Jacob New

Radiation-induced fibrosis: mechanisms and implications for therapy

PurposeRadiation-induced fibrosis (RIF) is a long-term side effect of external beam radiation therapy for the treatment of cancer. It results in a multitude of symptoms that significantly impact quality of life. Understanding the mechanisms of RIF-induced changes is essential to developing effective strategies to prevent long-term disability and discomfort following radiation therapy. In this review, we describe the current understanding of the etiology, clinical presentation, pathogenesis, treatment, and directions of future therapy for this condition.MethodsA literature review of publications describing mechanisms or treatments of RIF was performed. Specific databases utilized included PubMed and clinicaltrials.gov, using keywords “Radiation-Induced Fibrosis,” “Radiotherapy Complications,” “Fibrosis Therapy,” and other closely related terms.ResultsRIF is the result of a misguided wound healing response. In addition to causing direct DNA damage, ionizing radiation generates reactive oxygen and nitrogen species that lead to localized inflammation. This inflammatory process ultimately evolves into a fibrotic one characterized by increased collagen deposition, poor vascularity, and scarring. Tumor growth factor beta serves as the primary mediator in this response along with a host of other cytokines and growth factors. Current therapies have largely been directed toward these molecular targets and their associated signaling pathways.ConclusionAlthough RIF is widely prevalent among patients undergoing radiation therapy and significantly impacts quality of life, there is still much to learn about its pathogenesis and mechanisms. Current treatments have stemmed from this understanding, and it is anticipated that further elucidation will be essential for the development of more effective therapies.

Everolimus downregulates estrogen receptor and induces autophagy in aromatase inhibitor-resistant breast cancer cells

BackgroundmTOR inhibition of aromatase inhibitor (AI)-resistant breast cancer is currently under evaluation in the clinic. Everolimus/RAD001 (Afinitor®) has had limited efficacy as a solo agent but is projected to become part of combination therapy for AI-resistant breast cancer. This study was conducted to investigate the anti-proliferative and resistance mechanisms of everolimus in AI-resistant breast cancer cells.MethodsIn this study we utilized two AI-resistant breast cancer cell lines, MCF-7:5C and MCF-7:2A, which were clonally derived from estrogen receptor positive (ER+) MCF-7 breast cancer cells following long-term estrogen deprivation. Cell viability assay, colony formation assay, cell cycle analysis and soft agar anchorage-independent growth assay were used to determine the efficacy of everolimus in inhibiting the proliferation and tumor forming potential of MCF-7, MCF-7:5C, MCF-7:2A and MCF10A cells. Confocal microscopy and transmission electron microscopy were used to evaluate LC3-II production and autophagosome formation, while ERE-luciferase reporter, Western blot, and RT-PCR analyses were used to assess ER expression and transcriptional activity.ResultsEverolimus inhibited the proliferation of MCF-7:5C and MCF-7:2A cells with relatively equal efficiency to parental MCF-7 breast cancer cells. The inhibitory effect of everolimus was due to G1 arrest as a result of downregulation of cyclin D1 and p21. Everolimus also dramatically reduced estrogen receptor (ER) expression (mRNA and protein) and transcriptional activity in addition to the ER chaperone, heat shock protein 90 protein (HSP90). Everolimus restored 4-hydroxy-tamoxifen (4OHT) sensitivity in MCF-7:5C cells and enhanced 4OHT sensitivity in MCF-7 and MCF-7:2A cells. Notably, we found that autophagy is one method of everolimus insensitivity in MCF-7 breast cancer cell lines.ConclusionThis study provides additional insight into the mechanism(s) of action of everolimus that can be used to enhance the utility of mTOR inhibitors as part of combination therapy for AI-resistant breast cancer.

Secretory Autophagy in Cancer-Associated Fibroblasts Promotes Head and Neck Cancer Progression and Offers a Novel Therapeutic Target

Despite therapeutic advancements, there has been little change in the survival of patients with head and neck squamous cell carcinoma (HNSCC). Recent results suggest that cancer-associated fibroblasts (CAF) drive progression of this disease. Here, we report that autophagy is upregulated in HNSCC-associated CAFs, where it is responsible for key pathogenic contributions in this disease. Autophagy is fundamentally involved in cell degradation, but there is emerging evidence that suggests it is also important for cellular secretion. Thus, we hypothesized that autophagy-dependent secretion of tumor-promoting factors by HNSCC-associated CAFs may explain their role in malignant development. In support of this hypothesis, we observed a reduction in CAF-facilitated HNSCC progression after blocking CAF autophagy. Studies of cell growth media conditioned after autophagy blockade revealed levels of secreted IL6, IL8, and other cytokines were modulated by autophagy. Notably, when HNSCC cells were cocultured with normal fibroblasts, they upregulated autophagy through IL6, IL8, and basic fibroblast growth factor. In a mouse xenograft model of HNSCC, pharmacologic inhibition of Vps34, a key mediator of autophagy, enhanced the antitumor efficacy of cisplatin. Our results establish an oncogenic function for secretory autophagy in HNSCC stromal cells that promotes malignant progression. Cancer Res; 77(23); 6679-91. ©2017 AACR.

Inhibition of fibroblast growth factor receptor with AZD4547 mitigates juvenile nasopharyngeal angiofibroma

Juvenile nasopharyngeal angiofibroma (JNA) is a benign tumor that presents in adolescent males. Although surgical excision is the mainstay of treatment, recurrences complicate treatment. There is a need to develop less invasive approaches for management. JNA tumors are composed of fibroblasts and vascular endothelial cells. We identified fibroblast growth factor receptor (FGFR) and vascular endothelial growth factor (VEGF) expression in JNA‐derived fibroblasts. FGFR influences fibroblast proliferation and VEGF is necessary for angiogenesis. We hypothesized that targeting FGFR would mitigate JNA fibroblast proliferation, invasion, and migration, and that targeting the VEGF receptor would attenuate endothelial tubule formation.

Potent Antitumor Effects of a Combination of Three Nutraceutical Compounds

Head and neck squamous cell carcinoma (HNSCC) is associated with low survival, and the current aggressive therapies result in high morbidity. Nutraceuticals are dietary compounds with few side effects. However, limited antitumor efficacy has restricted their application for cancer therapy. Here, we examine combining nutraceuticals, establishing a combination therapy that is more potent than any singular component, and delineate the mechanism of action. Three formulations were tested: GZ17-S (combined plant extracts from Arum palaestinum, Peganum harmala and Curcuma longa); GZ17-05.00 (16 synthetic components of GZ17-S); and GZ17-6.02 (3 synthetic components of GZ17S; curcumin, harmine and isovanillin). We tested the formulations on HNSCC proliferation, migration, invasion, angiogenesis, macrophage viability and infiltration into the tumor and tumor apoptosis. GZ17-6.02, the most effective formulation, significantly reduced in vitro assessments of HNSCC progression. When combined with cisplatin, GZ17-6.02 enhanced anti-proliferative effects. Molecular signaling cascades inhibited by GZ17-6.02 include EGFR, ERK1/2, and AKT, and molecular docking analyses demonstrate GZ17-6.02 components bind at distinct binding sites. GZ17-6.02 significantly inhibited growth of HNSCC cell line, patient-derived xenografts, and murine syngeneic tumors in vivo (P < 0.001). We demonstrate GZ17-6.02 as a highly effective plant extract combination and pave the way for future clinical application in HNSCC.

Development and Characterization of an In Vitro Model for Radiation-Induced Fibrosis

Radiation-induced fibrosis (RIF) is a major side effect of radiotherapy in cancer patients with no effective therapeutic options. RIF involves excess deposition and aberrant remodeling of the extracellular matrix (ECM) leading to stiffness in tissues and organ failure. Development of preclinical models of RIF is crucial to elucidate the molecular mechanisms regulating fibrosis and to develop therapeutic approaches. In addition to radiation, the main molecular perpetrators of fibrotic reactions are cytokines, including transforming growth factor-β (TGF-β). We hypothesized that human oral fibroblasts would develop an in vitro fibrotic reaction in response to radiation and TGF-β. We demonstrate here that fibroblasts exposed to radiation followed by TGF-β exhibit a fibrotic phenotype with increased collagen deposition, cell proliferation, migration and invasion. In this in vitro model of RIF (RIFiv), the early biological processes involved in fibrosis are demonstrated, along with increased levels of several molecules including collagen 1α1, collagen XIα1, integrin-α2 and cyclin D1 mRNA in irradiated cells. A clinically relevant antifibrotic agent, pentoxifylline, and a curcumin analogue both mitigated collagen deposition in irradiated fibroblast cultures. In summary, we have established an in vitro model for RIF that facilitates the elucidation of molecular mechanisms in radiation-induced fibrosis and the development of effective therapeutic approaches.

Differential Gene Expression and Pathway Analysis in Juvenile Nasopharyngeal Angiofibroma Using RNA Sequencing

Juvenile nasopharyngeal angiofibroma (JNA) is a highly vascularized and locally aggressive tumor that typically presents in adolescent males. The molecular biology of this tumor remains understudied. We sought to identify differentially expressed genes in the JNA transcriptome through messenger RNA sequencing of primary fibroblasts from 2 tumor explants and tonsil tissue from tumor-free subjects. In total, 1088 significant, differentially expressed genes were identified with 749 upregulated and 339 downregulated. Pathway analysis identified a number of activated signaling pathways, most notably, the vascular endothelial growth factor (VEGF) pathway (adjusted overlap P = .03). VEGF-A showed a 4.4-fold upregulation in JNA samples. In addition, the angiogenic receptor, fibroblast growth factor receptor 2 (FGFR2), was not present in tumor-free samples but increased in JNA. We validate these findings with immunohistochemistry, demonstrating upregulation of VEGF and FGFR2 in patient sections. Inhibition of the VEGF or FGFR signaling axes may have therapeutic potential in the treatment of JNA.

Cancer-Associated Fibroblasts Drive Glycolysis in a Targetable Signaling Loop Implicated in Head and Neck Squamous Cell Carcinoma Progression

Despite aggressive therapies, head and neck squamous cell carcinoma (HNSCC) is associated with a less than 50% 5-year survival rate. Late-stage HNSCC frequently consists of up to 80% cancer-associated fibroblasts (CAF). We previously reported that CAF-secreted HGF facilitates HNSCC progression; however, very little is known about the role of CAFs in HNSCC metabolism. Here, we demonstrate that CAF-secreted HGF increases extracellular lactate levels in HNSCC via upregulation of glycolysis. CAF-secreted HGF induced basic FGF (bFGF) secretion from HNSCC. CAFs were more efficient than HNSCC in using lactate as a carbon source. HNSCC-secreted bFGF increased mitochondrial oxidative phosphorylation and HGF secretion from CAFs. Combined inhibition of c-Met and FGFR significantly inhibited CAF-induced HNSCC growth in vitro and in vivo (P < 0.001). Our cumulative findings underscore reciprocal signaling between CAF and HNSCC involving bFGF and HGF. This contributes to metabolic symbiosis and a targetable therapeutic axis involving c-Met and FGFR.Significance: HNSCC cancer cells and CAFs have a metabolic relationship where CAFs secrete HGF to induce a glycolytic switch in HNSCC cells and HNSCC cells secrete bFGF to promote lactate consumption by CAFs. Cancer Res; 78(14); 3769-82. ©2018 AACR.

Abstract B116: Mechanistic insights into the antitumor efficacy of nutraceutical GZ17-06.02, a highly effective formulation of Arum palaestinum extract, on head and neck squamous cell carcinoma

Although Arum palaestinum has been used as a natural prevention and treatment of cancer in Palestine for many years, few studies have examined its efficacy and mechanism of action. Chemically synthesized components of Arum palaestinum extract mixed in a ratio that was present in the natural extract were tested on head and neck squamous cell carcinoma (HNSCC), which affects annually 50,000 new people and causes 10,000 deaths a year in the US alone. We examined the effects of the nutraceutical on cell lines and patient-derived HNSCC tumors, and we delineated the mechanism of action. Among three formulations tested of Arum palaestinum (GZ17-S, a fortified version of the plant extract; GZ17-05.00, 16 components of the original plant extract; and GZ17-06.02, 3 components of the original plant extract), we found formulation GZ17-06.02 to be the most effective at reducing cancer cell proliferation, migration, and invasion. Further, GZ17-06.02 decreased angiogenesis in a tubule formation assay. When combined with a standard chemotherapeutic, cisplatin, GZ17-06.02 decreased cancer cell proliferation to a similar level of cisplatin, and enhanced the effect of cisplatin when used in combination. In comparison to radiotherapy, GZ17-06.02 performed better at reducing HNSCC cell proliferation than 3, 6, or 9 gy of radiation alone, and sequential treatment of HNSCC with radiation followed by GZ17-06.02 did not enhance the cytotoxic effects compared to GZ17-06.02 alone. We identified molecular signaling cascades inhibited by GZ17-06.02, including Src, ERK1/2, EGFR, AKT1/2/3, STAT-2, and Chk2, and we performed molecular docking analyses between GZ17-06.02 components and EGFR and AKT. We found that GZ17-06.02 components bind simultaneously at distinct binding sites of the kinase domains of EGFR and AKT. We found GZ17-06.02 induced significant apoptosis in HNSCC cells, increasing cleaved PARP, and activating caspase-3. Intratumoral injections of GZ17-06.02 were well tolerated in mice, and inhibited the growth and induced necrosis of HNSCC xenografts when injected intratumorally. In addition, orally administered GZ17-06.02 not only mitigated the growth of patient-derived HNSCC xenografts, but significantly decreased the tumor volume compared to the initially implanted tumor. Response to treatment correlated with a reduction in ERK1/2, which establishes it as an excellent biomarker for future clinical trials. Taken together, we demonstrate GZ17-06.02 as a highly effective nutraceutical, and pave the way for future clinical application in HNSCC. Citation Format: Jacob New, Vikalp Vishwakarma, Dhruv Kumar, Kyle Crooker, Vusala Snyder, Yelizaveta Shnayder, Kiran Kakarala, Terance T. Tsue, Douglas Girod, Lisa Stehno-Bittel, Sufi M. Thomas. Mechanistic insights into the antitumor efficacy of nutraceutical GZ17-06.02, a highly effective formulation of Arum palaestinum extract, on head and neck squamous cell carcinoma. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr B116.