2-TH signaling.

Metastasis of Lung adenocarcinoma (LUAD) is a major cause of death in patients. Aryl hydrocarbon receptor (AHR) is an important transcription factor involved in the initiation and progression of lung cancer. Polo-like kinase 1 (PLK1), a serine/threonine kinase, is an oncogene that promotes the malignancy of multiple cancer types. Nonetheless, the interaction between these two factors and significance in lung cancer remains to be determined. Here, we demonstrate that PLK1 phosphorylates AHR at S489 in LUAD, which leads to epithelial-mesenchymal transition (EMT) and metastatic events. RNA-seq analyses show that type 2 deiodinase (DIO2) is responsible for EMT and enhanced metastatic potential. DIO2 converts tetraiodothyronine (T4) to triiodothyronine (T3), which then activates thyroid hormone signaling. In vitro and in vivo experiments demonstrate that treatment with T3 or T4 promotes the metastasis of LUAD, whereas depletion of DIO2 or deiodinase inhibitor disrupts this property. Taken together, our results identify the phosphorylation of AHR by PLK1 as a mechanism leading to the progression of LUAD and provide possible therapeutic interventions for this event.

Rab21 attenuates EGF-mediated MAPK signaling through enhancing EGFR internalization and degradation.

Epidermal growth factor (EGF) receptor (EGFR) signal transduction is regulated by endocytosis where many Rab proteins play an important role in the determination of the receptor recycle or degradation. In an effort to better understand how EGF signaling is regulated, we examined the role of Rab21 in regulation of the degradation and signal transduction of the EGFR. Using a transient expression protocol in HEK293T and HeLa cells, we found that Rab21 enhanced the degradation of EGFR through accelerating its internalization in both EGF-independent and EGF-dependent manners. We further demonstrated that Rab21 interacted with EGFR by immunoprecipitation experiments. Interestingly, we observed that overexpression of Rab21 attenuated EGF-mediated mitogen-activated protein kinase (MAPK) signaling by inducing EGFR degradation. Taken together, these data suggest that Rab21 plays a negative role in the EGF-mediated MAPK signaling pathway.

Development of personalized classifier based on metastasis and the immune microenvironment to predict the prognosis of osteosarcoma patients.

Background: Osteosarcoma is a common malignant bone tumor with a poor prognosis. The progression and metastasis of osteosarcoma are significantly influenced by the tumor microenvironment (TME). This study aimed to develop a personalized classifier based on metastasis and immune cells in the TME to achieve better prognostic prediction in osteosarcoma. Methods: Firstly, osteosarcoma metastasis-related differentially expressed genes (DEGs) and infiltrating immune cells in the TME were analyzed using a series of bioinformatics methods. The metastasis-related gene signature (MRS) and TME score of osteosarcoma patients were then developed. On this basis, a personalized MRS-TME classifier was constructed and validated in other clinical cohorts and different subgroups. In addition, the relationship between the MRS-related genes and the immune microenvironment was also clarified. Finally, the signaling pathways and immune response genes in osteosarcoma patients among different MRS-TME subgroups were analyzed to explore the underlying molecular mechanism. Results: We first identified the metastasis-related DEGs in osteosarcoma, which were primarily involved in the muscle system process, calcium ion homeostasis, cell chemotaxis, and leukocyte migration. A personalized MRS-TME classifier was then constructed by integrating the MRS (10 genes) and TME (six immune cells) scores. The MRS-TME classifier demonstrated a potent capacity of predicting the survival prognosis in diverse osteosarcoma cohorts as well as in the clinical feature subgroups. The MRS score was negatively associated with the TME score, and patients in the MRSlow/TMEhigh subgroup exhibited a better prognosis compared to all other subgroups. Significant differences existed between the cellular signaling pathways and immune response profiles among the different MRS-TME subgroups, especially in relation to the metabolism-related biological processes and the inflammatory response. Conclusions: The MRS-TME classifier might be a beneficial tool to aid in the prognostic evaluation and risk stratification of osteosarcoma patients.

GSTM2 is a key molecular determinant of resistance to SG-ARIs.

Prostate cancer (PCa) continues to threaten men's health, and treatment targeting the androgen receptor (AR) pathway is the major therapy for PCa patients. Several second-generation androgen receptor inhibitors (SG-ARIs), including enzalutamide (ENZ), apalutamide (APA) and darolutamide (DARO), have been developed to better block the activity of AR. Unavoidably, emergence of resistance to these novel drugs still persists. Herein, we identified glutathione S-transferase Mu 2 (GSTM2) as an important determinant in the acquisition of resistance to SG-ARIs. Elevated GSTM2 was detected in enzalutamide-resistant (ENZ-R) PCa, and overexpression of GSTM2 in naïve enzalutamide-sensitive (ENZ-S) cells effectively transformed them to ENZ-R PCa. Aryl hydrocarbon receptor (AhR), the upstream transcription factor, was implicated in the overexpression of GSTM2 in ENZ-R cells. Mechanistically, GSTM2 antagonized the effect of ENZ by rescuing cells from oxidative stress-associated damage and activation of p38 MAPK pathway. Surprisingly, high GSTM2 levels also associated with cross-resistance to APA and DARO. Taking together, these results provide new insight to ameliorate resistance to SG-ARIs and improve treatment outcome.

The kinase PLK1 promotes the development of Kras/Tp53-mutant lung adenocarcinoma through transcriptional activation of the receptor RET.

Increased abundance of polo-like kinase 1 (PLK1) is observed in various tumor types, particularly in lung adenocarcinoma (LUAD). Here, we found that PLK1 accelerated the progression of LUAD through a mechanism that was independent of its role in mediating mitotic cell division. Analysis of human tumor databases revealed that increased PLK1 abundance in LUAD correlated with mutations in KRAS and p53, with tumor stage, and with reduced survival in patients. In a mouse model of KRASG12D-driven, p53-deficient LUAD, PLK1 overexpression increased tumor burden, decreased tumor cell differentiation, and reduced animal survival. PLK1 overexpression in cultured cells and mice indirectly increased the expression of the gene encoding the receptor tyrosine kinase RET by phosphorylating the transcription factor TTF-1. Signaling by RET and mutant KRAS in these tumors converged to activate the mitogen-activated protein kinase (MAPK) pathway. Pharmacological inhibition of the MAPK pathway kinase MEK combined with inhibition of either RET or PLK1 markedly suppressed tumor growth. Our findings show that PLK1 can amplify MAPK signaling and reveal a potential target for stemming progression in lung cancers with high PLK1 abundance.

Decreased Monocyte Count Is Associated With Gestational Diabetes Mellitus Development, Macrosomia, and Inflammation.

CONTEXT: The immune system plays a central role in the pathophysiology of gestational diabetes mellitus (GDM). Monocytes, the main innate immune cells, are especially important in the maintenance of a normal pregnancy. OBJECTIVE: Here, we investigated the potential effect of monocytes in GDM. METHODS: Monocyte count was monitored throughout pregnancy in 214 women with GDM and 926 women without in a case-control and cohort study. Circulating levels of inflammatory cytokines, placenta-derived macrophages, and their products were measured. RESULTS: Throughout pregnancy, monocyte count was significantly decreased in women with GDM, and was closely associated with glucose level, insulin resistance, and newborn weight. First-trimester monocyte count outperformed that of the second and third trimester as a risk factor and diagnostic predictor of GDM and macrosomia both in the case-control and cohort study. In addition, our cohort study showed that as first-trimester monocyte count decreased, GDM and macrosomia incidence, glucose level, and newborn weight increased in a stepwise manner. Risk of GDM started to decrease rapidly when first-trimester monocyte count exceeded 0.48 × 109/L. Notably, CD206 and interleukin 10 (IL-10) were significantly lower, whereas CD80, CD86, tumor necrosis factor α (TNF-α), and interleukin 6 (IL-6) were higher both in GDM placental tissue and peripheral blood. First-trimester monocyte count was positively related to IL-10 and CD206, but negatively related to CD80, CD86, TNF-α, and IL-6. CONCLUSION: Decreased monocyte count throughout pregnancy was closely associated with the development of GDM, macrosomia, and the chronic inflammatory state of GDM. First-trimester monocyte count has great potential as an early diagnostic marker of GDM.

p15RS attenuates Wnt/{beta}-catenin signaling by disrupting {beta}-catenin·TCF4 Interaction.

The formation of a ß-catenin·TCF4 complex in the nucleus of cells is well known as a prerequisite for the transcription of Wnt target genes. Although many co-factors have been identified to regulate the activity of the ß-catenin·TCF4 complex, it remains unclear how the complex association is negatively regulated. In this study, we report that p15RS, a negative regulator of the cell cycle, blocks ß-catenin·TCF4 complex formation and inhibits Wnt signaling. We observed that p15RS interacts with ß-catenin and TCF4. Interestingly, whereas the interaction of p15RS with ß-catenin is increased, its interaction with TCF4 is decreased upon Wnt1 stimulation. Moreover, overexpression of p15RS reduces the interaction of ß-catenin with TCF4, whereas the depletion of p15RS enhances their interaction. We further demonstrate that overexpression of p15RS suppresses canonical Wnt signaling and results in retarded cell growth, whereas depletion of p15RS shows an enhanced effect on Wnt signaling. We analyzed that inhibition of Wnt signaling by p15RS leads to decreased expression of CYCLIN D1 and c-MYC, two Wnt targeted genes critical for cell growth. Our data suggest that p15RS inhibits Wnt signaling by interrupting ß-catenin·TCF4 complex formation and that Wnt signaling initiates downstream gene expression by removing p15RS from promoters.