| 1. |
- Huang, Junchi, et al.
(author)
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Magnetic Resonance Imaging as a Tool for Monitoring Intratibial Growth of Experimental Prostate Cancer Metastases in Mice
- 2023
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In: Methods and Protocols (MP). - 2409-9279. ; 6:6
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Journal article (peer-reviewed)abstract
- Bone metastases cause morbidity and mortality in several human cancer forms. Experimental models are used to unravel the mechanisms and identify possible treatment targets. The location inside the skeleton complicates accurate assessment. This study evaluates the performance of magnetic resonance imaging (MRI) of prostate cancer tumors growing intratibially in mice. MRI detected intratibial tumor lesions with a sensitivity and specificity of 100% and 89%, respectively, compared to histological evaluation. Location and some phenotypical features could also be readily detected with MRI. Regarding volume estimation, the correlation between MRI and histological assessment was high (p < 0.001, r = 0.936). In conclusion, this study finds MRI to be a reliable tool for in vivo, non-invasive, non-ionizing, real-time monitoring of intratibial tumor growth.
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| 2. |
- Huang, Junchi, et al.
(author)
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MYB alternative promoter activity is increased in adenoid cystic carcinoma metastases and is associated with a specific gene expression signature
- 2024
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In: ORAL ONCOLOGY. - 1368-8375 .- 1879-0593. ; 151
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Journal article (peer-reviewed)abstract
- Objective: Adenoid cystic carcinoma (ACC) is a head and neck cancer with a poor long-term prognosis that shows frequent local recurrences and distant metastases. The tumors are characterized by MYB oncogene activation and are notoriously unresponsive to systemic therapies. The biological underpinnings behind therapy resistance of disseminated ACC are largely unknown. Here, we have studied the molecular and clinical significance of MYB alternative promoter (TSS2) usage in ACC metastases. Materials and methods: MYB TSS2 activity was investigated in primary tumors and metastases from 26 ACC patients using RNA-sequencing and quantitative real-time PCR analysis. Differences in global gene expression between MYB TSS2 high and low cases were studied, and pathway analyses were performed. Results: MYB TSS2 activity was significantly higher in ACC metastases than in primary tumors (median activity 15.1 vs 3.0, P = 0.0003). MYB TSS2 high ACC metastases showed a specific gene expression signature, including increased expression of multi-drug resistance genes and canonical MYB target genes, and suppression of the p53 and NOTCH pathways. Conclusions: Collectively, our findings indicate that elevated MYB TSS2 activity is associated with metastases, potential drug resistance, and augmented MYB-driven gene expression in ACC. Our study advocates the need for new therapies that specifically target MYB and drug resistance mechanisms in disseminated ACC.
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| 3. |
- Huang, Junchi, et al.
(author)
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Osteoclasts directly influence castration-resistant prostate cancer cells
- 2022
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In: Clinical and Experimental Metastasis. - : Springer Nature. - 0262-0898 .- 1573-7276. ; 39:5, s. 801-814
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Journal article (peer-reviewed)abstract
- Metastasis to bone is the leading cause of death from prostate cancer. Interaction between tumor cells and bone cells can promote progression and influence tumor phenotype. It is known that prostate cancer cells support osteoclast differentiation, and degradation of bone matrix by osteoclasts releases growth factors stimulating tumor cell proliferation and invasion. In the present study osteolytic (PC-3) and osteoblastic (LNCaP-19) castration-resistant prostate cancer (CRPC) cells were co-cultured with mature osteoclasts or their precursor cells (RAW 264.7) to characterize direct effects of mature osteoclasts on CRPC cells. Osteoclasts increased proliferation and decrease apoptosis of CRPC cells as assessed with flow cytometry. RNA sequencing revealed that osteolytic CRPC cells were more responsive to osteoclast stimulation regarding gene expression, but the overall induced expression patterns were similar between the prostate cancer cell lines. Genes related to DNA repair were upregulated by osteoclasts, while genes related to endoplasmic reticulum stress-induced apoptosis and cholesterol synthesis were downregulated. The results of this study shows that osteoclasts directly influence CRPC cells, increasing proliferation, decreasing apoptosis, and affecting gene expression pathways that can affect sensitivity to DNA damage and endoplasmic reticulum function. This suggests targeting of osteoclasts to be a possible way to affect efficacy of other drugs by combination regimens in treating prostate cancer metastases.
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| 4. |
- Huang, Junchi
(author)
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The roles of osteoclasts and RUNX2 in the progression of prostate cancer bone metastases
- 2021
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Doctoral thesis (other academic/artistic)abstract
- Metastasis to the skeleton is the major cause of death from prostate cancer (PC). Patients with metastatic PC are treated with androgen deprivation therapy (ADT) to decrease testosterone levels and thereby inhibit further growth of the tumor. However, a castration-resistant prostate cancer (CRPC) inevitably develops, often with activated androgen receptor (AR) signaling due to increased sensitivity of the AR or intratumoral steroidogenesis enabling AR activation despite castrate levels of testosterone in the circulation. In the skeleton, PC cells interact with the bone microenvironment. It is known that degradation of bone matrix, one effect of androgen deprivation, releases growth factors stimulating tumor growth. We have previously identified the role of osteoblasts, bone-building cells, in promoting tumor growth and intratumoral steroidogenesis. A direct effect of their balancing counterpart, the bone-degrading osteoclasts, has previously not been investigated. In the present thesis, osteoclasts were found to stimulate proliferation and inhibit apoptosis of both osteolytic and osteoblastic CRPC cells in an in vitro co-culture model. Gene expression was affected by osteoclast co-culture, more extensively so in the osteolytic model, where for example DNA repair genes were upregulated by osteoclasts. In both cell lines, genes related to endoplasmic reticulum stress-induced apoptosis were downregulated by osteoclasts. Osteoclasts were also found to increase expression of the osteoblast transcription factor RUNX2 in the osteoblastic CRPC cell line, while the high levels in the osteolytic cell line was not affected. RUNX2 was found to promote expression of steroidogenic enzymes and the androgen regulated prostate-specific antigen (PSA) in CRPC cells co-cultured with osteoclasts. To evaluate the importance of RUNX2 for CRPC growth in bone, RUNX2 was knocked-out (KO) in osteoblastic CRPC cells which then was implanted in the tibia of immune-deficient mice. Magnetic resonance imaging (MRI) was validated and used to give accurate size and location of intratibial CRPC xenografts. It was shown that RUNX2-KO CRPC cells grew slower and formed smaller intratibial tumors compared to control cells. Both expression of steroidogenic enzymes and PSA-expression was inhibited by depletion of RUNX2. In conclusion, this thesis show that both osteoclasts and RUNX2 affect CRPC growth and steroidogenesis. Treatment for metastatic PC include further targeting of the AR axis, a strategy that may be counteracted by both RUNX2 and interaction with osteoclasts. In addition, the effect of targeted therapy towards cells with defect DNA repair, such as PARP-inhibitors, may be affected by the action of osteoclasts. Thus, the results of the present thesis suggest targeting osteoclasts or RUNX2 in combinatory therapeutic approaches to be investigated.
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| 5. |
- Huang, Junchi, et al.
(author)
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The roles of RUNX2 and osteoclasts in regulating expression of steroidogenic enzymes in castration-resistant prostate cancer cells
- 2021
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In: Molecular and Cellular Endocrinology. - : Elsevier BV. - 0303-7207 .- 1872-8057. ; 535
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Journal article (peer-reviewed)abstract
- Intratumoral steroidogenesis is involved in development of castration-resistant prostate cancer (CRPC) as bone metastases. The osteoblast transcription factor RUNX2 influences steroidogenesis and is induced in CRPC cells by osteoblasts. This study investigates osteoclastic influence on RUNX2 in intratumoral steroidogenesis. Steroidogenic enzymes and steroid receptors were detected with immunohistochemistry in xenograft intratibial tumors from CRPC cells. In vitro, expression of RUNX2 was increased by osteoclasts in osteoblastic LNCaP-19 cells, but not in osteolytic PC-3. Silencing of RUNX2 downregulates expression of CYP11A1, CYP17A1 and HSD3B1 in LNCaP-19 cells co-cultured with osteoclasts, leading to inhibition of KLK3 expression. Osteoclasts promoted CYP11A1 and RUNX2 promoted AKR1C3, HSD17B3 and CYP19A1, but suppressed ESR2 in PC-3 cells. This study shows that osteoclasts promote RUNX2 regulated induction of key steroidogenic enzymes, influencing activation of androgen receptor in CRPC cells. The potential of RUNX2 as a target to inhibit progression of skeletal metastases of CRPC needs further investigation.
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| 6. |
- Peng, B., et al.
(author)
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Targeting Bcl-2 stability to sensitize cells harboring oncogenic ras
- 2015
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In: OncoTarget. - : Impact Journals, LLC. - 1949-2553. ; 6:26, s. 22328-22337
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Journal article (peer-reviewed)abstract
- The pro-survival factor Bcl-2 and its family members are critical determinants of the threshold of the susceptibility of cells to apoptosis. Studies are shown that cells harboring an oncogenic ras were extremely sensitive to the inhibition of protein kinase C (PKC) and Bcl-2 could antagonize this apoptotic process. However, it remains unrevealed how Bcl-2 is being regulated in this apoptotic process. In this study, we investigate the role of Bcl-2 stability in sensitizing the cells harboring oncogenic K-ras to apoptosis triggered by PKC inhibitor GO6976. We demonstrated that Bcl-2 in Swiss3T3 cells ectopically expressing or murine lung cancer LKR cells harboring K-ras rapidly underwent ubiquitin-dependent proteasome pathway after the treatment of GO6976, accompanied with induction of apoptosis. In this process, Bcl-2 formed the complex with Keap-1 and Cul3. The mutation of serine-17 and deletion of BH-2 or 4 was required for Bcl-2 ubiquitination and degradation, which elevate the signal threshold for the induction of apoptosis in the cells following PKC inhibition. Thus, Bcl-2 appears an attractive target for the induction of apoptosis by PKC inhibition in cancer cells expressing oncogenic K-ras.
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| 7. |
- Zhou, Xiaodong, et al.
(author)
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Regulation of the viability of Nf1 deficient cells by PKC isoforms.
- 2014
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In: Oncotarget. - 1949-2553. ; 5:21, s. 10709-17
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Journal article (peer-reviewed)abstract
- Suppression of protein kinase C (PKC) is known to be synthetically lethal with ras mutations in various types of cancer cells. The studies also showed that blockade of PKC affected the viability of Nf1 deficient cells. Since PKC family consists of more than 10 isoforms, our study aimed at identifying which isoform(s) played the crucial role in sensitizing Nf1 deficient cells to apoptosis. Using genetic and chemical PKC inhibitors, we demonstrated that the concurrent inhibition of PKC α and β induced Nf1 deficient ST or 96.2 cells, but not SNF02.2 cells with a normal Nf1 or ST cells ectopically expressing Nf1 effective domain gene, to apoptosis. In this process, PKC δ in Nf1 deficient cells, but not in ST/Nf1 cells, was upregulated and translocated to the nucleus. Furthermore, caspase 3 was cleaved and cytochrome c was released to the cytosol. Thus, it appeared that PKC δ and α/β are the crucial components for sustaining the aberrant Ras signaling and further viability of Nf1 deficient cells. The abrogation of these two isoforms activated their opponent PKC δ for switching on the caspase 3-governed apoptotic machinery.
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