Migration of breast cancer cell lines in response to pulmonary laminin 332

Because tumor cell motility is a requirement for metastasis, we hypothesized that lung tissue harbors substances that induce tumor cell migration. MCF-7 breast carcinoma cells exposed to small airway epithelial cells and conditioned medium exhibited dose-dependent tumor cell migration. Among the extracellular matrix proteins in the conditioned medium identified by mass spectrometry, laminin 332 (LM332) had the greatest contribution to the migration of MCF-7 cells. Immunoblotting and immunohistochemistry for LM332-specific chains identified LM332 in the lung and in pulmonary epithelial cells. Antibodies to either LM332 or its integrin receptor inhibited MCF-7 motility, and knockdown of LM332 chains also reduced its migration-inducing activity. Taken together, these findings implicate LM332 as a component of lung tissue that can induce motility in breast carcinoma cells that have been transported to lung during metastasis. Earlier studies on LM332 in tumor progression have examined LM332 expression in tumor cells. This investigation, in comparison, provides evidence that the tumor promoting potential of LM332 may originate in the lung microenvironment rather than in tumor cells alone. Furthermore, this study provides evidence that the motility-inducing properties of the microenvironment can reside in epithelial cells. The findings raise the possibility that LM332 plays a role in the pulmonary metastases of breast carcinoma and may provide a target for antimetastasis therapy.

Abstract C05: Pulmonary laminin 332 in tumor cell migration and breast cancer survival

Metastasis to the lung often leads to the demise of the patient, thus a greater understanding of the process might lead to strategies for better cancer control. Tumor cell metastatic ability is determined by both intrinsic properties of tumor cells and contributions from the microenvironment. The goal of this study was to determine the role of the extracellular matrix protein laminin 332 (LN332) in breast cancer progression. Because tumor cell motility is a requirement for metastasis, we hypothesize that lung tissue harbors substances that induce tumor cell migration. In order to better characterize the interaction of breast carcinoma cells and lung tissue, MCF-7 breast carcinoma cells were added to slides of frozen sections of lung tissue. MCF-7 cells in contact with the lung tissue exhibited properties associated with tumor cell migration, including pseudopodia and lamellipodia. In contrast, MCF-7 cells on glass without lung tissue had smooth borders. Similarly, MCF-7 cells showed migratory properties when co-cultured with small airway epithelial cells (SAEC). LN332 is a component of the basement membrane of lung epithelium, and is thought to induce the migration of several tumor cell types. Immunoblotting revealed all three chains of LN332 in SAEC conditioned medium. To confirm that LN332 was among the components of the lung cells that induced the migration of the breast carcinoma cells, siRNA knockdown of the α3, β3 and γ2 chains of LN332 was performed on SAEC. The conditioned media from knock down and control SAEC was collected for motility assays. Knockdown of the α3 chain alone was sufficient to decrease the expression of the other two chains, but the greatest knockdown of LN332 protein was achieved with simultaneous use of siRNA against the α3, β3 and γ2 chains combined. Conditioned medium from cells with knockdown of LN332 induced tumor cell migration to a lesser extent than conditioned medium from control cells. Taken together, these in vitro data provide evidence that LN332 in the microenvironment has the potential to promote the invasion of metastatic foci into the pulmonary parenchyma. Next, we sought to determine whether LN332 expressed in breast carcinoma cells was associated with any particular phenotype of the tumors, or were associated with tumor prognosis. Tissue microarrays of breast carcinomas excised in 1994 and 1995 from 312 patients were stained for estrogen receptor, progesterone receptor, HER2 and the LN332 β3 chain by immunohistochemistry. LN332 expression was greatest in triple negative and HER2 expressing breast carcinomas. Follow-up for over 20 years on this cohort revealed that patients with tumors expressing LN332 β3 chain had a worse prognosis than patients without LN332 β3 chain in their tumors. Taken together, these studies provide evidence that LN332 in either tumor cells or the microenvironment may be implicated in breast cancer progression.

Citation Format: Philip M. Carpenter, Priyanka Sivadas, Argyrios Ziogas, Hoda Anton-Culver. Pulmonary laminin 332 in tumor cell migration and breast cancer survival. [abstract]. In: Proceedings of the AACR Special Conference: Function of Tumor Microenvironment in Cancer Progression; 2016 Jan 7–10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2016;76(15 Suppl):Abstract nr C05.

Myc-binding protein orthologue interacts with AKAP240 in the central pair apparatus of the Chlamydomonas flagella

Background

Flagella and cilia are fine thread-like organelles protruding from cells that harbour them. The typical ‘9 + 2’ cilia confer motility on these cells. Although the mechanistic details of motility remain elusive, the dynein-driven motility is regulated by various kinases and phosphatases. A-kinase anchoring proteins (AKAPs) are scaffolds that bind to a variety of such proteins. Usually, they are known to possess a dedicated domain that in vitro interacts with the regulatory subunits (RI and RII) present in the cAMP-dependent protein kinase (PKA) holoenzyme. These subunits conventionally harbour contiguous stretches of a.a. residues that reveal the presence of the Dimerization Docking (D/D) domain, Catalytic interface domain and cAMP-Binding domain. The Chlamydomonas reinhardtii flagella harbour two AKAPs; viz., the radial spoke AKAP97 or RSP3 and the central pair AKAP240. Both these were identified on the basis of their RII-binding property. Interestingly, AKAP97 binds in vivo to two RII-like proteins (RSP7 and RSP11) that contain only the D/D domain.

Results

We found a Chlamydomonas Flagellar Associated Protein (FAP174) orthologous to MYCBP-1, a protein that binds to organellar AKAPs and Myc onco-protein. An in silico analysis shows that the N-terminus of FAP174 is similar to those RII domain-containing proteins that have binding affinities to AKAPs. Binding of FAP174 was tested with the AKAP97/RSP3 using in vitro pull down assays; however, this binding was rather poor with AKAP97/RSP3. Antibodies were generated against FAP174 and the cellular localization was studied using Western blotting and immunoflourescence in wild type and various flagella mutants. We show that FAP174 localises to the central pair of the axoneme. Using overlay assays we show that FAP174 binds AKAP240 previously identified in the C2 portion of the central pair apparatus.

Conclusion

It appears that the flagella of Chlamydomonas reinhardtii contain proteins that bind to AKAPs and except for the D/D domain, lack the conventional a.a. stretches of PKA regulatory subunits (RSP7 and RSP11). We add FAP174 to this growing list.

Electronic supplementary material

The online version of this article (doi:10.1186/s12860-016-0103-y) contains supplementary material, which is available to authorized users.

A flagellar A-kinase anchoring protein with two amphipathic helices forms a structural scaffold in the radial spoke complex

Amphipathic helices in the A-kinase anchoring protein RSP3 bind to spoke proteins involved in the assembly and modulation of the flagellar radial spoke complex, expanding the repertoire of these versatile helical protein motifs.

A-kinase anchoring proteins (AKAPs) contain an amphipathic helix (AH) that binds the dimerization and docking (D/D) domain, RIIa, in cAMP-dependent protein kinase A (PKA). Many AKAPs were discovered solely based on the AH–RIIa interaction in vitro. An RIIa or a similar Dpy-30 domain is also present in numerous diverged molecules that are implicated in critical processes as diverse as flagellar beating, membrane trafficking, histone methylation, and stem cell differentiation, yet these molecules remain poorly characterized. Here we demonstrate that an AKAP, RSP3, forms a dimeric structural scaffold in the flagellar radial spoke complex, anchoring through two distinct AHs, the RIIa and Dpy-30 domains, in four non-PKA spoke proteins involved in the assembly and modulation of the complex. Interestingly, one AH can bind both RIIa and Dpy-30 domains in vitro. Thus, AHs and D/D domains constitute a versatile yet potentially promiscuous system for localizing various effector mechanisms. These results greatly expand the current concept about anchoring mechanisms and AKAPs.

The versatile molecular complex component LC8 promotes several distinct steps of flagellar assembly

LC8 is present in various molecular complexes. However, its role in these complexes remains unclear. We discovered that although LC8 is a subunit of the radial spoke (RS) complex in Chlamydomonas flagella, it was undetectable in the RS precursor that is converted into the mature RS at the tip of elongating axonemes. Interestingly, LC8 dimers bound in tandem to the N-terminal region of a spoke phosphoprotein, RS protein 3 (RSP3), that docks RSs to axonemes. LC8 enhanced the binding of RSP3 N-terminal fragments to purified axonemes. Likewise, the N-terminal fragments extracted from axonemes contained LC8 and putative spoke-docking proteins. Lastly, perturbations of RSP3's LC8-binding sites resulted in asynchronous flagella with hypophosphorylated RSP3 and defective associations between LC8, RSs, and axonemes. We propose that at the tip of flagella, an array of LC8 dimers binds to RSP3 in RS precursors, triggering phosphorylation, stalk base formation, and axoneme targeting. These multiple effects shed new light on fundamental questions about LC8-containing complexes and axoneme assembly.

Chlamydomonas mutants display reversible deficiencies in flagellar beating and axonemal assembly

Axonemal complexes in flagella are largely prepackaged in the cell body. As such, one mutation often results in the absence of the co-assembled components and permanent motility deficiencies. For example, a Chlamydomonas mutant defective in RSP4 in the radial spoke (RS), which is critical for bend propagation, has paralyzed flagella that also lack the paralogue RSP6 and three additional RS proteins. Intriguingly, recent studies showed that several mutant strains contain a mixed population of swimmers and paralyzed cells despite their identical genetic background. Here we report a cause underlying these variations. Two new mutants lacking RSP6 swim processively and other components appear normally assembled in early log phase indicating that, unlike RSP4, this paralogue is dispensable. However, swimmers cannot maintain the typical helical trajectory and reactivated cell models tend to spin. Interestingly the motile fraction and the spokehead content dwindle during stationary phase. These results suggest that (1) intact RS is critical for maintaining the rhythm of oscillatory beating and thus the helical trajectory; (2) assembly of the axonemal complex with subtle defects is less efficient and the inefficiency is accentuated in compromised conditions, leading to reversible dyskinesia. Consistently, several organisms only possess one RSP4/6 gene. Gene duplication in Chlamydomonas enhances RS assembly to maintain optimal motility in various environments.

HEALTH AND PERFORMANCE OF MILITARY PERSONNEL IN COLD CLIMATIC ENVIRONMENT OF THE WESTERN HIMALAYAS

Indian Armed Forces are constrained to deploy a large number of troops in the western Himalayas in the interest of national security and territorial integrity. The region represents extremely rugged, arid and cold climatic conditions. The altitude ranges from 8000 to 23000 feet with winter temperatures ranging from -35°C to - 55°C in some regions. Low environmental humidity, hypo-baric hypoxia and high solar ultra-violet radiation with its attendant problems further compound the hardships faced by the troops in these climatic conditions. The role of the Armed Forces medical personnel is extremely challenging, as they have to ensure maintenance of health and physical fitness of the troops to ensure optimal performance during peace and during operations. These considerations include nutrition, physical fitness programmes suitable for the terrain and climatic conditions, protection against cold and hypoxia induced health problems, clothing and shelter taking into consideration the ergonomic factors, human waste disposal and prompt medical attention and evacuation in case of illness. An overview of the effects of cold hypoxic environment on health and performance of Indian troops, measures employed by the Armed Forces to maintain health of troops including psychological factors and the incidence of various cold induced health problems during peace time compared to operational period over the last 10 years is presented in this paper.

MICROWAVE STIMULATED FIXATION AND RAPID PROCESSING OF TISSUE FOR HISTOPATHOLOGY

A rapid method for obtaining high quality paraffin sections is described. This method enables preparation of paraffin blocks in about 20 minutes and is based on microwave stimulated tissue fixation and processing. A total of 200 tissues were processed. Tissue blocks of size 1×1×0.5 were found ideal for processing. Three protocols were evaluated for tissue processing using different timings of exposure to graded alcohols, chloroform and wax. It was observed that utilizing an additional step of exposure to 70 per cent alcohol during tissue dehydration resulted in preparation of paraffin blocks which were light microscopically excellent and highly comparable to conventional methods.

HORMONAL MARKERS IN THE STUDY OF PITUITARY ADENOMAS

Twenty pituitary adenomas were studied using light microscopy, immunohistochemistry and electron microscopy. Based on clinical manifestations of hormonal hypersecretion they were divided into two groups, i.e. group-I (12 patients) with no endocrine dysfunction and group-II (8 patients) with endocrine dysfunction. Group-I could be further sub-divided into two groups based on IHC : group LA in which no hormone could be localised in the tissue (null cell adenomas) and group IB where hormones could be localised in the tissue (1). Tumours in group II, with light microscopy, were acidophil (n=5), basophil (n=1) or mixed (n=2) adenomas. Eight of these 20 cases were plurihormonal. Growth hormone, and prolactin were the commonest combination. This study has helped in the reclassification of the pituitary adenomas according to the hormone they produce.

IMMUNOPHENOTYPING OF ACUTE LEUKAEMIAS : A CRITICAL ANALYSIS OF 35 CASES

Accurate classification of acute leukaemias is essential for proper case management. The utility of monoclonal antibodies in the diagnosis and classification of acute leukaemias is well established. This diagnostic utility relates primarily to two points : firstly the distinction between acute myeloid leukaemia and acute lymphoblastic leukaemia and secondly to subtypes of acute lymphoblastic leukaemia. Leukaemic cells were immunophenotyped using the alkaline phosphatase antialkaline phosphatase techniques. The monoclonal antibodies were very useful in distinguishing cases of acute myeloid leukaemia from acute lymphoblastic leukaemia. Cases of acute lymphoblastic leukaemia with CD10 positivity showed a better prognosis. T-cell acute lymphoblastic leukaemia was uncommon and was associated with unfavourable prognosis. The alkaline phosphatase antialkaline phosphatase technique served as a reliable and convenient method for immunophenotyping of leukaemias.

HYPOFIBRINOGENEMIA (A Report of Two Cases)

Hypofibrinogenemia is an uncommon bleeding disorder. Two siblings with mild bleeding diathesis were investigated and diagnosed as suffering from this disorder. The cases are discussed keeping in view of their rarity.

ELECTRON MICROSCOPY IN LUPUS NEPHRITIS (A Case Report)

A female patient aged 8 years presented with mild proteinuria and microscopical haematuria, The serological markers and histological findings in renal needle biopsy were inconclusive. Ultrastructural study revealed features of lupus nephritis. Case is presented to elucidate value of electron microscopy in such cases.

High frequency embryoid and plantlet formation from tissue cultures of the Finger millet-Eleusine coracana (L.) Gaertn

Compact nodulated embryogenic callus differentiated from cultured seeds of Eleusine coracana (Finger Millet) on Murashige and Skoog (1962) basal medium with 2,4-dichlorophenoxyacetic acid (1.0, 3.0 mg (l)). This embryogenic callus was maintained on a medium with a lower level of 2,4 - dichlorophenoxyacetic acid. At every subculture the embryogenic callus had some preexisting embryoids in it. With this method of subculture the callus has retained its morphogenic potential for four years. Following transfer to media with different levels of auxins and cytokinins, the callus showed varied patterns of growth and morphogenesis. Embryoids could be germinated in profusion to form plantlets which could be transferred to the field. Shoot buds also differentiated from the whole surface of the embryoid or from the flattened meristemoids.