Safety, efficacy, and long-term follow-up evaluation of perioperative epirubicin, Cisplatin, and capecitabine chemotherapy in esophageal resection for adenocarcinoma

BACKGROUND

Perioperative epirubicin, cisplatin, and capecitabine (ECC) chemotherapy was evaluated in patients who underwent esophageal resection for adenocarcinoma of the esophagus or gastroesophageal junction (GEJ).

METHODS

A cohort of 93 consecutive patients was analyzed. The median follow-up period was 60 months. Source data verification of adverse events was performed by two independent observers.

RESULTS

All three planned preoperative chemotherapy cycles were administered to 65 patients (69.9 %). Only 27 % of the patients completed both pre- and postoperative chemotherapy. The reasons for not receiving postoperative adjuvant chemotherapy could be separated in two main problems: toxicity of the preoperative chemotherapy and postoperative problems involving difficulty in recovery and postoperative complications. Finally, 25 patients (27 %), completed three preoperative and three postoperative cycles. Grades 3 and 4 nonhematologic adverse events of preoperative chemotherapy mainly consisted of thromboembolic events (16.2 %) and cardiac complications (7.5 %). A history of cardiac and vascular disease was independently associated with discontinuation of preoperative chemotherapy and the occurrence of grade 3 or higher adverse events. Surgery was performed for 94 % of all the patients who started with ECC chemotherapy. A radical resection (R0) was achieved in 93 % of the patients. A complete pathologic response was observed in 8 % of the patients. During a median follow-up period of 60 months, the median disease-free survival time was 28 months, and the median overall survival time was 36 months. The 3-year overall survival rate was 50 %, and the 5-year overall survival rate was 42 %.

CONCLUSION

For patients with adenocarcinoma of the esophagus or GEJ, six cycles of ECC-based perioperative chemotherapy is associated with a relatively high number of adverse events. Although this toxicity did not affect the esophageal resectability rate, this regimen should be used with caution in this patient population.

Cancer-selective therapy of the future: Apoptin and its mechanism of action

Classical chemotherapy, that specifically targets rapidly proliferating cells, has been in existence for over eighty years and has proven to be fully successful in only a limited number of cancers. Thus, this review focuses on a novel, emerging approach for cancer therapy that uses alternative, and more unique features of cancer cells. This new approach facilitates the selective targeting of cancer, while sparing normal, non-transformed cells. Examples of molecules that kill cancer cells selectively are: apoptin, E4orf4, viral protein R (VpR), and Brevinin-2R. Below we focus on apoptin, a product of the third open reading frame (VP3) of the chicken anemia virus. Besides discussing apoptin's mechanism of action, we also provide concise insight into the biology of a chicken anemia virus infection. Since apoptin's cancer-selective toxicity depends on its nuclear localization, we broadly discuss mechanism(s) involved in its nuclear retention (both nuclear import and export). We also discuss recent findings on apoptin's molecular mechanism of action, with a focus on the role of Nur77 in apoptin's nucleo-cytoplasmic signaling. Finally, we compare the current findings on apoptin to the mechanism of cancer selective toxicity of E4orf4. In the 'summary' -section, besides highlighting important issues related to cancer-selective therapy, we also discuss concurrent approaches towards therapy personalization, particularly those related to the in vivo-, and real time cancer-therapy efficacy monitoring, using "lab-on-the-chip" and other emerging technologies.

A randomized phase III study comparing pegylated liposomal doxorubicin with capecitabine as first-line chemotherapy in elderly patients with metastatic breast cancer: results of the OMEGA study of the Dutch Breast Cancer Research Group BOOG

BACKGROUND

Prospective data on chemotherapy for elderly patients with metastatic breast cancer (MBC) remain scarce. We compared the efficacy and safety of first-line chemotherapy with pegylated liposomal doxorubicin (PLD) versus capecitabine in MBC patients aged ≥65 years in a multicentre, phase III trial.

PATIENTS AND METHODS

Patients were randomized to six cycles of PLD (45 mg/m(2) every 4 weeks) or eight cycles of capecitabine (1000 mg/m(2) twice daily, day 1-14 every 3 weeks).

RESULTS

The study enrolled 78 of the planned 154 patients and was closed prematurely due to slow accrual and supply problems of PLD. Many included patients were aged ≥75 years (54%) and vulnerable (≥1 geriatric condition: 71%). The median dose intensity was 85% for PLD and 84% for capecitabine, respectively. In both arms, the majority of patients completed at least 12 weeks of treatment (PLD 73%; capecitabine 74%). After a median follow-up of 39 months, 77 patients had progressed and 62 patients had died of MBC. Median progression-free survival was 5.6 versus 7.7 months (P = 0.11) for PLD and capecitabine, respectively. Median overall survival was 13.8 months for PLD and 16.8 months for capecitabine (P = 0.59). Both treatments were feasible, grade 3 toxicities consisting of fatigue (both arms: 13%), hand-foot syndrome (PLD: 10%; capecitabine: 16%), stomatitis (PLD: 10%; capecitabine: 3%), exanthema (PLD: 5%) and diarrhoea (PLD: 3%; capecitabine: 5%). Only 1 of 10 patients aged ≥80 years completed chemotherapy, while 3 and 6 patients discontinued treatment due to toxicity or progressive disease, respectively.

CONCLUSION

Both PLD and capecitabine demonstrated comparable efficacy and acceptable tolerance as first-line single-agent chemotherapy in elderly patients with MBC, even in vulnerable patients or patients aged ≥75 years. However, patients aged ≥80 years were unlikely to complete chemotherapy successfully.

CLINICAL TRIAL NUMBERS

EudraCT 2006-002046-10; ISRCTN 11114726; CKTO 2006-09; BOOG 2006-02.

Abstract OT3-1-03: DIRECT: A phase II/III randomized trial with dietary restriction as an adjunct to neoadjuvant chemotherapy for HER2-negative breast cancer

Background:

Preclinical evidence shows that short-term fasting protects normal cells, while cancer cells are sensitized to chemotherapy. Furthermore, a specifically designed very low calorie, low amino acid substitution diet (“Fasting Mimicking Diet”, FMD) has similar effects on chemotherapy as short-term fasting. This trial evaluates the impact of FMD on tolerance to and efficacy of neoadjuvant chemotherapy in women with HER2-negative early breast cancer.

Trial design:

DIRECT is a Dutch, randomized, open-label multicenter phase II/III trial. Women receiving neoadjuvant TAC courses (docetaxel/adriamycin/cyclophosphamide; day 1, q 3 weeks with G-CSF support at day 2) will be randomized with or without FMD for 3 days prior to and the day of chemotherapy and 3 days prior to surgery.

Eligibility criteria:

Eligible women are WHO 0-2, age ≥18 years, HER2-negative, stage II or III breast cancer and adequate bone marrow, liver and renal function, BMI > 19kg/m2 and absence of diabetes mellitus.

Study endpoints:

The primary endpoints are grade III/IV toxicity (phase II) and the pathologic complete response rate (pCR) (phase III). Secondary endpoints are grade I/II toxicity, metabolic and inflammatory response to chemotherapy, DNA damage, apoptosis, immunology and nutrient sensing pathways in the tumor, biomarkers as single nucleotide polymorphisms, Ki67 and tumor stroma/ratio, patient's quality of life and (disease free) survival. Optional side studies include chemotherapy-induced DNA damage and nutrient sensing pathways in leukocytes and proteomics.

Statistical Methods:

Using a 5% significance level based on the two-sided Fisher's exact test with a power of 80%, 128 patients (64/arm) will be enrolled to show a 50% decrease of grade III/IV adverse events in the experimental arm (phase II) and 250 patients (125/arm) are needed to show an improvement of the pCR rate from 18% to 36% (phase III).

Target accrual:

Recruitment will start in September 2013. The expected end of accrual of 250 patients from multiple centers in the Netherlands will be the last quarter of 2015.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr OT3-1-03.

Baseline comprehensive geriatric assessment is associated with toxicity and survival in elderly metastatic breast cancer patients receiving single-agent chemotherapy: results from the OMEGA study of the Dutch breast cancer trialists' group

AIM

To evaluate the association between baseline comprehensive geriatric assessment (CGA) or the Groningen Frailty Indicator (GFI) and toxicity in elderly metastatic breast cancer (MBC) patients treated with first-line palliative chemotherapy.

PATIENTS AND METHODS

MBC patients (≥65 years) were randomized between pegylated liposomal doxorubicine or capecitabine. CGA included instrumental activities of daily living (IADL), cognition using the mini-mental state examination (MMSE), mood using the geriatric depression scale (GDS), comorbidity using the Charlson index, polypharmacy and nutritional status using the body mass index. Frailty on CGA was defined as one or more of the following: IADL ≤ 13, MMSE ≤ 23, GDS ≥ 5, BMI ≤ 20, ≥5 medications or Charlson ≥2. The cut-off for frailty on the GFI was ≥4.

RESULTS

Of the randomized 78 patients (median age 75.5 years, range 65.8-86.8 years), 73 were evaluable for CGA; 52 (71%) had one or more geriatric conditions. Grade 3-4 chemotherapy-related toxicity was experienced by 19% of patients without geriatric conditions compared to 56% of patients with two geriatric conditions and 80% of those with three or more (p = 0.002). Polypharmacy was the only individual factor significantly associated with toxicity (p = 0.001). GFI had a sensitivity of 69% and a specificity of 76% for frailty on CGA, and was not significantly associated with survival or toxicity.

CONCLUSION

In this study of elderly patients with MBC, the number of geriatric conditions correlated with grade 3-4 chemotherapy-related toxicity. Therefore, in elderly patients for whom chemotherapy is being considered, a CGA could be a useful addition to the decision-making process.

Ehrlichia chaffeensis uses its surface protein EtpE to bind GPI-anchored protein DNase X and trigger entry into mammalian cells

Ehrlichia chaffeensis, an obligatory intracellular rickettsial pathogen, enters and replicates in monocytes/macrophages and several non-phagocytic cells. E. chaffeensis entry into mammalian cells is essential not only for causing the emerging zoonosis, human monocytic ehrlichiosis, but also for its survival. It remains unclear if E. chaffeensis has evolved a specific surface protein that functions as an 'invasin' to mediate its entry. We report a novel entry triggering protein of Ehrlichia, EtpE that functions as an invasin. EtpE is an outer membrane protein and an antibody against EtpE (the C-terminal fragment, EtpE-C) greatly inhibited E. chaffeensis binding, entry and infection of both phagocytes and non-phagocytes. EtpE-C-immunization of mice significantly inhibited E. chaffeensis infection. EtpE-C-coated latex beads, used to investigate whether EtpE-C can mediate cell invasion, entered both phagocytes and non-phagocytes and the entry was blocked by compounds that block E. chaffeensis entry. None of these compounds blocked uptake of non-coated beads by phagocytes. Yeast two-hybrid screening revealed that DNase X, a glycosylphosphatidyl inositol-anchored mammalian cell-surface protein binds EtpE-C. This was confirmed by far-Western blotting, affinity pull-down, co-immunoprecipitation, immunofluorescence labeling, and live-cell image analysis. EtpE-C-coated beads entered bone marrow-derived macrophages (BMDMs) from wild-type mice, whereas they neither bound nor entered BMDMs from DNase X(-/-) mice. Antibody against DNase X or DNase X knock-down by small interfering RNA impaired E. chaffeensis binding, entry, and infection. E. chaffeensis entry and infection rates of BMDMs from DNase X(-/-) mice and bacterial load in the peripheral blood in experimentally infected DNase X(-/-) mice, were significantly lower than those from wild-type mice. Thus this obligatory intracellular pathogen evolved a unique protein EtpE that binds DNase X to enter and infect eukaryotic cells. This study is the first to demonstrate the invasin and its mammalian receptor, and their in vivo relevance in any ehrlichial species.

Abstract P1-12-05: First-line chemotherapy with pegylated liposomal doxorubicin versus capecitabine in elderly patients with metastatic breast cancer: results of the phase III OMEGA study of the Dutch Breast Cancer Trialists' Group (BOOG)

Background The efficacy and feasibility of chemotherapy in elderly metastatic breast cancer (MBC) patients (pts) have been studied in various phase II studies. However, results of prospective randomized studies in elderly MBC pts are scarce.

Methods In this phase III multicenter study, MBC pts ≥ 65 years eligible for first-line chemotherapy were randomized between pegylated liposomal doxorubicin (PEGdoxo) (45mg/m2, IV, q 4 wks) or capecitabine (Cape) (1000 mg/m2 PO bid, days 1–14, q 3 wks). Other eligibility criteria were ECOG performance status (PS) ≤ 2 (3 allowed if due to pain or pre existing comorbidity), adequate bone marrow and organ functions. Stratification factors were PS (0–1 vs 2–3), HER2 status, visceral/non-visceral disease, adjuvant hormonal therapy (HTx), and HTx for MBC. Baseline geriatric assessment (GA) included functional status, instrumental activities of daily living, cognition, mood, comorbidity, polypharmacy and nutritional status. Chemotherapy was continued for 24 wks in the absence of progressive disease (PD) or unacceptable toxicity. Primary endpoint was progression-free survival (PFS), secondary endpoints were response rate, overall survival (OS), toxicity (CTC criteria) and compliance.

Results Between April 2007 and August 2011, 78 pts were randomized to PEGdoxo (n = 40) or Cape (n = 38). The study was prematurely closed due to slow accrual and supply problems with PEGdoxo. Mean age was 74 years (range 65–86; 75+ 54%; 80+ 13%). Pt characteristics were balanced between the two arms: PS 0–1 77%, ER+ 68%, HER2+ 5%, visceral/non-visceral disease 76%/24%, adjuvant HTx 46%, HTx for MBC 56%, ≥ 3 metastatic sites 50%. Only 22 out of 75 pts with a baseline GA had no geriatric condition (29%), while 32 pts (43%) and 21 pts (28%) had one or ≥ 2 geriatric conditions, respectively. Chemotherapy was given for 6 months in 38%, with a mean dose intensity of 84% in both arms. Reasons for early treatment discontinuation were: PD (31%), toxicity (28%), pt withdrawal (3%). After a median follow up of 32 months, 74 pts had PD and 56 pts had died. The median PFS was 5.7 and 7.7 months with PEGdoxo and Cape (HR 0.68, 95% CI: 0.42–1.11, p = 0.12) and the median OS was 13.8 and 16.8 months, respectively (HR 0.84, 95% CI: 0.49–1.42, p = 0.51). Response was evaluable in 64 pts, with a partial response (PR) in 7 (21%) and 6 pts (19%), and stable disease in 21 (64%) and 17 pts (55%) for PEGdoxo and Cape, respectively. Toxicity was acceptable, mainly being grade 1–2, with for PEGdoxo/Cape grade 1 alopecia in 14/4 pts (grade 2 in 1 PEGdoxo pt), grade 3 fatigue in 5/5 pts, grade 3 HFS in 4/6 pts and grade 3 mucositis in 4/1 pts, respectively. Pts with ≥ 1 geriatric condition more frequently experienced grade 3–4 toxicity, after correcting for type of chemotherapy, age and PS (HR 2.24, 95% CI: 1.21–4.16). Pts aged 75+ had a twofold higher risk of dying, irrespective of treatment arm (HR 2.31, 95% CI: 1.31–4.07).

Conclusions First-line chemotherapy with either PEGdoxo or Cape was feasible in elderly MBC pts, with adequate dose intensity and acceptable toxicity, even in non-fit pts or pts aged 75+. Baseline GA correlated with toxicity.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P1-12-05.

PD07-07: Combination of Paclitaxel and Bevacizumab without or with Capecitabine as First-Line Treatment of HER2−Negative Locally Recurrent or Metastatic Breast Cancer (LR/MBC): First Results from a Randomized, Multicenter, Open-Label, Phase II Study of the Dutch Breast Cancer Trialists' Group (BOOG)

Background: First-line treatment of HER2−negative LR/MBC with paclitaxel (T) and bevacizumab (A) has demonstrated improved progression-free survival (PFS) and overall response rate (ORR) when compared with T alone (E2100). We determined whether addition of capecitabine (X) to AT is safe and would be better effective than AT in women with HER2−negative LR/MBC.

Methods: Eligibility criteria were age ≥18 & ≤75 years, measurable or non-measurable HER2−negative LR/MBC, ECOG PS 0–1 and no prior chemotherapy for LR/MBC. Patients were randomized in 1:1 ratio to receive AT (4-week cycle of T 90 mg/m2 on days 1, 8, 15 and A 10 mg/kg on days 1, 15 for 6 cycles, followed by A 15 mg/kg on day 1 given 3-weekly for subsequent cycles) or ATX (3-week cycle of T 90 mg/m2 on days 1, 8, A 15 mg/kg on day 1 and X 825 mg/m2 bid on days 1–14 for 8 cycles, followed by A 15 mg/kg on day 1 and X 825 mg/m2 bid on days 1–14 given 3-weekly for subsequent cycles). Treatment was discontinued at disease progression, unmanageable toxicity or withdrawal of consent. The primary endpoint was PFS. Secondary endpoints were overall survival, ORR, duration of response and toxicity. Efficacy was evaluated according to RECIST 1.0 and toxicity was assessed according to NCI CTCAE 3.0.

Results: From June 2007 till December 2010, 312 patients were recruited at 36 sites. The median age was 56 years (range 32–76). Among all patients, 52% had ECOG 0, 85% were hormone-receptor positive, 86% had measurable disease and 8% had bone-only metastases. These factors were well balanced between both arms. A total of 48% and 33% of patients, respectively, received prior hormonal therapy or radiotherapy for LR/MBC. At the data cut-off of 1st June 2011, the median follow-up duration was 23 months. 311 patients received at least one cycle of treatment and were evaluable for safety. The median number of treatment cycles in AT was 9 and in ATX was 11 (both 33 weeks). An ORR of ≥40% was reached in patients with measurable disease in both groups. The incidence of serious adverse events (SAEs) was 47% and 40% for AT and ATX, respectively, while that of treatment-related SAEs was 12% and 19%, respectively. Treatment-related deaths were 2% for AT and 2% for ATX. The overall rate of AEs grade 3 or 4 was similar in both arms as shown in Table 1, except for hand-foot syndrome grade 3 and neutropenia grade 3 in ATX. In addition, 6 patients with pulmonary embolism were reported in ATX.

Virus-triggered autophagy in viral hepatitis - possible novel strategies for drug development

Autophagy is a very tightly regulated process that is important in many cellular processes including development, differentiation, survival and homoeostasis. The importance of this process has already been proven in numerous common diseases such as cancer and neurodegenerative disorders. Emerging data indicate that autophagy plays an important role in some liver diseases including liver injury induced by ischaemia reperfusion and alpha-1 antitrypsin Z allele-dependent liver disease. Autophagy may also occur in viral infection, and it may play a crucial role in antimicrobial host defence against pathogens, while supporting cellular homoeostasis processes. Here, the latest findings on the role of autophagy in viral hepatitis B and C infection, which are both serious health threats, will be reviewed.

CLASSIFICATION OF THE DECAYS OF THE Z0 INTO b AND c QUARK PAIRS USING A NEURAL NETWORK

A classifier based on a Feed-Forward Neural Network has been used for separating a sample of about 123,500 selected hadronic decays of the Z0, collected by DELPHI during 1991, into three classes according to the flavour of the original quark pair: [Formula: see text] (unresolved), [Formula: see text] and [Formula: see text] The classification has been used to compute the partial widths of the Z0 into b and C quark pairs.

Mevalonate cascade regulation of airway mesenchymal cell autophagy and apoptosis: a dual role for p53

Statins inhibit the proximal steps of cholesterol biosynthesis, and are linked to health benefits in various conditions, including cancer and lung disease. We have previously investigated apoptotic pathways triggered by statins in airway mesenchymal cells, and identified reduced prenylation of small GTPases as a primary effector mechanism leading to p53-mediated cell death. Here, we extend our studies of statin-induced cell death by assessing endpoints of both apoptosis and autophagy, and investigating their interplay and coincident regulation. Using primary cultured human airway smooth muscle (HASM) and human airway fibroblasts (HAF), autophagy, and autophagosome formation and flux were assessed by transmission electron microscopy, cytochemistry (lysosome number and co-localization with LC3) and immunoblotting (LC3 lipidation and Atg12-5 complex formation). Chemical inhibition of autophagy increased simvastatin-induced caspase activation and cell death. Similarly, Atg5 silencing with shRNA, thus preventing Atg5-12 complex formation, increased pro-apoptotic effects of simvastatin. Simvastatin concomitantly increased p53-dependent expression of p53 up-regulated modulator of apoptosis (PUMA), NOXA, and damage-regulated autophagy modulator (DRAM). Notably both mevalonate cascade inhibition-induced autophagy and apoptosis were p53 dependent: simvastatin increased nuclear p53 accumulation, and both cyclic pifithrin-α and p53 shRNAi partially inhibited NOXA, PUMA expression and caspase-3/7 cleavage (apoptosis) and DRAM expression, Atg5-12 complex formation, LC3 lipidation, and autophagosome formation (autophagy). Furthermore, the autophagy response is induced rapidly, significantly delaying apoptosis, suggesting the existence of a temporally coordinated p53 regulation network. These findings are relevant for the development of statin-based therapeutic approaches in obstructive airway disease.

Switching Akt: from survival signaling to deadly response

Akt, a protein kinase hyperactivated in many tumors, plays a major role in both cell survival and resistance to tumor therapy. A recent study,1 along with other evidences, shows interestingly, that Akt is not a single-function kinase, but may facilitate rather than inhibit cell death under certain conditions. This hitherto undetected function of Akt is accomplished by its ability to increase reactive oxygen species and to suppress antioxidant enzymes. The ability of Akt to down-regulate antioxidant defenses uncovers a novel Achilles' heel, which could be exploited by oxidant therapies in order to selectively eradicate tumor cells that express high levels of Akt activity.

Apoptosis and cancer: mutations within caspase genes

The inactivation of programmed cell death has profound effects not only on the development but also on the overall integrity of multicellular organisms. Beside developmental abnormalities, it may lead to tumorigenesis, autoimmunity, and other serious health problems. Deregulated apoptosis may also be the leading cause of cancer therapy chemoresistance. Caspase family of cysteinyl-proteases plays the key role in the initiation and execution of programmed cell death. This review gives an overview of the role of caspases, their natural modulators like IAPs, FLIPs, and Smac/Diablo in apoptosis and upon inactivation, and also in cancer development. Besides describing the basic mechanisms governing programmed cell death, a large part of this review is dedicated to previous studies that were focused on screening tumours for mutations within caspase genes as well as their regulators. The last part of this review discusses several emerging treatments that involve modulation of caspases and their regulators. Thus, we also highlight caspase cascade modulating experimental anticancer drugs like cFLIP-antagonist CDDO-Me; cIAP1 antagonists OSU-03012 and ME-BS; and XIAP small molecule antagonists 1396-11, 1396-12, 1396-28, triptolide, AEG35156, survivin/Hsp90 antagonist shephedrin, and some of the direct activators of procaspase-3.

Obesity: pathophysiology and clinical management

Obesity is an increasingly serious socioeconomic and clinical problem. Between (1/4)-(1/3) of population in the developed countries can be classified as obese. Four major etiological factors for development of obesity are genetic determinants, environmental factors, food intake and exercise. Obesity increases the risk of the development of various pathologic conditions including: insulin-resistant diabetes mellitus, cardiovascular disease, non-alcoholic fatty liver disease, endocrine problems, and certain forms of cancer. Thus, obesity is a negative determinant for longevity. In this review we provide broad overview of pathophysiology of obesity. We also discuss various available, and experimental therapeutic methods. We highlight functions of adipocytes including fat storing capacity and secretory activity resulting in numerous endocrine effects like leptin, IL-6, adiponectin, and resistin. The anti-obesity drugs are classified according to their primary action on energy balance. Major classes of these drugs are: appetite suppressants, inhibitors of fat absorption (i.e. orlistat), stimulators of thermogenesis and stimulators of fat mobilization. The appetite suppressants are further divided into noradrenergic agents, (i.e. phentermine, phendimetrazine, benzphetamine, diethylpropion), serotoninergic agents (i.e. dexfenfluramine), and mixed noradrenergic-serotoninergic agents (i.e. sibutramine). Thus, we highlight recent advances in the understanding of the central neural control of energy balance, current treatment strategies for obesity and the most promising targets for the development of novel anti-obesity drugs.

Unscheduled Akt-triggered activation of cyclin-dependent kinase 2 as a key effector mechanism of apoptin's anticancer toxicity

Apoptin, a protein from the chicken anemia virus, has attracted attention because it specifically kills tumor cells while leaving normal cells unharmed. The reason for this tumor selectivity is unclear and depends on subcellular localization, as apoptin resides in the cytoplasm of normal cells but in the nuclei of transformed cells. It was shown that nuclear localization and tumor-specific killing crucially require apoptin's phosphorylation by an as yet unknown kinase. Here we elucidate the pathway of apoptin-induced apoptosis and show that it essentially depends on abnormal phosphatidylinositol 3-kinase (PI3-kinase)/Akt activation, resulting in the activation of the cyclin-dependent kinase CDK2. Inhibitors as well as dominant-negative mutants of PI3-kinase and Akt not only inhibited CDK2 activation but also protected cells from apoptin-induced cell death. Akt activated CDK2 by direct phosphorylation as well as by the phosphorylation-induced degradation of the inhibitor p27(Kip1). Importantly, we also identified CDK2 as the principal kinase that phosphorylates apoptin and is crucially required for apoptin-induced cell death. Immortalized CDK2-deficient fibroblasts and CDK2 knockdown cells were markedly protected against apoptin. Thus, our results not only decipher the pathway of apoptin-induced cell death but also provide mechanistic insights for the selective killing of tumor cells.

Prolonged survival and expression of neural markers by bone marrow-derived stem cells transplanted into brain lesions

BACKGROUND

Bone marrow-derived stem cell transplantation is a potentially viable therapeutic option for the treatment of neurodegenerative disease.

MATERIAL/METHODS

We have isolated bone marrow stem cells by standard method. We then evaluated the survival of rats' bone marrow mononuclear cells implanted in rats' brain. The cells were extracted from rats' femurs, and marked for monitoring purposes by adenoviral transduction with Green Fluorescent Protein (GFP). Labeled cells were implanted within the area of rats' striatum lesions that were induced a month earlier employing quinolinic acid-based method. The implants were phenotyped by monitoring CD34; CD38; CD45 and CD90 expression. Bone marrow stromal cells were extracted from rats' femurs and cultivated until monolayer bone marrow stromal cells were obtained. The ability of bone marrow stromal cells to express NGF and GDNF was evaluated by RT-PCR.

RESULTS

Implanted cells survived for at least one month after transplantation and dispersed from the area of injection towards corpus callosum and brain cortex. Interestingly, passaged rat bone marrow stromal cells expressed NGF and GDNF mRNA.

CONCLUSIONS

The bone marrow cells could be successfully transplanted to the brain either for the purpose of trans-differentiation, or for the expression of desired growth factors.

Adult stem cells and their trans-differentiation potential--perspectives and therapeutic applications

Stem cells are self-renewing multipotent progenitors with the broadest developmental potential in a given tissue at a given time. Normal stem cells in the adult organism are responsible for renewal and repair of aged or damaged tissue. Adult stem cells are present in virtually all tissues and during most stages of development. In this review, we introduce the reader to the basic information about the field. We describe selected stem cell isolation techniques and stem cell markers for various stem cell populations. These include makers for endothelial progenitor cells (CD146/MCAM/MUC18/S-endo-1, CD34, CD133/prominin, Tie-2, Flk1/KD/VEGFR2), hematopoietic stem cells (CD34, CD117/c-Kit, Sca1), mesenchymal stem cells (CD146/MCAM/MUC18/S-endo-1, STRO-1, Thy-1), neural stem cells (CD133/prominin, nestin, NCAM), mammary stem cells (CD24, CD29, Sca1), and intestinal stem cells (NCAM, CD34, Thy-1, CD117/c-Kit, Flt-3). Separate section provides a concise summary of recent clinical trials involving stem cells directed towards improvement of a damaged myocardium. In the last part of the review, we reflect on the field and on future developments.

Cancer stem cell markers in common cancers - therapeutic implications

Rapid advances in the cancer stem cell (CSC) field have provided cause for optimism for the development of more reliable cancer therapies in the future. Strategies aimed at efficient targeting of CSCs are becoming important for monitoring the progress of cancer therapy and for evaluating new therapeutic approaches. Here, we characterize and compare the specific markers that have been found to be present on stem cells, cancer cells and CSCs in selected tissues (colon, breast, liver, pancreas and prostate). We then discuss future directions of this intriguing new research field in the context of new diagnostic and therapeutic opportunities.