Growth factors as active participants in carcinogenesis: a perspective

The relationships of platelet-derived growth factor, microvascular proliferation, and tumor cell proliferation in canine high-grade oligodendrogliomas: Immunohistochemistry of 45 tumors and an AFOB-01 xenograft mouse model

High-grade oligodendroglioma (HGOG) is the most common type of glioma in dogs and expresses platelet-derived growth factor receptor-α (PDGFR-α). Microvascular proliferation is often observed in HGOG. Therefore, the present study investigated the functional relationships between PDGFR-α, microvascular proliferation, and tumor cell proliferation in canine HGOG. The expression of PDGFR-α and PDGF-subunit A (PDGF-A) in tumor cells, as well as endothelial cells and pericytes of tumor-associated microvascular proliferations, in 45 canine HGOGs were examined immunohistochemically. Microvascular proliferation was observed in 24/45 cases (53%). PDGFR-α expression in tumor cells and microvascular proliferations was observed in 45/45 (100%) and 2/24 cases (8%), respectively. Furthermore, PDGF-A expression in tumor cells and microvascular proliferations was detected in 13/45 (29%) and 24/24 cases (100%), respectively. In vitro, stimulation of the canine HGOG cell line AOFB-01 with PDGF-A showed that the doubling time of AOFB-01 cells was significantly shorter with PDGF-A than without PDGF-A. Crenolanib (a PDGFR inhibitor) inhibited AOFB-01 cell proliferation. In vivo, the AOFB-01 xenograft mouse model was treated with crenolanib. Tumor xenografts were smaller in crenolanib-treated mice than in untreated control mice. PDGFR-α expression in tumor cells and PDGF-A expression in microvascular proliferations and tumor cells suggest autocrine and paracrine effects of PDGF-A in canine HGOG. The results of in vitro assays indicate that canine HGOG expresses functional PDGFR-α, which responds to PDGF-A. Therefore, PDGF-A produced by microvascular proliferations and tumor cells may promote the proliferation of PDGFR-α-expressing tumor cells in canine HGOG. PDGFR-α signaling has potential as a therapeutic target.

Latozinemab, a novel progranulin-elevating therapy for frontotemporal dementia

BACKGROUND

Heterozygous loss-of-function mutations in the progranulin (PGRN) gene (GRN) cause a reduction in PGRN and lead to the development of frontotemporal dementia (FTD-GRN). PGRN is a secreted lysosomal chaperone, immune regulator, and neuronal survival factor that is shuttled to the lysosome through multiple receptors, including sortilin. Here, we report the characterization of latozinemab, a human monoclonal antibody that decreases the levels of sortilin, which is expressed on myeloid and neuronal cells and shuttles PGRN to the lysosome for degradation, and blocks its interaction with PGRN.

METHODS

In vitro characterization studies were first performed to assess the mechanism of action of latozinemab. After the in vitro studies, a series of in vivo studies were performed to assess the efficacy of a mouse-cross reactive anti-sortilin antibody and the pharmacokinetics, pharmacodynamics, and safety of latozinemab in nonhuman primates and humans.

RESULTS

In a mouse model of FTD-GRN, the rodent cross-reactive anti-sortilin antibody, S15JG, decreased total sortilin levels in white blood cell (WBC) lysates, restored PGRN to normal levels in plasma, and rescued a behavioral deficit. In cynomolgus monkeys, latozinemab decreased sortilin levels in WBCs and concomitantly increased plasma and cerebrospinal fluid (CSF) PGRN by 2- to threefold. Finally, in a first-in-human phase 1 clinical trial, a single infusion of latozinemab caused a reduction in WBC sortilin, tripled plasma PGRN and doubled CSF PGRN in healthy volunteers, and restored PGRN to physiological levels in asymptomatic GRN mutation carriers.

CONCLUSIONS

These findings support the development of latozinemab for the treatment of FTD-GRN and other neurodegenerative diseases where elevation of PGRN may be beneficial. Trial registration ClinicalTrials.gov, NCT03636204. Registered on 17 August 2018, https://clinicaltrials.gov/ct2/show/NCT03636204 .

Biological and Mechanical Factors and Epigenetic Regulation Involved in Tendon Healing

Tendons are an important part of the musculoskeletal system. Connecting muscles to bones, tendons convert force into movement. Tendon injury can be acute or chronic. Noticeably, tendon healing requires a long time span and includes inflammation, proliferation, and remodeling processes. The mismatch between endogenous and exogenous healing may lead to adhesion causing further negative effects. Management of tendon injuries and complications such as subsequent adhesion formation are still challenges for clinicians. Due to numerous factors, tendon healing is a complex process. This review introduces the role of various biological and mechanical factors and epigenetic regulation processes involved in tendon healing.

Cellular signals integrate cell cycle and metabolic control in cancer

Growth factors are the small peptides that can promote growth, differentiation, and survival of most living cells. However, aberrant activation of receptor tyrosine kinases by GFs can generate oncogenic signals, resulting in oncogenic transformation. Accumulating evidence support a link between GF/RTK signaling through the major signaling pathways, Ras/Erk and PI3K/Akt, and cell cycle progression. In response to GF signaling, the quiescent cells in the G₀ stage can re-enter the cell cycle and become the proliferative stage. While in the proliferative stage, tumor cells undergo profound changes in their metabolism to support biomass production and bioenergetic requirements. Accumulating data show that the cell cycle regulators, specifically cyclin D, cyclin B, Cdk2, Cdk4, and Cdk6, and anaphase-promoting complex/cyclosome (APC/C-Cdh1) play critical roles in modulating various metabolic pathways. These cell cycle regulators can regulate metabolic enzyme activities through post-translational mechanisms or the transcriptional factors that control the expression of the metabolic genes. This fine-tune control allows only the relevant metabolic pathways to be active in a particular phase of the cell cycle, thereby providing suitable amounts of biosynthetic precursors available during the proliferative stage. The imbalance of metabolites in each cell cycle phase can induce cell cycle arrest followed by p53-induced apoptosis.

Ayurveda-based Botanicals as Therapeutic Adjuvants in Paclitaxel-induced Myelosuppression

Chemotherapy-induced myelosuppression is one of the major challenges in cancer treatment. Ayurveda-based immunomodulatory botanicals Asparagus racemosus Willd (AR/Shatavari) and Withania somnifera (L.). Dunal (WS/Ashwagandha) have potential role to manage myelosuppression. We have developed a method to study the effects of AR and WS as therapeutic adjuvants to counter paclitaxel (PTX)-induced myelosuppression. Sixty female BALB/c mice were divided into six groups—vehicle control (VC), PTX alone, PTX with aqueous and hydroalcoholic extracts of AR (ARA, ARH) and WS (WSA, WSH). The myelosuppression was induced in mice by intraperitoneal administration of PTX at 25 mg/kg dose for three consecutive days. The extracts were orally administered with a dose of 100 mg/kg for 15 days prior to the induction with PTX administration. The mice were observed daily for morbidity parameters and were bled from retro-orbital plexus after 2 days of PTX dosing. The morbidity parameters simulate clinical adverse effects of PTX that include activity (extreme tiredness due to fatigue), behavior (numbness and weakness due to peripheral neuropathy), body posture (pain in muscles and joints), fur aspect and huddling (hair loss). The collected samples were used for blood cell count analysis and cytokine profiling using Bio-Plex assay. The PTX alone group showed a reduction in total leukocyte and neutrophil counts (4,800 ± 606; 893 ± 82) when compared with a VC group (9,183 ± 1,043; 1,612 ± 100) respectively. Pre-administration of ARA, ARH, WSA, and WSH extracts normalized leukocyte counts (10,000 ± 707; 9,166 ± 1,076; 10,333 ± 1,189; 9,066 ± 697) and neutrophil counts (1,482 ± 61; 1,251 ± 71; 1,467 ± 121; 1,219 ± 134) respectively. Additionally, higher morbidity score in PTX group (7.4 ± 0.7) was significantly restricted by ARA (4.8 ± 1.1), ARH (5.1 ± 0.6), WSA (4.5 ± 0.7), and WSH (5 ± 0.8). (Data represented in mean ± SD). The extracts also significantly modulated 20 cytokines to evade PTX-induced leukopenia, neutropenia, and morbidity. The AR and WS extracts significantly prevented PTX-induced myelosuppression (p < 0.0001) and morbidity signs (p < 0.05) by modulating associated cytokines. The results indicate AR and WS as therapeutic adjuvants in cancer management.

Growth Factor Roles in Soft Tissue Physiology and Pathophysiology

Repair and healing of injured and diseased tendons has been traditionally fraught with apprehension and difficulties, and often led to rather unsatisfactory results. The burgeoning research field of growth factors has opened new venues for treatment of tendon disorders and injuries, and possibly for treatment of disorders of the aorta and major arteries as well. Several chapters in this volume elucidate the role of transforming growth factor β (TGFß) in pathogenesis of several heritable disorders affecting soft tissues, such as aorta, cardiac valves, and tendons and ligaments. Several members of the bone morphogenetic group either have been approved by the FDA for treatment of non-healing fractures or have been undergoing intensive clinical and experimental testing for use of healing bone fractures and tendon injuries. Because fibroblast growth factors (FGFs) are involved in embryonic development of tendons and muscles among other tissues and organs, the hope is that applied research on FGF biological effects will lead to the development of some new treatment strategies providing that we can control angiogenicity of these growth factors. The problem, or rather question, regarding practical use of imsulin-like growth factor I (IGF-I) in tendon repair is whether IGF-I acts independently or under the guidance of growth hormone. FGF2 or platelet-derived growth factor (PDGF) alone or in combination with IGF-I stimulates regeneration of periodontal ligament: a matter of importance in Marfan patients with periodontitis. In contrast, vascular endothelial growth factor (VEGF) appears to have rather deleterious effects on experimental tendon healing, perhaps because of its angiogenic activity and stimulation of matrix metalloproteinases-proteases whose increased expression has been documented in a variety of ruptured tendons. Other modalities, such as local administration of platelet-rich plasma (PRP) and/or of mesenchymal stem cells have been explored extensively in tendon healing. Though treatment with PRP and mesenchymal stem cells has met with some success in horses (who experience a lot of tendon injuries and other tendon problems), the use of PRP and mesenchymal stem cells in people has been more problematic and requires more studies before PRP and mesenchymal stem cells can become reliable tools in management of soft tissue injuries and disorders.

Assessing the Angiogenic Efficacy of Pleiotrophin Released from Injectable Heparin-Alginate Gels

With this work, we design alginate-based hydrogels for therapeutically directing revascularization and repair processes in vivo. We immobilize pleiotrophin (PTN) in injectable hydrogel formulations as the target factor to stimulate proangiogenic responses in endothelial cells. The optimized heparin-alginate/chitosan hydrogels, produced by internal crosslinking with calcium carbonate, show good biocompatibility and injectability and allow controlling the release of immobilized proteins in the subcutaneous tissue over a period of 7 days. In vitro assays, performed with translational human induced pluripotent stem cell-derived endothelial cells, and the in vivo Matrigel plug assay are conducted to demonstrate the angiogenic effects of PTN on endothelial cells. Our results indicate that PTN stimulates endothelial cell morphogenesis in vitro and the migration of endothelial cells and macrophages as soon as 4 days after injections of the developed hydrogels, promoting the formation of structures similar to the healthy granulation tissue, which is an indicator of healing in ischemic wounds. These studies provide the rationale for further investigating this novel therapeutic for pursuing increased vascular density for efficient regeneration of ischemic tissues, by leveraging the host endothelial cell population to initiate angiogenic and reparative processes in vivo. Impact statement Localized, sustained, and controlled delivery of angiogenic factors is crucial for enabling the formation of novel vascular networks in ischemic tissues. This study describes the development of an injectable heparin-alginate/collagen hydrogel for controlling the in vivo release and bioactivity of pleiotrophin (PTN), a heparin-binding factor with significant angiogenic activity. We demonstrate that PTN promotes angiogenesis in an in vitro model of hypoxia and in preclinical subcutaneous models. These results advance our understanding of PTN function in guiding therapeutic angiogenesis and are critical to inform the development of novel translational strategies for ischemic tissue repair and regeneration.

Implications of Insulin-Like Growth Factor-1 in Skeletal Muscle and Various Diseases

Skeletal muscle is an essential tissue that attaches to bones and facilitates body movements. Insulin-like growth factor-1 (IGF-1) is a hormone found in blood that plays an important role in skeletal myogenesis and is importantly associated with muscle mass entity, strength development, and degeneration and increases the proliferative capacity of muscle satellite cells (MSCs). IGF-1R is an IGF-1 receptor with a transmembrane location that activates PI3K/Akt signaling and possesses tyrosine kinase activity, and its expression is significant in terms of myoblast proliferation and normal muscle mass maintenance. IGF-1 synthesis is elevated in MSCs of injured muscles and stimulates MSCs proliferation and myogenic differentiation. Mechanical loading also affects skeletal muscle production by IGF-1, and low IGF-1 levels are associated with low handgrip strength and poor physical performance. IGF-1 is potentially useful in the management of Duchenne muscular dystrophy, muscle atrophy, and promotes neurite development. This review highlights the role of IGF-1 in skeletal muscle, its importance during myogenesis, and its involvement in different disease conditions.

Association of Serum Progranulin Levels With Disease Progression, Therapy Response and Survival in Patients With Metastatic Breast Cancer

BACKGROUND

Progranulin (GP88) is a critical player in breast tumorigenesis. GP88 tumor expression is associated with increased recurrence and mortality, whereas GP88 circulating levels are elevated in patients with breast cancer compared with healthy individuals. We examined here the correlation between serum GP88 levels in patients with metastatic breast cancer (MBC) with overall survival and disease status determined as response to therapy or progression of disease.

PATIENTS AND METHODS

An institutional review board (IRB)-approved study prospectively enrolled 101 patients with MBC at the University of Maryland Marlene and Stewart Greenebaum Comprehensive Cancer Center. GP88 serum levels were correlated with patients' disease status determined by Response Evaluation Criteria In Solid Tumors (RECIST) 1.1 criteria and survival outcomes by Kaplan-Meier analysis and log rank statistics.

RESULTS

Patients' survival was stratified by serum GP88 level. Patients with serum GP88 < 55 ng/mL had a 4-fold increased survival compared with patients with GP88 > 55 ng/mL. Examination of GP88 serum levels in association with disease status showed a statistically significant association between serum GP88 levels and disease progression or response to therapy while CA15-3 level was only associated to progression.

CONCLUSION

The association of serum GP88 level with survival and disease status suggests the potential of using the serum GP88 test for monitoring disease status in patients with MBC. Measurement of serum GP88 levels in patients with MBC may have clinical value as a cost-effective adjunct to the management of patients with MBC with imaging.

Stimuli-Responsive Delivery of Growth Factors for Tissue Engineering

Growth factors (GFs) play a crucial role in directing stem cell behavior and transmitting information between different cell populations for tissue regeneration. However, their utility as therapeutics is limited by their short half-life within the physiological microenvironment and significant side effects caused by off-target effects or improper dosage. "Smart" materials that can not only sustain therapeutic delivery over a treatment period but also facilitate on-demand release upon activation are attracting significant interest in the field of GF delivery for tissue engineering. Three properties are essential in engineering these "smart" materials: 1) the cargo vehicle protects the encapsulated therapeutic; 2) release is targeted to the site of injury; 3) cargo release can be modulated by disease-specific stimuli. The aim of this review is to summarize the current research on stimuli-responsive materials as intelligent vehicles for controlled GF delivery; Five main subfields of tissue engineering are discussed: skin, bone and cartilage, muscle, blood vessel, and nerve. Challenges in achieving such "smart" materials and perspectives on future applications of stimuli-responsive GF delivery for tissue regeneration are also discussed.

TBKBP1 and TBK1 form a growth factor signalling axis mediating immunosuppression and tumourigenesis

The kinase TBK1 responds to microbial stimuli and mediates type I interferon (IFN-I) induction. We show that TBK1 is also a central mediator of growth factor signaling; this function relies on a specific adaptor, TBK-binding protein 1 (TBKBP1). TBKBP1 recruits TBK1 to PKCθ via a scaffold protein, Card10, which allows PKCθ to phosphorylate TBK1 at serine-716, a crucial step for TBK1 activation by growth factors but not by innate immune stimuli. While the TBK1/TBKBP1 signaling axis is dispensable for IFN-I induction, it mediates mTORC1 activation and oncogenesis. Lung epithelial cell-conditional deletion of either TBK1 or TBKBP1 inhibits tumorigenesis in a mouse model of lung cancer. In addition to promoting tumor growth, the TBK1/TBKBP1 axis facilitates tumor-mediated immunosuppression by a mechanism involving induction of the checkpoint molecule PD-L1 and stimulation of glycolysis. These findings suggest a PKCθ-TBKBP1-TBK1 growth factor signaling axis mediating both tumor growth and immunosuppression.

Connective Tissue and Age-Related Diseases

We begin this chapter by describing normal characteristics of several pertinent connective tissue components, and some of the basic changes they undergo with ageing. These alterations are not necessarily tied to any specific disease or disorders, but rather an essential part of the normal ageing process. The general features of age-induced changes, such as skin wrinkles, in selected organs with high content of connective or soft tissues are discussed in the next part of the chapter. This is followed by a section dealing with age-related changes in specific diseases that fall into at least two categories. The first category encompasses common diseases with high prevalence among mostly ageing populations where both genetic and environmental factors play roles. They include but may not be limited to atherosclerosis and coronary heart disease, type II diabetes, osteopenia and osteoporosis, osteoarthritis, tendon dysfunction and injury, age-related disorders of spine and joints. Disorders where genetics plays the primary role in pathogenesis and progression include certain types of progeria, such as Werner syndrome and Hutchinson-Gilford progeria belong to the second category discussed in this chapter. These disorders are characterized by accelerated signs and symptoms of ageing. Other hereditary diseases or syndromes that arise from mutations of genes encoding for components of connective tissue and are less common than diseases included in the first group will be discussed briefly as well, though they may not be directly associated with ageing, but their connective tissue undergoes some changes compatible with ageing. Marfan and Ehlers-Danlos syndromes are primary examples of such disorders. We will probe the role of specific components of connective tissue and extracellular matrix if not in each of the diseases, then at least in the main representatives of these disorders.

Does BMP2 play a role in the pathogenesis of equine degenerative suspensory ligament desmitis?

Objective

Horses afflicted with degenerative suspensory ligament desmitis (DSLD) suffer from progressive leg pain and lameness without history of trauma. DSLD is a systemic disorder caused by abnormal accumulation of proteoglycans in many connective tissues. One proteoglycan found in higher quantities in DSLD is decorin. The accumulated decorin has an abnormally glycosylated glycosaminoglycan chain in DSLD. In addition to acellular accumulations of proteoglycans foci of active fibroblasts/tenoblasts were observed in some tendons and suspensory ligaments (SLs) from DSLD cases We have hypothesized that this represents an early event in DSLD and that production of chondrogenic growth factors, such as BMP2, and/or enzyme participating in glycosylation of glycosaminoglycans is a major factor in initiation and progression of DSLD.

Results

Using immunohistochemistry we have identified BMP2 in these cellular foci, indicating association with proteoglycan production, but not in other cells in the tendon and SLs. In contrast, very little staining for TGFβ and dermatan sulfate epimerase, an enzyme involved in glycosylation of glycosaminoglycan chains, was observed in these foci and other cells in both control and DSLD-affected tendons and SLs. Our data support our hypothesis that chondrogenic growth factors may be responsible, at least in part for progression of DSLD in horses.

Inhibiting the proliferation and metastasis of hilar cholangiocarcinoma cells by blocking the expression of vascular endothelial growth factor with small interfering RNA

The aim of the present study was to investigate whether the proliferation and metastasis of hilar cholangiocarcinoma cells can be suppressed and whether apoptosis can be induced by small interfering RNA (siRNA) repression of vascular endothelial growth factor (VEGF). siRNA sequences targeting the VEGF gene were designed and the human hilar cholangiocarcinoma QBC939, HCCC-9810 and RBE cell lines were transfected with VEGF-siRNA plasmids for 48 h. Reverse transcription-quantitative polymerase chain reaction and western blotting measured the levels of VEGF-A, VEGF-C and matrix metalloproteinase 2 (MMP2) mRNA expression and protein content. The cell invasion potential was evaluated using the Transwell invasion and migration assay and the MTT assay was employed to detect the proliferation of hilar cholangiocarcinoma cells. Flow cytometry was used to quantify cell apoptosis and necrosis. Following the transfection of VEGF-siRNA, a significant reduction of mRNA and protein levels of VEGF-A, VEGF-C and MMP2 was observed in the hilar cholangiocarcinoma cells. The invasion, migration and proliferation of tumor cells were also notably decreased. The rate of tumor cell apoptosis was increased in the VEGF-siRNA group (15.42%) compared with the non-siRNA control (2.22%) and the negative control (2.71%) groups. It was concluded that blocking the expression of VEGF via VEGF-siRNA effectively inhibited the invasion, migration and proliferation, and induced apoptosis in hilar cholangiocarcinoma cells. These observations suggested that targeting VEGF with RNAi may be an effective therapeutic strategy for treating hilar cholangiocarcinoma.

Determination of GP88 (progranulin) expression in breast tumor biopsies improves the risk predictive value of the Nottingham Prognostic Index

Background

The Nottingham Prognostic Index (NPI), which combines numerical values for nodal status, tumor size and histological grade, is used in the standard of care to provide predictive value information on post-surgery survival for patients with primary breast cancer. Attempts to improve the performance of the NPI algorithm have been carried out by testing the inclusion of other biomarker expression and morphological features such as vascular invasion. In the present study, we investigated whether expression of the autocrine growth and survival factor GP88 (progranulin), known to be overexpressed in breast cancer, would improve NPI’s predictive value.

Methods

We examined by immunohistochemistry (IHC) the GP88 expression in 508 cases of estrogen receptor positive invasive ductal carcinoma with known clinical outcomes and for which NPI had been determined. GP88 IHC expression was scored by two board certified pathologists and classified into two score groups of GP88 <3+ (0, 1+, 2+) and GP88 = 3+. The correlation between GP88 scoring, NPI and disease-free (DFS) or overall survival (OS) outcomes was then examined by Kaplan-Meier analysis, Cox proportional Hazard (CPH) ratio and Pearson’s X² test.

Results

Kaplan-Meier survival graphs of cases categorized by their NPI scores (<3.4, 3.4–5.4, >5.4) and GP88 expression showed that for patients within the same NPI subgroup, patients having tumors with a high GP88 expression (GP88 IHC score of 3+) had a worse DFS than patients with tumors that had a low GP88 expression (GP88 IHC score <3+). When adjusted for NPI, high GP88 score was significantly associated with recurrence with a hazard ratio of 3.30 (95 % CI 2.12 to 5.14).

Conclusions

The data suggest that the determination of GP88 tumor expression at time of diagnosis for early stage breast cancer patients can provide additional survival information to that provided by NPI alone and thus may be useful for risk management of patients diagnosed with breast cancer.

Signaling Pathway of GP88 (Progranulin) in Breast Cancer Cells: Upregulation and Phosphorylation of c-myc by GP88/Progranulin in Her2-Overexpressing Breast Cancer Cells

Her2 is a receptor tyrosine kinase overexpressed in 25% of breast tumors. We have shown that the 88 kDa autocrine growth and survival factor GP88 (progranulin) stimulated Her2 phosphorylation and proliferation and conferred Herceptin resistance in Her2-overexpressing cells. Herein, we report that GP88 stimulates c-myc phosphorylation and upregulates c-myc levels in Her2-overexpressing cells. c-myc phosphorylation and upregulation by GP88 were not observed in non-Her2-overexpressing breast cancer cells. c-myc activation was inhibited upon treatment with ERK, PI3 kinase, and c-src pathway inhibitors, U0126, LY294002, and PP2. GP88 also stimulated c-src phosphorylation, a known upstream regulator of c-myc. Thus, we describe here a signaling pathway for GP88 in Her2-overexpressing cells, with GP88 stimulating Src phosphorylation, followed by phosphorylation and upregulation of c-myc. These data would suggest that targeting GP88 could provide a novel treatment approach in breast cancer.

Localized experimental bone metastasis drives osteolysis and sensory hypersensitivity at distant non-tumor-bearing sites

Patients with breast cancer metastasis to bone suffer from inadequate pain relief. Animal models provide increased understanding of cancer-induced bone and sensory alterations. The objective of this study was to investigate the measures of pain at distant non-tumor-bearing sites in animals with localized bone metastasis. Immunocompetent BALB/c mice are injected intra-tibially with murine mammary carcinoma cells (4T1) or saline, and the sensitivity to mechanical and thermal stimuli in the contralateral paw was examined. In addition to previously demonstrated development of osteolysis and hypersensitivity to mechanical and thermal stimuli in the cancer-injected tibia, these animals exhibited an increase in sensory hypersensitivity in the contralateral limb. No bone lesions were evident on radiographs of the contralateral limbs. Histomorphometry detected decreased bone volume per tissue volume and increased osteoclast number in the contralateral tibia and vertebral bones of cancer-bearing animals. Neuroplasticity was examined by immunofluorescence for calcitonin gene-related peptide (CGRP) in sensory neurons and glial fibrillary acidic protein (GFAP) in lumbar spinal cords. CGRP-immunoreactivity and GFAP-immunoreactivity were significantly elevated both ipsilateral and contralateral in tumor-bearing animals. The anti-inflammatory and osteolysis-targeting drug rapamycin reduced hypersensitivity to mechanical and cold stimuli, attenuated GFAP over-expression, and lowered osteoclast number. The osteoclast-targeting drug pamidronate reduced sensitivity to cold and protected against bone loss. Localized bone cancer drives hypersensitivity, bone remodeling, and sensory neuron plasticity at sites distant from the primary tumor area. Drugs targeting these mechanisms may be useful in the treatment of pain distant from the primary tumor site.

Tarantula cubensis extract alters the degree of apoptosis and mitosis in canine mammary adenocarcinomas

In the present study, 13 clinical cases of canine mammary adenocarcinoma were evaluated in order to understand the effect of Tarantula cubensis extract (TCE) on tumor tissue. Punch biopsies were taken from the tumors before treatment with TCE. Subcutaneous injections of TCE were administered three times at weekly intervals (3 mL per dog). Between days 7 and 10 after the third injection, the tumor masses were extirpated by complete unilateral mastectomy. Pre- and post-treatment tumor tissues were immunohistochemically assessed. The expression of B-cell lymphoma 2 (Bcl-2) was found to be higher in pre-treatment compared to post-treatment tissues (p < 0.01) whereas Ki-67 expression was lower in post-treatment tissues (p < 0.01). No significant differences in fibroblast growth factor or vascular endothelial growth factor expression were observed between pre- and post-treatment tissues (p > 0.05). The apoptotic index was determined to be low before treatment and increased during treatment. These results suggest that TCE may be effective for controlling the local growth of canine mammary adenocarcinoma by regulating apoptosis.

Platelet-derived growth factors and receptors in Canine Lymphoma

Platelet-derived growth factors (PDGFs) belong to a family of polypeptide growth factors that signal through cell surface tyrosine kinase receptors to stimulate growth, proliferation and differentiation. Platelet-derived growth factor receptors (PDGFRs) are also considered important targets for specific kinase inhibitors in the treatment of several human tumours. The aim of this study was to investigate the role of PDGF-A, PDGF-B, PDGFR-α and PDGFR-β in canine lymphoma by determining gene and protein expression in lymph nodes of dogs with diffuse large B-cell lymphoma (DLBCL), peripheral T-cell lymphoma (PTCL), T-lymphoblastic lymphoma (T-LBL) and in healthy control dogs. One lymph node was also studied at the end of therapy in a subset of dogs in remission for DLBCL. In controls, PDGF-A, PDGFR-α and PDGFR-β mRNA levels were significantly higher than in DLBCLs, PTCLs and T-LBLs. However, PDGFR-α and PDGFR-β were minimally expressed by lymphocytes and plasma cells in normal lymph nodes as determined by immunohistochemistry, while neoplastic B and T cells showed the highest score (P <0.05). This discordant result may be compatible with the constitutive expression of these molecules by endothelial cells and fibroblasts in normal lymph nodes, thereby influencing gene expression results. Furthermore, these cells were not included in the immunohistochemical analysis. Similarly, dogs with DLBCL that were in remission at the end of therapy showed significantly higher gene expression of PDGFs and receptors than at the time of diagnosis and with an opposite trend to the protein assay. PDGF-B protein and mRNA were overexpressed in PTCLs and T-LBLs when compared with DLBCLs and controls (P <0.05). Additionally, there was a correlation between protein expression of PDGF-B and both PDGFRs in PTCLs and T-LBLs, suggesting an autocrine or paracrine loop in the aetiology of aggressive canine T-cell lymphomas. These data provide a rationale for the use of PDGFR antagonists in the therapy of aggressive T-cell lymphomas, but not in DLBCLs.

GP88 (progranulin): a novel tissue and circulating biomarker for non-small cell lung carcinoma

GP88 (progranulin) is a growth and survival factor implicated in tumorigenesis and drug resistance. Previous studies showed that GP88 was expressed in breast cancer tissue in inverse correlation with survival. This study evaluates GP88 tissue expression in localized/locally advanced lung cancer and GP88 serum levels in advanced disease. GP88 expression was determined by immunohistochemistry in tumor tissue from non-small cell lung carcinoma (NSCLC) patients, 85 with localized (stage I-II), and 40 with locally advanced disease (stage IIIa) and correlated with clinical outcome. Serum GP88 levels from stage IIIb/IV patients, quantified by enzyme immunoassay were compared with GP88 levels from patients with chronic obstructive pulmonary disease and healthy individuals. GP88 was expressed in more than 80% adenocarcinoma and squamous cell carcinoma in contrast to normal lung or small cell lung cancer. There was a statistically significant inverse association of GP88 expression (GP88 immunohistochemistry score, 3+ versus < 3+) with survival for patients with localized resected NSCLC with hazard ratio (HR) = 2.28 (P = .0076) for disease-free survival and HR = 2.17 (P = .014) for overall survival. A statistically significant decrease in progression-free survival (HR = 2.9; P = .022) for GP88 scores of 3+ versus less than 3+ was observed for stage IIIa after chemoradiotherapy. In addition, serum GP88 was significantly elevated in stage IIIb/IV NSCLC compared with control subjects (49.9 ng/mL versus 28.4 ng/mL; P < .0001). This is the first study demonstrating GP88 tissue and serum expression as a prognostic biomarker in localized and advanced disease. Future research will determine utility of monitoring GP88 and the potential of GP88 expression as a predictive marker for anti-GP88 therapeutics.

Silibinin inhibits VEGF secretion and age-related macular degeneration in a hypoxia-dependent manner through the PI-3 kinase/Akt/mTOR pathway

BACKGROUND AND PURPOSE

Hypoxia-mediated neovascularization plays an important role in age-related macular degeneration (AMD). There are few animal models or effective treatments for AMD. Here, we investigated the effects of the flavonoid silibinin on hypoxia-induced angiogenesis in a rat AMD model.

EXPERIMENTAL APPROACH

Retinal pigmented epithelial (RPE) cells were subjected to hypoxia in vitro and the effects of silibinin on activation of key hypoxia-induced pathways were examined by elucidating the hypoxia-inducible factor-1 alpha (HIF-1α) protein level by Western blot. A rat model of AMD was developed by intravitreal injection of VEGF in Brown Norway rats, with or without concomitant exposure of animals to hypoxia. Animals were treated with oral silibinin starting at day 7 post-VEGF injection and AMD changes were followed by fluorescein angiography on days 14 and 28 post-injection.

KEY RESULTS

Silibinin pretreatment of RPE cells increased proline hydroxylase-2 expression, inhibited HIF-1α subunit accumulation, and inhibited VEGF secretion. Silibinin-induced HIF-1α and VEGF down-regulation required suppression of hypoxia-induced phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin (mTOR) pathway. In the rat model of AMD, silibinin administration prevented VEGF- and VEGF plus hypoxia-induced retinal oedema and neovascularization.

CONCLUSION AND IMPLICATIONS

The effects of silibinin, both in vitro and in vivo, support its potential as a therapeutic for the prevention of neovascular AMD.

Growth factors and craniofacial surgery

The specialty of craniofacial surgery is broad and includes trauma, aesthetics, reconstruction of congenital deformities, and regeneration of tissues. Moreover, craniofacial surgery deals with a diverse range of tissues including both "soft" and "hard" tissues. Technological advances in materials and biological sciences and improved surgical techniques have remarkably improved clinical outcomes. The quest to raise the bar for patient care continues to inspire advances for predictable biological regeneration of soft and hard tissues. As a consequence of this quest for advancement, a wide spectrum of biologicals is becoming available to surgeons. Is the use of recombinant DNA engineered biologicals daring? Sensible? Logical? Timely? Safe? It is crucial for the practicing craniofacial surgeon to take a step back periodically and carefully review the biological factors that have the potential for dramatically altering the discipline of craniofacial surgery. With this emphasis, the coauthors of this article will focus on growth factor technology underscoring bone tissue regeneration. As the 21st-century matures, recombinant human biologicals will have an overwhelming impact on the practice of craniofacial surgery.

Extract of Pleurotus pulmonarius suppresses liver cancer development and progression through inhibition of VEGF-induced PI3K/AKT signaling pathway

Liver cancer or hepatocellular carcinoma is one of the leading causes of cancer-related deaths. Conventional chemotherapies are limited by the development of drug resistance and various side effects. Because of its non-toxicity and potent biopharmacological activity, metabolites derived from mushrooms have received more attention in cancer therapy. Our previous studies have demonstrated the anticancer effects of polysaccharide-protein complexes derived from the Pleurotus mushrooms. The aim of this study was to investigate the underlying molecular mechanism of the anticancer activity of a hot water extract containing a polysaccharide-protein complex isolated from Pleurotus pulmonarius (PP) in liver cancer cells. Our results indicated that exposure of liver cancer cells to PP not only significantly reduced the in vitro cancer cell proliferation and invasion but also enhanced the drug-sensitivity to the chemotherapeutic drug Cisplatin. Both oral administration and intraperitoneal injection of PP significantly inhibited the tumor growth in xenograft BALB/c nude mice. PP triggered a marked suppression of the PI3K/AKT signaling pathway in liver cancer cells in vitro and in vivo, and overexpression of the constitutively active form of AKT, Myr-AKT, abrogated this effect and the inhibited proliferation and invasion by PP. Both western blot and ELISA results showed that PP-treated liver cancer cells had reduced expression and secretion of vascular endothelial growth factor (VEGF). Addition of recombinant human VEGF attenuated the inhibitory effects of PP on PI3K/AKT pathway and the cancer phenotypes. Our results demonstrated that PP suppressed the proliferation, invasion, and drug-resistance of liver cancer cells in vitro and in vivo, mediated by the inhibition of autocrine VEGF-induced PI3K/AKT signaling pathway. This study suggests the potential therapeutic implication of PP in the treatment of human liver cancer.

PDGF-D/PDGF-ββ receptor-regulated chemotaxis of malignant mesothelioma cells

BACKGROUND/AIMS

Our earlier study suggested that platelet-derived growth factor (PDGF)- ββ receptor regulates chemotaxis of human malignant mesothelioma cells such as MSTO-211H, NCIH-2052, NCIH-2452, and NCIH-28 cells, but not non-malignant Met5A cells. The present study was designed to gain further insight into the PDGF-ββ receptor signals underlying the chemotaxis.

METHODS

PDGF-D secreted from cells, activation of Akt and ERK, and cell migration were monitored for cells with and without knocking-down PDGF-ββ receptor.

RESULTS

FBS significantly stimulated PDGF-D secretion from malignant mesothelioma cells, but not Met5A cells. PDGF-D activated Akt and ERK in both the non-malignant and malignant cells. PDGF-D significantly facilitated migration of malignant mesothelioma cells, but not Met5A cells, with the extent varying among the cell types. The facilitatory action of PDGF-D was clearly prevented by knocking-down PDGF-ββ receptor or inhibitors of PI3 kinase, PDK1, Akt, Rac1, ROCK, and MEK.

CONCLUSION

The results of the present study indicate that PDGF-D promotes malignant mesothelioma cell chemotaxis through PDGF-ββ receptor signaling pathways along a PI3 kinase/PDK1/Akt/Rac1/ROCK axis and relevant to ERK activation.

Progranulin (GP88) tumor tissue expression is associated with increased risk of recurrence in breast cancer patients diagnosed with estrogen receptor positive invasive ductal carcinoma

Introduction

GP88 (progranulin) has been implicated in tumorigenesis and resistance to anti-estrogen therapies for estrogen receptor positive (ER⁺) breast cancer. Previous pathological studies showed that GP88 is expressed in invasive ductal carcinoma (IDC), but not in normal mammary epithelial tissue, benign lesions or lobular carcinoma. Based on these results, the present study examines GP88 prognostic significance in association with recurrence and death risks for ER⁺ IDC patients.

Methods

Two retrospective multi-site clinical studies examined GP88 expression by immunohistochemistry (IHC) analysis of paraffin-embedded breast tumor tissue sections from ER⁺ IDC patients (lymph node positive and negative, stage 1 to 3) in correlation with patients' survival outcomes. The training study established a GP88 cut-off value associated with decreased disease-free (DFS) and overall (OS) survivals. The validation study verified the GP88 cut-off value and compared GP88 prognostic information with other prognostic factors, particularly tumor size, grade, disease stage and lymph node status in multivariate analysis.

Results

GP88 expression is associated with a statistically significant increase in recurrence risk for ER⁺ IDC patients. The training study established that GP88 3+ score was associated with decreased DFS (P = 0.0004) and OS (P = 0.0036). The independent validation study verified that GP88 3+ score was associated with a 5.9-fold higher hazard of disease recurrence and a 2.5-fold higher mortality hazard compared to patients with tumor GP88 < 3+. GP88 remained an independent risk predictor after considering age, ethnicity, nodal status, tumor size, tumor grade, disease stage, progesterone receptor expression and treatments.

Conclusions

The survival factor GP88 is a novel prognostic biomarker, predictive of recurrence risk and increased mortality for non-metastatic ER⁺ IDC patients. Of importance, our data show that GP88 continues to be a prognostic factor even after five years. These results also provide evidence that GP88 provides prognostic information independent of tumor and clinical characteristics and would support prospective study to examine whether GP88 expression could help stratify patients with ER⁺ tumors for adjuvant therapy.

Lewis Y promotes growth and adhesion of ovarian carcinoma-derived RMG-I cells by upregulating growth factors

Lewis y (LeY) antigen is a difucosylated oligosaccharide carried by glycoconjugates on the cell surface. Overexpression of LeY is frequently observed in epithelial-derived cancers and has been correlated to the pathological staging and prognosis. However, the effects of LeY on ovarian cancer are not yet clear. Previously, we transfected the ovarian cancer cell line RMG-I with the α1,2-fucosyltransferase gene to obtain stable transfectants, RMG-I-H, that highly express LeY. In the present study, we examined the proliferation, tumorigenesis, adhesion and invasion of the cell lines with treatment of LeY monoclonal antibody (mAb). Additionally, we examined the expression of TGF-β1, VEGF and b-FGF in xenograft tumors. The results showed that the proliferation and adhesion in vitro were significantly inhibited by treatment of RMG-I-H cells with LeY mAb. When subcutaneously inoculated in nude mice, RMG-I-H cells produced large tumors, while mock-transfected cells RMG-I-C and the parental cells RMG-I produced small tumors. Moreover, the tumor formation by RMG-I-H cells was inhibited by preincubating the cells with LeY mAb. Notably, the expression of TGF-β1, VEGF and b-FGF all increased in RMG-I-H cells. In conclusion, LeY plays an important role in promoting cell proliferation, tumorigenecity and adhesion, and these effects may be related to increased levels of growth factors. The LeY antibody shows potential application in the treatment of LeY-positive tumors.

A fusion fragment from Flt-1 and KDR, acted as VEGF decoy receptor and exhibited anti-tumor function

Angiogenesis is important in tumor development. Vascular endothelial growth factor (VEGF) is involved in this process. In this report, we constructed a recombinant protein (called FK) by fusing the second immunoglobulin-like (Ig-like) domain of a human fms-like tyrosine kinase (Flt-1) with the third Ig-like domain of human kinase insert domain-containing receptor (KDR). FK bound to VEGF(165) in a dose-dependent manner with a disocciation constant (Kd) of 2.7 pM. In addition, FK specifically inhibited the proliferation of human microvascular endothelial cell (HMEC) and human umbilical vein endothelial Cell (HUVEC) stimulated by VEGF(165). Subsequent studies also demonstrate that FK efficaciously suppresses growth of a variety of tumors, which could make FK a potential drug candidate in anti-tumor therapy.