Evaluation of circulating cell-free KRAS mutational status as a molecular monitoring tool in patients with pancreatic cancer

BACKGROUND

Pancreatic carcinoma carries a devastating prognosis and is the 4th leading cause for cancer related death in the US and most European countries. Apart from imaging and CA 19-9, pancreatic carcinoma is still lacking reliable markers to assess tumor dynamics and to monitor treatment response over time. The aim of this study was to evaluate the feasibility of cell free tumor-DNA (cft-DNA), respectively KRAS mutation in peripheral blood, detection as a prognostic and predictive value for chemotherapy monitoring.

METHODS

Serial plasma samples from 42 patients with KRAS mutated pancreatic cancer were prospectively collected and the ctKRAS Mutation Assay (Idylla™, Biocartis, Mechelen, Belgium) of cft-DNA was performed on 29 patients that did not receive curative surgery and went on to palliative chemotherapy. To monitor cft-DNA KRAS mutation levels during treatment quantitative assessment of cft-DNA was performed at baseline and during follow up at predetermined times.

RESULTS

All 29 patients included in our analyses had a detected KRAS mutation in the tumor biopsy. In almost half (48.2%) of patients a KRAS mutation could also be detected in peripheral plasma. Patients with detectable KRAS mutations before treatment start in plasma had a significantly worse survival (16.8 months vs not reached, p < 0.031 and HR 3.303). Looking for a dynamic assessment of tumor response, we found a statistically significant association between the KRAS mutant ratio from first staging CT scan to basal levels with tumor response or progress (p = 0.014).

CONCLUSION

Performing KRAS testing from peripheral blood for patients, who have no elevated tumor markers, might be a novel option for treatment monitoring complementing routine imaging techniques.

Overcoming negative predictions of microRNA expressions to gemcitabine response with FOLFIRINOX in advanced pancreatic cancer patients

FOLFIRINOX is superior to gemcitabine in patients with pancreatic cancer, but this regimen is associated with toxicity and biomarkers for response are warranted. MicroRNAs can mediate drug resistance and could provide predictive information. Altered expressions of several microRNAs including miR-21-5p, miR-10b-5p and miR-34a-5p have been previously linked to a worse response to gemcitabine. We investigated the influence of expression levels in tumor tissue of those three microRNAs on outcome to FOLFIRINOX. Twenty-nine patients with sufficient formalin-fixed paraffin-embedded tumor tissue were identified. There was no significant association between high and low expression groups for these three microRNA. We conclude that polychemotherapy combination can overcome intrinsic negative prognostic factors.

Antenatal Diagnosis of Dizygotic, Monochorionic Twins Following IVF/ICSI

Monochorionic twins are usually monozygotic and thus usually have the same sex. A case of monochorionic diamniotic twins following IVF/ICSI and laser treatment of the zona pellucida ("assisted hatching") is presented in which partial embryo amalgamation appears to have occurred. Discordant sex between the twins was suspected on detailed antenatal ultrasound at 13 + 3 weeks gestation and was confirmed on subsequent examinations. The sexual phenotype at birth was female for one twin and male for the other. Placental histology confirmed the monochorionic, diamniotic situation. Cytogenetic analysis of both twins was carried out postpartum on various tissues. On karyotyping of blood lymphocytes the male and female twins each had one mosaic of male and female cells. Oral mucosal cells showed normal male and female karyotypes respectively. Analysis of urothelium showed a normal result for the male infant, and a weak gonosomal mosaic with an XX and XY constellation for the female infant. At least for blood lymphocytes, a diagnosis of chimerism was proven.

Silver-Russell patients showing a broad range of ICR1 and ICR2 hypomethylation in different tissues

In all known congenital imprinting disorders an association with aberrant methylation or mutations at specific loci was well established. However, several patients with transient neonatal diabetes mellitus (TNDM), Silver-Russell syndrome (SRS) and Beckwith-Wiedemann syndrome (BWS) exhibiting multilocus hypomethylation (MLH) have meanwhile been described. Whereas TNDM patients with MLH show clinical symptoms different from carriers with isolated 6q24 aberrations, MLH carriers diagnosed as BWS or SRS present only the syndrome-specific features. Interestingly, SRS and BWS patients with nearly identical MLH patterns in leukocytes have been identified. We now report on the molecular findings in DNA in three SRS patients with hypomethylation of both 11p15 imprinted control regions (ICRs) in leukocytes. One patient was a monozygotic (MZ) twin, another was a triplet. While the hypomethylation affected both oppositely imprinted 11p15 ICRs in leukocytes, in buccal swab DNA only the ICR1 hypomethylation was visible in two of our patients. In the non-affected MZ twin of one of these patients, aberrant methylation was also present in leukocytes but neither in buccal swab DNA nor in skin fibroblasts. Despite mutation screening of several factors involved in establishment and maintenance of methylation marks including ZFP57, MBD3, DNMT1 and DNMT3L the molecular clue for the ICR1/ICR2 hypomethylation in our patients remained unclear. Furthermore, the reason for the development of the specific SRS phenotype is not obvious. In conclusion, our data reflect the broad range of epimutations in SRS and illustrate that an extensive molecular and clinical characterization of patients is necessary.

Phase I study of obatoclax mesylate (GX15–070MS), a bcl-2 antagonist, plus topotecan in relapsed small cell lung carcinoma and other solid tumors

3504

Background: Bcl-2 is a rational target in SCLC since it is overexpressed in 60%-90% of tumors and may play a role in resistance of SCLC to chemotherapy. Obatoclax is a small molecule BH3 mimetic that blocks bcl-2 binding to proapoptotic family members. Obatoclax has growth inhibitory effects in several solid tumor cell lines and xenografts, with at least additive effects in combination with topotecan. The primary objective of this study was to evaluate the safety profile and maximum tolerated dose (MTD) of obatoclax plus topotecan in patients with relapsed SCLC and other solid tumors. Methods: We conducted a phase I dose escalation study using a standard “3+3” design. Obatoclax was administered at 14 or 20 mg/m2 over 3 hours on day 1 every 21 days. A subsequent cohort received obatoclax 14mg/m2 on days 1 and 3. Topotecan was given at 1.25 mg/m2 days 1–5. All patients received pegfilgrastim on day 8. Eligible patients were adults with solid tumors appropriate for treatment with topotecan. Patients with neurologically stable, treated brain mets were eligible. Results: 14 patients have been treated including 8 SCLC, 3 extrapulmonary small cell, 1 carcinoid, 1 Merkel cell and 1 melanoma previously treated with 1 or 2 lines of chemotherapy. Nearly all patients experienced neurologic toxicities during the obatoclax infusion which included ataxia, dysarthria, somnolence and/or mood alteration; these typically resolved 1–2 hours after completion of the infusion. The MTD of obatoclax was 20 mg/m2 on day 1 with Dose Limiting Toxicities (DLT) including grade 3 neurotoxicity (2 pts) and febrile neutropenia. Hematologic toxicity included grade 3/4 anemia (6 pts), thrombocytopenia (5 pts) and neutropenia (5 pts). Other toxicities included mild nausea/vomiting, fatigue, pruritus, and constipation. Clinical activity was seen in patients with SCLC including 1 PR and 4 SD out of 7 evaluable. The median TTP for these SCLC patients was 11 weeks. Conclusions: The recommended phase II dose is obatoclax 14 mg/m2 on days 1 and 3 with topotecan 1.25 mg/m2 on days 1–5 in 21 day cycles. A phase II study in second-line SCLC is open. Supported by NCI U01-CA69856.

No significant financial relationships to disclose.

Enhanced antitumor efficacy of a herpes simplex virus mutant isolated by genetic selection in cancer cells

Replication-competent, attenuated herpes simplex virus-1 (HSV-1) derivatives that contain engineered mutations into the viral gamma 34.5 virulence gene have been used as oncolytic agents. However, as attenuated mutants often grow poorly, they may not completely destroy some tumors and surviving cancer cells simply regrow. Thus, although HSV-1 gamma 34.5 mutants can reduce the growth of human tumor xenografts in mice and have passed phase I safety studies, their efficacy is limited because they replicate poorly in many human tumor cells. Previously, we selected for a gamma 34.5 deletion mutant variant that regained the ability to replicate efficiently in tumor cells. Although this virus contains an extragenic suppressor mutation that confers enhanced growth in tumor cells, it remains attenuated. Here, we demonstrate that the suppressor virus replicates to greater levels in prostate carcinoma cells and, importantly, is a more potent inhibitor of tumor growth in an animal model of human prostate cancer than the gamma 34.5 parent virus. Thus, genetic selection in cancer cells can be used as a tool to enhance the antitumor activity of a replication-competent virus. The increased therapeutic potency of this oncolytic virus may be useful in the treatment of a wide variety of cancers.

RT-PCR amplification of various canine cytokines and so-called house-keeping genes in a species-specific macrophage cell line (DH82) and canine peripheral blood leukocytes

Total ribonucleic acid (RNA) isolated from a continuous canine macrophage cell line (DH82) was used in reverse transcription polymerase chain reactions (RT-PCR) for the detection of transcripts of interleukin (IL)-8, -12, and tumour necrosis factor-alpha (TNF). Three different methods of RNA isolation (standard guanidinium-thiocyanate method with and without application of RNA matrix, and boiling) were used and compared in regard to RT-PCR results. The most suitable method was used to establish RT-PCR amplification of mRNA transcripts of IL-2, -10, and interferon-gamma (IFN) in RNA isolated from canine peripheral blood leukocytes. Integrity of RNA isolates was ensured by amplification of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) or beta-actin, IL-8, -12, and TNF were amplified from RNA isolated by various methods. Use of guanidinium-thiocyanate with and without RNA matrix gave the most consistent results. Boiling as a mean of RNA isolation was quick and easy, but the RT-PCR results were extremely variable and multiple smaller bands were observed in the agarose gel in some preparations. IL-2, -10 and IFN transcripts were amplified from RNA isolated with guanidinium-thiocyanate from leukocytes stimulated with concanavalin A. DNase-treatment of RNA isolates was necessary to assure the destruction of genomic DNA and to avoid amplification of genomic sequences. This was especially a problem when using primers for GAPDH, beta-actin, IL-12, and TNF. Lack of DNase-treatment may lead to false positive results. This may be especially a problem when amplification of so-called house-keeping genes is used as internal control for RNA integrity. These findings demonstrated that isolation of total RNA with guanidinium-thiocyanate followed by DNase-treatment gave reliable and consistent results for detection of cytokine transcripts by RT-PCR in a canine macrophage cell line and canine peripheral blood leukocytes.

A deaf woman learning to control her excessive vocal loudness through a portable feedback system

A deaf woman learned to control her excessive vocal loudness through a portable feedback system, which provided vibratory stimulation when her voice was too loud. The mean percentage of excessively loud talking decreased from 45 prior to the use of feedback to 3 during the use of feedback. This improvement (documented by formal observation) was confirmed by normally hearing people sharing the work environment with the woman. The woman preferred a system with a contact microphone since this was virtually unaffected by environmental noise.

A portable visual-feedback device for reducing excessive vocal loudness in persons with mental retardation

A simple portable device was employed to reduce excessive vocal loudness in two adults who functioned within the moderate mental retardation range (one in the lower and one in the upper half). The device provided these adults visual feedback when the voice exceeded a preset level of loudness. Data showed that the device was useful in helping both adults reduce excessive vocal loudness across different daily situations. Characteristics and applicability of the device are discussed.

Long-term follow-up of treatment and potential cure of adult acute lymphocytic leukemia with MOAD: a non-anthracycline containing regimen

A total of 55 previously untreated adults with acute lymphocytic leukemia (ALL), median age 38 years (range 15-73 years), were treated with MOAD (methotrexate, vincristine, L-asparaginase, and dexamethasone). This regimen includes five phases--induction, consolidation, cytoreduction, maintenance, and central nervous system (CNS) prophylaxis with parenteral high-dose methotrexate. Of the 55 evaluable patients, 42 achieved complete remission 76%), with a median CR duration of 12+ months (range 0.5-195+ months). The median survival in remission is 22+ months (range 1-198+ months), with 33% of remitters continuing in long-term remissions (> 5 years). Two out of four patients who developed CNS leukemia did so without marrow relapse, were successfully treated for that complication, and continue in total complete remission at 8+ and 16+ years. Another patient with extramedullary relapse (breast) was treated with radiation to that site and remains in total CR at 16+ years. Expected toxicities included myelosuppression during the induction phase of treatment, with 65% of patients requiring intravenous antibiotics. Mucositis was the next most frequent toxicity and required dose-reduction in seven patients. Minimal toxicity was seen during the post-remission phases of treatment. L-Asparaginase toxicity was more prominent during intravenous administration (24 patients) than when the intramuscular route of administration (30 patients) was used. The remission rate and long-term survivorship achieved with this regimen, without the use of an anthracycline, is comparable to that of other regimens for adult ALL. MOAD was well-tolerated by young and old adults with ALL. Aseptic necrosis of bone, successfully treated in each instance, occurred in four long-term disease-free survivors. The effect of this complication and its treatment on quality of life has been negligible.

Modulation of Na+/H+ exchange and intracellular pH by protein kinase C and protein phosphatase in blood platelets

Phosphorylation of the Na+/H+ exchanger in human platelets is apparently controlled by the balancing activities of protein kinase C (PKC) and protein phosphatase (PP). To explore cellular expressions of these activities, we have examined the impact of modulation of PKC and PP on Na+/H+ exchange activity, its pHi set point and intracellular pH (pHi). These parameters were followed spectrofluorimetrically in BCECF-loaded platelets. Phorbol 12-myristate 13-acetate (PMA) and dihexanoylglycerol (DHG), which stimulate PKC, and okadaic acid, which inhibits PP 1 and 2A, elevate the measured parameters in concert, while staurosporine, which inhibits protein kinases, had opposite effects. The stimulatory and inhibitory effects are similarly very rapid, being discerned within seconds. It is concluded that: (a) phosphorylation of the Na+/H+ exchanger is the common origin of the diverse effects of PMA, DHG, okadaic acid and staurosporine, (b) Na+/H+ exchange properties are tightly regulated by phosphorylation and dephosphorylation, and (c) the exchanger plays a major role in pHi regulation in platelets.

Interaction of calcium and vanadate with fluorescein isothiocyanate labeled Ca2+-ATPase from sarcoplasmic reticulum: kinetics and equilibria

The interaction of Ca2+ and vanadate with fluorescein isothiocyanate (FITC) labeled sarcoplasmic reticulum (SR) Ca2+-ATPase has been studied by following the kinetics of changes in the reporter group fluorescence and equilibrium fluorescence levels. The vanadate species bound to the enzyme is clearly monomeric orthovanadate, probably H2VO4-. Vanadate binding is noncooperative, suggesting an absence of interactions between the Ca2+-ATPase subunits. The fluorescence experiments confirm the existence of a calcium-enzyme-vanadate complex (in the presence of magnesium). On the basis of the fluorescence properties of this complex, it is similar in its conformation to the calcium-enzyme complex, i.e., "E1-like" rather than "E2-like". However, Ca2+ binds to the enzyme-vanadate complex via sites that are only accessible from the interior of the SR vesicles. The complex Ca2E*Van, which is rapidly formed, isomerizes very slowly (t1/2 approximately 1 min) to the stable ternary complex. The mutual destabilization between bound vanadate and two bound Ca2+ ions is only 1.6 kcal/mol, much smaller than that produced by the interaction of calcium and phosphate.

Intensive maintenance therapy improves survival in adult acute nonlymphocytic leukemia: an eight-year follow-up

Although a large majority of adult patients with acute nonlymphocytic leukemia (ANLL) achieve complete remission with present day therapy, eventual relapse and death is the rule rather than the exception. In an effort to improve survival, an intensive maintenance therapy approach was evaluated in 86 patients with ANLL in remission (median age 47 years) entered on study from 1978 to 1982. One-third of patients in remission were randomized to chemotherapy alone, one-third to splenectomy in addition to chemotherapy, and one-third to immunotherapy in addition to chemotherapy. The chemotherapy, which was identical in the three arms of the study, consisted of cytosine arabinoside plus 6-thioguanine, each given at a dose of 100 mg/m2 every 12 hr for a variable number of days, to render the patient's marrow aplastic, and was repeated every three months for three or more years. Median remission duration for patients in all three study groups is 21 months, with 58% of patients remaining in remission at one year. Twenty-five per cent of complete remitters are in continuous complete remission five to nine years after beginning intensive maintenance therapy. The median duration of survival of remitters is 25 months. Neither splenectomy nor immunotherapy had additional impact on remission duration or survival. In comparison with the results of earlier studies at the same institution in patients with similar characteristics, using identical remission induction therapy but less intensive maintenance therapy (46 patients), there has been a significant improvement in remission duration (p less than 0.001) and a significant impact on survival (p = 0.03) attributable to the use of intensive maintenance therapy. Intensive maintenance therapy may cure some adult patients with ANLL.

Simultaneous binding of calcium and vanadate to the Ca2+-ATPase of sarcoplasmic reticulum

The interaction of vanadate with the Ca2+-ATPase of sarcoplasmic reticulum vesicles has been studied by making use of the ATPase activity as a measure of uncomplexed enzyme. The binding/dissociation is slow, so that initial rates can be used to study the equilibrium binding. The results indicate that in addition to a Ca2+-free complex E.Van (KV = 0.4 microM), there must also be a Ca2+-enzyme-vanadate complex (K'V = 7 microM). This observation is confirmed by the difference between the kinetics of decay of activity on vanadate addition, and on addition of ATP to enzyme preincubated with vanadate and Ca2+, which requires two enzyme-vanadate complexes. ATP increases the apparent affinity of the enzyme for vanadate by inducing calcium release. Upper limits for the kinetic parameters for vanadate binding and dissociation are estimated.

High-dose cisplatin therapy using mannitol versus furosemide diuresis: comparative pharmacokinetics and toxicity

The dose-limiting toxic effect of high-dose (100 mg/m2) cisplatin is renal insufficiency. Hydration with furosemide- or mannitol-induced diuresis has been reported to ameliorate this toxicity. Animal studies suggest that mannitol may be superior to furosemide in this regard. Twenty-two patients with advanced neoplasms refractory to conventional therapy were treated with cisplatin at a dose of 100 mg/m2 every 21--28 days. Patients were randomized to receive 37.5 g of mannitol by 6-hour infusion with cisplatin or 40 mg of furosemide prior to cisplatin therapy. Hydration with at least 1 liter of normal saline was given prior to cisplatin. Nephrotoxicity (creatinine greater than 2 mg/100 ml, creatinine clearance greater than 50 ml/minute) occurred in 19% of courses in the furosemide-treated group and in 28% of courses in the mannitol-treated group. Peak plasma platinum concentration, terminal half-life, urinary excretion, and percent protein-bound plasma platinum were similar in both groups. The use of cisplatin at this dose schedule resulted in similar toxicity and pharmacokinetics when using hydration with either furosemide or mannitol.

Cis-Dichlorodiammine platinum and adriamycin therapy for advanced gynecological and genitourinary neoplasms

Cis-Dichlorodiammine platinum (DDP) 75 mg/m2 on days 1 and 8 and Adriamycin (ADR) 60 mg/m2 on day 1 were used in 31 patients with advanced gynecological and genitourinary neoplasms. The DDP was given by 6 hours intravenous infusion with 2 liters of 5% Dextrose and 0.5 normal saline using Mannitol and/or furosemide diuresis. Courses were repeated every 21 to 28 days. Responses were seen in 7 of 8 patients with germinal cell neoplasms (5 complete, 2 partial) with a median duration of eight months. A partial response was obtained in 3 of 7 patients with bladder carcinoma with a median duration of three months. There were four partial responses obtained in 9 patients with ovarian carcinoma with a median duration of five months. Toxicities included nausea and vomiting in all 31 patients, nephrotoxicity (serum creatinine > 2 g/100 ml) in patients, tinnitus and/or high frequency hearing loss in 10 patients, and neurotoxicity (peripheral neuropathy, normal pressure hydrocephalus, papilledema) in 8 patients. Severe leukopenia (WBC < 2000/cu mm) and thrombocytopenia (< 100,000/cu mm) occurred in 25% and 45% of evaluable courses, respectively and necessitated dosage reduction in all and delay of therapy in some patients. Peak plasma Pt levels were 2.61 +/- .18 microgram/cc on day 1 and 3.52 +/- .39 microgram/cc on day 8 with a longer terminal half-life on day 8 (252 hours) compared to day 1 (156 hours). Peak plasma ADR levels ranged from .53 to 1.67 N moles/cc with an average terminal half-life of 22.8 hours. This agrees with values of ADR when given alone. This dose and schedule of DDP-ADR is active against advanced gynecological and genitourinary neoplasms, but the amount of toxicity seen indicates that modifications will have to be made.