HMBA is a Putative HSP70 Activator Stimulating HEXIM1 Expression that is Down-regulated by Estrogen

Hexamethylene bis-acetamide inducible protein 1 (HEXIM1) is identified as a novel inhibitor of estrogen stimulated breast cell growth, and it suppresses estrogen receptor-a transcriptional activity. HEXIM1 protein level has been found to be downregulated by estrogens. Recently, HEXIM1 has been found to inhibit androgen receptor transcriptional activity as well. Researchers have used Hexamethylene bisacetamide (HMBA) for decades to stimulate HEXIM1 expression, which also inhibit estrogen stimulated breast cancer cell gene activation and androgen stimulated prostate cancer gene activation. However, the direct molecular targets of HMBA that modulate the induction of HEXIM1 expression in mammalian cells have not been identified. Based on HMBA and its more potent analog 4a1, we designed molecular probes to pull down the binding proteins of these compounds. Via proteomic approach and biological assays, we demonstrate that HMBA and 4a1 are actually heat shock protein 70 (HSP70) binders. The known HSP70 activator showed similar activity as HMBA and 4a1 to induce HEXIM1 expression, suggesting that HMBA and 4a1 might be putative HSP70 activators. Molecular target identification of HMBA and 4a1 could lead to further structural optimization of the parental compound to generate more potent derivatives to stimulate HEXIM1 expression, which could be a novel approach for hormone dependent breast cancer and prostate cancer treatment

HMBA is a Putative HSP70 Activator Stimulating HEXIM1 Expression that is Down-regulated by Estrogen

Hexamethylene bis-acetamide inducible protein 1 (HEXIM1) is identified as a novel inhibitor of estrogen stimulated breast cell growth, and it suppresses estrogen receptor-a transcriptional activity. HEXIM1 protein level has been found to be downregulated by estrogens. Recently, HEXIM1 has been found to inhibit androgen receptor transcriptional activity as well. Researchers have used Hexamethylene bisacetamide (HMBA) for decades to stimulate HEXIM1 expression, which also inhibit estrogen stimulated breast cancer cell gene activation and androgen stimulated prostate cancer gene activation. However, the direct molecular targets of HMBA that modulate the induction of HEXIM1 expression in mammalian cells have not been identified. Based on HMBA and its more potent analog 4a1, we designed molecular probes to pull down the binding proteins of these compounds. Via proteomic approach and biological assays, we demonstrate that HMBA and 4a1 are actually heat shock protein 70 (HSP70) binders. The known HSP70 activator showed similar activity as HMBA and 4a1 to induce HEXIM1 expression, suggesting that HMBA and 4a1 might be putative HSP70 activators. Molecular target identification of HMBA and 4a1 could lead to further structural optimization of the parental compound to generate more potent derivatives to stimulate HEXIM1 expression, which could be a novel approach for hormone dependent breast cancer and prostate cancer treatment

Transcriptomic-metabolomic reprogramming in EGFR-mutant NSCLC early adaptive drug escape linking TGFβ2-bioenergetics-mitochondrial priming.

The impact of EGFR-mutant NSCLC precision therapy is limited by acquired resistance despite initial excellent response. Classic studies of EGFR-mutant clinical resistance to precision therapy were based on tumor rebiopsies late during clinical tumor progression on therapy. Here, we characterized a novel non-mutational early adaptive drug-escape in EGFR-mutant lung tumor cells only days after therapy initiation, that is MET-independent. The drug-escape cell states were analyzed by integrated transcriptomic and metabolomics profiling uncovering a central role for autocrine TGFβ2 in mediating cellular plasticity through profound cellular adaptive Omics reprogramming, with common mechanistic link to prosurvival mitochondrial priming. Cells undergoing early adaptive drug escape are in proliferative-metabolic quiescent, with enhanced EMT-ness and stem cell signaling, exhibiting global bioenergetics suppression including reverse Warburg, and are susceptible to glutamine deprivation and TGFβ2 inhibition. Our study further supports a preemptive therapeutic targeting of bioenergetics and mitochondrial priming to impact early drug-escape emergence using EGFR precision inhibitor combined with broad BH3-mimetic to interrupt BCL-2/BCL-xL together, but not BCL-2 alone

The Crucial p53-Dependent Oncogenic Role of JAB1 in Osteosarcoma in vivo

Osteosarcoma (OS) is the most common primary bone cancer and ranks amongst the leading causes of cancer mortality in young adults. Jun activation domain binding protein 1 (JAB1) is overexpressed in many cancers and has recently emerged as a novel target for cancer treatment. However, the role of JAB1 in osteosarcoma was virtually unknown. In this study, we demonstrate that JAB1-knockdown in malignant osteosarcoma cell lines significantly reduced their oncogenic properties, including proliferation, colony formation, and motility. We also performed RNA-sequencing analysis in JAB1-knockdown OS cells and identified 4110 genes that are significantly differentially expressed. This demonstrated for the first time that JAB1 regulates a large and specific transcriptome in cancer. We also found that JAB1 is overexpressed in human OS and correlates with a poor prognosis. Moreover, we generated a novel mouse model that overexpresses Jab1 specifically in osteoblasts upon a TP53 heterozygous sensitizing background. Interestingly, by 13 months of age, a significant proportion of these mice spontaneously developed conventional OS. Finally, we demonstrate that a novel, highly specific small molecule inhibitor of JAB1, CSN5i-3, reduces osteosarcoma cell viability and has specific effects on the ubiquitin-proteasome system in OS. Thus, we show for the first time that the overexpression of JAB1 in vivo can result in accelerated spontaneous tumor formation in a p53-dependent manner. In summary, JAB1 might be a unique target for the treatment of osteosarcoma and other cancers

Treatment of atypical central neurocytoma in a child with high dose chemotherapy and autologous stem cell rescue

The authors describe a 9 month old female with recurrent atypical central neurocytoma and leptomeningeal spread treated with high dose chemotherapy, autologous stem cell rescue, and adjuvant therapy. She had a complete response to therapy and was disease free at 4 years of age until a recurrence 6 months later. The use of intensive chemotherapy followed by autologous stem cell rescue for atypical neurocytoma may be considered as an adjunct to surgical therapy in young patients with atypical neurocytoma not amenable to radiation therapy

Stroma Regulates Increased Epithelial Lateral Cell Adhesion in 3D Culture: A Role for Actin/Cadherin Dynamics

Cell shape and tissue architecture are controlled by changes to junctional proteins and the cytoskeleton. How tissues control the dynamics of adhesion and cytoskeletal tension is unclear. We have studied epithelial tissue architecture using 3D culture models and found that adult primary prostate epithelial cells grow into hollow acinus-like spheroids. Importantly, when co-cultured with stroma the epithelia show increased lateral cell adhesions. To investigate this mechanism further we aimed to: identify a cell line model to allow repeatable and robust experiments; determine whether or not epithelial adhesion molecules were affected by stromal culture; and determine which stromal signalling molecules may influence cell adhesion in 3D epithelial cell cultures.The prostate cell line, BPH-1, showed increased lateral cell adhesion in response to stroma, when grown as 3D spheroids. Electron microscopy showed that 9.4% of lateral membranes were within 20 nm of each other and that this increased to 54% in the presence of stroma, after 7 days in culture. Stromal signalling did not influence E-cadherin or desmosome RNA or protein expression, but increased E-cadherin/actin co-localisation on the basolateral membranes, and decreased paracellular permeability. Microarray analysis identified several growth factors and pathways that were differentially expressed in stroma in response to 3D epithelial culture. The upregulated growth factors TGFβ2, CXCL12 and FGF10 were selected for further analysis because of previous associations with morphology. Small molecule inhibition of TGFβ2 signalling but not of CXCL12 and FGF10 signalling led to a decrease in actin and E-cadherin co-localisation and increased paracellular permeability.In 3D culture models, paracrine stromal signals increase epithelial cell adhesion via adhesion/cytoskeleton interactions and TGFβ2-dependent mechanisms may play a key role. These findings indicate a role for stroma in maintaining adult epithelial tissue morphology and integrity

Radiation-induced lung injury in vivo: Expression of transforming growth factor—Beta precedes fibrosis

Cytokine release from irradiated cells has been postulated to start soon after irradiation preceding detectable clinical and pathological manifestation of lung injury. The expression of transforming growth factor beta (TGF β ), a fibrogenic and radiation-inducible cytokine, was studied from 1–16 weeks after the 15 and 30 Gray (Gy) of thoracic irradiation to rats. Thoracic irradiation caused an increase in TGF β protein in bronchoalveolar lavage (BAL) fluid peaking at 3–6 weeks as compared to sham-irradiated control rats. Steady state TGF β mRNA expression as shown by whole lung northern blot assay paralleled the TGF β protein expression in BAL fluid. The peak of TGF β protein increase in BAL fluid between 3 and 6 weeks coincided with the initial influx of inflammatory cells in BAL fluid, but preceded histologically discernable pulmonary fibrosis that was not apparent until 8–10 weeks after irradiation. In conclusion, TGF β and mRNA and protein upregulation preceded the radiation-induced pulmonary fibrosis, suggesting a pathogenetic role in the development of radiation fibrosis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44516/1/10753_2005_Article_BF01486737.pd

Autocrine control of MTW9/PL2 rat mammary tumor cell growth

Breast cancer is among a group of conditional neoplasias derived from endocrine target tissues and retain the ability to be influenced by their hormonal background. However, a gradual progression of breast neoplasias towards greater estrogen autonomy is known to occur in nearly all cases studied, seriously compromising the efficacy of hormone therapy. The mechanism responsible for the acquisition of estrogen autonomy was investigated in this dissertation, using the estrogen-responsive MTW9/PL rat mammary tumor cell line. In an attempt to select for highly estrogen-autonomous clonal variants these cells were passaged twice through castrated male rats for a total of 16 weeks, and the resulting cell line (MTW9B) was cloned. Unexpectedly, greater than 40% of the resulting clones were either estrogen-responsive or dependent in vivo, and along with further studies suggested that their survival depended on the residence of autonomous cells within the population via a non-host mediated mechanism. The possibility that the estrogen-dependent cells were supported by a growth factor activity secreted from autonomous cells was examined. In a serum-free defined medium (DDM-3) MTW9/PL2 (rederived MTW9/PL) cells were able to grow in the absence of exogenous growth factors for over ten days, at 60% to 80% of the serum-stimulated rate. Remarkably, a very potent, acid and heat labile, mitogenic activity was identified in DDM-3 conditioned by MTW9/PL2 cells when assayed on COMMA-D normal mouse mammary epithelial cells. This activity was not attributable to IGF-I, IGF-II, PDGF, EGF, TGF$\alpha$ or TGF$\beta$. The MTW9/PL2 derived growth factor activity was purified over 1000-fold from medium conditioned by cells in culture and from tumors in vivo. The physical properties of this activity(s) were very similar to those reported basic-fibroblast growth factor (bFGF), such as acid and heat lability, affinity to heparin, and competitive binding to FGF receptors. Consistent with their activities on normal mouse mammary cells, partially purified conditioned medium and tumor derived growth factor activity(s) and bFGF were active on MTB2 (estrogen-dependent clonally derived MTW9B) cells. These results support the notion that: (1) a bFGF-like activity is the major autocrine mitogen secreted by MTW9/PL2 rat mammary tumor cells, and is present in sufficient quantities to account for tumor epithelial and fibroblastic cell growth, and tumor angiogenesis, and (2) the progression to estrogen autonomy may be triggered by constitutive production of bFGF, or a bFGF-like molecule