Cabazitaxel (CBZ) is approved for docetaxel‐resistant castration‐resistant prostate cancer (CRPC). However, efficacy of CBZ for CRPC is limited and there are no effective treatments for CBZ‐resistant ...CRPC. In order to investigate the CBZ‐resistant mechanism, the establishment of a CBZ‐resistant cell line is urgently needed. We established CBZ‐resistant CRPC cell lines DU145CR and PC3CR by incubating DU145 and PC3 cells with gradually increasing concentrations of CBZ for approximately 2 years. We analyzed the gene expression profiles and cell cycle changes using microarray and flow cytometry. Pathway analysis revealed DU145CR cells had enhanced gene clusters of cell division and mitotic nuclear division. Enhancement of ERK signaling was detected in DU145CR cells. DU145CR cells had resistance to G2/M arrest induced by CBZ through ERK signaling activation. The MEK inhibitor PD184352 significantly inhibited cell proliferation of DU145CR. In contrast to DU145CR, PC3CR cells had enhancement of PI3K/AKT signaling. The PI3K/mTOR inhibitor NVP‐BEZ 235 had a significant antitumor effect in PC3CR cells. Cabazitaxel ‐resistant CRPC cells established in our laboratory had enhancement of cell cycle progression signals and resistance to G2/M arrest induced by CBZ. Enhancement of ERK signaling or PI3K/AKT signaling were detected in the cell lines, so ERK or PI3K/AKT could be therapeutic targets for CBZ‐resistant CRPC.
Efficacy of cabazitaxel (CBZ) for castration‐resistant prostate cancer (CRPC) is limited and there are no effective treatments for CBZ‐resistant CRPC. Results of analysis in CBZ‐resistant CRPC cell lines show that MAPK and PI3K/AKT signaling might be therapeutic targets for CBZ‐resistant CRPC.
Neuroendocrine prostate cancer (NEPC) is an aggressive malignancy with no effective targeted therapies. The oncogenic MUC1-C protein is overexpressed in castration-resistant prostate cancer (CRPC) ...and NEPC, but its specific role is unknown. Here, we demonstrate that upregulation of MUC1-C in androgen-dependent PC cells suppresses androgen receptor (AR) axis signaling and induces the neural BRN2 transcription factor. MUC1-C activates a MYC→BRN2 pathway in association with induction of MYCN, EZH2 and NE differentiation markers (ASCL1, AURKA and SYP) linked to NEPC progression. Moreover, MUC1-C suppresses the p53 pathway, induces the Yamanaka pluripotency factors (OCT4, SOX2, KLF4 and MYC) and drives stemness. Targeting MUC1-C decreases PC self-renewal capacity and tumorigenicity, suggesting a potential therapeutic approach for CRPC and NEPC. In PC tissues, MUC1 expression associates with suppression of AR signaling and increases in BRN2 expression and NEPC score. These results highlight MUC1-C as a master effector of lineage plasticity driving progression to NEPC.
Opportunities for genetic counseling and germline BRCA1/2 (BRCA) testing are increasing in Japan owing to cancer genomic profiling testing and companion diagnostics being covered by national health ...insurance for patients with BRCA-related cancers. These tests are useful not only to judge whether platinum agents and PARP inhibitors are indicated but also to reveal an autosomal-dominant inherited cancer syndrome: hereditary breast and ovarian cancer. In individuals with germline BRCA variants, risk of cancers of the breast, ovary, pancreas, and prostate is significantly increased at various ages of onset, but the stomach, uterus, biliary tract, and skin might also be at risk. For women with pathogenic BRCA variants, breast awareness and image analyses should be initiated in their 20s, and risk-reducing procedures such as mastectomy are recommended starting in their 30s, with salpingo-oophorectomy in their late 30s. For male BRCA pathogenic variant carriers, prostatic surveillance should be applied using serum prostate-specific antigen starting in their 40s. For both sexes, image examinations ideally using endoscopic ultrasound and magnetic resonance cholangiopancreatography and blood testing should begin in their 50s for pancreatic surveillance. Homologous recombination pathway-associated genes are also causative candidates. Variant pathogenicity needs to be evaluated every 6-12 months when results are uncertain for clinical significance. Genetic counseling needs to be offered to the blood relatives of the pathogenic variant carriers with suitable timing. We review the recommended cross-organ BRCA risk management in Japan.
Interactive networks of transcription factors (TFs) have critical roles in epigenetic and gene regulation for cancer progression. It is required to clarify underlying mechanisms for transcriptional ...activation through concerted efforts of TFs. Here, we show the essential role of disease phase-specific TF collaboration changes in advanced prostate cancer (PC). Investigation of the transcriptome in castration-resistant PC (CRPC) revealed OCT4 as a key TF in the disease pathology. OCT4 confers epigenetic changes by promoting complex formation with FOXA1 and androgen receptor (AR), the central signals for the progression to CRPC. Meanwhile, OCT4 facilitates a distinctive complex formation with nuclear respiratory factor 1 (NRF1) to gain chemo-resistance in the absence of AR. Mechanistically, we reveal that OCT4 increases large droplet formations with AR/FOXA1 as well as NRF1 in vitro. Disruption of TF collaborations using a nucleoside analogue, ribavirin, inhibited treatment-resistant PC tumor growth. Thus, our findings highlight the formation of TF collaborations as a potent therapeutic target in advanced cancer.
The taxane cabazitaxel (CBZ) is a promising treatment for docetaxel-resistant castration-resistant prostate cancer (CRPC). However, the survival benefit with CBZ for patients with CRPC is limited. ...This study used screening tests for candidate drugs targeting CBZ-resistant-related gene expression and identified pimozide as a potential candidate for overcoming CBZ resistance in CRPC.
We established CBZ-resistant cell lines, DU145CR and PC3CR by incubating DU145 cells and PC3 cells with gradually increasing concentrations of CBZ. We performed in silico drug screening for candidate drugs that could reprogram the gene expression signature of a CBZ-resistant prostate cancer cells using a Connectivity Map. The in vivo effect of the drug combination was tested in xenograft mice models.
We identified pimozide as a promising candidate drug for CBZ-resistant CRPC. Pimozide had a significant antitumor effect on DU145CR cells. Moreover, combination treatment with pimozide and CBZ had a synergic effect for DU145CR cells in vitro and in vivo. Microarray analysis identified AURKB and KIF20A as potential targets of pimozide in CBZ-resistant CRPC. DU145CR had significantly higher AURKB and KIF20A expression compared with a non-CBZ-resistant cell line. Inhibition of AURKB and KIF20A had an antitumor effect in DU145CR xenograft tumors. Higher expression of AURKB and KIF20A was a poor prognostic factor of TGCA prostate cancer cohort. CBZ-resistant prostate cancer tissues in our institution had higher AURKB and KIF20A expression.
Pimozide appears to be a promising drug to overcome CBZ resistance in CRPC by targeting AURKB and KIF20A.
The prognostic role of CD44v9, a variant isoform of CD44 and a new cell surface marker of cancer stem cells, remains unclear in bladder cancer (BC) patients. Furthermore, limited information is ...available on the functional role of sulfasalazine (SSZ), which could modulate the CD44v9‐xCT system in order to enhance cisplatin (CDDP)‐induced cytotoxicity and inhibit the metastatic potential of BC. CD44v9 protein expression was examined immunohistochemically in 63 muscle invasive BC (MIBC) patients who underwent radical cystectomy. CD44v9 expression was independently associated with disease recurrence and cancer‐specific death in MIBC. Cytotoxic effects, glutathione levels, and reactive oxygen species production by SSZ and CD44v9 and phospho‐p38MAPK protein expression by SSZ with or without CDDP were assessed in MBT‐2V cells with highly metastatic potential. Sulfasalazine exerted cytotoxic effects against MBT‐2V cells by inhibiting glutathione levels and inducing the production of reactive oxygen species. Sulfasalazine in combination with CDDP appeared to exert strong cytotoxic effects against MBT‐2V cells by inhibiting CD44v9 expression and upregulating phospho‐p38MAPK expression. The inhibitory effects of SSZ with or without CDDP were also investigated using an MBT‐2V lung metastatic model. In the murine lung metastatic BC model, SSZ significantly prolonged animal survival. Furthermore, the combination of SSZ with CDDP exerted stronger inhibitory effects on the establishment of lung tumor nodules than SSZ or CDDP alone. CD44v9 expression could be a clinical biomarker for predicting poor outcomes in MIBC patients. Sulfasalazine in combination with CDDP has potential as a novel therapy against metastatic BC.
This is the first report to show the therapeutic effects of not only sulfasalazine (SSZ), but also the combination of SSZ and cisplatin (CDDP) in a metastatic bladder cancer model, suggesting the potential of SSZ and CDDP combination therapy for metastatic bladder cancer.
Cabazitaxel (CBZ) is approved for the treatment of docetaxel-resistant castration-resistant prostate cancer (CRPC). However, its efficacy against CRPC is limited, and there are no effective ...treatments for CBZ-resistant CRPC. This study explored the optimal treatment for CRPC in the post-cabazitaxel setting. PC3 (CBZ-sensitive) and PC3CR cells (CBZ-resistant) were used in this study. We performed in silico drug screening for candidate drugs that could reprogram the gene expression signature of PC3CR cells. The in vivo effect of the drug combination was tested in xenograft mice models. We identified etoposide (VP16) as a promising treatment candidate for CBZ-resistant CRPC. The WST assay revealed that VP16 had a significant antitumor effect on PC3CR cells. PC3CR cells exhibited significantly higher topoisomerase II alpha (TOP2A) expression than PC3 cells. Higher TOP2A expression was a poor prognostic factor in The Cancer Genome Atlas prostate cancer cohort. In the Fred Hutchinson Cancer Research Center dataset, docetaxel-exposed tissues and metastatic tumors had higher TOP2A expression. In addition, VP16 significantly inhibited the growth of tumors generated from both cell lines. Based on these findings, VP16-based chemotherapy may be an optimal treatment for CPRC in the post-CBZ setting.
Mucin 1 C‐terminal subunit (MUC1‐C) has been introduced as a key regulator for acquiring drug resistance in various cancers, but the functional role of MUC1‐C in urothelial carcinoma (UC) cells ...remains unknown. We aimed to elucidate the molecular mechanisms underlying the acquisition of cisplatin (CDDP) resistance through MUC1‐C oncoprotein in UC cells. MUC1‐C expression was examined immunohistochemically in tumor specimens of 159 UC patients who received CDDP‐based perioperative chemotherapy. As a result, moderate to high MUC1‐C expression was independently associated with poor survival in UC patients. Using human bladder cancer cell lines and CDDP‐resistant (CR) cell lines, we compared the expression levels of MUC1‐C, multiple drug resistance 1 (MDR1), the PI3K‐AKT‐mTOR pathway, and x‐cystine/glutamate transporter (xCT) to elucidate the biological mechanisms contributing to the acquisition of chemoresistance. MUC1‐C was strongly expressed in CR cell lines, followed with MDR1 expression via activation of the PI3K‐AKT‐mTOR pathway. MUC1‐C also stabilized the expression of xCT, which enhanced antioxidant defenses by increasing intracellular glutathione (GSH) levels. MUC1 down‐regulation showed MDR1 inhibition along with PI3K‐AKT‐mTOR pathway suppression. Moreover, it inhibited xCT stabilization and resulted in significant decreases in intracellular GSH levels and increased reactive oxygen species (ROS) generation. The MUC1‐C inhibitor restored sensitivity to CDDP in CR cells and UC murine xenograft models. In conclusion, we found that MUC1‐C plays a pivotal role in the acquisition of CDDP resistance in UC cells, and therefore the combined treatment of CDDP with a MUC1‐C inhibitor may become a novel therapeutic option in CR UC patients.
Our present study demonstrated that mucin 1 C‐terminal peptide (MUC1‐C) plays a pivotal role in the acquisition of cisplatin (CDDP) resistance via multiple drug resistance 1 regulation and x‐cystine/glutamate transporter stabilization in urothelial cancer cells. The combined treatment of CDDP with a MUC1‐C inhibitor, GO‐203, may become a novel therapeutic option in CDDP‐resistant UC patients.
ABSTRACT
Sphingomyelin synthase 2 (SMS2) is the synthetic enzyme of sphingomyelin (SM), which regulates membrane fluidity and microdomain structure. SMS2 plays a role in LPS‐induced lung injury and ...inflammation; however, its role in inflammation‐mediated tumorigenesis is unclear. We investigated the effect of SMS2 deficiency on dextran sodium sulfate (DSS)–induced murine colitis and found inhibition of DSS‐induced inflammation in SMS2‐deficient (SMS2−/−) mice. DSS treatment induced a significant increase in ceramide levels, with a decrease of SM levels in SMS2−/− colon tissue, and demonstrated attenuation of the elevation of both inflammation‐related gene expression and proinflammatory cytokines and chemokines, leukocyte infiltration, and MAPK and signal transducer and activator of transcription 3 activation. After undergoing transplantation of wild‐type bone marrow, SMS2−/− mice also exhibited inhibition of DSS‐induced inflammation in the colon, which suggested that SMS2 deficiency in bone marrow–derived immune cells was not involved in the inhibition of colitis. Finally, in an azoxymethane/DSS‐induced cancer model, SMS2 deficiency significantly decreased tumor incidence in the colon. Our results demonstrate that SMS2 deficiency inhibits DSS‐induced colitis and subsequent colitis‐associated colon cancer via inhibition of colon epithelial cell–mediated inflammation; therefore, inhibition of SMS2 may be a potential therapeutic target for human colitis and colorectal cancer.—Ohnishi, T., Hashizume, C., Taniguchi, M., Furumoto, H., Han, J., Gao, R., Kinami, S., Kosaka, T., Okazaki, T. Sphingomyelin synthase 2 deficiency inhibits the induction of murine colitis‐associated colon cancer. FASEB J. 31, 3816–3830 (2017). www.fasebj.org—Ohnishi, Toshio, Hashizume, Chieko, Taniguchi, Makoto, Furumoto, Hidehiro, Han, Jia, Gao, Rongfen, Kinami, Shinichi, Kosaka, Takeo, Okazaki, Toshiro Sphingomyelin synthase 2 deficiency inhibits the induction of murine colitis‐associated colon cancer. FASEB J. 31, 3816–3830 (2017)
To stratify the heterogeneity of prostate cancer (PCa) with seminal vesicle invasion (SVI) immunologically after radical prostatectomy focusing on the tumor microenvironment. We retrospectively ...reviewed the clinicopathological data of 71 PCa patients with SVI, which is known as a factor of very high-risk PCa. Preoperative clinical variables and postoperative pathological variables were evaluated as predictors of biochemical recurrence (BCR) with a multivariate logistic regression. Immune cell infiltration including the CD8-positive cell (CD8
cell) and CD204-positive M2-like macrophage (CD204
cell) was investigated by immunohistochemistry. The cumulative incidence and risk of BCR were assessed with a Kaplan-Meier analysis and competing risks regression. A higher CD8
cell count in the SVI area significantly indicated a favorable prognosis for cancers with SVI (p = 0.004). A lower CD204
cell count in the SVI area also significantly indicated a favorable prognosis for cancers with SVI (p = 0.004). Furthermore, the combination of the CD8
and CD204
cell infiltration ratio of the SVI area to the main tumor area was a significant factor for BCR in the patients with the PCa with SVI (p = 0.001). In PCa patients with SVI, the combination of CD8
and CD204
cell infiltration is useful to predict the prognosis.
PDF
