A systematic review of primary large cell neuroendocrine carcinoma of the prostate

Background

Large cell neuroendocrine carcinoma (LCNEC) is a rare subtype of prostate cancer. The pathogenesis, clinical manifestation, treatment options, and prognosis are uncertain and underreported.

Materials and methods

A systematic search was conducted in April 2022 through PubMed, Embase, and Cochrane. We reviewed cases of LCNEC developed either from de novo or transformation from prostate adenocarcinoma and summarized the relevant pathophysiological course, treatment options, and outcomes.

Results

A total of 25 patients with a mean age of 70.4 (range 43 87 years old) from 18 studies were included in this review. 13 patients were diagnosed with de novo LCNEC of the prostate. 12 patients were from the transformation of adenocarcinoma post-hormonal therapy treatment. Upon initial diagnosis, patients diagnosed with de novo prostatic LCNEC had a mean serum PSA value of 24.6 ng/ml (range: 0.09-170 ng/ml, median 5.5 ng/ml), while transformation cases were significantly lower at 3.3 ng/ml (range: 0-9.3 ng/ml, median 0.05 ng/ml). The pattern of metastasis closely resembles prostate adenocarcinoma. Six out of twenty-three cases displayed brain metastasis matching the correlation between neuroendocrine tumors and brain metastasis. Three notable paraneoplastic syndromes included Cushings syndrome, dermatomyositis, and polycythemia. Most patients with advanced metastatic disease received conventional platinum-based chemotherapy with a mean survival of 5 months. There was one exception in the transformation cohort with a somatic BRCA2 mutation who was treated with a combination of M6620 and platinum-based chemotherapy with an impressive PFS of 20 months. Patients with pure LCNEC phenotype have worse survival outcomes when compared to those with mixed LCNEC and adenocarcinoma phenotypes. It is unclear whether there is a survival benefit to administering ADT in pure pathologies.

Conclusion

LCNEC of the prostate is a rare disease that can occur de novo or transformation from prostatic adenocarcinoma. Most patients present at an advanced stage with poor prognosis and are treated with conventional chemotherapy regimens. Patients who had better outcomes were those who were diagnosed at an early stage and received treatment with surgery or radiation and androgen deprivation therapy (ADT). There was one case with an exceptional outcome that included a treatment regimen of M6620 and chemotherapy.

Commentary on a combined approach to the problem of developing biomarkers for the prediction of spontaneous preterm labor that leads to preterm birth

INTRODUCTION

Globally, preterm birth has replaced congenital malformation as the major cause of perinatal mortality and morbidity. The reduced rate of congenital malformation was not achieved through a single biophysical or biochemical marker at a specific gestational age, but rather through a combination of clinical, biophysical and biochemical markers at different gestational ages. Since the aetiology of spontaneous preterm birth is also multifactorial, it is unlikely that a single biomarker test, at a specific gestational age will emerge as the definitive predictive test.

METHODS

The Biomarkers Group of PREBIC, comprising clinicians, basic scientists and other experts in the field, with a particular interest in preterm birth have produced this commentary with short, medium and long-term aims: i) to alert clinicians to the advances that are being made in the prediction of spontaneous preterm birth; ii) to encourage clinicians and scientists to continue their efforts in this field, and not to be disheartened or nihilistic because of a perceived lack of progress and iii) to enable development of novel interventions that can reduce the mortality and morbidity associated with preterm birth.

RESULTS

Using language that we hope is clear to practising clinicians, we have identified 11 Sections in which there exists the potential, feasibility and capability of technologies for candidate biomarkers in the prediction of spontaneous preterm birth and how current limitations to this research might be circumvented.

DISCUSSION

The combination of biophysical, biochemical, immunological, microbiological, fetal cell, exosomal, or cell free RNA at different gestational ages, integrated as part of a multivariable predictor model may be necessary to advance our attempts to predict sPTL and PTB. This will require systems biological data using "omics" data and artificial intelligence/machine learning to manage the data appropriately. The ultimate goal is to reduce the mortality and morbidity associated with preterm birth.

Abstract P3-03-36: Not presented

This abstract was not presented at the conference.

Citation Format: Khan RN, Baig M, Mohtasham S, Khan A, Pervaiz A. Not presented [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-03-36.

Systematic review of atraumatic splenic rupture (Br J Surg 2009; 96: 1114-1121)

The Editors welcome topical correspondence from readers relating to articles published in the Journal. Responses should be sent electronically via the BJS website (www.bjs.co.uk). All letters will be reviewed and, if approved, appear on the website. A selection of these will be edited and published in the Journal. Letters must be no more than 250 words in length.

Infection control education: impact on ventilator-associated pneumonia rates in a public sector intensive care unit in Pakistan

We describe efforts towards introducing infection control (IC) practices and establishment of antimicrobial resistance (AMR) surveillance in a public sector hospital in Pakistan. The study was conducted in an eight-bed intensive care unit. IC principles, introduced through interactive sessions, were used as an intervention and their impact was observed by conducting surveillance for ventilator-associated pneumonia (VAP) before and after the intervention. Respiratory isolates of VAP patients in the period after intervention were screened for AMR, and empiric antibiotic at the time of admission was compared with the antimicrobial sensitivity pattern reported. VAP rates were high in general and declined in the period after intervention, although the difference was not significant. Of 37 VAP patients in the period after intervention, 68% had more than one clinically significant organism isolated from the respiratory specimen. Acinetobacter spp. were isolated from 76% of patients and Pseudomonas aeruginosa from 43%. All Acinetobacter spp. and 72% P. aeruginosa were multidrug resistant. The mean stay of the nosocomially infected patients was significantly higher than for the uninfected group (6.5 vs. 2.1 days, P<0.001). Our study suggests IC education needs to be supplemented by a hospital system that facilitates IC practices and development of surveillance programmes.

Effects of the trematode Microphallus turgidus on locomotion and prey capture in the grass shrimp Palaemonetes pugio

The grass shrimp, Palaemonetes pugio, is common in estuaries and marshes along the east coast of the USA and is frequently infected with metacercariae of the trematode, Microphallus turgidus. To test whether or not M. turgidus has an effect on intermediate host behaviour, the length of time spent swimming and walking over 1 min and 3 min intervals and prey (Artemia) capture rates of uninfected grass shrimp and those infected with 1-10, 11-20 or 21-30 metacercarial cysts were compared. Uninfected shrimps spent significantly more time swimming than infected shrimps during the first minute of observation. There were no differences between the control and infected groups in terms of swimming at 3 min, walking at 1 and 3 min, or in numbers of prey captured. These results indicate that M. turgidus may induce little or no change in grass shrimp locomotion nor in prey capture behaviour. This is in contrast to other parasites that modify intermediate host behaviour to enhance their transmission to definitive hosts. Furthermore, these data support earlier studies indicating that M. turgidus does not affect the growth and survival of P. pugio.

Immunolocalization and protein expression of the alpha subunit of the large-conductance calcium-activated potassium channel in human myometrium

Large-conductance calcium-activated potassium (BKCa) channels play an important role in the control of myometrial excitability. The aim of the present study was to determine the localization and protein expression of the alpha subunit of BKCa channels in the pregnant and parturient human uterus. An anti-alpha BKCa channel monoclonal antibody (anti-alpha(995-1113)) was used to localize and quantitate immunoreactive BKCa channel protein in myometrium of singleton term pregnant women undergoing either elective (n=26) or emergency Caesarean section following the onset of spontaneous labour (n=25). Data are presented as medians (interquartile range). Differences between groups were analysed using the Mann-Whitney U test. Immunohistochemistry studies localized the alpha subunit of the BKCa channel to the plasma membrane and the cytosol of myometrial cells with similar reaction end product in pregnant women who were or were not undergoing labour. Expression of this subunit, observed as a 125 kDa band in western blots, was significantly higher in pregnant women who were not undergoing labour (30.6% (20.3, 43.9)) than in those who were undergoing labour (15.7% (11.3, 22.4); P<0.01). Reduced BKCa alpha subunit expression in pregnant women during labour may underlie the initiation of uterine contractility during parturition.

Down-regulation of the alpha- and beta-subunits of the calcium-activated potassium channel in human myometrium with parturition

Large-conductance, calcium-dependent potassium (BKCa) channels are implicated in maintaining uterine quiescence during pregnancy. The mechanisms whereby calcium sensitivity of the BKCa channel is dramatically removed at parturition remain unknown. The aim of the present study was to investigate whether this loss of calcium sensitivity of the BKCa channel with the onset of labor is associated with changes in the protein expression of the alpha- and/or beta-subunit or arises from a physical dissociation of the alpha-subunit from the beta-subunit. The beta-subunit is a key determinant of BKCa-channel Ca2+ sensitivity. Western blot analysis, using alpha- and beta-subunit-specific antibodies, detected bands of 110-125 and 36 kDa, respectively. Protein expression levels of the alpha-subunit in term labor myometrium were significantly reduced compared with term pregnancy without labor. Furthermore, alpha-subunit levels at term pregnancy were significantly increased relative to the nonpregnant state, whereas levels at preterm gestations were unchanged. Densitometric analysis demonstrated significantly decreased beta-subunit levels in term and preterm labor samples compared with term nonlabor samples. Immunoprecipitation studies revealed the presence of both the alpha- and beta-subunits in samples taken before or after the onset of labor. We conclude that during labor, the alpha-subunit is not physically uncoupled from the beta-subunit, but a decline occurs in the level of beta-subunit protein, which may underlie the loss of calcium and voltage sensitivity of the BKCa channel with labor. Furthermore, reduced beta-subunit protein in preterm labor myometrium implies that ion channels may also contribute to pathophysiological labor.

Protozoan colonization on artificial substrates in relation to water quality in a tropical Indian harbour

A field study was conducted to evaluate the protozoan colonization patterns on artificial substrates in relation to organic pollution within a tropical harbour. The composition of protozoans and their succession rates on artificial substrates(polyurethane foam units) were compared between two field stations(A and B), and their presence were considered with regards to the prevailing water quality conditions at the study sites. Altogether 44 genera of flagellates and ciliates were documented. The common genera of flagellates encountered included Monas, Polytoma, and Chromalina. Among the ciliates, the predominant genera were Tetrahymena, Vorticella, Lagymophyra, and Heloiphyra. These groups exhibited characteristic successional patterns in relation to ambient water quality. At Station A, located close to the sewage outfall, the water quality parameters included poor Secchi-disc transparency(0.48 m), dissolved oxygen of 1.93 mg/ml, salinity of 18 psu, and temperature 31.3 degrees C. Here, the nanoflagellates (spumella) colonized first, followed by microcilliate(Tetrahymena) and sessile form(Vorticella). Station B, located on the seaward side, was characterized by relatively less-stressed environmental conditions with transparency 1.85 m and dissolved oxygen value of 6.04 mg/ml. Salinity of 27.27 psu, and mean temperature of 30 degrees C were recorded at "B". At this station, the nanoflagellate Polytoma was first documented to colonize on the substrates, followed by microcilliate(Lagynophrya) and suctorid(Heliophyra). These findings support the use of protozoans as indicator species for evaluating the hazards posed by organic pollution to natural estuarine communities.

Potassium channels in the human myometrium

The contractility of the human uterus is under the fine control of a variety of interacting bioactive agents. During labour, the excitability of the uterus is drastically transformed in comparison with the non-labour state and is manifest at the membrane level via the activity of uterine ion channels. This article reviews the contribution of potassium (K(+)) channels to human uterine excitability. Experimental Physiology (2001) 86.2, 255-264.

Effect of maitotoxin on guanine nucleotide interaction with G-protein alpha subunits

Maitotoxin is a potent water-soluble polyether toxin produced by the marine dinofiagellate Gambierdiscus toxicus. Although associated with increased calcium uptake, mobilization of internal calcium stores, and enhanced phosphoinositide metabolism, the primary molecular mechanism underlying its actions remains unclear. In this study, we evaluated the effects of maitotoxin (MTX) on the interaction of guanine nucleotides with G-protein alpha subunits. Equilibrium binding of the nonhydrolyzable GTP analog, GTPgammaS, to alpha subunits (Go, Gs, Gi1, Gi2, and Gi3) was decreased in the presence of MTX. Furthermore, reconstitution of Galpha with Gbetagamma dimer showed a reversal of the inhibition elicited by MTX. GDP/GTP exchange rate for Galpha subunits was significantly inhibited in the presence of MTX. MTX had no effect on the rate of GDP or GTP dissociation from alpha subunits. Also, the mastoparan-induced component of nucleotide exchange is not effected by MTX. These results suggest that MTX acts on Galpha subunits to modulate their interaction with guanine nucleotides, perhaps by stabilizing an empty state of the alpha subunit. Accordingly, MTX may disrupt the normal signal transduction pathways by inhibiting GTP binding to Galpha subunits and interfering with the GDP/GTP exchange.

Activation of large-conductance potassium channels in pregnant human myometrium by pinacidil

OBJECTIVE

The aim was to investigate the effects of the potassium-channel opener pinacidil on single uterine potassium channels and the contribution of the latter to pinacidil-induced myometrial relaxation.

STUDY DESIGN

Myometrial strips and freshly dispersed uterine myocytes were prepared from the myometrial biopsy samples of women undergoing elective, nonlabor caesarean section at term gestation.

RESULTS

In isometric tension experiments pinacidil potently relaxed pregnant nonlabor human myometrial strips, with an agonist concentration yielding the half maximal response of 0.4 +/- 0.1 micromol/L. This effect was antagonized by 500 nmol/L charybdotoxin. Application of 10 micromol/L glibenclamide also inhibited the pinacidil-induced relaxation. Coapplication of charybdotoxin (500 nmol/L) and glibenclamide (10 micromol/L) produced a biphasic curve, which was fitted to a two-site model with values for agonist concentration yielding the half maximal response of 0.6 +/- 0.2 micromol/L and 189.7 +/- 0.8 micromol/L. Large-conductance calcium-dependent potassium channel activity was dramatically increased after application of pinacidil (between 10 and 100 micromol/L) to both inside-out and outside-out patches. The activation required the presence of calcium ions at the intracellular aspect of the membrane. Charybdotoxin but not glibenclamide blocked pinacidil-induced unitary large-conductance calcium-dependent potassium channel activity.

CONCLUSION

Pinacidil-mediated relaxation of human pregnant myometrial strips may be partially attributable to the opening of uterine large-conductance calcium-dependent potassium channels in addition to adenosine triphosphate potassium channel activation. Drugs with specific potassium channel-activating properties may have important clinical application as novel tocolytics in the treatment of preterm labor.

Contribution of calcium-sensitive potassium channels to NS1619-induced relaxation in human pregnant myometrium

Large-conductance, calcium-sensitive potassium channels (BK(Ca)) are found at high density in the pregnant human myometrium. We have investigated, using isolated myometrial strips and freshly dispersed human myometrial cells, the action of a novel drug (NS1619) which has potassium channel opening activity. Isometric tension experiments demonstrated that NS1619 has a potent, relaxant effect on the pregnant human myometrium. Using both the inside-out and outside-out configurations of the patch-clamp technique, NS1619 appears to act directly on myometrial BK(Ca) channels to stimulate channel activity by increasing the time spent in the open state by this group of potassium channels. Consequently, the myometrial BK(Ca) channel may be a novel target site for drug intervention in clinical conditions, e.g. failure to labour, preterm labour or dysmenorrhoea, which may require either the augmentation or inhibition of uterine K+ channel activity.

Ca2+ dependence and pharmacology of large-conductance K+ channels in nonlabor and labor human uterine myocytes

Two populations, Ca(2+)-dependent (BKCa) and Ca(2+)-independent K+ (BK) channels of large conductance were identified in inside-out patches of nonlabor and labor freshly dispersed human pregnant myometrial cells, respectively. Cell-attached recordings from nonlabor myometrial cells frequently displayed BKCa channel openings characterized by a relatively low open-state probability, whereas similar recordings from labor tissue displayed either no channel openings or consistently high levels of channel activity that often exhibited clear, oscillatory activity. In inside-out patch recordings, Ba2+ (2-10 mM), 4-aminopyridine (0.1-1 mM), and Shaker B inactivating peptide ("ball peptide") blocked the BKCa channel but were much less effective on BK channels. Application of tetraethylammonium to inside-out membrane patches reduced unitary current amplitude of BKCa and BK channels, with dissociation constants of 46 mM and 53 microM, respectively. Tetraethylammonium applied to outside-out patches decreased the unitary conductance of BKCa and BK channels, with dissociation constants of 423 and 395 microM, respectively. These results demonstrate that the properties of human myometrial large-conductance K+ channels in myocytes isolated from laboring patients are significantly different from those isolated from nonlaboring patients.

Effect of englitazone on KATP and calcium-activated non-selective cation channels in CRI-G1 insulin-secreting cells

1. The effects of englitazone sodium, an antidiabetic agent, on ion channel activity in the CRI-G1 insulin secreting cell line was examined by use of the patch clamp technique. 2. Application of englitazone to the outside of CRI-G1 cells in the whole-cell recording configuration produced concentration-dependent inhibition of KATP currents with an IC50 value of 8 microM. The inhibition of the K+ current was not affected by the removal of Mg2+ ions from or the addition of trypsin to the solution bathing the intracellular surface of the cell membrane. 3. Englitazone also inhibited KATP channel activity in recordings from inside out excise membrane patches. The concentration-dependence of inhibition was identical to that observed in whole-cell recordings and was voltage-independent. Single channel recordings confirmed that neither the absence or presence of Mg2+ ions nor the addition of trypsin at the intracellular surface of the membrane influenced the inhibition of KATP channels by englitazone. 4. Englitazone also inhibited Ca(2+)-activated non-selective cation (NSCa) channels in inside-out patches in a concentration-dependent and voltage-independent manner with an IC50 value of 10 microM. In comparison, the non-sulphonylurea KATP channel blocker ciclazindol produced a slight voltage-dependent inhibition of the NSCa channel at a concentration of 20 microM. 5. In whole-cell recordings englitazone, at a relatively high concentration (50 microM) in comparison with that required to block KATP and NSCa channels, inhibited voltage-activated Ca2+ currents by 33% but did not inhibit voltage-activated K+ and Na+ currents. 6. It is concluded that englitazone is a novel blocker of NSCa and KATP channels. The inhibition of KATP channels occurs following procedures that dissociate sulphonylurea receptor coupling to the channel. The equipotent and voltage-independent inhibition of NSCa and KATP channels by englitazone may indicate a common mechanism of block.

Ciclazindol inhibits ATP-sensitive K+ channels and stimulates insulin secretion in CR1-G1 insulin-secreting cells

Ciclazindol, an anorectic drug, was shown to inhibit ATP-sensitive K+ (K(ATP)) channel currents and stimulate insulin secretion from CRI-G1 insulin-secreting cells. In contrast, the structurally related anorectic agent mazindol and the amphetamine-based anorectic compounds diethylpropion, fenfluramine, and phentermine had no effect on K(ATP) channel activity in this cell line. Similarly, cicliazindol elicited insulin secretion from CRI-G1 cells, whereas mazindol had no secretagogue action. The mechanism by which ciclazindol acts to inhibit K(ATP) channel activity is different than that of the sulfonylureas as ciclazindol is effective after procedures that decouple the sulfonylurea receptor from the K(ATP) channel. In agreement with this finding, ciclazindol failed to displace [3H]glibenclamide from CRI-G1 microsomal membranes. Further experiments demonstrated that ciclazindol has no significant effect on voltage-activated currents in this cell line.

Cloning and functional expression of the cDNA encoding an inwardly-rectifying potassium channel expressed in pancreatic beta-cells and in the brain

A cDNA clone encoding an inwardly-rectifying K-channel (BIR1) was isolated from insulinoma cells. The predicted amino acid sequence shares 72% identity with the cardiac ATP-sensitive K-channel rcKATP (KATP-1;[6]). The mRNA is expressed in the brain and insulinoma cells. Heterologous expression in Xenopus oocytes produced currents which were K(+)-selective, time-independent and showed inward rectification. The currents were blocked by external barium and caesium, but insensitive to tolbutamide and diazoxide. In inside-out patches, channel activity was not blocked by 1 mM internal ATP. The sequence homology with KATP-1 suggests that BIR1 is a subunit of a brain and beta-cell KATP channel. However, pharmacological differences and the lack of ATP-sensitivity, suggest that if, this is the case, heterologous subunits must exert strong modulatory influences on the native channel.

The effects of potassium channel openers on isolated pregnant human myometrium before and after the onset of labor: potential for tocolysis

OBJECTIVE

Our purpose was to investigate the effects and pharmacologic properties of potassium channel openers in isolated pregnant human myometrium.

STUDY DESIGN

Biopsy specimens of myometrium obtained from 67 women during pregnancy and labor were used for isometric recording under physiologic conditions.

RESULTS

Levcromakalim and pinacidil, two prototype potassium channel openers, are potent inhibitors of spontaneous and induced (0.5 nmol/L oxytocin and 10 mumol/L phenylephrine) contractions in isolated human pregnant myometrium, obtained before and after the onset of labor. The sulfonylurea glibenclamide is an apparent competitive antagonist of this inhibition. No antagonism was observed with the sulfonylurea tolbutamide. Both potassium channel openers significantly inhibited contractility evoked by low (10 and 20 mmol/L) but not high (40 and 80 mmol/L) concentrations of extracellular potassium chloride.

CONCLUSION

These findings suggest that the relaxant ability of levcromakalim and pinacidil in human pregnant myometrium is because of potassium channel activation. This introduces a potential new approach for tocolysis.

Dissociation of KATP channel and sulphonylurea receptor in the rat clonal insulin-secreting cell line, CRI-D11

It is generally considered that the sulphonylurea receptor is an integral part of the ATP-sensitive K+ channel. We have investigated this proposal by comparing the binding and functional characteristics of the sulphonylurea receptor and KATP channel by using two rat insulinoma cell lines (CRI-G1 and CRI-D11) of common origin. Insulin release was increased in both cell lines by a variety of metabolizable and non-metabolizable secretagogues but glibenclamide induced an increase in insulin release in G1 cells only. [3H]glibenclamide binding studies showed a substantial reduction in the number of glibenclamide binding sites (Bmax) in the D11 cells compared with G1 cells. Single-channel studies of these cell lines show that the KATP channel is generally unchanged in its biophysical properties and in the number of channels observed. Slight differences were apparent: the KATP channels in D11 cells were much less susceptible to rundown and were slightly less sensitive to block by ATP. However, one major distinction was the lack or much reduced sensitivity of the KATP channel in D11 cells to tolbutamide and glibenclamide. We conclude that the KATP channel can exist and function independently of the sulphonylurea receptor, and therefore it is unlikely that they exist as a single protein assembly.

Properties of large-conductance K+ channels in human myometrium during pregnancy and labour

The conversion of the electrically silent pregnant uterus to highly excitable at term represents a dramatic physiological event which is poorly understood. Here we provide the first description, from single-channel recordings, of a large conductance (212 pS) calcium-activated potassium channel (BKCa) in human pregnant myometrium which, in labour tissue, is either absent or has been considerably altered in its physiological and pharmacological properties. In the latter, the K+ channels have an identical conductance (221 pS) and K+ selectivity to BKCa channels but exhibit no Ca2+ or voltage sensitivity. We have termed these BK channels. Furthermore, the activity of the BKCa channel from pregnant tissue is inhibited by internal application of Ba2+ but not tetraethylammonium (TEA), whereas the activity of the BK channel is sensitive to internal TEA but not Ba2+. The role of the BKCa channel may be to suppress myometrial activity during gestation whereas BK channel activity may be important in providing a Ca(2+)-independent K+ conductance which would allow cytoplasmic Ca2+ levels to rise without activating a counteracting Ca(2+)-dependent outward current, normally provided by the BKCa channels which, by its very nature, would tend to oppose depolarization. The findings suggest that K+ channels may have an important role in determining the functional activity of the myometrium.

Dracunculiasis: an approach to hasten worm expulsion

Twenty patients with Guinea worm disease having a total of 29 emerging worms in a rural village of North West Frontier Province, were put on a 5-day course of antibiotics and antiinflammatory drugs and compared with age-matched control patients. The ulcer sites of emerging worms were kept continuously moist, and 18 worms were extracted from 14 patients during the above mentioned period. The average time taken for the entire worm to be expelled in these patients was considerably shorter (13.6 days) than in controls (89 days). Seven (39%) of these worms were expelled spontaneously whereas the remaining 11 (61%) were pulled out manually with relative ease. Fifteen (75%) patients in this study had a single emerging worm, three (15%) had two emerging worms and two (10%) patients had four or more emerging worms.