Current Perspectives on the Importance of Pathological Features in Prognostication and Guidance of Adjuvant Chemotherapy in Colon Cancer.

There is not a clear consensus on which pathological features and biomarkers are important in guiding prognosis and adjuvant therapy in colon cancer. The Pathology in Colon Cancer, Prognosis and Uptake of Adjuvant Therapy (PiCC UP) Australia and New Zealand questionnaire was distributed to colorectal surgeons, medical oncologists and pathologists after institutional board approval. The aim of this study was to understand current specialist attitudes towards pathological features in the prognostication of colon cancer and adjuvant therapy in stage II disease. A 5-scale Likert score was used to assess attitudes towards 23 pathological features for prognosis and 18 features for adjuvant therapy. Data were analysed using a rating scale and graded response model in item response theory (IRT) on STATA (Stata MP, version 15; StataCorp LP). One hundred and sixty-four specialists (45 oncologists, 86 surgeons and 33 pathologists) participated. Based on IRT modelling, the most important pathological features for prognosis in colon cancer were distant metastases, lymph node metastases and liver metastases. Other features seen as important were tumour rupture, involved margin, radial margin, CRM, lymphovascular invasion and grade of differentiation. Size of tumour, location, lymph node ratio and EGFR status were considered less important. The most important features in decision making for adjuvant therapy in stage II colon cancer were tumour rupture, lymphovascular invasion and microsatellite instability. BRAF status, size of tumour, location, tumour budding and tumour infiltrating lymphocytes were factored as lesser importance. Biomarkers such as CDX2, EGFR, KRAS and BRAF status present areas for further research to improve precision oncology. This study provides the most current status on the importance of pathological features in prognostication and recommendations for adjuvant therapy in Australia and New Zealand. Results of this nationwide study may be useful to help in guiding prognosis and adjuvant treatment in colon cancer.

Screening for sexual health concerns in survivors of gynecological cancer.

OBJECTIVE: To assess the impact of a screening tool, the Brief Sexual Symptom Checklist for Women, on referral rates to physiotherapists, sexual counselors, and psychologists for sexual issues among patients attending the practices of two gynecological oncologists. METHODS: A prospective observational cohort study. A retrospective cohort of consecutive patients matched for age, diagnosis, and stage was used as a control group. RESULTS: Seventy-eight women were recruited to the intervention group. Diagnoses were endometrial carcinoma (38%), ovarian carcinoma (33%), and cervical carcinoma (24%). Sixty percent had completed adjuvant treatment, and 89% were married or in a de facto relationship. More than half of participants reported at least one sexual difficulty and were not satisfied with their sexual function. The most commonly reported sexual issue was decreased sexual desire. Twelve of 77 (15%) women screened in the intervention group were referred to a sexual counselor and/or a physiotherapist for a sexual issue. Twelve percent of women in the intervention group were referred to a sexual counselor, compared with 5% in the control group (p = 0.072). There was no difference in the proportion of women referred to a pelvic floor physiotherapist between the two groups (8% of women in the intervention group vs. 8% in the control group; p = 1.000). CONCLUSIONS: In the current study, the Brief Sexual Symptom Checklist for Women identified sexual health concerns in over half of gynecological cancer survivors and resulted in a non-significant trend to more referrals for sexual counseling.

The efficacy of sodium channel blockers to prevent phencyclidine-induced cognitive dysfunction in the rat: potential for novel treatments for schizophrenia.

Sodium channel inhibition is a well precedented mechanism used to treat epilepsy and other hyperexcitability disorders. The established sodium channel blocker and broad-spectrum anticonvulsant lamotrigine is also effective in the treatment of bipolar disorder and has been evaluated in patients with schizophrenia. Double-blind placebo-controlled clinical trials found that the drug has potential to reduce cognitive symptoms of the disorder. However, because of compound-related side-effects and the need for dose titration, a conclusive evaluation of the drug's efficacy in patients with schizophrenia has not been possible. (5R)-5-(4-{[(2-Fluorophenyl)methyl]oxy}phenyl)-l-prolinamide (GSK2) and (2R,5R)-2-(4-{[(2-fluorophenyl)methyl]oxy}phenyl)-7-methyl-1,7-diazaspiro[4.4]nonan-6-one (GSK3) are two new structurally diverse sodium channel blockers with potent anticonvulsant activity. In this series of studies in the rat, we compared the efficacy of the two new molecules to prevent a cognitive deficit induced by the N-methyl-d-aspartic acid receptor antagonist phencyclidine (PCP) in the reversal-learning paradigm in the rat. We also explored the effects of the drugs to prevent brain activation and neurochemical effects of PCP. We found that, like lamotrigine, both GSK2 and GSK3 were able to prevent the deficit in reversal learning produced by PCP, thus confirming their potential in the treatment of cognitive symptoms of schizophrenia. However, higher doses than those required for anticonvulsant efficacy of the drugs were needed for activity in the reversal-learning model, suggesting a lower therapeutic window relative to mechanism-dependent central side effects for this indication.

Population patch-clamp electrophysiology analysis of recombinant GABAA alpha1beta3gamma2 channels expressed in HEK-293 cells.

Gamma-amino butyric acid (GABA)-activated Cl- channels are critical mediators of inhibitory postsynaptic potentials in the CNS. To date, rational design efforts to identify potent and selective GABA(A) subtype ligands have been hampered by the absence of suitable high-throughput screening approaches. The authors describe 384-well population patch-clamp (PPC) planar array electrophysiology methods for the study of GABA(A) receptor pharmacology. In HEK293 cells stably expressing human alpha1beta3gamma2 GABA(A) channels, GABA evoked outward currents at 0 mV of 1.05 +/- 0.08 nA, measured 8 s post GABA addition. The I(GABA) was linear and reversed close to the theoretical E(Cl) (-56 mV). Concentration-response curve analysis yielded a mean pEC(50) value of 5.4 and Hill slope of 1.5, and for a series of agonists, the rank order of potency was muscimol > GABA > isoguvacine. A range of known positive modulators, including diazepam and pentobarbital, produced concentration-dependent augmentation of the GABA EC( 20) response (1 microM). The competitive antagonists bicuculline and gabazine produced concentration-dependent, parallel, rightward displacement of GABA curves with pA(2) and slope values of 5.7 and 1.0 and 6.7 and 1.0, respectively. In contrast, picrotoxin (0.2-150 microM) depressed the maximal GABA response, implying a non-competitive antagonism. Overall, the pharmacology of human alpha1beta3gamma2 GABA(A) determined by PPC was highly similar to that obtained by conventional patch-clamp methods. In small-scale single-shot screens, Z' values of >0.5 were obtained in agonist, modulator, and antagonist formats with hit rates of 0% to 3%. The authors conclude that despite the inability of the method to resolve the peak agonist responses, PPC can rapidly and usefully quantify pharmacology for the alpha1beta3gamma2 GABA(A) isoform. These data suggest that PPC may be a valuable approach for a focused set and secondary screening of GABA(A) receptors and other slow ligand-gated ion channels.

Population patch clamp electrophysiology: a breakthrough technology for ion channel screening.

Population patch clamp (PPC) is a novel high throughput planar array electrophysiology technique that allows ionic currents to be recorded from populations of cells under voltage clamp. For the drug discovery pharmacologist, PPC promises greater speed and precision than existing methods for screening compounds at voltage-gated ion channel targets. Moreover, certain constitutively active or slow-ligand gated channels that have hitherto proved challenging to screen with planar array electrophysiology (e.g. SK/IK channels) are now more accessible. In this article we review early findings using PPC and provide a perspective on its likely impact on ion channel drug discovery. To support this, we include some new data on ion channel assay duplexing and on modulator assays, approaches that have thus far not been described.

Novel 384-well population patch clamp electrophysiology assays for Ca2+-activated K+ channels.

Planar array electrophysiology techniques were applied to assays for modulators of recombinant hIK and hSK3 Ca2+-activated K+ channels. In CHO-hIK-expressing cells, under asymmetric K+ gradients, small-molecule channel activators evoked time- and voltage-independent currents characteristic of those previously described by classical patch clamp electrophysiology methods. In single-hole (cell) experiments, the large cell-to-cell heterogeneity in channel expression rendered it difficult to generate activator concentration-response curves. However, in population patch clamp mode, in which signals are averaged from up to 64 cells, well-to-well variation was substantially reduced such that concentration-response curves could be easily constructed. The absolute EC50 values and rank order of potency for a range of activators, including 1-EBIO and DC-EBIO, corresponded well with conventional patch clamp data. Activator responses of hIK and hSK3 channels could be fully and specifically blocked by the selective inhibitors TRAM-34 and apamin, with IC50 values of 0.31 microM and 3 nM, respectively. To demonstrate assay precision and robustness, a test set of 704 compounds was screened in a 384-well format of the hIK assay. All plates had Z' values greater than 0.6, and the statistical cutoff for activity was 8%. Eleven hits (1.6%) were identified from this set, in addition to the randomly spiked wells with known activators. Overall, our findings demonstrate that population patch clamp is a powerful and enabling method for screening Ca2+-activated K+ channels and provides significant advantages over single-cell electrophysiology (IonWorks(HT)) and other previously published approaches. Moreover, this work demonstrates for the 1st time the utility of population patch clamp for ion channel activator assays and for non-voltage-gated ion channels.