c-MET-positive circulating tumor cells and cell-free DNA as independent prognostic factors in hormone receptor-positive/HER2-negative metastatic breast cancer

BACKGROUND

Endocrine therapy resistance in hormone receptor-positive/HER2-negative (HR+/HER2-) breast cancer (BC) is a significant clinical challenge that poses several unmet needs in the management of the disease. This study aimed to investigate the prognostic value of c-MET-positive circulating tumor cells (cMET+ CTCs), ESR1/PIK3CA mutations, and cell-free DNA (cfDNA) concentrations in patients with hormone receptor-positive (HR+) metastatic breast cancer (mBC).

METHODS

Ninety-seven patients with HR+ mBC were prospectively enrolled during standard treatment at Samsung Medical Center. CTCs were isolated from blood using GenoCTC® and EpCAM or c-MET CTC isolation kits. PIK3CA and ESR1 hotspot mutations were analyzed using droplet digital PCR. CfDNA concentrations were calculated using internal control copies from the ESR1 mutation test. Immunocytochemistry was performed to compare c-MET overexpression between primary and metastatic sites.

RESULTS

The proportion of c-MET overexpression was significantly higher in metastatic sites than in primary sites (p = 0.00002). Survival analysis showed that c-MET+ CTC, cfDNA concentration, and ESR1 mutations were significantly associated with poor prognosis (p = 0.0026, 0.0021, and 0.0064, respectively) in HR+/HER2- mBC. By contrast, EpCAM-positive CTC (EpCAM+ CTC) and PIK3CA mutations were not associated with progression-free survival (PFS) in HR+/HER2- mBC. Multivariate analyses revealed that c-MET+ CTCs and cfDNA concentration were independent predictors of PFS in HR+/HER2- mBC.

CONCLUSIONS

Monitoring c-MET+ CTC, rather than assessing c-MET expression in the primary BC site, could provide valuable information for predicting disease progression, as c-MET expression can change during treatment. The c-MET+ CTC count and cfDNA concentration could provide complementary information on disease progression in HR+ /HER2- mBC, highlighting the importance of integrated liquid biopsy.

Abstract P5-06-04: The prognostic value of c-MET monitoring by using c-MET-enriched circulating tumor cells in HR-positive HER2-negative metastatic breast cancer

[Background] As the development of endocrine resistance and late recurrences are the major clinical concerns in hormone receptor (HR)-positive/HER2-negative metastatic breast cancer (MBC) patients, biomarkers to predict the occurrence of endocrine resistance or disease progression are crucial for improving patient outcomes. Aberrant HGF/c-MET signaling pathway has been reported to play a role in various cellular processes in cancer. Estrogen Receptor 1 (ESR1) mutations, encoding estrogen receptor α, are associated with endocrine resistance in HR+ breast cancer. PIK3CA hotspot mutations that induce hyperactivation of the PI3K are found in 30-40% of HR+ advanced breast cancers. In this context, we evaluated the prognostic values of c-MET-enriched CTC, ESR1 mutations, PIK3CA mutations, and cfDNA concentrations detected in the blood of HR+HER2- MBC patients. [Methods] MBC patients were prospectively enrolled during standard treatments at Samsung Medical Center (IRB No.2019-08-119). Circulating tumor cells (CTCs) were isolated using the GenoCTC® with c-MET-enriched or EpCAM-enriched CTC isolation kits (Genobio Corp., South Korea) from 4mL of blood each. PIK3CA and ESR1 hotspot mutations were analyzed by droplet digital PCR kits (Gencurix Inc., South Korea). cfDNA concentrations were calculated using ESR1 gene copy numbers from plasma. To compare the proportion of c-MET overexpression between primary breast tumors and metastatic sites in HR+HER2- breast cancer patients, primary breast (n=358) and metastatic sites (n=27) were independently collected. c-MET expression was evaluated by an immunohistochemistry assay using an anti-total c-MET (SP44) antibody with a Ventana Discovery XY automated system according to the manufacturer’s instruction. c-MET overexpression was defined if the staining was scored as 2+ or 3+. Progression-free survival (PFS) was defined as the time from blood draw to the first of either disease progression or death during standard therapy. [Results] Out of 93 patients with HR+ MBC, analysis was performed in 63 HR+HER2- MBC patients. Seventeen patients (27%) had one or more EpCAM-enriched CTCs, and fourteen patients (22%) had one or more c-MET-enriched CTCs detected in their blood. The median follow-up time and median time to censoring were 8.4 months and 18.7 months, respectively. According to the Kaplan-Meier survival analysis by log-rank test, c-MET-enriched CTCs, cfDNA concentrations, and ESR1 mutations were significantly associated with PFS (p=0.0026, 0.0064, and 0.011, respectively). However, PIK3CA mutations and EpCAM-enriched CTCs were not statistically significant with PFS (p=0.38 and 0.86, respectively). Multivariate analysis showed that both c-MET-enriched CTCs (HR=3.5, p=0.014) and cfDNA concentrations (HR=2.2, p=0.031) were independent predictors for PFS in HR+HER2- MBC. The proportion of c-MET overexpression was significantly higher in metastatic sites (22.2%) than in primary breast tumors (4.7%) in HR+HER2- breast cancer patients (p=0.00002). As c-MET-enriched CTCs and cfDNA concentrations were independent predictors of disease progression, patients were divided into two groups depending on the result of c-MET-enriched CTCs and cfDNA concentration. When patients with low c-MET-enriched CTC and cfDNA concentrations were classified as a low-risk group and other patients into a high-risk group, the high-risk group had a shorter PFS than the low-risk group (p=0.003). [Conclusion] This study provided c-MET-enriched CTCs and cfDNA concentrations calculated by ESR1 copy numbers in patient blood were significant independent predictors of disease progression in HR+HER2- MBC. The poor prognosis in the c-MET-enriched CTC-high group and the difference in the c-MET overexpression rate between the primary breast and metastatic sites suggested the importance of monitoring c-MET-enriched CTCs in the blood of HR+HER2- MBC patients.

Citation Format: Jieun Park, Eun Sol Chang, Ji-Yeon Kim, Chaithanya Chelakkot, Minjung Sung, Ji-Young Song, Kyungsoo Jung, Na Young Kim, Hyegyeong Lee, Mi-Ran Kang, Yeon Hee Park, Young Kee Shin, Yoon-La Choi. The prognostic value of c-MET monitoring by using c-MET-enriched circulating tumor cells in HR-positive HER2-negative metastatic breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-06-04.

Analysis of PIK3CA Mutation Concordance and Frequency in Primary and Different Distant Metastatic Sites in Breast Cancer

PURPOSE

The purpose of this study was to investigate the concordance rate of PIK3CA mutations between primary and matched distant metastatic sites in patients with breast cancer and to verify whether there are differences in the frequency of PIK3CA hotspot mutations depending on the metastatic sites involved.

MATERIALS AND METHODS

Archived formalin-fixed paraffin-embedded (FFPE) specimens of primary breast and matched distant metastatic tumors were retrospectively obtained for 49 patients. Additionally, 40 archived FFPE specimens were independently collected from different breast cancer metastatic sites, which were limited to three common sites: the liver, brain, and lung. PIK3CA mutations were analyzed using droplet digital PCR, including hotspots involving exons 9 and 20.

RESULTS

After analysis of 49 breast tumors with matched metastasis sites, 87.8% showed concordance in PIK3CA mutation status. According to PIK3CA hotspot mutation testing in 89 cases of breast cancer metastatic sites, the proportion of PIK3CA mutations at sites of metastasis involving the liver, brain, and lung was 37.5%, 28.6%, and 42.9%, respectively, which did not result in statistical significance.

CONCLUSION

The high concordance of PIK3CA mutation status between primary and matched metastasis sites suggests that metastatic sites, regardless of the metastatic organ, could be considered sample sources for PIK3CA mutation testing for improved therapeutic strategies in patients with metastatic breast cancer.

Cancer-Specific Sequences in the Diagnosis and Treatment of NUT Carcinoma

PURPOSE

NUT carcinoma (NC) is a solid tumor caused by the rearrangement of NUTM1 that usually develops in midline structures, such as the thorax. No standard treatment has been established despite high lethality. Thus, we investigated whether targeting the junction region of NUTM1 fusion breakpoints could serve as a potential treatment option for NC.

Materials and Methods

We designed and evaluated a series of small interfering RNAs (siRNAs) targeting the junction region of BRD4-NUTM1 fusion (B4N), the most common form of NUTM1 fusion. Droplet digital polymerase chain reaction using the blood of patients was also tested to evaluate the treatment responses by the junction sequence of the B4N fusion transcripts.

RESULTS

As expected, the majority of NC fusion types were B4N (12 of 18, 67%). B4N fusion-specific siRNA treatment on NC cells showed specific inhibitory effects on the B4N fusion transcript and fusion protein without affecting the endogenous expression of the parent genes, resulting in decreased relative cell growth and attenuation of tumor size. In addition, the fusion transcript levels in platelet-rich-plasma samples of the NC patients with systemic metastasis showed a negative correlation with therapeutic effect, suggesting its potential as a measure of treatment responsiveness.

CONCLUSION

This study suggests that tumor-specific sequences could be used to treat patients with fusion genes as part of precision medicine for a rare but deadly disease.

Unearthing novel fusions as therapeutic targets in solid tumors using targeted RNA sequencing

Detection of oncogenic fusion genes in cancers, particularly in the diagnosis of uncertain tumors, is crucial for determining effective therapeutic strategies. Although novel fusion genes have been discovered through sequencing, verifying their oncogenic potential remain difficult. Therefore, we evaluated the utility of targeted RNA sequencing in 165 tumor samples by identifying known and unknown fusions. Additionally, by applying additional criteria, we discovered eight novel fusion genes that are expected to process oncogenicity. Among the novel fusion genes, RAF1 fusion genes were detected in two cases. PTPRG-RAF1 fusion led to an increase in cell growth; while dabrafenib, a BRAF inhibitor, reduced the growth of cells expressing RAF1. This study demonstrated the utility of RNA panel sequencing as a theragnostic tool and established criteria for identifying oncogenic fusion genes during post-sequencing analysis.

TM4SF4 and LRRK2 Are Potential Therapeutic Targets in Lung and Breast Cancers through Outlier Analysis

Purpose

To find biomarkers for disease, there have been constant attempts to investigate the genes that differ from those in the disease groups. However, the values that lie outside the overall pattern of a distribution, the outliers, are frequently excluded in traditional analytical methods as they are considered to be ‘some sort of problem.’ Such outliers may have a biologic role in the disease group. Thus, this study explored new biomarker using outlier analysis, and verified the suitability of therapeutic potential of two genes (TM4SF4 and LRRK2).

Materials and Methods

Modified Tukey’s fences outlier analysis was carried out to identify new biomarkers using the public gene expression datasets. And we verified the presence of the selected biomarkers in other clinical samples via customized gene expression panels and tissue microarrays. Moreover, a siRNA-based knockdown test was performed to evaluate the impact of the biomarkers on oncogenic phenotypes.

Results

TM4SF4 in lung cancer and LRRK2 in breast cancer were chosen as candidates among the genes derived from the analysis. TM4SF4 and LRRK2 were overexpressed in the small number of samples with lung cancer (4.20%) and breast cancer (2.42%), respectively. Knockdown of TM4SF4 and LRRK2 suppressed the growth of lung and breast cancer cell lines. The LRRK2 overexpressing cell lines were more sensitive to LRRK2-IN-1 than the LRRK2 under-expressing cell lines

Conclusion

Our modified outlier-based analysis method has proved to rescue biomarkers previously missed or unnoticed by traditional analysis showing TM4SF4 and LRRK2 are novel target candidates for lung and breast cancer, respectively.

Juvenile hormone-binding protein from the cytosol of Drosophila Kc cells

Insect cells of an established line, Drosophila Kc cells, take up and metabolize juvenile hormone (JH). The cytoplasm of these cells contains a protein that binds JH with specificity, saturability, and high affinity (K(d) = 1.56 x 10(-8) M). The kinetics for the specific binding and dissociation of JH I were independently measured, and the rate constants were found to be k(a) = 1.3 x 10(6) M(-1) min(-1), k(d) = 1.3 x 10(-2) min(-1), respectively. All three juvenile hormones bind to the protein with comparable affinities; the corresponding acid or diol metabolites of JH I are not bound. About 2500 hormone-binding protein molecules are present per cell. The protein has a molecular weight of 80,000 as estimated by gel permeation chromatography and by sucrose gradient sedimentation. The properties of this protein suggest that it functions as a cytoplasmic receptor for juvenile hormone.

Three calpains and ecdysone receptor in the land crab Gecarcinus lateralis: sequences, expression and effects of elevated ecdysteroid induced by eyestalk ablation

Crustacean muscle has four calpain-like proteinase activities (CDP I, IIa, IIb and III) that are involved in molt-induced claw muscle atrophy, as they degrade myofibrillar proteins in vitro and in situ. Using PCR cloning techniques, three full-length calpain cDNAs (Gl-CalpB, Gl-CalpM and Gl-CalpT) were isolated from limb regenerates of the tropical land crab Gecarcinus lateralis. All three had highly conserved catalytic (dII) and C2-like (dIII) domains. Gl-CalpB was classified as a typical, or EF-hand, calpain, as the deduced amino acid sequence had a calmodulin-like domain IV in the C-terminus and was most similar to Drosophila calpains A and B. Based on its estimated mass (approximately 88.9 kDa) and cross-immunoreactivity with a polyclonal antibody raised against Dm-CalpA, Gl-CalpB may encode CDP IIb, which is a homodimer of a 95-kDa subunit. It was expressed in all tissues examined, including skeletal muscle, heart, integument, gill, digestive gland, hindgut, nerve ganglia, gonads and Y-organ (molting gland). Both Gl-CalpM and Gl-CalpT were classified as atypical, or non-EF-hand, calpains, as they lacked a domain IV sequence. Gl-CalpM was a homolog of Ha-CalpM from lobster, based on similarities in deduced amino acid sequence, estimated mass (approximately 65.2 kDa) and structural organization (both were truncated at the C-terminal end of dIII). It was expressed at varying levels in most tissues, except Y-organ. Gl-CalpT (approximately 74.6 kDa) was similar to TRA-3 in the nematode Caenorhabditis elegans; domain IV was replaced by a unique ;T domain' sequence. It was expressed in most tissues, except eyestalk ganglia and Y-organ. The effects of elevated ecdysteroid, induced by eyestalk ablation, on calpain and ecdysone receptor (Gl-EcR) mRNA levels in skeletal muscles were quantified by real-time PCR. At 1 day after eyestalk ablation, Gl-EcR and Gl-CalpT mRNA levels increased 15- and 19.3-fold, respectively, in claw muscle but not in thoracic muscle. At 3 days after eyestalk ablation, Gl-EcR and Gl-CalpT mRNA levels in claw muscle had decreased to 2.8-fold and 4.3-fold higher than those in intact controls, respectively, suggesting a feedback inhibition by ecdysteroid. There was no significant effect of eyestalk ablation on Gl-CalpB and Gl-CalpM mRNA levels. Gl-CalpT and Gl-EcR mRNA levels were significantly correlated in both claw and thoracic muscles from intact and eyestalk-ablated animals. The data suggest that Gl-CalpT is involved in initiation of claw muscle atrophy by ecdysteroids. Premolt reduction in claw muscle mass and concomitant remodeling of the sarcomere probably result from post-transcriptional regulation of calpains.

Carbohydrate dynamics and the crustacean hyperglycemic hormone (CHH): effects of parasitic infection in Norway lobsters (Nephrops norvegicus)

The effects of a dinoflagellate parasite (Hematodinium sp.) on carbohydrate metabolism were examined in the Norway lobster, Nephrops norvegicus. Five stages of infection were observed. These included uninfected (Stage 0), subpatently infected (SP), and patently infected (Stage 1-4) lobsters. During patent infection, the concentration of glucose in the hemolymph was reduced significantly from its value of 180 microg ml(-1) in uninfected (Stage 0) lobsters to 25.3 microg ml(-1) in Stage 3-4. These changes were accompanied by significantly lower levels of hepatopancreatic glycogen in lobsters at Stage 2 (2.01 mg g(-1)) and Stage 3-4 (0.84 mg g(-1)) of infection than in those at Stage 0 (16.19 mg g(-1)) and Stage 1 (14.71 mg g(-1)). Due to disruption of the normal feedback loops which control the release of crustacean hyperglycemic hormone (CHH), plasma concentrations increased with the severity of infection from 32.2 fmol ml(-1) in Stage 0 to 106.6 fmol ml(-1) in Stage 3-4. The increased CHH concentrations occurred concomitantly with reduced concentrations of plasma glucose and tissue glycogen. A significantly increased hemolymph CHH titer (107.7 fmol ml(-1)) was also observed during SP infection. It is concluded that the parasite places a heavy metabolic load on the host lobster.

Effects of exogenous serotonin on a motor behavior and shelter competition in juvenile lobsters (Homarus americanus)

Three experiments were conducted to determine (1) the pharmacodynamics of 5-hydroxytryptamine in juvenile lobsters; (2) the effects of 5-hydroxytryptamine, using a range of dosages, on a motor behavior used to escape an aversive situation; and (3) the effect of doses that did and did not inhibit this motor behavior on measures of dominance and shelter competition. The fate of 5-hydroxytryptamine in hemolymph over a 60-min post-injection period showed that the concentration fell rapidly to a low plateau that was maintained for at least 1 h. Low doses of 5-hydroxytryptamine did not affect locomotor behavior, but higher doses inhibited it. Dominance and subsequent possession of a shelter were unaffected by a low dose of 5-hydroxytryptamine but a higher dose that inhibited locomotion resulted in lobsters that lost fights and did not secure or retain possession of the shelter. In the context of dominance and shelter competition, we were unable to demonstrate any advantage of the low dose of exogenous 5-hydroxytryptamine and a severe disadvantage with the higher dose. Previous reports of transient increases in aggression in 5-hydroxytryptamine-treated subordinate lobsters did not take into account motor inhibition as a possible critical variable in aggression.

Crustacean hyperglycemic hormone in the lobster nervous system: localization and release from cells in the subesophageal ganglion and thoracic second roots

Crustacean hyperglycemic hormones (CHHs) are neuropeptides involved in the regulation of hemolymph glucose. The primary source of CHHs has been identified as the neurosecretory neurons of the eyestalk X-organ and its associated neurohemal organ, the sinus gland. We have identified another source of CHH-like peptides in the nervous system. With the use of immunocytochemistry, cells in the second roots of the thoracic ganglia have been observed to stain positively for CHH-reactive material. We also identified a pair of cells in the subesophageal ganglion that contain large amounts of CHH-reactive material. Depolarization of these cells with elevated potassium mediates a calcium-dependent release of CHH-like material from the ganglion as quantified with an enzyme-linked immunosorbent assay (ELISA).

Quantification of crustacean hyperglycemic hormone by ELISA in hemolymph of the lobster, Homarus americanus, following various stresses

An ELISA was developed for the crustacean hyperglycemic hormone (CHH) from the lobster, Homarus americanus. It is sensitive to as little as 0.2 fmol of peptide. The assay was used to measure CHH in the hemolymph of intact lobsters after various environmental stresses. Increases in CHH were observed following emersion, exposure to high temperatures (23 degrees and 28 degreesC), and salinity stress (50 and 150% seawater). During emersion, concentrations of hemolymph glucose increased concomitantly with increases in CHH. Significant levels of hemolymph CHH were also measured in lobsters that had been eyestalk-ablated. These latter observations indicate that there may be a source of CHH other than the X-organ/sinus gland in the lobster.

The NO/cGMP pathway and the development of neural networks in postembryonic lobsters

The nitric oxide/cyclic 3',5'-guanosine monophosphate (NO/cGMP) signaling pathway has been implicated in certain forms of developmental and adult neuronal plasticity. Here we use whole-mount immunocytochemistry to identify components of this pathway in the nervous system of postembryonic lobsters as they develop through metamorphosis. We find that the synthetic enzyme for NO (nitric oxide synthase, or NOS) and the receptor for this transmitter (NO-sensitive soluble guanylate cyclase) are broadly distributed in the central nervous system (CNS) at hatching. In the brain, NOS immunoreactivity is intensified during glomerular development in the olfactory and accessory lobes. Whereas only a few neurons express NOS in the CNS, many more neurons synthesize cGMP in the presence of NO. NO-sensitive guanylate cyclase activity is a stable feature of some cells, while in others it is regulated during development. In the stomatogastric nervous system, a subset of neurons become responsive to NO at metamorphosis, a time when larval networks are reorganized into adult motor circuits. cGMP accumulation was occasionally detected in the nucleus of many cells in the CNS, which suggests that cGMP may have a role in transcription. Based on these findings, we conclude that the NO/cGMP signaling pathway may participate in the development of the lobster nervous system. Furthermore, NO may serve as a modulatory neurotransmitter for diverse neurons throughout the CNS.

Limb Regeneration in the Eye Sockets of Crabs

The eyestalks of crabs were removed and various tissues of the limbs were autotransplanted into the empty eye sockets to study the capacity of the limb tissue to regenerate in a heterotopic site. Autotransplantation of walking leg tissues into the eye sockets was able to regenerate complete walking legs in the new site. Autotransplantation of tissues of claw digit (dactyl and pollex) or more proximal claw segments (ischium and merus/carpus joint) could regenerate complete claws in the eye sockets. If the autotransplant of claw tissue was contralateral, claws could regenerate with host-site handedness. Sham operations or autotransplantation of frozen claw tissue did not induce regeneration in the eye sockets. These results demonstrate that complete crab claws can regenerate from the eye sockets by autotransplantation of live limb tissue and that the regeneration is not due to the traumatic effect of transplantation. The structure of the limbs regenerated in the eye sockets was determined by the source of the transplanted tissue. Complete claws resulted from autotransplantation of the tissues of the most distal claw segments (claw digits), and the most distal claw segments regenerated first, followed by the proximal claw segments in subsequent molts. Thus tissue from distal portions of crab claw can regenerate proximal portions of the claw in the eye sockets. Such a mode of regeneration is not consistent with the distalization rule of the polar coordinate model, which proposes that distal portions of the limb cannot regenerate proximal portions and that the direction of limb regeneration is always from proximal to distal.

An ecdysteroid-responsive gene in a lobster - a potential crustacean member of the steroid hormone receptor superfamily

The role of ecdysteroids in modulating exoskeletal growth during the moult cycle of Crustacea has been well described. However, little is known about the action of ecdysteroids at the level of gene transcription and regulation in Crustacea. This paper reports the cloning of an ecdysteroid responsive gene, HHR3, a potential Manduca sexta MHR3 homologue in the American lobster, Homarus americanus. Levels of HHR3 expression are up-regulated in response to in vivo injections of premoult concentrations (10(-6) M) of 20-hydroxyecdysone in the epidermal and muscle tissue of the lobster after 6 h. Maximal mRNA levels are observed after 21 h before returning to basal levels. In muscle tissue, elevated levels of HHR3 mRNA follow a time course similar to elevated actin mRNA expression in response to hormonal injection. In contrast, in eyestalk tissue, the HHR3 levels decline up to 21 h post-injection before rising to basal levels after 48 h. Eyestalk, epidermal and leg muscle tissue was extracted over the moult cycle to determine the levels of expression. In muscle, HHR3 is high during the premoult period that corresponds to the period of the moult cycle when the ecdysteroid titre is high. In the epidermis, HHR3 levels are also high during the premoult with elevated levels maintained into the postmoult period. In the eyestalk, mRNA levels of HHR3 show an opposite pattern of expression with low levels during premoult and postmoult and high levels found during the intermoult period. Our results provide novel evidence for an ecdysteroid responsive gene in a crustacean that has many similarities to MHR3 in Manduca and DHR3 in Drosophila melanogaster. This raises the question of whether a similar cascade of ecdysteroid responsive genes exist in other members of Arthropoda such as the Crustacea, as has been demonstrated in Drosophila. In addition, we provide further evidence for negative feedback regulation of ecdysteroids at the site of moult-inhibiting hormone (MIH) production in the lobster eyestalk.

Distribution and regulation of esterases that hydrolyze methyl farnesoate in Homarus americanus and other crustaceans

Ester hydrolysis of methyl farnesoate (MF) by crustacean tissue homogenates was measured using the substrate [3H]MF in a radiochemical partition assay. Tissues were obtained from the lobster Homarus americanus, penaeid shrimp Sicyonia ingentis, thalanassid shrimp Callianassa californiensis, sand crab Emerita analoga, and spider crab Pugettia producta. The greatest specific activities were recovered from the hepatopancreas (239 to 11,500 pmol MF/min-mg total protein). Hepatopancreatic homogenates of C. californiensis were significantly more active than homogenates from the other species. In the lobster, esterases that hydrolyze MF were associated with lipid storage (R) cells of the hepatopancreas. Enzyme activity of lobster larval homogenates increased 1.5-fold during the second stage of development. The rate of MF hydrolysis by esterases extracted from the juvenile lobster hepatopancreas could not be correlated with molt stage or sex and was not significantly influenced by eyestalk ablation, mandibular organ ablation, or MF injection.

Identification and characterization of methyl farnesoate binding proteins from the crab, Cancer magister

Methyl farnesoate (MF) binding proteins were identified in the hemolymph of male crabs, Cancer magister, using a tritium-labeled photoaffinity analog of MF, farnesyl diazomethyl ketone (FDK). Crab hemolymph was incubated with [3H]FDK in the presence of increasing amounts of unlabeled MF and the proteins were separated using SDS-PAGE. The associated fluorogram revealed the presence of two specific MF binding proteins with apparent molecular masses of 34 and 44 kDa. MF binding proteins were not detected in other tissues including testes, eyestalks, hepatopancreas, heart, muscle, epidermis, and Y-organs. Unlabeled MF and FDK were capable of displacing [3H]FDK from hemolymph MF binding proteins in a dose-dependent way. The apparent dissociation constant (Kd) of each binding protein for MF and FDK was approximately 65 and 100 nM, respectively, as determined by saturation binding studies. A ligand binding assay followed by Scatchard analysis was used to determine a more accurate apparent Kd value of 145 +/- 10 nM. A single MF binding peak was demonstrated when hemolymph samples incubated with [3H]FDK were electrophoresed under nondenaturing conditions.

Homeotic Transformation of Crab Walking Leg into Claw by Autotransplantation of Claw Tissue

Homeotic transformation is defined as transformation of one body part into the likeness of something else. By autotransplantation of crab claw tissue into the autotomized stump of the fourth walking leg, the stump can regenerate a complete claw. Frozen claw tissue, sham operation, or walking leg tissue had no such activity. Contralateral autotransplantation of claw tissue into the autotomized stump of the fourth walking leg can induce the regeneration of a claw with normal handedness. Most of the transformed claws combined features of the claw and the walking leg, suggesting that both host and donor tissues play a role in regeneration. Three possible mechanisms that might account for limb transformation are discussed. Simple intercalary regeneration does not explain all of the observations, but some regulatory events might be taking place during regeneration. Two other processes--secretion of some morphogen by the claw tissue and alteration in the expression of Hox genes--offer alternatives that might explain the results of this study.

Expression of HLA-DR antigen in large bowel carcinoma

One hundred large bowel carcinomas were studied immunohistochemically with regard to expression of HLA-DR antigen (DR). One or two sections from each tumor including surrounding normal mucosa were examined by a semiquantitative counting system for tumor cells and mucosal and stromal infiltrates of lymphocytes and mononuclear cells (MNCs) with DR expression and the results were applied Chi-square test. The rate of presence of DR positive (DR+) lymphocytes in lymphoid nodules and DR+ lymphocytes/ MNC in the adjacent mucosa and stroma in DR+ carcinoma (50%) was higher (P < 0.01) than in DR- carcinoma (21.9%). Thirty-six carcinomas (36%) were DR+. Three (75%) out of 4 DR+ poorly differentiated carcinomas and six (20%) out of 30 DR+ moderately differentiated carcinomas showed homogeneously strong DR+ expression. There was tendency for poorly differentiated carcinoma to be more homogeneous DR+ expression. According to Dukes' stage, four (80%) out of 5 carcinomas in Dukes' stage D were DR-. An increased infiltration of lymphocytes/MNCs into adjacent mucosa and stroma in large bowel carcinomas is possibly related with DR expression by carcinoma. From the results of this study, we postulated as follows: 1) DR+ tumor cells may act as antigen-presenting cells, 2) They may have an inhibitory effect for distant metastasis, 3) Poorly differentiated carcinoma expressed more DR+ homogeneously.

Metastatic malignant melanoma with "rhabdoid" features

The authors propose the addition of malignant melanoma to the list of extrarenal neoplasms that may be predominantly composed of polygonal cells with the cytologic features of "rhabdoid" tumor. A review of 313 metastatic melanomas disclosed 49 examples with rhabdoid features, from which 31 had sufficient material for further pathologic and immunohistologic characterization. A control group of 46 nonrhabdoid metastatic melanomas was examined in parallel fashion. In 39% of cases, rhabdoid melanomas manifested relative deletion of S100 protein compared with the control tumors. However, there were no differences in staining with HMB-45. Vimentin immunoreactivity was concentrated in the paranuclear cytoplasm of rhabdoid melanoma cells. However, ultrastructural studies of these cases failed to show corresponding whorls of intermediate filaments and instead demonstrated paracrystalline paranuclear inclusions in profiles of rough endoplasmic reticulum. It is concluded that metastatic rhabdoid melanoma exhibits significant morphologic similarity to other rhabdoid tumors at a light-microscopic level. However, it usually retains enough melanocytic attributes to allow for accurate diagnostic recognition. Probably because patients with metastatic melanoma have an extremely poor prognosis overall, no worsening of biologic behavior was associated with rhabdoid cytomorphologic findings in this tumor type when compared with the control cases.

Intraluminal bypass technique using a condom for protection of coloanal anastomosis

PURPOSE

Most surgeons carry out temporary diverting colostomy in coloanal anastomosis for mid-rectal or lower-rectal carcinomas. It has been reported that proximal fecal diversion provides no guarantee against anastomotic leaks. Some have proposed the use of the intracolonic bypass tube to prevent anastomotic leakage and colostomy, but colonic necrosis has been reported; it is important to use a safe technique that obviates this.

METHODS

The rectum is fully mobilized and transected at the level of the levator diaphragm. The mobilized sigmoid and rectum are resected with their mesenteries, and the prepared distal colon is everted 5 cm using Babcock clamps. The ring of a sterilized condom is then sutured to the mucosa and submucosa of the colon with 4/0 chromic catgut sutures. After completion of coloanal anastomosis, the condom is brought to the exterior, and the mid part is transected.

RESULTS

We have used a condom for intraluminal bypass procedures in ten rectal carcinoma patients including five preoperative radiation cases. There was no anastomotic dehiscence, leakage, or colonic necrosis because of a condom.

CONCLUSION

We believe that the intraluminal bypass technique using a condom is a very safe, cost-effective, and easily available alternative for coloanal anastomosis.

Methyl farnesoate stimulates ecdysteroid secretion from crab Y-organs in vitro

Methyl farnesoate (MF) stimulation of ecdysteroid secretion by Y-organs of the crab, Cancer magister, is demonstrated. Isolated Y-organs that were incubated with a mandibular organ (MO) secreted significantly higher levels of ecdysteroids into the medium when compared to those incubated in the absence of a MO. MOs secrete both farnesoic acid (FA) and MF into the medium and are not themselves a source of ecdysteroids. To determine if MF has a role in the regulation of ecdysteroid secretion, Y-organs from C. magister were incubated with various concentrations of MF. Y-organs in the presence of MF secreted significantly more ecdysteroids into the medium after a 24-hr incubation when compared to controls (P < or = 0.05). The magnitude of this stimulation increased with higher concentrations of MF and increasing incubation times. The response was specific to (2E,6E)-MF. The cis,trans isomer of MF ((2Z,6E)-MF), FA, and farnesyl diazomethyl ketone, a photoaffinity analog of MF, did not have any effect on ecdysteroid secretion from Y-organs. The primary ecdysteroid secreted by C. magister Y-organs comigrates with authentic ecdysone and its secretion is stimulated by MF.

Expression of interstitial collagenase, 92-kDa gelatinase, and tissue inhibitor of metalloproteinases-1 in granuloma annulare and necrobiosis lipoidica diabeticorum

Granuloma annular (GA) and necrobiosis lipoidica diabeticorum (NLD) are disorders characterized by granulomatous inflammation and degenerative changes in collagen and elastic fibers. Because these disorders have often been described as being associated with altered extracellular matrix deposition, we studied the in situ expression of interstitial collagenase, 92-kDa gelatinase, and tissue inhibitor of metalloproteinases (TIMP)-1. Twelve lesions each of GA and NLD of different histopathologic types and durations were examined. Interstitial collagenase mRNA was seen in histiocyte-like cells in one-third of the cases of both diseases, typically in younger lesions. In GA, collagenase mRNA was only detected in lesions of the palisading type. Signal for 92-kDa gelatinase mRNA was observed in eosinophils, which were present in low numbers in five of 12 GA and three of 12 NLD samples. The signal for this enzyme and the presence of eosinophils did not correlate with the age of lesion. TIMP-1 mRNA was consistently expressed by histiocyte-like cells in both disorders. In GA, TIMP-1 mRNA was detected at the outer edge of the palisading granulomas, but in NLD, inhibitor expression was seen in the perivascular and periadnexal accumulation of inflammatory cells. Our data indicate that collagenase and TIMP are expressed early in these disorders and that these proteins may contribute to stromal remodeling associated with necrobiotic lesions. Our results further indicate that the localization of TIMP-1 production may provide a distinction between the two disorders, whereas metalloproteinase expression is not sufficiently specific to aid in the differential diagnosis of GA and NLD.

Acetylcholinesterase histochemistry of rectal suction biopsies in the diagnosis of Hirschsprung's disease

Rectal suction biopsy with acetylcholinesterase (AChE) histochemistry has gained increased acceptance as the means of definitely diagnosing Hirschsprung's disease (HD) as well as of excluding this diagnosis when evaluating children with low intestinal obstruction or chronic constipation since the report of Meier-Ruge et al. in 1972. But this AChE histochemical study has not been reported yet in Korea. During the 14-month period from April, 1991 through June, 1992, 37 children, aged 3 days to 17 years had rectal suction biopsies for the diagnosis or exclusion of HD. In this study, AChE histochemistry (N = 37) was compared with hematoxylin & eosin (H&E) staining of same suction biopsy specimens (N = 35) for diagnostic accuracy. The histochemical criterion used for the diagnosis of Hirschsprung's disease was that of Chow et al. (1977), i.e., the presence of many coarse discrete cholinergic fibers in the muscularis mucosae and in the immediately subjacent submucosa regardless of an infiltration of cholinergic fibers in the lamina propria. Of 13 biopsies from the patients with Hirschsprung's disease (N = 13), there were 12 positive reactions, and one false negative reaction in a neonate with total colonic aganglionosis. All biopsies from 24 unaffected children demonstrated negative reactions with no false positive reaction. In comparison, of the 35 specimens examined by H&E staining, ganglion cells were present in the submucosal Meissner's plexus only in 15 of these 24 unaffected children. In conclusion, a 97% diagnostic accuracy was achieved with AChE histochemistry compared with a 74% accuracy with H&E staining (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Distinct localization of collagenase and tissue inhibitor of metalloproteinases expression in wound healing associated with ulcerative pyogenic granuloma

To examine the role of metalloproteinases in tissue remodeling associated with wound healing, we used in situ hybridization to localize the expression of collagenase and tissue inhibitor of metalloproteinases (TIMP) in samples of pyogenic granuloma. Strong hybridization for collagenase mRNA was detected in basal keratinocytes near the advancing edge of all ulcerative lesions, but no collagenase mRNA was seen in samples without ulceration. Distinct from the sites of collagenase expression, TIMP mRNA was detected in stromal cells and in cells surrounding proliferating vessels. No collagenase mRNA was found in the epidermis of healthy skin, although occasional stromal cells contained collagenase or TIMP mRNAs, and TIMP mRNA was detected in hair follicles and sebaceous glands. Our results suggest that basal keratinocytes adjacent to wounded epidermis are critically involved in matrix remodeling, much more so than adjacent or underlying dermal fibroblasts. Furthermore, as several reports have suggested, TIMP may play a role in angiogenesis. Finally, in contrast to findings from other models which indicate that collagenase and TIMP proteins are secreted by the same cells, our data also demonstrate that these proteins can be produced in vivo independently of each other.

Role of the midgut gland in metabolism and excretion of ecdysteroids by lobsters, Homarus americanus

The chromatographic profile of ecdysteroids (Ecds) from the midgut gland (MG) of juvenile female lobsters, Homarus americanus, was examined using high-performance liquid chromatography (HPLC) and radioimmunoassay (RIA) over four stages of the molt cycle. Upon initial examination, highly polar Ecd conjugates appeared to be the principal metabolites found in all molt stages. HPLC fractions containing apolar Ecds initially exhibited low RIA activity. Upon hydrolysis with a Helix pomatia enzyme preparation and reanalysis, significant amounts of other Ecds were released. Amounts of apolar Ecd conjugates were estimated, at their highest levels, to be at least 50% of the total Ecds in MGs of molt stage D3 lobsters. Only the MG formed significant amounts of apolar Ecds upon in vitro culture with [3H]ecdysone ([3H]E). Epidermis and antennal gland significantly increased their rates of [3H]E metabolism in vitro between molt stages C4 and D1. This result further supports the idea that regulation of ecdysteroid metabolism, at least in selected tissues, may be important in the molt cycle regulation of hormone titers. Using gel filtration column chromatography and sucrose density gradient centrifugation analyses, evidence was found for association of apolar Ecds with a protein(s) from MG cytosol. The protein was estimated to have a molecular weight of 180,000-200,000 and specifically bound apolar Ecds.

Binding proteins for a peptide hormone in the shrimp, Sicyonia ingentis: evidence from photoaffinity labeling with red pigment concentrating hormone analogs

Two photoaffinity analogs of the crustacean erythrophore (red pigment) concentrating hormone (RPCH) have been synthesized and shown to cause pigment concentration in the shrimp Sicyonia ingentis. These two modified oligopeptides have azidosalicylamide groups which allow introduction of an 125I label and enable photochemically induced covalent attachment to a specific binding site. Incubation of [125I]-ASA-Glu1-CC-2 with the 100,000g membrane pellet and cytosol fraction from epidermis, eyestalks, muscle, and central nervous system (CNS), followed by irradiation, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and autoradiography results in covalent modification of certain protein bands in the membranes of selected tissues. Two such proteins were observed in neural tissues and showed competitive displacement by excess RPCH, indicative of specific high-affinity binding. This is the first report of peptide hormone-binding proteins in an invertebrate and provides further evidence of a role for RPCH as a neurotransmitter in the CNS.

Scanning electron microscopic study of capillary change in bleomycin-induced pulmonary fibrosis

The architectural changes which occur in the capillaries are difficult to illustrate without a three-dimensional tool, such as scanning electron microscopy. Therefore, a scanning electron microscopic study was occasionally undertaken to show the capillary changes of lung fibrosis. Fibrosis was induced in twenty rats by an intratracheal injection of bleomycin. After 30 days the rats were sacrificed, and light microscopy and scanning electron microscopy were performed. The vascular trees of both lungs were cast with methacrylate. Light microscopically, the pulmonary fibrosis was patchy and inflammatory cell infiltration was rather sparse. Scanning electron microscopically, the intercapillary spaces became wider; and some capillaries revealed large irregular dilatation. The pleural and alveolar capillaries were variably dilated. The pleural capillary diameter was increased (P = 0.06), and the capillary plexus diameter was decreased (P = 0.00). Distance between the capillary branches of the pleural surface was increased (P = 0.06). The appearance of irregularly shaped capillaries, an increase in diameter with variable dilatation of alveolar capillary rings and a decrease in branching between the capillaries, resulting in a loss of surface area are the main scanning electron microscopic findings of the remodeling which occurs pulmonary capillaries in bleomycin-induced pulmonary fibrosis.