Intracellular Calcium Mobilization in Response to Ion Channel Regulators via a Calcium-Induced Calcium Release Mechanism.

Free intracellular calcium ([Ca2+]i), in addition to being an important second messenger, is a key regulator of many cellular processes including cell membrane potential, proliferation, and apoptosis. In many cases, the mobilization of [Ca2+]i is controlled by intracellular store activation and calcium influx. We have investigated the effect of several ion channel modulators, which have been used to treat a range of human diseases, on [Ca2+]i release, by ratiometric calcium imaging. We show that six such modulators [amiodarone (Ami), dofetilide, furosemide (Fur), minoxidil (Min), loxapine (Lox), and Nicorandil] initiate release of [Ca2+]i in prostate and breast cancer cell lines, PC3 and MCF7, respectively. Whole-cell currents in PC3 cells were inhibited by the compounds tested in patch-clamp experiments in a concentration-dependent manner. In all cases [Ca2+]i was increased by modulator concentrations comparable to those used clinically. The increase in [Ca2+]i in response to Ami, Fur, Lox, and Min was reduced significantly (P < 0.01) when the external calcium was reduced to nM concentration by chelation with EGTA. The data suggest that many ion channel regulators mobilize [Ca2+]i We suggest a mechanism whereby calcium-induced calcium release is implicated; such a mechanism may be important for understanding the action of these compounds.

Match criteria for human cell line authentication: where do we draw the line?

Continuous human cell lines have been used extensively as models for biomedical research. In working with these cell lines, researchers are often unaware of the risk of cross-contamination and other causes of misidentification. To reduce this risk, there is a pressing need to authenticate cell lines, comparing the sample handled in the laboratory to a previously tested sample. The American Type Culture Collection Standards Development Organization Workgroup ASN-0002 has developed a Standard for human cell line authentication, recommending short tandem repeat (STR) profiling for authentication of human cell lines. However, there are known limitations to the technique when applied to cultured samples, including possible genetic drift with passage. In our study, a dataset of 2,279 STR profiles from four cell banks was used to assess the effectiveness of the match criteria recommended within the Standard. Of these 2,279 STR profiles, 1,157 were grouped into sets of related cell lines-duplicate holdings, legitimately related samples or misidentified cell lines. Eight core STR loci plus amelogenin were used to unequivocally authenticate 98% of these related sets. Two simple match algorithms each clearly discriminated between related and unrelated samples, with separation between related samples at ≥80% match and unrelated samples at <50% match. A small degree of overlap was noted at 50-79% match, mostly from cell lines known to display variable STR profiles. These match criteria are recommended as a simple and effective way to interpret results from STR profiling of human cell lines.

Function of mutant and wild-type plexinb1 in prostate cancer cells.

BACKGROUND: Semaphorins act as chemotactic cues for cell movement via their transmembrane receptors, plexins. Somatic missense mutations in the plexinB1 gene coupled with overexpression of the protein frequently occur in prostate tumors, indicating a role for plexinB1 in the pathogenesis of prostate cancer. However, the effect of semaphorin/plexin signaling is highly context dependent and whether plexinB1 acts as an inducer or inhibitor of prostate tumor progression in this context is not known. METHODS: The response of prostate cancer cell lines to plexinB1 activation was assessed in migration, invasion, proliferation and protein phosphorylation assays. Expression was assessed by quantitative RTPCR and immunoblotting. RESULTS: Different prostate cancer cell lines respond to Sema4D (the ligand for plexinB1) in diverse ways. Activation of endogenous plexinB1 enhances migration, invasion and anchorage-independent growth of LNCaP prostate cancer cells via activation of ErbB2 and Akt. In contrast, Sema4D-stimulation decreased the motility and proliferative capacity of PC3 cells. LNCaP has a missense mutation (Thr1697Ala) in the plexinB1 gene while LNCaP-LN3, a derivative of LNCaP, expresses high levels of wild-type plexinB1 only. Sema4D stimulation increases the motility and anchorage independent growth of both cell lines, showing that these responses are not dependent on the presence of the Thr1697Ala form of plexinB1. ErbB2 and plexinB1 are expressed in primary prostate epithelial cells. CONCLUSIONS: PlexinB1 signals via ErbB2 to increase the invasive phenotype of prostate cancer cells. Both wild-type and mutant forms of plexinB1 are potential targets for anti-cancer therapy in prostate tumors that express ErbB2.

Evaluation in vitro and in animals of a new 11C-labeled PET radioligand for metabotropic glutamate receptors 1 in brain.

PURPOSE: Two allosteric modulators of the group I metabotropic glutamate receptors (mGluR1 and mGluR5) were evaluated as positron emission tomography (PET) radioligands for mGluR1. METHODS: LY2428703, a full mGluR1 antagonist (IC(50) 8.9 nM) and partial mGluR5 antagonist (IC(50) 118 nM), and LSN2606428, a full mGluR1 and mGluR5 antagonist (IC(50) 35.3 nM and 10.2 nM, respectively) were successfully labeled with (11)C and evaluated as radioligands for mGluR1. The pharmacology of LY2428703 was comprehensively assessed in vitro and in vivo, and its biodistribution was investigated by liquid chromatography-mass spectrometry/mass spectrometry, and by PET imaging in the rat. In contrast, LSN2606428 was only evaluated in vitro; further evaluation was stopped due to its unfavorable pharmacological properties and binding affinity. RESULTS: (11)C-LY2428703 showed promising characteristics, including: (1) high potency for binding to human mGluR1 (IC(50) 8.9 nM) with no significant affinity for other human mGlu receptors (mGluR2 through mGluR8); (2) binding to brain displaceable by administration of an mGluR1 antagonist; (3) only one major radiometabolite in both plasma and brain, with a negligible brain concentration (with 3.5 % of the total radioactivity in cerebellum) and no receptor affinity; (4) a large specific and displaceable signal in the mGluR1-rich cerebellum with no significant in vivo affinity for mGluR5, as shown by PET studies in rats; and (5) lack of substrate behavior for efflux transporters at the blood-brain barrier, as shown by PET studies conducted in wild-type and knockout mice. CONCLUSION: (11)C-LY2428703, a new PET radioligand for mGluR1 quantification, displayed promising characteristics both in vitro and in vivo in rodents.

Curing metastatic cancer: lessons from testicular germ-cell tumours.

Most metastatic cancers are fatal. More than 80% of patients with metastatic testicular germ-cell tumours (TGCTs), however, can be cured using cisplatin-based combination chemotherapy. Why are TGCTs more sensitive to chemotherapeutics than most other tumour types? Answers to this question could lead to new treatments for metastatic cancers.

The development of a rural breast reconstruction service: patient reported outcomes and benefits.

BACKGROUND: In 2021, breast cancer was one of the most commonly diagnosed cancer in Australia. While a mastectomy remains a treatment of choice, only a small percentage of women have access to a breast reconstruction after. Women living in a rural area are less likely to have a breast reconstruction; compared to their metropolitan counterparts. This study analyses the impact of single breast reconstruction service on a Modified Monash 3 (MM3) region and informs consumers and providers of the importance of a breast reconstruction unit embedded in a rural health network. [Corrections added on 2 May 2023, after online publication. Expanded reference citations have been deleted from Abstract section.] METHODS: Following ethics approval, all 64 patients who had undergone a breast reconstruction with this service between 2017 and 2021 were contacted. Patient reported outcomes were recorded through phone interviews, using a standardized questionnaire. For each patient that presented to the rural centre, cost of travel and productivity loss were also calculated, and compared to the closest metropolitan centre. RESULT: Ninety-seven percent of the 38 participants strongly valued having a breast reconstruction service within their community. Eighty percent of participants were satisfied with their result. Patients were estimated to save on average $8478, by attending the rural breast reconstruction service. CONCLUSION: Access to a breast reconstruction is significantly impacted by geographical barriers. A rural breast reconstruction service can improve patient access and satisfaction, while also reducing the financial burden on patients.

Effect of cancer-associated mutations in the PlexinB1 gene.

BACKGROUND: Semaphorins act as chemotactic cues for cell movement via their transmembrane receptors, plexins. Somatic missense mutations in the plexinB1 gene coupled with overexpression of the protein frequently occur in prostate tumours, indicating a role for plexinB1 in the pathogenesis of prostate cancer. RESULTS: Two specific mutations found in prostate cancer enhance RhoD binding and one other mutation results in loss of inhibition of Rac-dependent Pak1 phosphorylation and lamellipodia formation and in impairment of trafficking of plexinB1 to the membrane. None of the three characterised mutations affect PDZRhoGEF binding, RhoA activity, the interaction of plexinB1 with the oncogenes ErbB2 or c-Met or ErbB2 phosphorylation. The mutations have the net effect of increasing cell motility by blocking plexinB1-mediated inhibition of Rac while enhancing the interaction with RhoD, an anti-migratory factor. CONCLUSIONS: PlexinB1 mutations block plexinB1-mediated signalling pathways that inhibit cell motility.

Biochemical relapse following radical prostatectomy and miR-200a levels in prostate cancer.

BACKGROUND: Radical prostatectomy cures the majority of men with clinically localized disease, but up to 30% of men relapse with rising serum PSA levels. Stage, Gleason grade, and pre-operative PSA levels are associated with outcome but do not accurately predict which individuals will relapse. MicroRNA (miRNA) levels are altered in cancer and are associated with progression of disease. The miR-200 family has roles in prostate cancer. METHODS: miR-200a levels were measured in 18 radical prostatectomy samples from men who did not relapse and from 18 who did relapse, matched for stage (all T3), grade, and PSA levels. A pair of cancer and normal prostate cell lines derived from the same radical prostatectomy specimen were transfected with miR-200a to determine the effects on growth, wound healing, and invasion. RESULTS: Comparing the matched samples, 11 of the relapsers contained lower, 2 higher and 5 similar levels to the non-relapsers. Transient transfection of miR-200a significantly reduced cell proliferation in prostate cancer cell lines but did not affect invasiveness. CONCLUSION: miR-200a overexpression reduced prostate cancer cell growth and may have potential, in combination with other markers, in stratifying prostate cancer patients for more intensive monitoring and therapy.

PAK4: a pluripotent kinase that regulates prostate cancer cell adhesion.

Hepatocyte growth factor (HGF) is associated with tumour progression and increases the invasiveness of prostate carcinoma cells. Migration and invasion require coordinated reorganisation of the actin cytoskeleton and regulation of cell-adhesion dynamics. Rho-family GTPases orchestrate both of these cellular processes. p21-activated kinase 4 (PAK4), a specific effector of the Rho GTPase Cdc42, is activated by HGF, and we have previously shown that activated PAK4 induces a loss of both actin stress fibres and focal adhesions. We now report that DU145 human prostate cancer cells with reduced levels of PAK4 expression are unable to successfully migrate in response to HGF, have prominent actin stress fibres, and an increase in the size and number of focal adhesions. Moreover, these cells have a concomitant reduction in cell-adhesion turnover rates. We find that PAK4 is localised at focal adhesions, is immunoprecipitated with paxillin and phosphorylates paxillin on serine 272. Furthermore, we demonstrate that PAK4 can regulate RhoA activity via GEF-H1. Our results suggest that PAK4 is a pluripotent kinase that can regulate both actin cytoskeletal rearrangement and focal-adhesion dynamics.

Check your cultures! A list of cross-contaminated or misidentified cell lines.

Continuous cell lines consist of cultured cells derived from a specific donor and tissue of origin that have acquired the ability to proliferate indefinitely. These cell lines are well-recognized models for the study of health and disease, particularly for cancer. However, there are cautions to be aware of when using continuous cell lines, including the possibility of contamination, in which a foreign cell line or microorganism is introduced without the handler's knowledge. Cross-contamination, in which the contaminant is another cell line, was first recognized in the 1950s but, disturbingly, remains a serious issue today. Many cell lines become cross-contaminated early, so that subsequent experimental work has been performed only on the contaminant, masquerading under a different name. What can be done in response-how can a researcher know if their own cell lines are cross-contaminated? Two practical responses are suggested here. First, it is important to check the literature, looking for previous work on cross-contamination. Some reports may be difficult to find and to make these more accessible, we have compiled a list of known cross-contaminated cell lines. The list currently contains 360 cell lines, drawn from 68 references. Most contaminants arise within the same species, with HeLa still the most frequently encountered (29%, 106/360) among human cell lines, but interspecies contaminants account for a small but substantial minority of cases (9%, 33/360). Second, even if there are no previous publications on cross-contamination for that cell line, it is essential to check the sample itself by performing authentication testing.

Plexin-B1 mutations in prostate cancer.

Semaphorins are a large class of secreted or membrane-associated proteins that act as chemotactic cues for cell movement via their transmembrane receptors, plexins. We hypothesized that the function of the semaphorin signaling pathway in the control of cell migration could be harnessed by cancer cells during invasion and metastasis. We now report 13 somatic missense mutations in the cytoplasmic domain of the Plexin-B1 gene. Mutations were found in 89% (8 of 9) of prostate cancer bone metastases, in 41% (7 of 17) of lymph node metastases, and in 46% (41 of 89) of primary cancers. Forty percent of prostate cancers contained the same mutation. Overexpression of the Plexin-B1 protein was found in the majority of primary tumors. The mutations hinder Rac and R-Ras binding and R-RasGAP activity, resulting in an increase in cell motility, invasion, adhesion, and lamellipodia extension. These results identify a key role for Plexin-B1 and the semaphorin signaling pathway it mediates in prostate cancer.

Monocyclic Quinone Structure-Activity Patterns: Synthesis of Catalytic Inhibitors of Topoisomerase II with Potent Antiproliferative Activity.

The monocyclic 1,4-benzoquinone, HU-331, the direct oxidation product of cannabidiol, inhibits the catalytic activity of topoisomerase II but without inducing DNA strand breaks or generating free radicals, and unlike many fused-ring quinones exhibits minimal cardiotoxicity. Thus, monocyclic quinones have potential as anticancer agents, and investigation of the structural origins of their biological activity is warranted. New syntheses of cannabidiol and (±)-HU-331 are here reported. Integrated synthetic protocols afforded a wide range of polysubstituted resorcinol derivatives; many of the corresponding novel 2-hydroxy-1,4-benzoquinone derivatives are potent inhibitors of the catalytic activity of topoisomerase II, some more so than HU-331, whose monoterpene unit replaced by a 3-cycloalkyl unit conferred increased antiproliferative properties in cell lines with IC50 values extending below 1 mM, and greater stability in solution than HU-331. The principal pharmacophore of quinones related to HU-331 was identified. Selected monocyclic quinones show potential for the development of new anticancer agents.

Systemic therapy for advancing or metastatic prostate cancer (STAMPEDE): a multi-arm, multistage randomized controlled trial.

There is a need to improve the outcomes for men with high-risk localised, nodal or metastatic prostate cancer, or with aggressively relapsing disease after initial therapy for local disease. This group of men is currently managed with long-term hormone therapy. Thus we aim to evaluate the toxicity and efficacy of three different systemic therapies (docetaxel, zoledronic acid and celecoxib) used alone or combined at the initiation of hormone manipulation for high-risk prostate cancer. A novel statistical design (multi-arm, multistage method) simultaneously tests multiple distinct strategies in parallel against a single control arm. The trial has several 'stages', from initial confirmation of safety to a phase III assessment of survival, with a series of intervening activity stages. This method provides a means of assessing several agents more quickly and efficiently, and allows inactive treatments to be dropped from further study at an early stage. STAMPEDE has been designed to address in parallel the activity and efficacy of these agents for this patient group. It is a flagship randomized clinical trial for academic research into prostate cancer in the UK. More than 500 patients have been recruited on schedule, confirming the acceptability of this complex trial design to patients and clinicians. The trial targets a population of approximately 3000 patients. STAMPEDE is a major new trial with a novel design applicable to the synchronous testing of several agents. It is hoped that the results will improve outcomes for patients with high-risk prostate cancer. The design could be applicable to the study of new therapies in other cancer types. Continued efforts are required by the urological cancer community to maintain the excellent recruitment shown to date.

A PAK4-LIMK1 pathway drives prostate cancer cell migration downstream of HGF.

Hepatocyte growth factor (HGF) is associated with tumour progression and increases the invasiveness of prostate carcinoma cells. Cell migration and invasion requires reorganisation of the actin cytoskeleton; processes mediated by the Rho family GTPases. p21 activated kinase 4 (PAK4), an effector of the Rho family protein Cdc42, is activated downstream of HGF. We report here the novel finding that in prostate cancer cells PAK4 binds to and phosphorylates LIM kinase 1 (LIMK1) in an HGF-dependent manner. We show for the first time that variations in the level of PAK4 expression change the level of cofilin phosphorylation in cells, a change we correlate with LIMK1 activity, cell morphology and migratory behaviour. We identify for the first time a direct and localised interaction between PAK4 and LIMK1 within cells using FRET: FLIM. Moreover we show here that HGF mediates this interaction which is concentrated in small foci at the cell periphery. PAK4 and LIMK1 act synergistically to increase cell migration speed, whilst a reduction in PAK4 expression decreases cell speed. It is well established that unphosphorylated (active) cofilin is a required to drive cell migration. Our results support a model whereby HGF-stimulated cell migration also requires a cofilin phosphorylation step that is mediated by PAK4.

Primary cultures of renal proximal tubule cells derived from individuals with primary hyperoxaluria.

The primary hyperoxalurias, PH1 and PH2, are inherited disorders caused by deficiencies of alanine:glyoxylate aminotransferase and glyoxylate reductase, respectively. Mutations in either of these enzymes leads to endogenous oxalate overproduction primarily in the liver, but most pathological effects are exhibited in the kidney ultimately leading to end-stage renal failure and systemic oxalosis. To provide a non-invasive means of accessing kidney cells from individuals with primary hyperoxaluria, we have derived primary cultures of renal proximal tubule cells from the urine of these patients. The cells stain positively for the epithelial markers pan-cytokeratin and zonula occludens 1 and the proximal tubule marker gamma-glutamyl transpeptidase. Mutation analysis confirmed that the cultured cells had the same genotype as the leucocytes of the patients and also expressed glyoxylate reductase at the mRNA level, illustrating their potential value as a source of renal material from these individuals.

Utility of tissue microarrays for profiling prognostic biomarkers in clinically localized prostate cancer: the expression of BCL-2, E-cadherin, Ki-67 and p53 as predictors of biochemical failure after radical prostatectomy with nested control for clinical and pathological risk factors.

A cure cannot be assured for all men with clinically localized prostate cancer undergoing radical treatment. Molecular markers would be invaluable if they could improve the prediction of occult metastatic disease. This study was carried out to investigate the expression of BCL-2, Ki-67, p53 and E-cadherin in radical prostatectomy specimens. We sought to assess their ability to predict early biochemical relapse in a specific therapeutic setting. Eighty-two patients comprising 41 case pairs were matched for pathological stage, Gleason grade and preoperative prostate-specific antigen (PSA) concentration. One patient in each pair had biochemical recurrence (defined as PSA >or= 0.2 ng mL(-1) within 2 years of surgery) and the other remained biochemically free of disease (defined as undetectable PSA at least 3 years after surgery). Immunohistochemical analysis was performed to assess marker expression on four replicate tissue microarrays constructed with benign and malignant tissue from each radical prostatectomy specimen. Ki-67, p53 and BCL-2, but not E-cadherin, were significantly upregulated in prostate adenocarcinoma compared with benign prostate tissue (P < 0.01). However, no significant differences in expression of any of the markers were observed when comparing patients who developed early biochemical relapse with patients who had no biochemical recurrence. This study showed that expression of p53, BCL-2 and Ki-67 was upregulated in clinically localized prostate cancer compared with benign prostate tissue, with no alteration in E-cadherin expression. Biomarker upregulation had no prognostic value for biochemical recurrence after radical prostatectomy, even after considering pathological stage, whole tumour Gleason grade and preoperative serum PSA level.

Elevation of XPA protein level in testis tumor cells without increasing resistance to cisplatin or UV radiation.

Most testicular germ cell tumors are curable using cisplatin-based chemotherapy, and cell lines from these tumors are unusually sensitive to cisplatin and other DNA-damaging agents. It has been suggested that this might be caused by a lower-than normal nucleotide excision repair (NER) activity. Previous studies found that cell lines from testicular germ cell tumors have on average about one-third the level of the NER protein XPA in comparison to cell lines from other tumors. We asked whether over-expression of XPA protein would alleviate the cellular sensitivity and increase the DNA repair capacity of a testis tumor cell line. Increasing XPA levels in 833K cells by 10-fold did not increase resistance to UV irradiation. XPA was localized to the cell nucleus in all cell lines, before and after exposure to UV-radiation. 833K cells were proficient in removing UV radiation-induced photoproducts from the genome and increased XPA did not enhance the rate of removal. Further, over-expressing functional XPA protein did not correlate with increased resistance of 833K testis tumor cells to cisplatin. Thus, although the amount of XPA in this testis tumor cell line is lower than normal, it is sufficient for NER in vivo. The relative sensitivity of testis tumor cells to cisplatin, UV radiation, and other DNA damaging agents is likely related not to NER capacity, but to other factors such as the integrity of the p53 pathway in these cells.