Differential expression of the multidrug resistance 1 (MDR1) protein in prostate cancer cells is independent from anticancer drug treatment and Y box binding protein 1 (YB-1) activity

Inhibition of protein translational machinery in triple-negative breast cancer as a promising therapeutic strategy

Y-box binding protein-1 (YB-1) is a proto-oncogenic protein associated with protein translation regulation. It plays a crucial role in the development and progression of triple-negative breast cancer (TNBC). In this study, we describe a promising approach to inhibit YB-1 using SU056, a small-molecule inhibitor. SU056 physically interacts with YB-1 and reduces its expression, which helps to restrain the progression of TNBC. Proteome profiling analysis indicates that the inhibition of YB-1 by SU056 can alter the proteins that regulate protein translation, an essential process for cancer cell growth. Preclinical studies on human cells, mice, and patient-derived xenograft tumor models show the effectiveness of SU056. Moreover, toxicological studies have shown that SU056 treatment and dosing are well tolerated without any adverse effects. Overall, our study provides a strong foundation for the further development of SU056 as a potential treatment option for patients with TNBC by targeting YB-1.

Emerging Proteins in CRPC: Functional Roles and Clinical Implications

Prostate cancer (PCa) is the most common cancer in men in the western world, but the lack of specific and sensitive markers often leads to overtreatment of prostate cancer which eventually develops into castration-resistant prostate cancer (CRPC). Novel protein markers for diagnosis and management of CRPC will be promising. In this review, we systematically summarize and discuss the expression pattern of emerging proteins in tissue, cell lines, and serum when castration-sensitive prostate cancer (CSPC) progresses to CRPC; focus on the proteins involved in CRPC growth, invasion, metastasis, metabolism, and immune microenvironment; summarize the current understanding of the regulatory mechanisms of emerging proteins in CSPC progressed to CRPC at the molecular level; and finally summarize the clinical applications of emerging proteins as diagnostic marker, prognostic marker, predictive marker, and therapeutic marker.

A comprehensive review of the functions of YB-1 in cancer stemness, metastasis and drug resistance

The Y Box binding protein 1 (YB-1) is a member of the highly conserved Cold Shock Domain protein family with multifunctional properties both in the cytoplasm and inside the nucleus. YB-1 is also involved in various cellular functions, including regulation of transcription, mRNA stability, and splicing. Recent studies have associated YB-1 with the regulation of the malignant phenotypes in several tumor types. In this review article, we provide an in-depth and expansive review of the literature pertaining to the multiple physiological functions of YB-1. We will also review the role of YB-1 in cancer development, progression, metastasis, and drug resistance in various malignancies, with more weight on literature published in the last decade. The methodology included querying databases PubMed, Embase, and Google Scholar for Y box binding protein 1, YB-1, YBX1, and Y-box-1.

Y box binding protein 1 inhibition as a targeted therapy for ovarian cancer

Y box binding protein 1 (YB-1) is a multifunctional protein associated with tumor progression and the emergence of treatment resistance (TR). Here, we report an azopodophyllotoxin small molecule, SU056, that potently inhibits tumor growth and progression via YB-1 inhibition. This YB-1 inhibitor inhibits cell proliferation, resistance to apoptosis in ovarian cancer (OC) cells, and arrests in the G1 phase. Inhibitor treatment leads to enrichment of proteins associated with apoptosis and RNA degradation pathways while downregulating spliceosome pathway. In vivo, SU056 independently restrains OC progression and exerts a synergistic effect with paclitaxel to further reduce disease progression with no observable liver toxicity. Moreover, in vitro mechanistic studies showed delayed disease progression via inhibition of drug efflux and multidrug resistance 1, and significantly lower neurotoxicity as compared with etoposide. These data suggest that YB-1 inhibition may be an effective strategy to reduce OC progression, antagonize TR, and decrease patient mortality.

Mechanisms of Taxane Resistance

The taxane family of chemotherapy drugs has been used to treat a variety of mostly epithelial-derived tumors and remain the first-line treatment for some cancers. Despite the improved survival time and reduction of tumor size observed in some patients, many have no response to the drugs or develop resistance over time. Taxane resistance is multi-faceted and involves multiple pathways in proliferation, apoptosis, metabolism, and the transport of foreign substances. In this review, we dive deeper into hypothesized resistance mechanisms from research during the last decade, with a focus on the cancer types that use taxanes as first-line treatment but frequently develop resistance to them. Furthermore, we will discuss current clinical inhibitors and those yet to be approved that target key pathways or proteins and aim to reverse resistance in combination with taxanes or individually. Lastly, we will highlight taxane response biomarkers, specific genes with monitored expression and correlated with response to taxanes, mentioning those currently being used and those that should be adopted. The future directions of taxanes involve more personalized approaches to treatment by tailoring drug-inhibitor combinations or alternatives depending on levels of resistance biomarkers. We hope that this review will identify gaps in knowledge surrounding taxane resistance that future research or clinical trials can overcome.

MDR1 gene polymorphism correlated with pathological characteristics and prognosis in patients with primary hepatocellular carcinoma receiving interventional therapy

The aim of this study was to explore the relationship of multidrug resistance gene 1 (MDR1) C1236T and C3435T single nucleotides polymorphisms (SNPs) with hepatocellular carcinoma (HCC) pathological features and prognosis. A total of 143 patients with HCC were treated with transcatheter arterial chemoembolization. Moreover, 251 controls were included in the study. C1236T and C3435T single nucleotide polymorphisms (SNPs) were detected by PCR-RFLP. Association of C1236T and C3435T SNPs with HCC was analyzed subsequently. There was no significant difference in genotypes distribution between HCC group and control group (P>0.05), indicating comparability. Among patients with portal vein tumor thrombus, the CC+CT genotype of C1236T locus was significantly higher than that of TT genotype (P=0.031). The median progression-free survival after interventional therapy for patients with C3435T genotype T (TC+TT) and C genotype (CC) was 36 and 18 months, respectively. CC and TC+TT genotype patients with C1236T loci showed statistically significant differences in tumor size stratification (χ=4.006, P=0.045). When tumor diameter was less than 5 cm, 5-10 cm, and more than 10 cm, the mean survival time of C and T genotypes was decreased gradually. The logistic regression model suggested that lesion size, blood volume value, and permeability surface value were influential factors for response to chemoradiotherapy (all P<0.05). Univariate analysis showed that postoperative chemotherapy, portal vein tumor thrombus, and capsular invasion were correlated with overall survival in patients with HCC. Cox proportional hazard model showed that postoperative chemotherapy, capsule invasion, and portal vein tumor thrombus were independent factors of overall survival after interventional therapy in patients with HCC (all P<0.05). C1236T genotype may predict changes in pathological features of patients with HCC to a certain extent, and C3435T SNP can be used as one of the prognostic factors of HCC. Postoperative chemotherapy and portal vein tumor thrombus are independent factors of overall survival in patients with HCC.

Impact of nuclear YAP1 expression in residual cancer after neoadjuvant chemohormonal therapy with docetaxel for high-risk localized prostate cancer

Background

Although docetaxel-based chemohormonal therapy (CHT) is one of the standard treatments for castration-resistant prostate cancer (CRPC), pertinent biomarkers and precise mechanisms involved in the resistance for CHT for CRPC remain unknown. We investigated the relationship between chemohormonal resistance and the expression of steroid receptors and Hippo pathway proteins using a docetaxel-resistant prostate cancer (PCa) cell line and human PCa tissues in patients who underwent surgery with and without neoadjuvant therapy.

Methods

A docetaxel-resistant subline (22Rv1-DR) was generated to assess Hippo pathway protein expression and the effect of YAP1 inhibition on cellular characteristics. A tissue microarray with 203 cores from 70 high-risk localized PCa tissues was performed to assess steroid receptor and Hippo pathway protein expressions.

Results

Nuclear YAP (nYAP) expression was higher in 22RV-1-DR than in parental 22Rv-1 and YAP1 knockdown suppressed cell proliferation of 22Rv1-DR. Steroid receptor and Hippo pathway protein expressions varied among three different neoadjuvant groups, and nYAP1 expression was the highest in the CHT group. The patients with high nYAP in residual cancer after neoadjuvant CHT had a significantly higher biochemical recurrence (BCR) rate than those with low nYAP1. On multivariate analysis, the high nYAP1 was an independent prognostic factor for BCR.

Conclusions

nYAP expression is a potential biomarker in high-risk patients treated with docetaxel-based CHT. Steroid receptors and Hippo pathway proteins may play a role in the chemohormonal resistance in advanced PCa.

Dirty deeds done dirt cheap: sensitization of prostate cancer cells to abiraterone treatment using hydroxylated polychlorinated biphenyls

Effective targeting of androgen biosynthesis by the 17α-hydroxylase/17,20-lyase inhibitor abiraterone prolongs survival in a variety of prostate cancer patients. However, resistance to abiraterone treatment occurs frequently and the development of new drugs supporting or complementing abiraterone therapy is urgently needed. We recently reported antiproliferative and proapoptotic effects of hydroxylated polychlorinated biphenyls (PCBs) on various blood cell lines in vitro. Here we report the biological evaluation of the PCB28 derived OH-metabolites 3-OHCB28 or 3'-OHCB28 in prostate cancer cells. Depending on concentration, both metabolites inhibit the growth of PC3 cells, a cell line representing later stages of advanced prostate cancer. In addition 3'-OHCB28 reduced the necessary concentration of abiraterone required for the inhibition of PC3 cells by a factor of 4. Western blot analysis of cytoprotective heatshock proteins (HSP) implicated a significant reduction of HSP27 expression by 3'-OHCB28 in PC3 cells. Given the known HSP27 suppressive role of abiraterone, our results therefore suggest, that that the pharmacological interaction between abiraterone and 3'-OHCB28 in PC3 cells could be produced by the combined effect of both substances on the expression of HSPs, especially the expression of HSP27. Including the known dose response linkages and pharmacokinetic characteristics of the OH-metabolites described here, we conclude, that the use of hydroxylated PCBs can be supportive for the anti-proliferative treatment of prostate cancer and merits further investigation.

Major glucuronide metabolites of testosterone are primarily transported by MRP2 and MRP3 in human liver, intestine and kidney

Testosterone glucuronide (TG), androsterone glucuronide (AG), etiocholanolone glucuronide (EtioG) and dihydrotestosterone glucuronide (DHTG) are the major metabolites of testosterone (T), which are excreted in urine and bile. Glucuronides can be deconjugated to active androgen in gut lumen after biliary excretion, which in turn can affect physiological levels of androgens. The goal of this study was to quantitatively characterize the mechanisms by which TG, AG, EtioG and DHTG are eliminated from liver, intestine, and kidney utilizing relative expression factor (REF) approach. Using vesicular transport assay with recombinant human MRP2, MRP3, MRP4, MDR1 and BCRP, we first identified that TG, AG, EtioG, and DHTG were primarily substrates of MRP2 and MRP3, although lower levels of transport were also observed with MDR1 and BCRP vesicles. The transport kinetic analyses revealed higher intrinsic clearances of TG by MRP2 and MRP3 as compared to that of DHTG, AG, and EtioG. MRP3 exhibited higher affinity for the transport of the studied glucuronides than MRP2. We next quantified the protein abundances of these efflux transporters in vesicles and compared the same with pooled total membrane fractions isolated from human tissues by quantitative LC-MS/MS proteomics. The fractional contribution of individual transporters (f_t) was estimated by proteomics-based physiological scaling factors, i.e., transporter abundance in whole tissue versus vesicles, and corrected for inside-out vesicles (determined by 5'-nucleotidase assay). The glucuronides of inactive androgens, AG and EtioG were preferentially transported by MRP3, whereas the glucuronides of active androgens, TG and DHTG were mainly transported by MRP2 in liver. Efflux by bile canalicular transport may indicate the potential role of enterohepatic recirculation in regulating the circulating active androgens after deconjugation in the gut. In intestine, MRP3 possibly contributes most to the efflux of these glucuronides. In kidney, all studied glucuronides seemed to be preferentially effluxed by MRP2 and MDR1 (for EtioG). These REF based analysis need to be confirmed with in vivo findings. Overall, characterization of the efflux mechanisms of T glucuronide metabolites is important for predicting the androgen disposition and interindividual variability, including drug-androgen interaction in humans. The mechanistic data can be extrapolated to other androgen relevant organs (e.g. prostate, testis and placenta) by integrating these data with quantitative tissue proteomics data.

Human cancer-associated fibroblasts enhance glutathione levels and antagonize drug-induced prostate cancer cell death

Drug resistance is a major problem in cancer therapy. A growing body of evidence demonstrates that the tumor microenvironment, including cancer-associated fibroblasts (CAFs), can modulate drug sensitivity in tumor cells. We examined the effect of primary human CAFs on p53 induction and cell viability in prostate cancer cells on treatment with chemotherapeutic drugs. Co-culture with prostate CAFs or CAF-conditioned medium attenuated DNA damage and the p53 response to chemotherapeutic drugs and enhanced prostate cancer cell survival. CAF-conditioned medium inhibited the accumulation of doxorubicin, but not taxol, in prostate cancer cells in a manner that was associated with increased cancer cell glutathione levels. A low molecular weight fraction (<3 kDa) of CAF-conditioned medium had the same effect. CAF-conditioned medium also inhibited induction of reactive oxygen species (ROS) in both doxorubicin- and taxol-treated cancer cells. Our findings suggest that CAFs can enhance drug resistance in cancer cells by inhibiting drug accumulation and counteracting drug-induced oxidative stress. This protective mechanism may represent a novel therapeutic target in cancer.