The emerging role of mammalian target of rapamycin inhibitors in the treatment of sarcomas

HMGA1 regulates trabectedin sensitivity in advanced soft-tissue sarcoma (STS): A Spanish Group for Research on Sarcomas (GEIS) study

HMGA1 is a structural epigenetic chromatin factor that has been associated with tumor progression and drug resistance. Here, we reported the prognostic/predictive value of HMGA1 for trabectedin in advanced soft-tissue sarcoma (STS) and the effect of inhibiting HMGA1 or the mTOR downstream pathway in trabectedin activity. The prognostic/predictive value of HMGA1 expression was assessed in a cohort of 301 STS patients at mRNA (n = 133) and protein level (n = 272), by HTG EdgeSeq transcriptomics and immunohistochemistry, respectively. The effect of HMGA1 silencing on trabectedin activity and gene expression profiling was measured in leiomyosarcoma cells. The effect of combining mTOR inhibitors with trabectedin was assessed on cell viability in vitro studies, whereas in vivo studies tested the activity of this combination. HMGA1 mRNA and protein expression were significantly associated with worse progression-free survival of trabectedin and worse overall survival in STS. HMGA1 silencing sensitized leiomyosarcoma cells for trabectedin treatment, reducing the spheroid area and increasing cell death. The downregulation of HGMA1 significantly decreased the enrichment of some specific gene sets, including the PI3K/AKT/mTOR pathway. The inhibition of mTOR, sensitized leiomyosarcoma cultures for trabectedin treatment, increasing cell death. In in vivo studies, the combination of rapamycin with trabectedin downregulated HMGA1 expression and stabilized tumor growth of 3-methylcholantrene-induced sarcoma-like models. HMGA1 is an adverse prognostic factor for trabectedin treatment in advanced STS. HMGA1 silencing increases trabectedin efficacy, in part by modulating the mTOR signaling pathway. Trabectedin plus mTOR inhibitors are active in preclinical models of sarcoma, downregulating HMGA1 expression levels and stabilizing tumor growth.

Effect of rapamycin on aging and age-related diseases-past and future

In 2009, rapamycin was reported to increase the lifespan of mice when implemented later in life. This observation resulted in a sea-change in how researchers viewed aging. This was the first evidence that a pharmacological agent could have an impact on aging when administered later in life, i.e., an intervention that did not have to be implemented early in life before the negative impact of aging. Over the past decade, there has been an explosion in the number of reports studying the effect of rapamycin on various diseases, physiological functions, and biochemical processes in mice. In this review, we focus on those areas in which there is strong evidence for rapamycin's effect on aging and age-related diseases in mice, e.g., lifespan, cardiac disease/function, central nervous system, immune system, and cell senescence. We conclude that it is time that pre-clinical studies be focused on taking rapamycin to the clinic, e.g., as a potential treatment for Alzheimer's disease.

Targeting Refractory Sarcomas and Malignant Peripheral Nerve Sheath Tumors in a Phase I/II Study of Sirolimus in Combination with Ganetespib (SARC023)

Purpose

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive soft tissue sarcomas. Combining Hsp90 inhibitors to enhance endoplasmic reticulum stress with mTOR inhibition results in dramatic MPNST shrinkage in a genetically engineered MPNST mouse model. Ganetespib is an injectable potent small molecule inhibitor of Hsp90. Sirolimus is an oral mTOR inhibitor. We sought to determine the safety, tolerability, and recommended dose of ganetespib and sirolimus in patients with refractory sarcomas and assess clinical benefits in patients with unresectable/refractory MPNSTs. Patients and Methods. In this multi-institutional, open-label, phase 1/2 study of ganetespib and sirolimus, patients ≥16 years with histologically confirmed refractory sarcoma (phase 1) or MPNST (phase 2) were eligible. A conventional 3 + 3 dose escalation design was used for phase 1. Pharmacokinetic and pharmacodynamic measures were evaluated. Primary objectives of phase 2 were to determine the clinical benefit rate (CBR) of this combination in MPNSTs. Patient-reported outcomes assessed pain.

Results

Twenty patients were enrolled (10 per phase). Toxicities were manageable; most frequent non-DLTs were diarrhea, elevated liver transaminases, and fatigue. The recommended dose of ganetespib was 200 mg/m² intravenously on days 1, 8, and 15 with sirolimus 4 mg orally once daily with day 1 loading dose of 12 mg. In phase 1, one patient with leiomyosarcoma achieved a sustained partial response. In phase 2, no responses were observed. The median number of cycles treated was 2 (1–4). Patients did not meet the criteria for clinical benefit as defined per protocol. Pain ratings decreased or were stable.

Conclusion

Despite promising preclinical rationale and tolerability of the combination therapy, no responses were observed, and the study did not meet parameters for further evaluation in MPNSTs. This trial was registered with (NCT02008877).

Assessing the efficacy of mammalian target of rapamycin inhibitors by phosphorylation of p70S6K in CD4-positive cells of liver transplant patients

The activity of p70S6 kinase located downstream of the mammalian target of rapamycin (mTOR) pathway is sensitive to mTOR inhibitors. However, the methods of assessing p70S6 kinase activity are still unclear. This study aimed to investigate p70S6 kinase activity in CD4-positive cells of liver transplant patients.Liver transplant patients treated with mTOR inhibitors were recruited from Beijing Chaoyang Hospital between October 2014 and October 2016. The influence of mycophenolic acid (MPA) derivatives and prednisone on p70S6 kinase phosphorylation in CD4-positive cells was examined in liver transplant patients and healthy controls (HCs). The phosphorylation of p70S6K in CD4 + CD25 regulatory T cells (Treg cells) and CD4 + CD25- T effector cells was analyzed by phospho-flow cytometry.The phospho-flow technique detected a significant loss of p70S6 kinase phosphorylation in CD4-positive cells of patients treated with mTOR inhibitors compared with HCs. MPA derivatives and prednisone did not affect p70S6 kinase phosphorylation significantly. No significant difference in p70S6 kinase phosphorylation was observed when the whole blood was stored within 3 hours at room temperature. The phosphorylation of p70S6K was significantly lower in CD4 + CD25 Treg cells than in CD4 + CD25-T effector cells in HCs. After liver transplant patients were treated with mTOR inhibitors, p70S6K phosphorylation was more reduced in CD4 + CD25-T effector cells than in CD4 + CD25 Treg cells.The presence of phosphorylation of p70S6 kinase in CD4-positive cells was reduced in liver transplant patients who were treated by mTOR inhibitors.

Dual-drug loaded micelle for combinatorial therapy targeting HIF and mTOR signaling pathways for ovarian cancer treatment

Mutations in the tumor protein (TP53) and the mammalian target of rapamycin (mTOR) pathway have been elucidated as driver mutations in ovarian carcinomas that transform into an invasive phenotype under hypoxic conditions. Chetomin (CHE) targets the hypoxic pathway while Everolimus (EVR) acts on the mTOR pathway. Poor aqueous solubilities of both compounds limit their clinical applications. Diblock copolymer nanoplatforms of methoxy poly(ethylene glycol)₂₀₀₀-block-poly (lactic acid)₁₈₀₀ (mPEG₂₀₀₀-b-PLA₁₈₀₀) and (mPEG₄₀₀₀-b-PLA₂₂₀₀) were used to formulate individual and dual drug loaded micelles (DDM) using the solvent evaporation method. The CHE micelles (CHE-M) had a size of 21 nm with CHE loading of 0.5 mg/mL while the EVR micelles (EVR-M) and the DDM had a size around 35 and 39 nm, respectively, with EVR loading up to 2.3 mg/mL. The anti-proliferative effects of these micelles have been tested in vitro in three ovarian cell lines (ES2, OVCAR3 and TOV21G) with the DDM exhibiting a strong synergistic anti-proliferative effect in the ES2 and the TOV21G cells. The DDM were able to significantly induce tumor regression in ES2 ovarian xenograft mouse models by inhibiting angiogenesis and inducing apoptosis when compared to the individual micelles. The inhibition of hypoxia inducible factor (HIF) and the mTOR pathways has been elucidated using immunohistochemistry studies. In conclusion, we have developed a mPEG-b-PLA based micellar nanoplatform that could prevent drug resistance by delivering multiple drugs at therapeutically relevant concentrations for effectively treating ovarian carcinomas.

The effect of fludrocortisone on the uterine receptivity partially mediated by ERK1/2-mTOR pathway

Implantation of embryos needs endometrial receptivity. Mineralocorticoids is one of the causes influencing the implantation window. This study targeted to evaluation fludrocortisone different properties on endometrial receptivity. The objective of this study was to assess whether treatment with fludrocortisone could impact the expression of diverse genes and proteins that are involved in uterine receptivity in mice. In this study, 40 female adult BALB/c mice were used. The samples were allocated to four groups of ten. Control group (C) received: vehicle; fludrocortisone group (FCA): received 1.5 mg/kg fludrocortisone; PP242 group (PP242): received 30 mg/kg PP242; fludrocortisone+PP242 group (FCA+PP242): received fludrocortisone and PP242. Mice were killed on window implantation day after mating and confirmed pregnancy. The endometrial epithelium of mouse was collected to assess mRNA expression of leukemia inhibitory factor (LIF), mucin-1 (MUC1), heparin-binding epidermal growth factor (HB-EGF), (Msx.1), miRNA Let-7a, and miRNA 223-3p as well as protein expression of extracellular signal-regulated kinase 1/2 (ERK1/2), mammalian target of rapamycin (mTOR), and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) in the uterine using real-time PCR and western blot, respectively. In comparison with the control group, fludrocortisone administration upregulated the expression of LIF, HB-EGF, Msx.1, miRNA Let-7a, ERK1/2, and mTOR in the epithelial endometrium. The PP242-treated group demonstrated a significant rise in the expression of MUC1, miRNA 223-3p and a remarkable decline in ERK1/2 and p-4E-BP1 levels in comparison with the control group. Combination therapy of (FCA+PP242) resulted in a remarkable rise in LIF, Msx-1, HB-EGF, ERK1/2, and mTOR levels, in comparison with the PP242 group. Furthermore, combination therapy of (FCA+PP242) downregulated the expression of MUC1 in comparison with the PP242-treated group. According to the results, fludrocortisone affected uterine receptivity possibly by means of modulating the expression of genes involved in the uterine receptivity and activation of the ERK1/2-mTOR pathway.

Treatment with epigenetic agents profoundly inhibits tumor growth in leiomyosarcoma

Leiomyosarcomas are rare mesenchymal neoplasms characterized by a smooth muscle differentiation pattern. Due to the extremely poor prognosis in patients, the development of novel chemotherapeutic regimens remains critically important. In this study, multiple leiomyosarcoma cell lines, SK-UT1, SK-LMS1, and MES-SA were treated with varying doses of the DNA Methyltransferase Inhibitors (DNMTi) 5-azacitidine (Aza), 5-aza-2-deoxycytidine (DAC), and guadecitabine (SGI-110). The effect of these epigenetic modulators was measured using both in-vitro and in-vivo models.

Of the three epigenetic modulators, Guadecitabine was the most effective at decreasing cell survival in LMS cell lines. SK-UT1 was found to be the more sensitive to all three epigenetic modulators, while SK-LMS1 and MES-SA were more resistant. The contrast in sensitivity seen was also represented by the increase in apoptosis in Aza and guadecitabine. In parallel with Aza, guadecitabine was observed to also arrest the cell cycle.

Treatment with guadecitabine led to a decrease in growth across the spectrum of sensitivity in LMS cell lines, both in a delayed in vitro and in vivo model; in parallel experiments, apoptotic pathways were activated in sensitive and less sensitive lines. Additional studies are required to explore potential therapeutic applications and mechanisms for leiomyosarcoma treatment.

The benefit of everolimus in recurrent/epithelioid angiosarcoma patients: Case reports and literature review

Epithelioid angiosarcoma (EA) is a kind of rare malignant soft tissue sarcoma, with high recurrence/metastatic rate and poor prognosis. To date, no effective standardized treatment regimen has been available for patients with recurrence/metastatic EA. Everolimus is an oral rapamycin derivative that highly inhibits the mechanistic target of rapamycin(mTOR) signal pathway. Previous studies have suggested that everolimus is effective and safe in some soft tissue sarcoma. We reported two cases with recurrence/metastatic EA, who received everolimus after failure of surgery, radiotherapy, chemotherapy or interventional therapy. Two cases obtained clinical benefit within 1 week, and were evaluated as partial response (PR). The progression free survival (PFS) time was nearly 12.0 and 6.0 months, respectively. The overall survival (OS) time was 18.0 and 10.0 months, respectively. The main adverse event was stomatitis syndrome (grade 1-2), which was well controllable and tolerable. It indicated that everolimus may be more beneficial for recurrence/metastatic EA patients.

Managing sarcoma: where have we come from and where are we going?

Sarcomas are a heterogeneous group of neoplasms of mesenchymal origin. Approximately 80% arise from soft tissue and 20% originate from bone. To date more than 100 sarcoma subtypes have been identified and they vary in molecular characteristics, pathology, clinical presentation and response to treatment. While sarcomas represent <1% of adult cancers, they account for approximately 21% of paediatric malignancies and thus pose some of the greatest risks of mortality and morbidity in children and young adults. Metastases occur in one-third of all patients and approximately 10-20% of sarcomas recur locally. Surgery in combination with preoperative and postoperative therapies is the primary treatment for localized sarcoma tumours and is the most promising curative possibility. Metastasized sarcomas, on the other hand, are treated primarily with single-agent or combination chemotherapy, but this rarely leads to a complete and robust response and often becomes a palliative form of treatment. The heterogeneity of sarcomas results in variable responses to current generalized treatment strategies. In light of this and the lack of curative strategies for metastatic and unresectable sarcomas, there is a need for novel subtype-specific treatment strategies. With the more recent understanding of the molecular mechanisms underlying the pathogenesis of some of these tumours, the treatment of sarcoma subtypes with targeted therapies is a rapidly evolving field. This review discusses the current management of sarcomas as well as promising new therapies that are currently underway in clinical trials.

Molecular Targets and Emerging Therapeutic Options for Uterine Leiomyosarcoma

Uterine leiomyosarcoma (uLMS) is an aggressive malignancy characterized by its early metastasis, high rates of recurrence, and poor prognosis. Multiple obstacles complicate the clinical management of uLMS. These include the fact that most uLMS are typically identified only after a woman has undergone hysterectomy or myomectomy, the limited efficacy of adjuvant therapy for early stage disease, and the poor response of metastatic disease to current treatments. Here, we discuss recent insights into the molecular basis of uLMS and discuss emerging options for its clinical management. Particular attention is given to the biologic basis of these strategies with the goal of understanding the rationale motivating their use.

Treatment of Bone Tumors

In this article, the authors summarize the state of the art and future potential in the management of Osteosarcoma, Ewing's sarcoma, and Chondrosarcoma. They cover systemic therapy, surgical therapy, and radiotherapy, along with targeted therapies to inhibit signal transduction pathways. They discuss staging and the role of imaging evaluation to provide an overview of bone tumor treatment. Images presenting pathologic-radiologic correlations are included.

Primary Angiosarcoma of the Breast: An Uncommon Histopathological Subtype

Primary angiosarcoma of the breast is extremely rare malignant tumour of the breast. The cytological and radiological findings are often non specific for diagnosis. Histopathology plays an important role in diagnosis and grading of tumour. Herewith we present a case of 55-year-old postmenopausal woman having history of rapidly enlarging right breast lump with prominent vascularity and associated bluish discolouration of overlying skin. Mammography shows ill defined mass lesion. Fine needle aspiration cytology was done which showed haemorrhagic aspirate with few clusters of highly pleomorphic neoplastic cells. Patient underwent modified radical mastectomy. On histopathological evaluation it showed primary angiosarcoma of the breast, poorly differentiated, grade-III. We are presenting this extremely rare malignancy of breast for its clinical, cytological and histopathological findings.

Off-label use of targeted therapies in osteosarcomas: data from the French registry OUTC'S (Observatoire de l'Utilisation des Thérapies Ciblées dans les Sarcomes)

Background

The objective of this study is to explore the off-label use of targeted therapies (TTs) for patients with osteosarcoma registered within the French Sarcoma Group – Bone Tumor Study Group (GSF-GETO) national registry.

Methods

All patients with an osteosarcoma, registered between January 1, 2009 and July 15, 2013 were analyzed.

Results

Twenty-nine patients with refractory relapsed osteosarcomas received 33 treatment lines of TTs. The median age at the beginning of treatment was 19 years (range 9–72). The median number of previous lines of chemotherapy was 3 (range 1–8). Before inclusion, 3 patients were in second complete remission, 26 were in progression for metastatic relapse. Twenty-three patients received sirolimus (in combination with cyclophosphamide for 18); 5, sunitinib; 4, sorafenib; and one, pazopanib. Stable disease was observed for 45.5 % of patients (95 % Confidence Interval (CI) [20–52.8]). The median Progression-Free Survival (PFS) was 3 months (95 % CI [2–5.4]) for patients treated by sirolimus and 1.8 months (95 % CI [1.3–2.8]) for patients receiving multi-targeted tyrosine kinase inhibitors; 6-month PFS 15 %. The median Overall Survival (OS) was 6.8 months (95 % CI [4.7–12.1]), and one-year OS was 24 %. In a multivariate analysis, PFS was superior for patients receiving sirolimus compared to other TTs (Hazard Ratio (HR) = 2.7, 95 % CI [1.05–7.1]). No toxic death was reported. Grade 3 and 4 toxicities were observed in 27 and 6 % of cases respectively.

Conclusion

Off-label TTs, especially sirolimus, reported benefit in the treatment of refractory osteosarcomas with an acceptable toxicity profile, including in pediatric population.

P70S6 kinase phosphorylation: a new site to assess pharmacodynamy of sirolimus

Background:

The phosphorylation of p70S6 kinase (p70S6K) represents an important target for sensitive detection on pharmacodynamic effects of sirolimus, but the methods of assessing p70S6K phosphorylation are still unclear. The aim of this study was to investigate p70S6K phosphorylation located down-stream of the mammalian target of rapamycin (mTOR) pathway in peripheral blood mononuclear cells (PBMCs) of liver transplant patients through different methods.

Methods:

Seventy-five liver transplant recipients from Beijing Chaoyang Hospital of the Capital Medical University were analyzed in this study. Patients were divided into three groups, patient treated with sirolimus (n = 22), patient treated with tacrolimus (n = 30), patient treated with cyclosporine (n = 23). The p70S6K phosphorylation of PBMCs in patients and healthy control (HC, n = 12) were analyzed by phospho-flow cytometry and Western blotting. A correlation analysis of data from phospho-flow cytometry and Western blotting was performed. Intra-assay variability of p70S6K phosphorylation in HC and different patients were measured.

Results:

Intra-assay variability of p70S6K phosphorylation in phospho-flow cytometry was from 4.1% to 8.4% and in Western blotting was from 8.2% to 18%. The p70S6K phosphorylation in patients receiving a sirolimus (19.5 ± 7.7) was significantly lower than in HC (50.1 ± 11.3, P < 0.001), tacrolimus (37.7 ± 15.7, P < 0.001) or cyclosporine treated patients (41.7 ± 11.7, P < 0.001). The p70S6K phosphorylation in HC (50.1 ± 11.3) was significantly higher than in tacrolimus (37.7 ± 15.7, P < 0.01) or cyclosporine-treated patients (41.7 ± 11.7, P < 0.01). There was correlation between data from phospho-flow cytometry and data from Western blotting (r = 0.88, P < 0.001).

Conclusions:

The degree of mTOR inhibition by assessing p70S6K phosphorylation was established by phospho-flow cytometry and Western blotting. Assessment of p70S6K phosphorylation may play an adjunct role to on pharmacodynamically guide and individualize sirolimus based on immunosuppression.

Rapamycin loaded magnetic Fe3O4/carboxymethylchitosan nanoparticles as tumor-targeted drug delivery system: Synthesis and in vitro characterization

A novel tumor-targeted drug delivery system (Fe3O4/CMCS-Rapa NPs) was prepared using magnetic Fe3O4/carboxymethylchitosan nanoparticles (Fe3O4/CMCS NPs) as carrier and rapamycin (Rapa) as the model anti-tumor drug. The morphology, composition, and properties of the Fe3O4/CMCS-Rapa NPs were characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscope (TEM), X-ray diffraction (XRD), thermal analysis (TG/DSC), vibration sample magnetometer (VSM), and drug release kinetics, cytotoxicity, cellular uptake, apoptosis studies in vitro. The results showed that the synthesized Fe3O4/CMCS-Rapa NPs were spherical in shape with an average size of 30±2 nm, the saturated magnetization reached 67.1 emu/g, and the loading efficiency of Rapa was approximately 6.32±0.34%. In addition, the in vitro drug release behavior displayed that the Fe3O4/CMCS NPs exhibited a biphasic drug release pattern with initial burst release and consequently sustained release. Furthermore, the Fe3O4/CMCS-Rapa NPs showed lower cytotoxicity to liver cell line (LO2) and comparatively higher cytotoxicity to human hepatocarcinoma cell line (HepG2) than native Rapa. Fe3O4/CMCS-Rapa NPs could enhance cellular uptake and reduce Rapa drug damage to the normal cells so as to improve the curative effect of drug to tumor cells. All these results demonstrated that the Fe3O4/CMCS-Rapa NPs may be useful as a promising candidate for targeted cancer diagnostic and therapy.

Significance of Akt activation and AKT gene increases in soft tissue tumors

To clarify the aberrations of AKT genes, their protein products and clinicopathologic significance in bone and soft tissue tumors, expression profiles of total Akt, its isoforms and activated Akt, and increases in copy number of AKT1/AKT2 genes were examined. Immunohistochemical analysis in 77 cases revealed overexpression of total Akt, Akt1, Akt2, and phosphorylated Akt in 84.4%, 67.5%, 72.7%, and 71.4%, respectively. Positive results were also observed in benign lesions but at a lower frequency. Overexpression of Akt1 was more frequent than that of Akt2 in well-differentiated liposarcoma (6/7 versus 3/7 cases) and schwannoma (4/4 versus 1/4 cases), whereas Akt2 overexpression and Akt activation were more frequent than Akt1 overexpression in malignant nerve sheath (3/4 and 4/4, respectively, versus 2/4 cases) and muscular tumors (8/9 and 8/9 versus 4/9 cases). By fluorescence in situ hybridization analysis, increase of gene copy number was observed in 13.3% for AKT1 and in 25.0% for AKT2 due to polysomy of chromosome 14 or 19, respectively, but not gene amplification. One case of schwannoma exhibited polysomy of both chromosomes 14 and 19. Akt activation was correlated with total Akt cytoplasmic localization (P = .0031) and subsequent metastasis (P = .0454). Moreover, AKT2 gene increase correlated with tumor size (P = .0352) and metastasis (P = .0344). In conclusion, in a defined subset of bone and soft tissue tumors, including benign tumors, Akt was frequently overexpressed and activated, and AKT1/2 copy number was increased. Because abnormality of Akt/AKT correlated with clinicopathologic profiles, novel therapies targeting isoform-specific Akts may be useful for these particular types of tumors.

The role of inflammation in sarcoma

Sarcomas encompass a heterogenous group of tumors with diverse pathologically and clinically overlapping features. It is a rarely curable disease, and their management requires a multidisciplinary team approach. Chronic inflammation has emerged as one of the hallmarks of tumors including sarcomas. Classical inflammation-associated sarcomas comprise the inflammatory malignant fibrous histiocytoma and Kaposi sarcoma. The identification of specific chromosomal translocations and important intracellular signaling pathways such as Ras/Raf/MAPK, insulin-like growth factor, PI3K/AKT/mTOR, sonic hedgehog and Notch together with the increasing knowledge of angiogenesis has led to development of targeted therapies that aim to interrupt these pathways. Innovative agents like oncolytic viruses opened the way to design new therapeutic options with encouraging findings. Preclinical evidence also highlights the therapeutic potential of anti-inflammatory nutraceuticals as they can inhibit multiple pathways while being less toxic. This chapter gives an overview of actual therapeutic standards, newest evidence-based studies and exciting options for targeted therapies in sarcomas.

Metabolic stress and cancer: is autophagy the common denominator and a feasible target?

OBJECTIVES

Autophagy facilitates the degradation of proteins or organelles into recyclable molecules, which are released into the cell to foster cell survival under energetic stress. Furthermore, autophagy has been associated with cancer cell survival and chemoresistance, and as such, it is an area of increasing interest. As autophagic activity and its regulation are related to metabolism and energy stress, it is critical to elucidate the exact molecular mechanisms that drive it.

KEY FINDINGS

Cancer is recognised to have specific metabolic changes, which include the switch from oxidative phosphorylation to glycolysis. Although the exact rationale is yet to be determined, it is proposed to limit hypoxic stress and generate substrates for biosynthesis. The various forms of energetic stress including hypoxia, glucose and amino acid deprivation have been reviewed in relation to their effect on autophagy and certain key molecules identified to date. These key molecules, which include AMP-activated protein kinase, mammalian target of rapamycin complex 1, adenosine triphosphate and reactive oxygen species, are all implicated as key stimuli of autophagic activity, as will be discussed in this review.

SUMMARY

These findings indicate that autophagic regulation could be a means to better cancer treatment.

Discovery of chemotherapy-associated ovarian cancer antigens by interrogating memory T cells

According to the immunogenic cell death hypothesis, clinical chemotherapy treatments may result in CD8(+) and CD4(+) T-cell responses against tumor cells. To discover chemotherapy-associated antigens (CAAs), T cells derived from ovarian cancer (OC) patients (who had been treated with appropriate chemotherapy protocols) were interrogated with proteins isolated from primary OC cells. We screened for immunogenicity using two-dimensional electrophoresis gel-eluted OC proteins. Only the selected immunogenic antigens were molecularly characterized by mass-spectrometry-based analysis. Memory T cells that recognized antigens associated with apoptotic (but not live) OC cells were correlated with prolonged survival in response to chemotherapy, supporting the model of chemotherapy-induced apoptosis as an adjuvant of anti-tumor immunity. The strength of both memory CD4(+) and CD8(+) T cells producing either IFN-γ or IL-17 in response to apoptotic OC antigens was also significantly greater in Responders to chemotherapy than in nonresponders. Immunogenicity of some of these antigens was confirmed using recombinant proteins in an independent set of patients. The T-cell interrogation system represents a strategy of reverse tumor immunology that proposes to identify CAAs, which may then be validated as possible prognostic tumor biomarkers or cancer vaccines.

Primary angiosarcoma of breast: A case report

INTRODUCTION

Primary breast angiosarcoma is a rare form of breast cancer, accounting for only 0.04% of all malignant breast tumours.

PRESENTATION OF CASE

A 28-year-old woman presented with a progressive lump in the right breast for one month. Fine needle aspiration cytology (FNAC) was highly suspicious of angiosarcoma, and this diagnosis was confirmed on core needle biopsy. Modified radical mastectomy was performed as sole treatment.

DISCUSSION

Primary breast angiosarcoma is a rare type of breast malignancy, usually occurring in the third to fourth decade and only reported in women. The histological features of angiosarcoma of the breast are conventionally graded I, II or III. Total mastectomy appears to be the only treatment conferring benefit, chemotherapy and radiation therapy being of little proven value to date. The 5-year disease-free survival for grade I tumours can be as high as 76%, and up to 70% for grade II tumours whereas for grade III tumours it is reportedly about 15%.

CONCLUSION

Primary angiosarcoma of the breast is a rare malignancy with a poor prognosis, even after complete resection. Surgery is the mainstay of treatment with a limited role for chemotherapy and radiotherapy.

The molecular biology of soft-tissue sarcomas and current trends in therapy

Basic research in sarcoma models has been fundamental in the discovery of scientific milestones leading to a better understanding of the molecular biology of cancer. Yet, clinical research in sarcoma has lagged behind other cancers because of the multiple clinical and pathological entities that characterize sarcomas and their rarity. Sarcomas encompass a very heterogeneous group of tumors with diverse pathological and clinical overlapping characteristics. Molecular testing has been fundamental in the identification and better definition of more specific entities among this vast array of malignancies. A group of sarcomas are distinguished by specific molecular aberrations such as somatic mutations, intergene deletions, gene amplifications, reciprocal translocations, and complex karyotypes. These and other discoveries have led to a better understanding of the growth signals and the molecular pathways involved in the development of these tumors. These findings are leading to treatment strategies currently under intense investigation. Disruption of the growth signals is being targeted with antagonistic antibodies, tyrosine kinase inhibitors, and inhibitors of several downstream molecules in diverse molecular pathways. Preliminary clinical trials, supported by solid basic research and strong preclinical evidence, promises a new era in the clinical management of these broad spectrum of malignant tumors.

Targeted agents for sarcoma: is individualized therapy possible in such a diverse tumor type?

A wide variety of cytogenetic abnormalities and molecular pathways have been implicated in the pathogenesis of sarcoma, and significant progress has been made in the past decade toward identifying potential therapeutic targets. However, apart from gastrointestinal stromal tumors (GISTs) and dermatofibrosarcoma protuberans (DFSP), little progress has been made toward translating that knowledge into effective therapeutic strategies. The identification of activating KIT mutations in the majority of GISTs was a defining moment that led to the first effective targeted therapy for sarcoma, and the subsequent use of imatinib mesylate has revolutionized the treatment of GISTs. Beyond imatinib, the most promising agents to date--and the agents most extensively studied--are the multitargeted tyrosine kinase inhibitors. Several other classes of agents have also shown some activity in soft tissue sarcomas, including mammalian target of rapamycin inhibitors, inhibitors of growth factor receptors, histone deacetylase inhibitors, agents that modulate the p53 pathway, inhibitors of molecular chaperone proteins (eg, heat shock protein 90 [Hsp90]), and other signal transduction inhibitors. Despite a large number of completed and ongoing phase II studies, few agents have moved to phase III testing, and much work remains to be done to fully validate the identified targets and determine the optimal treatment strategy. Ongoing studies are exploring a wide range of combination strategies. This review will highlight some of the emerging targeted therapies that appear to hold promise and may eventually contribute to improved systemic therapy for sarcoma.

P2X7 Receptor Function in Bone-Related Cancer

Modulation of tumor microenvironment by different mediators is central in determining neoplastic formation and progression. Among these molecules extracellular ATP is emerging as a good candidate in promoting cell growth, neovascularization, tumor-host interactions, and metastatization. This paper summarizes recent findings on expression and function of P2X7 receptor for extracellular ATP in primary and metastatic bone cancers. Search of mRNA expression microchip databases and literature analysis demonstrate a high expression of P2X7 in primary bone tumors as well as in other malignancies such as multiple myeloma, neuroblastoma, breast, and prostate cancer. Evidence that P2X7 triggers NFATc1, PI3K/Akt, ROCK, and VEGF pathways in osteoblasts promoting either primary tumor development or osteoblastic lesions is also reported. Moreover, P2X7 receptor is involved in osteoclast differentiation, RANKL expression, matrix metalloproteases and cathepsin secretion thus promoting bone resorption and osteolytic lesions. Taken together these data point to a pivotal role for the P2X7 receptor in bone cancer biology.

Primary breast angiosarcoma: avoiding a common trap

Background. Primary breast angiosarcoma is a rare entity. Case. Initial diagnosis was a benign hemangioma at core biopsy. Wide local excision was performed, with positive margins. Pathology after surgery reported a moderately differentiated angiosarcoma. Tumor was finally treated using mastectomy and radiations. She developed a second angiosarcoma in contralateral breast, with an initial diagnosis on core biopsy of an atypical vascular lesion and was again treated using mastectomy and radiations. She developed bones and lung metastases. Conclusion. Primary breast angiosarcoma is a rare entity often difficult to diagnose on core biopsy, and a benign differential diagnosis is frequent. A highly vascular breast mass should always be considered malignant until proven otherwise. Surgical treatment seems to be the best course of action. There is a lack of data proving efficacy of adjuvant chemotherapy and radiation therapy.

Clinical activity of mammalian target of rapamycin inhibitors in solid tumors

The phosphatidylinositol 3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) pathway is vital for cell metabolism, growth, and proliferation. mTOR is frequently upregulated in many tumor types and hence has become an important target in cancer treatment. Sirolimus and its derivatives (rapalogs) interact with the intracellular receptor FK506 binding protein 12 (FKBP12), forming a complex with high affinity for mTOR and thus disrupting its activity. Rapalogs are being evaluated extensively in cancer patients with different formulations and schedules. Significant clinical activity has led to their approval for the treatment of kidney cancer, mantle cell lymphoma, and subependymal giant cell astrocytoma; however, despite increasing knowledge about cancer cell biology, their activity in other malignancies is unclear. Further research is needed to identify optimal dosage, administration and targeted combination as well as the subset of patients likely to respond to mTOR/PI3K inhibition. This review focuses on a discussion of the pathway, its implications in cancer biology and results of clinical trials of rapalogs alone or in combination, organizing them by common malignancy type.