Charge order and its connection with Fermi-liquid charge transport in a pristine high-T(c) cuprate

Electronic inhomogeneity appears to be an inherent characteristic of the enigmatic cuprate superconductors. Here we report the observation of charge-density-wave correlations in the model cuprate superconductor HgBa2CuO(4+δ) (T(c)=72 K) via bulk Cu L3-edge-resonant X-ray scattering. At the measured hole-doping level, both the short-range charge modulations and Fermi-liquid transport appear below the same temperature of about 200 K. Our result points to a unifying picture in which these two phenomena are preceded at the higher pseudogap temperature by q=0 magnetic order and the build-up of significant dynamic antiferromagnetic correlations. The magnitude of the charge modulation wave vector is consistent with the size of the electron pocket implied by quantum oscillation and Hall effect measurements for HgBa2CuO(4+δ) and with corresponding results for YBa2Cu3O(6+δ), which indicates that charge-density-wave correlations are universally responsible for the low-temperature quantum oscillation phenomenon.

In-plane magnetoresistance obeys Kohler's rule in the pseudogap phase of cuprate superconductors

We report in-plane resistivity (ρ) and transverse magnetoresistance (MR) measurements for underdoped HgBa(2)CuO(4+δ) (Hg1201). Contrary to the long-standing view that Kohler's rule is strongly violated in underdoped cuprates, we find that it is in fact satisfied in the pseudogap phase of Hg1201. The transverse MR shows a quadratic field dependence, δρ/ρ(0)=aH(2), with a(T)∝T(-4). In combination with the observed ρ∝T(2) dependence, this is consistent with a single Fermi-liquid quasiparticle scattering rate. We show that this behavior is typically masked in cuprates with lower structural symmetry or strong disorder effects.

Photo-enhanced antinodal conductivity in the pseudogap state of high-Tc cuprates

A major challenge in understanding the cuprate superconductors is to clarify the nature of the fundamental electronic correlations that lead to the pseudogap phenomenon. Here we use ultrashort light pulses to prepare a non-thermal distribution of excitations and capture novel properties that are hidden at equilibrium. Using a broadband (0.5–2 eV) probe, we are able to track the dynamics of the dielectric function and unveil an anomalous decrease in the scattering rate of the charge carriers in a pseudogap-like region of the temperature (T) and hole-doping (p) phase diagram. In this region, delimited by a well-defined T*_neq(p) line, the photoexcitation process triggers the evolution of antinodal excitations from gapped (localized) to delocalized quasiparticles characterized by a longer lifetime. The novel concept of photo-enhanced antinodal conductivity is naturally explained within the single-band Hubbard model, in which the short-range Coulomb repulsion leads to a k-space differentiation between nodal quasiparticles and antinodal excitations.

The pseudogap phase exhibited by the cuprates is almost as enigmatic as superconductivity in these materials itself. A time-resolved study performed by Cilento et al. suggests that this state can be photoexcited into a transient non-equilibrium state that is more conductive than the equilibrium state.

Non-invasive prenatal testing for fetal chromosomal abnormalities by low-coverage whole-genome sequencing of maternal plasma DNA: review of 1982 consecutive cases in a single center

OBJECTIVE

To review the performance of non-invasive prenatal testing (NIPT) by low-coverage whole-genome sequencing of maternal plasma DNA at a single center.

METHODS

The NIPT result and pregnancy outcome of 1982 consecutive cases were reviewed. NIPT was based on low coverage (0.1×) whole-genome sequencing of maternal plasma DNA. All subjects were contacted for pregnancy and fetal outcome.

RESULTS

Of the 1982 NIPT tests, a repeat blood sample was required in 23 (1.16%). In one case, a conclusive report could not be issued, probably because of an abnormal vanished twin fetus. NIPT was positive for common trisomies in 29 cases (23 were trisomy 21, four were trisomy 18 and two were trisomy 13); all were confirmed by prenatal karyotyping (specificity=100%). In addition, 11 cases were positive for sex-chromosomal abnormalities (SCA), and nine cases were positive for other aneuploidies or deletion/duplication. Fourteen of these 20 subjects agreed to undergo further investigations, and the abnormality was found to be of fetal origin in seven, confined placental mosaicism (CPM) in four, of maternal origin in two and not confirmed in one. Overall, 85.7% of the NIPT-suspected SCA were of fetal origin, and 66.7% of the other abnormalities were caused by CPM. Two of the six cases suspected or confirmed to have CPM were complicated by early-onset growth restriction requiring delivery before 34 weeks. Fetal outcome of the NIPT-negative cases was ascertained in 1645 (85.15%). Three chromosomal abnormalities were not detected by NIPT, including one case each of a balanced translocation, unbalanced translocation and triploidy. There were no known false negatives involving the common trisomies (sensitivity=100%).

CONCLUSIONS

Low-coverage whole-genome sequencing of maternal plasma DNA was highly accurate in detecting common trisomies. It also enabled the detection of other aneuploidies and structural chromosomal abnormalities with high positive predictive value.

Absence of static loop-current magnetism at the apical oxygen site in HgBa2CuO4+δ from NMR

The simple structure of HgBa(2)CuO(4+δ) (Hg1201) is ideal among cuprates for study of the pseudogap phase as a broken symmetry state. We have performed (17)O nuclear magnetic resonance on an underdoped Hg1201 crystal with a transition temperature of 74 K to look for circulating loop currents proposed theoretically and inferred from neutron scattering. The narrow spectra preclude static local fields in the pseudogap phase at the apical site, suggesting that the moments observed with neutrons are fluctuating. The nuclear magnetic resonance frequency shifts are consistent with a dipolar field from the Cu(2+) site.

Doping-dependent photon scattering resonance in the model high-temperature superconductor HgBa2CuO4+δ revealed by Raman scattering and optical ellipsometry

We study the model high-temperature superconductor HgBa(2)CuO(4+δ) with electronic Raman scattering and optical ellipsometry over a wide doping range. The dependence of the resonant Raman cross section on the incident photon energy changes drastically as a function of doping, in a manner that corresponds to a rearrangement of the interband optical transitions seen with ellipsometry. This doping-dependent Raman resonance allows us to reconcile the apparent discrepancy between Raman and x-ray detection of magnetic fluctuations in superconducting cuprates. Intriguingly, the strongest variation occurs across the doping level where the antinodal superconducting gap appears to reach its maximum.

Influence of fasting and sample collection time on 38 biochemical markers in healthy children: a CALIPER substudy

OBJECTIVES

Fasting samples can be difficult to obtain in the pediatric setting, particularly in neonates. As part of the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER), we aimed to determine if there are differences in serum concentrations of pediatric biochemical markers measured at fasting, postprandial, and random time points throughout the day.

DESIGN AND METHODS

Blood was drawn from 27 healthy children and adolescents (aged 4-18) with informed consent at 4 time points: after overnight fast, mid-morning after breakfast, within 2h after lunch, and late afternoon. The effect of fasting on 38 chemistries was evaluated by paired, two-tailed student'st-tests. Analysis of the effect of time of day was done using paired, repeated-measures ANOVA.

RESULTS

Fasting significantly affected 22 analytes, with HDL cholesterol being the most highly affected. Values tended to decrease postprandially, except for five analytes, including triglycerides, which increased. By ANOVA, 28 chemistries significantly differed across times of day tested.

CONCLUSIONS

Fasting is necessary for analysis of certain chemistries in pediatric subjects. Pediatricians should consider diurnal factors when ordering non-fasting tests and interpreting test results.

Feedback effect on high-energy magnetic fluctuations in the model high-temperature superconductor HgBa2CuO(4+δ) observed by electronic Raman scattering

We use electronic Raman scattering to study the model single-layer cuprate superconductor HgBa(2)CuO(4+δ). In an overdoped sample, we observe a pronounced amplitude enhancement of a high-energy peak related to two-magnon excitations in insulating cuprates upon cooling below the critical temperature T(c). This effect is accompanied by the appearance of the superconducting gap and a pairing peak above the gap in the Raman spectrum, and it can be understood as a hitherto-undetected feedback effect on the high-energy magnetic fluctuations due to the Cooper pairing interaction. This implies a direct involvement of the high-energy magnetic fluctuations in the pairing mechanism. All of these effects occur already above T(c) in two underdoped samples, demonstrating a related feedback mechanism associated with the pseudogap.

Electrical measurement of the direct spin hall effect in Fe/InxGa(1-x)As heterostructures

We report on an all-electrical measurement of the spin Hall effect in epitaxial Fe/InxGa(1-x)As heterostructures with n-type (Si) channel doping and highly doped Schottky tunnel barriers. A transverse spin current generated by an ordinary charge current flowing in the InxGa(1-x)As is detected by measuring the spin accumulation at the edges of the channel. The spin accumulation is identified through the observation of a Hanle effect in the voltage measured by pairs of ferromagnetic Hall contacts. We investigate the bias and temperature dependence of the resulting Hanle signal and determine the skew and side-jump contributions to the total spin Hall conductivity.

Hyperthermia potentiates oncolytic herpes viral killing of pancreatic cancer through a heat shock protein pathway

BACKGROUND

Oncolytic herpes simplex virus-1 (HSV-1) is designed to specifically infect, replicate in, and lyse cancer cells. This study investigates a novel therapeutic regimen, combining the effects of NV1066 (a recombinant HSV-1) and hyperthermia in the treatment of pancreatic cancer.

METHODS

NV1066 is an attenuated HSV-1 that replicates in cells resistant to apoptosis. Heat shock protein 72 (Hsp72) is a member of a family of proteins that is upregulated after hyperthermic insult, lending cellular protection by inhibiting apoptosis. In these experiments, we test the hypothesis that increased Hsp72 expression in response to hyperthermia enhances anti-apoptotic mechanisms, thereby increasing viral replication and tumor cell kill. Hs 700T pancreatic cancer cells were treated with hyperthermia alone (42 degrees C), NV1066 alone, and combination therapy. Cell survival and viral growth were measured. The effect of siRNA-directed Hsp72 knockdown was also measured.

RESULTS

Combining hyperthermia and viral treatment produced a synergistic effect on cell kill. Viral growth increased greater than 6-fold in the presence of hyperthermia (P < .05). Hyperthermia alone showed minimal cytotoxic activity against Hs 700T cells, while NV1066 infection resulted in approximately 50% cell kill. The combination of hyperthermia and viral infection significantly increased cell kill to approximately 80% (P < .01). Hsp72 knockdown attenuated this synergistic effect.

CONCLUSION

Hyperthermia enhances NV1066 replication, thereby potentiating the viral oncolytic response against pancreatic cancer cells. This finding has potential clinical application in the use of heated perfusion or permissive hyperthermia for delivery of oncolytic viral therapies.

Dynamic changes in chromatin structure through post-translational modifications of histone H3 during replication origin activation

Genome duplication relies on the timely activation of multiple replication origins throughout the genome during S phase. Each origin is marked by the assembly of a multiprotein pre-replication complex (pre-RC) and the recruitment of the replicative machinery, which can gain access to replication origins on the DNA through the barrier of specific chromatin structures. Inheritance of the genetic information is further accompanied by maintenance and inheritance of the epigenetic marks, which are accomplished by the activity of histone and DNA modifying enzymes traveling with the replisome. Here, we studied the changes in the chromatin structure at the loci of three replication origins, the early activated human lamin B2 (LB2) and monkey Ors8 (mOrs8) origins and the late-activated human homologue of the latter (hOrs8), during their activation, by measuring the abundance of post-translationally modified histone H3. The data show that dynamic changes in the levels of acetylated, methylated and phosphorylated histone H3 occur during the initiation of DNA replication at these three origin loci, which differ between early- and late-firing origins as well as between human- and monkey-derived cell lines. These results suggest that specific histone modifications are associated with origin firing, temporal activation and replication fork progression and underscore the importance of species specificity.

Persistent sciatic artery complicated by aneurysm formation and thrombosis

A persistent sciatic artery is a rare embryological anomaly. We report a case of a persistent sciatic artery with aneurysm formation and thrombosis in a patient with rheumatoid arthritis/systemic lupus erythematosus overlap syndrome and Raynaud's phenomenon. The diagnosis and complete, accurate evaluation of the arterial anatomy of the lower limb were achieved using computed tomographic angiography.

Bronchial artery embolisation can be equally safe and effective in the management of chronic recurrent haemoptysis

OBJECTIVE

To examine the efficacy and safety of bronchial artery embolisation in patients with acute major haemoptysis and those with chronic recurrent haemoptysis.

DESIGN

Retrospective review of clinical records.

SETTING

Regional hospital, Hong Kong.

PATIENTS

Clinical records of 70 consecutive patients who had undergone bronchial artery embolisation in Queen Elizabeth Hospital from 1998 to 2003 were reviewed. Altogether 74 bronchial artery embolisation procedures were attempted, 46 (62%) for acute major haemoptysis, and 28 (38%) for chronic recurrent bleeding. Follow-up data were available for 32 patients.

MAIN OUTCOME MEASURES

After bronchial artery embolisation, the Kaplan-Meier method and log-rank tests were used to compare the probability of recurrence in the two patient categories.

RESULTS

Overall immediate control was attained following 99% of the procedures, with a complication rate of 13%; all complications were mild and self-limiting. For the 32 patients (19 having acute major haemoptysis and 13 having chronic recurrent bleeding) with follow-up data available, the overall recurrence rate was 36% (26% in the acute and 47% in chronic group). No statistically significant difference in recurrence probability between the two groups was observed (P=0.24). Presence of active pulmonary tuberculosis was associated with increased risk of recurrence (P=0.005).

CONCLUSION

Bronchial artery embolisation was noted to be effective and safe in both acute major and chronic recurrent haemoptysis.

Intraoperative localization of lymph node metastases with a replication-competent herpes simplex virus

OBJECTIVES

Lymph node status is the most important prognostic factor determining recurrence and survival in patients with mesothelioma and other thoracic malignancies. Accurate localization of lymph node metastases is therefore necessary to improve selection of resectable and curable patients for surgical intervention. This study investigates the potential to identify lymph node metastases intraoperatively by using herpes-guided cancer cell-specific expression of green fluorescent protein.

METHODS

After infection with NV1066, a herpes simplex virus carrying green fluorescent protein transgene, human mesothelioma cancer cell lines were assessed for cancer cell-specific infection, green fluorescent protein expression, viral replication, and cytotoxicity. Murine models of lymphatic metastasis were established by means of surgical implantation of cancer cells into the preauricular (drainage to cervical lymph nodes) and pleural (mediastinal and retroperitoneal lymph nodes) spaces of athymic mice. Fluorescent thoracoscopy, laparoscopy, and stereomicroscopy were used to localize lymph node metastases that were confirmed by means of immunohistochemistry.

RESULTS

In vitro NV1066 infected, replicated (5- to 17,000-fold), and expressed green fluorescent protein in all cancer cells, even when infected at a low ratio of one viral plaque-forming unit per 100 tumor cells. In vivo NV1066 injected into primary tumors was able to locate and infect lymph node metastases producing green fluorescent protein that was visualized by means of fluorescent imaging. Histology confirmed lymphatic metastases, and immunohistochemistry confirmed viral presence in regions that expressed green fluorescent protein.

CONCLUSIONS

Herpes virus-guided cancer cell-specific production of green fluorescent protein can facilitate accurate localization of lymph node metastases. Fluorescent filters that detect green fluorescent protein can be incorporated into operative scopes to precisely localize and biopsy lymph node metastases.

Radiation-induced cellular DNA damage repair response enhances viral gene therapy efficacy in the treatment of malignant pleural mesothelioma

BACKGROUND

Malignant pleural mesothelioma (MPM) treated with radiotherapy (RT) has incomplete responses as a result of radiation-induced tumoral stress response that repairs DNA damage. Such stress response is beneficial for oncolytic viral therapy. We hypothesized that a combination of RT and NV1066, an oncolytic herpes virus, might exert an additive or synergistic effect in the treatment of MPM.

METHODS

JMN, a MPM cell line, was infected with NV1066 at multiplicities of infection of .05 to .25 in vitro with and without radiation (1 to 5 Gy). Virus replication was determined by plaque assay, cell kill by lactate dehydrogenase assay, and GADD34 (growth arrest and DNA damage repair 34, a DNA damage-repair protein) by real-time reverse transcriptase-polymerase chain reaction and Western blot test. Synergistic cytotoxicity dependence on GADD34 upregulation was confirmed by GADD34 small inhibitory RNA (siRNA).

RESULTS

Synergism was demonstrated between RT and NV1066 across a wide range of doses. As a result of such synergism, a dose-reduction for each agent (up to 5500-fold) can be accomplished over a wide range of therapeutic-effect levels without sacrificing tumor cell kill. This effect is correlated with increased GADD34 expression and inhibited by transfection of siRNA directed against GADD34.

CONCLUSIONS

RT can be combined with oncolytic herpes simplex virus therapy in the treatment of malignant pleural mesothelioma to achieve synergistic efficacy while minimizing dosage and toxicity.

Uterine fibroid embolisation in Chinese women: medium-term results

OBJECTIVE

To evaluate the medium-term results of uterine fibroid embolisation in Chinese women with symptomatic uterine fibroids.

DESIGN

Prospective case series study.

SETTING

Gynaecology and Interventional Radiology units in a public hospital, Hong Kong.

PATIENTS

Patients with symptomatic fibroids who underwent uterine fibroid embolisation in Queen Elizabeth Hospital from October 1998 to June 2004.

RESULTS

Fifty women (mean age, 42.9 years; median follow-up period, 27.5 months) were recruited. Most (82%) had menorrhagia as the chief presenting symptom. Embolisation was successful in 49 (98%) women. Complications occurred in 12 (24%) patients, but were all self-limiting. Significant decrease in the median clinical uterine size (14 weeks vs 10 weeks) and median volume of the largest fibroid on magnetic resonance imaging (157.9 mL vs 45 mL) were observed during the first year. The reduction seemed to be maintained till the last follow-up. Menorrhagia improved in 34 (84%) patients, dysmenorrhoea in 28 (88%), pelvic pain in 18 (82%) and abdominal mass in 15 (83%). Poor response was found for urinary symptoms (29% improvement). Eight (16%) patients underwent hysterectomies after uterine fibroid embolisation. On logistic regression analysis, the only significant predictive factor for symptomatic improvement was fibroid volume reduction at 6 months (P=0.03).

CONCLUSION

Uterine fibroid embolisation is an effective uterine-preserving therapy in patients with symptomatic fibroids; overall symptomatic improvement was estimated as 80%. Uterine or fibroid size reduction correlated well with clinical outcome. The impact of uterine fibroid embolisation on young women wishing to conceive is yet to be determined.

Radiation therapy potentiates effective oncolytic viral therapy in the treatment of lung cancer

BACKGROUND

Replication-competent oncolytic herpes simplex viruses with deletion of the gamma(1)34.5 gene preferentially replicate in and kill malignant cells. The gamma(1)34.5 gene codes for ICP 34.5, a protein that enhances viral replication, and is homologous to growth arrest and DNA damage protein 34 (GADD34), a radiation-inducible DNA repair gene. We hypothesized that radiation therapy may potentiate efficacy of oncolytic viral therapy by upregulating GADD34 and promoting viral replication.

METHODS

The A549 and H1299 lung cancer cell lines were infected with NV1066, an oncolytic herpes simplex virus, at multiplicities of infection (number of viral particles per tumor cell) of 0.1 to 0.5 in vitro with radiation (2 to 10 Gy) or without radiation. Viral replication was determined by plaque assay, cell-to-cell spread was determined by flow cytometry, cell kill was determined by lactate dehydrogenase assay, and GADD34 induction was determined by real-time reverse transcription-polymerase chain reaction and Western blot method. Evidence of synergistic cytotoxicity dependence with GADD34 induction is further confirmed by small inhibitory RNA inhibition of GADD34 expression.

RESULTS

Using both the isobologram method and combination index method of Chou and Talalay, significant synergism was demonstrated between radiation therapy and NV1066 both in vitro and in vivo. As a result of such synergism, a dose reduction for each agent (2- to 6,000-fold) can be accomplished for a wide range of therapeutic effect levels without sacrificing tumor cell kill. This effect is correlated with increased GADD34 expression and inhibited by transfection of small inhibitory RNA directed against GADD34.

CONCLUSIONS

These data provide the cellular basis for the clinical investigation of combined use of radiation therapy with oncolytic herpes simplex virus therapy in the treatment of lung cancer to achieve synergistic efficacy while minimizing dosage and toxicity.

Minimally invasive localization of oncolytic herpes simplex viral therapy of metastatic pleural cancer

Herpes simplex virus-1 (HSV-1) oncolytic therapy and gene therapy are promising treatment modalities against cancer. NV1066, one such HSV-1 virus, carries a marker gene for enhanced green fluorescent protein (EGFP). The purpose of this study was to determine whether NV1066 is cytotoxic to lung cancer and whether EGFP is a detectable marker of viral infection in vitro and in vivo. We further investigated whether EGFP expression in infected cells can be used to localize the virus and to identify small metastatic tumor foci (<1 mm) in vivo by means of minimally invasive endoscopic systems equipped with fluorescent filters. In A549 human lung cancer cells, in vitro viral replication was determined by plaque assay, cell kill by LDH release assay, and EGFP expression by flow cytometry. In vivo, A549 cells were injected into the pleural cavity of athymic mice. Mice were treated with intrapleural injection of NV1066 or saline and examined for EGFP expression in tumor deposits using a stereomicroscope or a fluorescent thoracoscopic system. NV1066 replicated in, expressed EGFP in infected cells and killed tumor cells in vitro. In vivo, treatment with intrapleural NV1066 decreased pleural disease burden, as measured by chest wall nodule counts and organ weights. EGFP was easily visualized in tumor deposits, including microscopic foci, by fluorescent thoracoscopy. NV1066 has significant oncolytic activity against a human NSCLC cell line and is effective in limiting the progression of metastatic disease in an in vivo orthotopic model. By incorporating fluorescent filters into endoscopic systems, a minimally invasive means for diagnosing small metastatic pleural deposits and localization of viral therapy for thoracic malignancies may be developed using the EGFP marker gene inserted in oncolytic herpes simplex viruses.

Computed tomography-guided percutaneous radiofrequency ablation of osteoid osteoma: local experience

Osteoid osteoma is a slow-growing tumour with limited growth potential. In the past, treatment comprised open surgery with en-bloc resection or curettage of the tumour. In recent years, various minimally invasive percutaneous treatments have gained popularity. We report on six patients who underwent computed tomography-guided percutaneous radiofrequency ablations of osteoid osteomas between January 2000 and December 2003 in a regional hospital in Hong Kong. Technical success was achieved in all procedures, with a mean follow-up of 40 months (range, 18-65 months). Five of the six patients achieved complete pain relief after the procedure and remained pain-free on subsequent follow-up. One patient with persistent symptoms after the first ablation was successfully treated with a second ablation. The mean in-hospital stay was 2.4 days. Progress in radiological healing was observed in all patients. There was one complication of skin burn over the needle entry site. Our experience shows that percutaneous computed tomography-guided radiofrequency ablation is a minimally invasive and cost-effective treatment for osteoid osteoma.

Imaging and therapy of malignant pleural mesothelioma using replication-competent herpes simplex viruses

BACKGROUND

Malignant pleural mesothelioma (MPM) is an aggressive cancer that is refractory to current treatment modalities. Oncolytic herpes simplex viruses (HSV) used for gene therapy are genetically engineered, replication-competent viruses that selectively target tumor cells while sparing normal host tissue. The localized nature, the potential accessibility and the relative lack of distant metastasis make MPM a particularly suitable disease for oncolytic viral therapy.

METHODS

The infectivity, selective replication, vector spread and cytotoxic ability of three oncolytic HSV: G207, NV1020 and NV1066, were tested against eleven pathological types of MPM cell lines including those that are resistant to radiation therapy, gemcitabine or cisplatin. The therapeutic efficacy and the effect on survival of NV1066 were confirmed in a murine MPM model.

RESULTS

All three oncolytic HSV were highly effective against all the MPM cell lines tested. Even at very low concentrations of MOI 0.01 (MOI: multiplicity of viral infection, ratio of viral particles per cancer cell), HSV were highly effective against MPM cells that are resistant to radiation, gemcitabine and cisplatin. NV1066, an oncolytic HSV that expresses green fluorescent protein (GFP), was able to delineate the extent of the disease in a murine model of MPM due to selective infection and expression of GFP in tumor cells. Furthermore, NV1066 was able to reduce the tumor burden and prolong survival even when treatment was at an advanced stage of the disease.

CONCLUSION

These findings support the continued investigation of oncolytic HSV as potential therapy for patients with therapy-resistant MPM.

Real-time intraoperative detection of breast cancer axillary lymph node metastases using a green fluorescent protein-expressing herpes virus

OBJECTIVE

To investigate the use of a green fluorescent protein (GFP)-expressing oncolytic herpes virus to enable real-time intraoperative detection of breast cancer lymph node metastases.

SUMMARY BACKGROUND DATA

Axillary lymph node status is the most important factor determining treatment, recurrence, and overall survival for women with breast cancer. The current methods of determining nodal status, however, have limitations. NV1066 is a novel oncolytic herpes viral strain that specifically infects cancer cells and expresses GFP.

METHODS

Seven human breast cancer cell lines were infected in vitro with NV1066 and assessed for GFP expression, viral replication, and cytotoxicity. An in vivo model of breast cancer lymphatic metastasis was established in mice. Tumor-bearing mice were treated with NV1066 via injection into the primary tumor. Axillary lymph nodes were analyzed using an in vivo fluorescent imaging system. Histologic and molecular assessment of lymph nodes were performed using immunohistochemistry and reverse transcriptase PCR and operating characteristics were determined.

RESULTS

NV1066 infected, expressed GFP, replicated within, and killed all human breast cancer cell lines in vitro. Injection of NV1066 into primary breast tumors resulted in viral transit to axillary lymph nodes, infection of lymphatic metastases, and GFP expression that was visualized with in vivo fluorescent imaging. Histologic and molecular confirmation demonstrated favorable operating characteristics of this method (sensitivity 80%; specificity 96%).

CONCLUSIONS

We introduce a novel, sensitive, and specific method of lymphatic mapping that utilizes NV1066-guided cancer cell-specific viral production of GFP to enable real-time intraoperative detection of lymphatic metastases.

Estrogen enhances the efficacy of an oncolytic HSV-1 mutant in the treatment of estrogen receptor-positive breast cancer

Oncolytic herpes simplex virus-1 (HSV-1) mutants selectively replicate in and lyse tumor cells. Viral replication is dependent on the cellular proliferative mechanism. Estrogen increases cellular proliferation and decreases apoptosis in estrogen receptor-positive (ER+) human breast cancer cells. We hypothesize that the cellular changes produced by estrogen may enhance oncolytic viral replication and improve the treatment of ER+ breast cancer cells. Estrogen increased proliferation and replication of the HSV-1 mutant, NV1066, in ER+ breast cancer cells. Additionally, cells grown with estrogen had lower rates of apoptosis and higher bcl-2 levels at baseline and after infection. Estrogen enhanced the oncolytic effect of NV1066, with cell kills of 95% and 97% at MOIs of 0.1 and 0.5, compared to 53 and 87% respectively without estrogen (p<0.001). Therapy of ER+ human breast cancer cells with a replication-competent HSV-1 mutant is improved in the presence of estrogen, in contrast to more standard therapies, such as chemotherapy and radiation, which demonstrate decreased efficacy in similar conditions. These data provide the mechanistic basis for the use of oncolytic HSV-1 in patients with hormone receptor-positive breast cancer, particularly if the disease progresses with conventional therapies.

Real-time diagnostic imaging of tumors and metastases by use of a replication-competent herpes vector to facilitate minimally invasive oncological surgery

Current efforts on expanding minimally invasive techniques into the realm of oncological surgery are hindered by lack of accurate visualization of tumor margins and failure to detect micro metastases in real time. We used a systemic delivery of a herpes viral vector with cancer-selective infection and replication to precisely differentiate between normal and malignant tissue. NV1066 is a genetically modified, replication-competent herpes simplex virus carrying a transgene for enhanced green fluorescent protein (GFP). We tested the potential of NV1066 in delineating tumor tissue in vitro and in vivo in a wide range of cancers and whether NV1066-induced GFP expression can detect small foci of tumors and metastases in in vivo models using an operating endoscope with fluorescent filters. Our findings indicate that NV1066 can be used for real-time intraoperative imaging and enhanced detection of early cancers and metastases. We demonstrate that a single dose of NV1066, administered either locally (intratumoral or intracavitary) or systemically, will detect loco-regional and distant disease throughout the body. Such cancer selectivity is confirmed in 110 types of cancer cells from 16 different primary organs. Fluorescence-aided minimally invasive endoscopy revealed microscopic tumor deposits unrecognized by conventional laparoscopy/thoracoscopy. Furthermore, NV1066 ability to transit and infect tumor and metastases is proven in syngenic and transplanted tumors in different animal models, both immunocompetent and immunodeficient. Cancer-selective GFP expression is confirmed by histology, immunohistochemistry, and qRT-PCR. These studies form the basis for real-time, intraoperative diagnostic imaging of tumor and metastases by minimally invasive endoscopic technology.