Abstract 4230: Transcriptomic evaluation of exercise-induced suppression of prostate cancer aggressiveness

Previous studies from our laboratory have showed that aerobic exercise significantly reduced the number of aggressive poorly differentiated tumors in the transgenic adenocarcinoma of the mouse prostate (TRAMP) model. Despite these encouraging data the underlying mechanism of how exercise reduces tumor aggressiveness remains undefined. We aimed to fill this scientific gap by utilizing a transcriptomics approach to identify potential mechanisms by which aerobic exercise suppresses prostate tumor aggressiveness.

Methods: Twelve TRAMP mice, 8-10 weeks of age, were equally randomized to exercise or control group. Mice in the exercise group were singularly housed in cages with running wheels for 12 weeks. Mice in the control group maintained normal group housing and activity conditions for 12 weeks. At euthanasia, prostate tumors were excised, weighed and processed for immunohistochemistry and transcriptome analysis. Two independent pathologists, blinded to the interventions, performed histological analysis of the genitourinary mass. Outputs of sequencing data were assessed for quality and accuracy. Counts for all known mRNA, differential expression, and heatmap were prepared. Differential expression was filtered to identify genes that had a ≥2-fold change with an adjusted p<0.05. Gene ontology and pathway analyses was performed to reveal selective pathways activated.

Results: No significant difference in genitourinary mass, body mass or tumor free body mass was found between groups. Pathology revealed majority of the tissue from the control group exhibited moderate to poorly differentiated tumors (3/6). On the other hand, none of the animals in the exercise intervention group showed such pathology. Four out of five showed well differentiated tumors including prostatic intraepithelial neoplasia (PIN) lesions in one animal. Transcriptomic analysis coupled with gene set enrichment identified pathways associated with triglyceride catabolic process, lipid homeostasis, lipid metabolic process, triglyceride metabolic process to be most impacted. Differentially expressed genes of interest include haptoglobin (HP) and hormone sensitive lipoprotein lipase (Lipe) were significantly lower in the exercise group.

Conclusion: Our preliminary findings provide novel evidence suggesting that exercise suppresses prostate tumor aggressiveness, in part, through transcriptomic modulation and altered cellular pathways associated with intratumoral energy metabolism. This project was supported by the National Center Institute designated Mays Cancer Center at UT Health San Antonio.

Citation Format: Darpan I. Patel, Paul Rivas, Yidong Chen, Zhao Lai, Robert L. Reddick, Yuji Ikeno, Rita Ghosh, A. Pratap Kumar. Transcriptomic evaluation of exercise-induced suppression of prostate cancer aggressiveness. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4230.

Androgen deprivation-induced elevated nuclear SIRT1 promotes prostate tumor cell survival by reactivation of AR signaling

The NAD⁺-dependent deacetylase, Sirtuin 1 (SIRT1) is involved in prostate cancer pathogenesis. However, the actual contribution is unclear as some reports propose a protective role while others suggest it is harmful. We provide evidence for a contextual role for SIRT1 in prostate cancer. Our data show that (i) mice orthotopically implanted with SIRT1-silenced LNCaP cells produced smaller tumors; (ii) SIRT1 suppression mimicked AR inhibitory effects in hormone responsive LNCaP cells; and (iii) caused significant reduction in gene signatures associated with E2F and MYC targets in AR-null PC-3 and E2F and mTORC1 signaling in castrate-resistant ARv7 positive 22Rv1 cells. Our findings further show increased nuclear SIRT1 (nSIRT1) protein under androgen-depleted relative to androgen-replete conditions in prostate cancer cell lines. Silencing SIRT1 resulted in decreased recruitment of AR to PSA enhancer selectively under androgen-deprivation conditions. Prostate cancer outcome data show that patients with higher levels of nSIRT1 progress to advanced disease relative to patients with low nSIRT1 levels. Collectively, we demonstrate that lowering SIRT1 levels potentially provides new avenues to effectively prevent prostate cancer recurrence.

Exercise preserves muscle mass and force in a prostate cancer mouse model

The purpose of this study was to examine the effects of exercise in modulating biomarkers of sarcopenia in a treatment naïve transgenic adenocardinoma of the mouse prostate (TRAMP) model. Thirty TRAMP mice were randomized to either exercise (voluntary wheel running) or no-treatment control group for a period of 20 weeks. During necropsy, gastrocnemius muscles and prostate tumors were harvested and weighed. Gastrocnemius concentrations of myostatin, insulin-like growth factor (IGF)-1 and tumor necrosis factor (TNF)-α were quantified. Exercise mice had greater muscle mass than controls (p=0.04). Myostatin was significantly lower in the exercise group compared to controls (p=0.01). Exercise mice maintained forelimb grip force while control mice had a significaint decrease (p=0.01). No significant difference was observed in pre-post all limb grip strength. Further, forelimb and all limb grip strength was negatively associated with tumor mass (p<0.01).

Abstract P2-06-12: Oncogenic potential of Trefoil factor 3 in initiation of mammary carcinoma through suppression of p53 pathway

Background

Oncogenic transformation is a complex multistep process where normal cells acquire the hallmarks of cancer, leading to unrestrained outgrowth of malignant clones. Trefoil Factor 3 (TFF3) is a clinically validated and functionally potent oncogene in mammary carcinoma. Elevated TFF3 expression has been consistently observed in mammary carcinoma, being involved in cancer progression. The present study investigates the potential functional role and the underlying mechanisms of TFF3 in promoting oncogenic transformation early in the onset of mammary carcinoma.

Material and method

Immortalized human mammary epithelial cells (HMECs): HMEC-hTERT, MCF10A and MCF12A, with forced expression of TFF3, were used as in vitro models and in an orthotopic xenograft model to study the oncogenic roles of TFF3. Furthermore, microarray analysis, immunofluorescence, and ubiquitination and CHX chase assays were used to examine the involvement of p53 pathway in TFF3 mediated-oncogenic transformation.

Results

Immortalized HMECs with forced expression of TFF3 exhibited the capacity of anchorage independent growth in the soft agar colony formation assay, which is a hallmark of oncogenic transformation. The forced expression of TFF3 also enhanced 3D growth of the immortalized HMECs in matrigel. Furthermore, immortalized HMECs with forced expression of TFF3 gaverise to orthotopic xenograft tumors in nude mice, which are not observed in mice injected with immortalized HMECs. These observations suggest that TFF3 stimulates the oncogenic transformation of non-malignant immortalized HMECs. In addition, the forced expression of TFF3 promoted aberrant cell proliferation, resistance to apoptosis, and increased cell migration and invasion of the HMECs, all these being important hallmarks of cancer. Here, we showed that TFF3-mediated oncogenic transformation of the immortalized HMEC-hTERT cells is dependent on p53 signaling pathway suppression. Mechanistically, TFF3 downregulated NF-κB (p65)-mediated transcription of p53 through decreasing NF-κB (p65) expression and nuclear accumulation. TFF3 also decreased p53 protein levels through post-transcriptional regulation. The forced expression of TFF3 increased MDM2 expression, resulting in an increased ubiquitin-mediated proteasomal degradation of p53. Moreover, forced expression of TFF3 decreased the cleaved form of MDM2, which is responsible for stabilizing p53 protein. Concordantly, HMECs with forced expression of TFF3 exhibited shorter p53 protein half-life as compared to vector control HMECs .

Conclusion

In summary, our study highlights the oncogenic potential of TFF3 in the initiation of mammary carcinoma through the suppression of the p53 pathway.

Citation Format: Chen RM, Pandey V, Chong QY, Poh HM, Zhang MY, Kumar AP, Lobie PE. Oncogenic potential of Trefoil factor 3 in initiation of mammary carcinoma through suppression of p53 pathway [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 P2-06-12.

Abstract P6-18-20: Targeting mitochondrial function for the treatment of triple negative breast cancer: Development of a small molecule inhibitor against mitochondrial STAT3

Background: Patients with Triple Negative Breast Cancer (TNBC) can benefit significantly from earlier diagnosis/prognosis, targeted therapy, and predictive biomarker panels for optimal therapy. However, currently there are no clinically accepted markers for the prognosis of TNBC and to predict its potential to metastasize. It is well documented that numerous cancer subtypes with increased mitochondrial oxidative phosphorylation in which enhanced mitochondrial activity is linked to aggressiveness. Also, there is greater awareness of metabolic heterogeneity within tumors, with some cells using glycolysis as their main energy source, whereas others use oxidative phosphorylation. Interestingly, TNBC has been shown to adopt increased mitochondrial biogenesis to "fuel" enhanced growth and aggressiveness. Signal Transducers and Activators of Transcription family 3 (STAT3) has been studied extensively as a transcription factor, however the finding that STAT3 also localizes to mitochondria has opened a new area to discover non-classical functions.

Methods: Targeting mitochondrial STAT3 functions challenge the current design of therapies that solely target STAT3 as a transcription factor and suggest the need for “design thinking,” to intervene the STAT3 pathway. With this in mind, we developed an in-house mitochondrial targeting - MitoTam. Data from in vitro cell-based assays, in vivo subcutaneous xenograft and patient-derived xenograft (PDX) models of TNBC will be reported.

Results:

Our data shows MitoTam robustly inhibited proliferation of TNBC cells at pharmacological doses and induced apoptosis. Mechanistically, we observed the MitoTam was able to target STAT3 leading to the downregulation of genes which is highly upregulated in most of the cancers. Furthermore, we show inhibition of STAT3 transcriptional activity hampers mitochondrial biogenesis, a prominent feature of cancer cell. Interestingly our in vivo and in vitro protein data showed the decreased phosphorylation of nuclear STAT3 and decreased mitochondria import of STAT3. We also found the decreased phosphorylation of STAT3 is associated with the interaction of GRIM-19 which is a cell death regulatory protein in complex1. Treatment of MitoTam was able to deplete the super complexes involved in OXPHOS and also in the regulation of mitochondrial transcription regulation. Our in vivo and PDX models show significant reduction of tumor size and tumor burden with treatment of MitoTam without effecting body mass. In addition we also found decrease in protein kinases associated with regulation of STAT3 for tumor survival. In addition, nuclear DNA encoded mitochondrial transcription factor A (TFAM), which enhances both transcription and replication of mitochondrial DNA is also shown to be downregulated with treatment, suggesting that MitoTam effectively inhibit TFAM binding to the mitochondrial DNA genes involved in OXPHOS regulation which was further validated by TFAM Chip-seq.

Conclusion: Our results places MitoTam is a promising candidate drug against TNBC and establish mitochondrial STAT3 as its molecular target.

Citation Format: Kanchi MM, Hirpara JL, Sachaphibulkij K, Tan TZ, Dietzel H, Lim LH, Huang RY-J, Pervaiz S, Neuzil J, Kumar AP. Targeting mitochondrial function for the treatment of triple negative breast cancer: Development of a small molecule inhibitor against mitochondrial STAT3 [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 P6-18-20.

Abstract P6-20-09: Pharmacological inhibition of TFF3 enhances chemo-sensitivity and overcomes acquired resistance in breast cancer

Background

Dose-dependent toxicity and acquired chemo-resistance are two major challenges in the use of doxorubicin in breast cancer treatment. Trefoil factor 3 (TFF3) is a secreted ligand that promotes breast cancer progression and predicts poor survival outcome of breast cancer patients. It has also been shown to confer resistance to anti-estrogens and trastuzumab in breast cancer. Here, the role of TFF3 in regulating the sensitivity and acquired resistance to doxorubicin in breast cancer was investigated.

Methods

MCF7, ZR-75-1 and BT474 breast cancer cell lines with siRNA-mediated depletion of TFF3, and doxorubicin-resistant MCF7 cells generated from the pulsatile exposure to doxorubicin, were used as in vitromodels. We have developed a novel non-toxic small molecule inhibitor of TFF3 (AMPC) that binds specifically to cysteine 57 residue of dimeric TFF3 and promotes its dissociation to monomers thereby, inhibiting its dimeric functions such as proliferation and apoptosis. Here, the effects of AMPC in enhancing doxorubicin sensitivity and overcoming acquired doxorubicin resistance in breast cancer cells were also explored.

Results

Consistent with siRNA-mediated depletion of TFF3, pharmacological inhibition of TFF3 by AMPC enhanced doxorubicin-mediated decrease in cell viability, foci formation and 3D growth of the breast cancer cells, suggesting that TFF3 inhibition increased the sensitivity of these cells to doxorubicin treatment. Notably, AMPC combined with doxorubicin in a synergistic manner, enabling doxorubicin dose reduction for the same inhibitory effect. Doxorubicin-induced AKT activation has been reported to antagonize the effects of doxorubicin and promote its resistance in breast cancer. Here, the inhibition of TFF3 by AMPC was shown to reduce AKT activation. Mechanistically, AMPC co-treatment suppressed doxorubicin-induced AKT activation thereby enhancing doxorubicin-induced apoptosis, with an overall up-regulation of pro-apoptotic and down-regulation of anti-apoptotic proteins, as compared to doxorubicin monotherapy. TFF3 also mediated the acquired doxorubicin resistance in MCF7 cells. Elevated expression of TFF3 was observed in the doxorubicin-resistant MCF7 cells as compared to the parental MCF7 cells, while the inhibition of TFF3 by AMPC completely abrogated the resistant phenotype of these cells as shown in the cell viability, foci formation and 3D growth assays. In concordance with the elevated levels of TFF3, doxorubicin-resistant MCF7 cells also exhibited increased activation of AKT with reduced susceptibility to doxorubicin-induced apoptosis as compared to the parental MCF7 cells. Consistently, this was reversed with AMPC co-treatment, which suppressed the elevated levels of activated AKT in the doxorubicin-resistant MCF7 cells, resulting in the re-sensitization of these resistant cells to doxorubicin-induced apoptosis. Similar to that in the parental cells, AMPC also exhibited a synergistic inhibitory effect with doxorubicin in the doxorubicin-resistant MCF7 cells.

Conclusion

The pharmacological inhibition of TFF3 with AMPC is a potential therapeutic approach to reduce the dose-dependent toxicity and to overcome the acquired resistance of doxorubicin in breast cancer.

Citation Format: Poh HM, Chong QY, Chen RM, Pandey V, Salundi B, Kumar AP, Lee SC, Lobie PE. Pharmacological inhibition of TFF3 enhances chemo-sensitivity and overcomes acquired resistance in breast cancer [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 P6-20-09.

Abstract P4-08-03: DEAD-box RNA helicase DP103 as a novel regulator of Wnt/β-catenin signaling pathway and promotes cancer stem cell-like behavior in triple negative breast cancers

Despite recent advances in breast cancer therapeutics, mortality of metastatic triple negative breast cancer (TNBC) subtype remains high; due to their lack of hormone receptors expression for targeted therapy. Aberrant activation of Wnt/β-catenin signaling has been associated with breast cancers; where 40% of total breast cancers have elevated β-catenin levels with increased Wnt activity. Recently, we identified DEAD-box RNA helicase DP103 as a novel prognostic biomarker and metastasis-driving oncogene; highly expressed in TNBC subtype. Interestingly, we found high DP103 expression to be positively correlated with high β-catenin expression in clinical specimens (n=400). This led us to hypothesize a possible role of DP103 in modulating the Wnt/β-catenin pathway in TNBCs. Depletion of DP103 in metastatic TNBC cells decreases Wnt/β-catenin activity and expression of downstream Wnt target genes, while overexpression of DP103 increases Wnt activity. Depletion of DP103 also decreases phosphorylation of LRP6 and several important Wnt modulators required for downstream Wnt activation. Moreover, induction of Wnt/β-catenin signaling in Wnt responsive TNBC cells also significantly increased DP103 expression, indicating a possible positive feedback loop. Both canonical and non-canonical Wnt signaling is known to independently promote stem cell growth in mammospheres. Herein, we will also provide evidence on the role of DP103 in promoting breast cancer stem cell-like properties. Collectively, our data show a novel regulatory role of DP103 in the Wnt/β-catenin signaling pathway and in promoting breast cancer stem cell-like behavior, presenting itself as a potential drug target in TNBC patients.

Citation Format: Cai W, Cheong JK, Edison E, Banerjee A, Tan TZ, Gaboury L, Yousef EM, Thiery JP, Lobie PE, Virshup DM, Yap CT, Kumar AP. DEAD-box RNA helicase DP103 as a novel regulator of Wnt/β-catenin signaling pathway and promotes cancer stem cell-like behavior in triple negative breast cancers. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-08-03.

Gene Microarray Analyses of Daboia russelli russelli Daboiatoxin Treatment of THP-1 Human Macrophages Infected with Burkholderia pseudomallei

Burkholderia pseudomallei is the causative agent of melioidosis and represents a potential bioterrorism threat. In this study, the transcriptomic responses of B. pseudomallei infection of a human macrophage cell model were investigated using whole-genome microarrays. Gene expression profiles were compared between infected THP-1 human monocytic leukemia cells with or without treatment with Daboia russelli russelli daboiatoxin (DRRDbTx) or ceftazidime (antibiotic control). Microarray analyses of infected and treated cells revealed differential upregulation of various inflammatory genes such as interleukin-1 (IL-1), IL-6, tumor necrosis factor-alpha (TNF-α), cyclooxygenase (COX-2), vascular endothelial growth factor (VEGF), chemokine C-X-C motif ligand 4 (CXCL4), transcription factor p65 (NF-kB); and several genes involved in immune and stress responses, cell cycle, and lipid metabolism. Moreover, following DRR-DbTx treatment of infected cells, there was enhanced expression of the tolllike receptor 2 (TLR-2) mediated signaling pathway involved in recognition and initiation of acute inflammatory responses. Importantly, we observed that highly inflammatory cytokine gene responses were similar in infected cells exposed to DRR-DbTx or ceftazidime after 24 h. Additionally, there were increased transcripts associated with cell death by caspase activation that can promote host tissue injury. In summary, the transcriptional responses during B. pseudomallei infection of macrophages highlight a broad range of innate immune mechanisms that are activated within 24 h post-infection. These data provide insights into the transcriptomic kinetics following DRR-DbTx treatment of human macrophages infected with B. pseudomallei.

Negative regulation of signal transducer and activator of transcription-3 signalling cascade by lupeol inhibits growth and induces apoptosis in hepatocellular carcinoma cells

Background:

Constitutive activation of signal transducer and activator of transcription signalling 3 (STAT3) has been linked with survival, proliferation and angiogenesis in a wide variety of malignancies including hepatocellular carcinoma (HCC).

Methods:

We evaluated the effect of lupeol on STAT3 signalling cascade and its regulated functional responses in HCC cells.

Results:

Lupeol suppressed constitutive activation of STAT3 phosphorylation at tyrosine 705 residue effectively in a dose- and time-dependent manner. The phosphorylation of Janus-activated kinases (JAKs) 1 and 2 and Src was also suppressed by lupeol. Pervanadate treatment reversed the downregulation of phospho-STAT3 induced by lupeol, thereby indicating the involvement of a phosphatase. Indeed, we observed that treatment with lupeol increased the protein and mRNA levels of SHP-2, and silencing of SHP-2 abolished the inhibitory effects of lupeol on STAT3 activation. Treatment with lupeol also downregulated the expression of diverse STAT3-regulated genes and decreased the binding of STAT3 to VEGF promoter. Moreover, the proliferation of various HCC cells was significantly suppressed by lupeol, being associated with substantial induction of apoptosis. Depletion of SHP-2 reversed the observed antiproliferative and pro-apoptotic effects of lupeol.

Conclusions:

Lupeol exhibited its potential anticancer effects in HCC through the downregulation of STAT3-induced pro-survival signalling cascade.

Abstract 2954: Novel interaction between FLIP/DAPK: role for RON in androgen-independent prostate cancer

Patients with Hormone refractory metastatic prostate cancer (HRPCA) have a 5-year survival of less than 30%. Therefore, it is imperative that new therapeutic strategies targeting advanced stage prostate cancer (PCA) be developed. 2-Methoxyestradio (2-ME2) is an endogenously produced compound that has been shown to successfully treat PCA. As part of our efforts in understanding its mechanism of action, we discovered that the tyrosine kinase RON (Recepteur ‘Origine Nantais) was a target for inhibition. RON Kinase has been previously shown to be upregulated in murine PCA. RON has also been reported to mediate cell migration, and invasion in various cancers. However, the precise role of RON signaling in prostate carcinogenesis is unclear. Our data revealed that RON is upregulated in HRPCA cell lines and human prostate tumors. Using genetic approaches we found novel, causal association between RON and FLICE-like inhibitory protein, also known as FLIP (a known target of 2-ME2), and an increase in Death Associated Protein Kinase (DAPK1). Interestingly, RON overexpression in early stage PCA cell lines induced the transcriptional activation of the Androgen Receptor (AR) and FLIP. Stimulation of RON with its ligand MSP (macrophage stimulating protein) also yielded heightened promoter activity of AR and its downstream target genes including PSA and FLIP. Functionally, these responses translated to increased cell migration in RON overexpressing cells and loss of this migratory potential with RON silencing. Interestingly, 2-ME2 treatment also reduced the migration of HRPCA cells. Migration in wild-type HRPCA cells is also sensitive to regulation with 2-ME2 treatment. Overall these data suggests that RON kinase is a major player in promoting advanced-stage prostate cancer in part due to its ability to regulate apoptosis through novel FLIP/DAPK1 interaction. Supported by NIH (CA 135451, APK).

Citation Format: Izhar S. Batth, Jingjing Gong, A. Pratap Kumar. Novel interaction between FLIP/DAPK: role for RON in androgen-independent prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2954. doi:10.1158/1538-7445.AM2013-2954

Deciphering the signaling networks underlying simvastatin-induced apoptosis in human cancer cells: evidence for non-canonical activation of RhoA and Rac1 GTPases

Although statins are known to inhibit proliferation and induce death in a number of cancer cell types, the mechanisms through which downregulation of the mevalonate (MVA) pathway activates death signaling remain poorly understood. Here we set out to unravel the signaling networks downstream of the MVA pathway that mediate the death-inducing activity of simvastatin. Consistent with previous reports, exogenously added geranylgeranylpyrophosphate, but not farnesylpyrophosphate, prevented simvastatin's growth-inhibitory effect, thereby suggesting the involvement of geranylgeranylated proteins such as Rho GTPases in the anticancer activity of simvastatin. Indeed, simvastatin treatment led to increased levels of unprenylated Ras homolog gene family, member A (RhoA), Ras-related C3 botulinum toxin substrate 1 (Rac1) and cell division cycle 42 (Cdc42). Intriguingly, instead of inhibiting the functions of Rho GTPases as was expected with loss of prenylation, simvastatin caused a paradoxical increase in the GTP-bound forms of RhoA, Rac1 and Cdc42. Furthermore, simvastatin disrupted the binding of Rho GTPases with the cytosolic inhibitor Rho GDIα, which provides a potential mechanism for GTP loading of the cytosolic Rho GTPases. We also show that the unprenylated RhoA- and Rac1-GTP retained at least part of their functional activities, as evidenced by the increase in intracellular superoxide production and JNK activation in response to simvastatin. Notably, blocking superoxide production attenuated JNK activation as well as cell death induced by simvastatin. Finally, we provide evidence for the involvement of the B-cell lymphoma protein 2 family, Bcl-2-interacting mediator (Bim), in a JNK-dependent manner, in the apoptosis-inducing activity of simvastatin. Taken together, our data highlight the critical role of non-canonical regulation of Rho GTPases and involvement of downstream superoxide-mediated activation of JNK pathway in the anticancer activity of simvastatin, which would have potential clinical implications.

Deformability study of breast cancer cells using microfluidics

Cell deformability is an important biomarker which can be used to distinguish between healthy and diseased cells. In this study, microfluidics is used to probe the biorheological behaviour of breast cancer cells in an attempt to develop a method to distinguish between non-malignant and malignant cells. A microfabricated fluidic channel design consisting of a straight channel and two reservoirs was used to study the biorheological behaviour of benign breast epithelial cells (MCF-10A) and non-metastatic tumor breast cells (MCF-7). Quantitative parameters such as entry time (time taken for the cell to squeeze into the microchannel) and transit velocity (speed of the cell flowing through the microchannel) were defined and measured from these studies. Our results demonstrated that a simple microfluidic device can be used to distinguish the difference in stiffness between benign and cancerous breast cells. This work lays the foundation for the development of potential microfluidic devices which can subsequently be used in the detection of cancer cells.

Oxidative repression of NHE1 gene expression involves iron-mediated caspase activity

The mechanism of Na(+)/H(+) exchanger 1 (NHE1) gene repression upon exposure of cells to non-apoptotic concentrations of hydrogen peroxide (H(2)O(2)) was investigated. We show that continuous presence of H(2)O(2) was not required for inhibition of NHE1 promoter activity. However, the downregulation of NHE1 promoter activity and protein expression was abrogated by the presence of beta mercaptoethanol (betaME) and dithiothreitol. The pan-caspase inhibitor zVAD-fmk also blocked the effect of H(2)O(2) on NHE1 promoter activity and expression, but unlike betaME, caspase inhibition was ineffective in rescuing the early phase of NHE1 repression. Interestingly, the effect of caspase inhibition was observed only after 9 h of exposure to H(2)O(2) and completely restored NHE1 promoter activity by 18-24 h. Using tetrapeptide inhibitors of a variety of caspases and siRNA-mediated gene silencing, caspases 3 and 6 were identified as mediators of H(2)O(2)-induced NHE1 repression, independent of initiator/amplifier caspase activation. Furthermore, incubation of cells with the iron chelator, desferioxamine, not only blocked the activities of caspases 3 and 6, but also affected NHE1 promoter and protein expression in a manner similar to zVAD-fmk. These data show that a mild oxidative stress represses NHE1 promoter activity and expression via an early oxidation phase blocked by reducing agents, and a late phase requiring an iron-dependent increase in caspases 3 and 6 activities.

Chemoprevention of prostate cancer

Prostate cancer is a common malignancy with multiple potential opportunities for cancer prevention. As the genetic basis of this malignancy is further understood, prevention strategies will be developed for individual patients based on specific risk factors and pathways of carcinogenesis. The PCPT has conclusively proven that prostate cancer prevention is possible. The results of the SELECT should be available within several years. An enormous challenge for the medical community will be the development of an efficient strategy to evaluate the substantial number of dietary, behavioral, and pharmacologic prevention opportunities. Ultimately, the goal of prostate can-cer prevention is to (1) identify men who are destined to develop clinically significant prostate cancer, and (2) provide individualized agents to prevent disease development.

2-methoxyestradiol blocks cell-cycle progression at G(2)/M phase and inhibits growth of human prostate cancer cells

2-Methoxyestradiol (2-ME), an endogenous metabolite of 17beta-estradiol, is present in human blood and urine. Here we show for the first time that 2-ME significantly inhibited the growth of normal prostate epithelial cells and androgen-dependent LNCaP and androgen-independent DU145 prostate cancer cells. This growth inhibition was accompanied by a twofold increase in the G(2)/M population, with a concomitant decrease in the G(1) population, as shown by cell-cycle analysis. 2-ME treatment affected the cell-cycle progression of prostate cancer cells specifically by blocking cells in the G(2) phase. Immunoblot analysis of the key cell-cycle regulatory proteins in the G(2)/M phase showed a 14-fold increase in the expression of p21 and an eightfold increase in the expression of p34 cell division cycle 2 (cdc2). We also found an accumulation of phosphorylated cdc2 after 2-ME treatment. Furthermore, Wee 1 kinase was detectable after 2-ME treatment. 2-ME treatment also led to an increase in the activity of caspase-3, followed by apoptosis, as shown by terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate-biotin nick end-labeling and fluorescein isothiocyanate-poly(ADP-ribose) polymerase assay. Estrogen receptor levels did not change after treatment with 2-ME. Examination of the signaling pathways that mediate 2-ME-induced apoptosis showed reduction in the level of p53 expression and its DNA-binding activity. Given the fact that p53 mutations are common in patients with metastatic prostate cancer, our finding that 2-ME-mediated growth inhibition of human prostate cancer cells occurred in a p53-independent manner has considerable clinical significance. These findings, combined with the limited toxicity of 2-ME, may have significant implications for alternative treatment of advanced prostate cancer.

A negative regulatory element within the proximal promoter region of the rat ornithine decarboxylase gene

A putative Ets site with a core of GGAA located at nt -88 to -85 of the rat ornithine decarboxylase (ODC) gene was characterized by site-directed mutagenesis and transient expression assays. Mutation of this site, when in pODClux2m, which contains a cluster of four Sp1-binding sites, resulted in a 2.6-fold increase in basal promoter activity in untreated cells, whereas the ratio of activity in 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated cells relative to the ratio in untreated cells (the induction ratio) remained largely unchanged. However, when the mutation was in pODClux168, which contains only a single Sp1-binding site (GC box V), it caused little alteration to either basal promoter activity or TPA induction ratio. A protein of 55-60 kDa was found specifically bound to this site, as shown by ultraviolet cross-linking assay. In competition assay and methylation interference assay, this protein was shown to occupy the GGAA core, although it showed no antigenic relation to c-Ets-1 in an supershift assay. We suggest that this protein binds specifically to the GGAA core and functions to inhibit activation of the ODC promoter by distal elements, including the upstream Sp1 sites.

Regulation of BRCA1 expression by the Rb-E2F pathway

Inheritance of a mutant allele of the breast cancer susceptibility gene BRCA1 confers increased risk of developing breast and ovarian cancers. Likewise, inheritance of a mutant allele of the retinoblastoma susceptibility gene (RB1) results in the development of retinoblastoma and/or osteosarcoma, and both alleles are often mutated or inactivated in sporadic forms of these and other cancers. We now demonstrate that the product of the RB1 gene, Rb, regulates the expression of the murine Brca1 and human BRCA1 genes through its ability to modulate E2F transcriptional activity. The Brca1 gene is identified as an in vivo target of E2F1 in a transgenic mouse model. The Brca1 promoter contains E2F DNA-binding sites that mediate transcriptional activation by E2F1 and repression by Rb. Moreover, ectopic expression of cyclin D1 and Cdk4 can stimulate the Brca1 promoter in an E2F-dependent manner, and this is inhibited by coexpression of the p16(INK4a) cyclin-dependent kinase inhibitor. The human BRCA1 promoter also contains a conserved E2F site and is similarly regulated by E2F1 and Rb. This functional link between the BRCA1 and Rb tumor suppressors may provide insight into the mechanism by which BRCA1 inactivation contributes to cancer development.

Enhanced Sp1 DNA-binding activity in murine keratinocyte cell lines and epidermal tumors

Altered regulation of ornithine decarboxylase (ODC) is frequently observed in epidermal tumors. We have shown that the transcription factor Sp1 is one of the regulators of ODC expression and that Sp3 antagonizes this Sp1-mediated activation of ODC expression. These results led us to examine the levels and binding activity of Sp1 and Sp3 in nuclear extracts prepared from cultured murine keratinocytes, transformed keratinocyte cell lines and epidermal tumors. Here we show that the Sp1 DNA-binding activity is higher in established keratinocyte cell line extracts than in primary keratinocyte extracts. Sp1 message levels and Sp1 DNA-binding activity was found to be low in 20-week papillomas and high in squamous cell carcinomas. These results suggest that increased levels of Sp1 and enhanced Sp1 DNA binding activity are correlated with epidermal tumor progression. Based on these results, we propose that increased Sp1 DNA binding may augment the proliferative capacity of tumor cells through overexpression of Sp1-responsive genes, possibly including ODC.

Serum responsive gene expression mediated by Sp1

We compared the Sp1 binding activity of Rat2 fibroblasts in nuclear extracts prepared from quiescent cells and cells stimulated with 20% serum. Increased DNA-binding activity was observed in extracts from serum-stimulated cells when an Sp1 oligonucleotide was used as radiolabeled probe in electrophoretic mobility shift assays. This increase in Sp1 DNA-binding activity is not due to changes in the amount of Sp1 in the nucleus as shown by immunoblot analysis. The transcriptional activity of a reporter construct containing six Sp1 sites upstream of a minimal adenovirus promoter or an Sp1-dependent promoter such as ornithine decarboxylase (ODC) containing Sp1 sites was enhanced following serum stimulation in transient transfection assays. Dephosphorylation of the nuclear extracts with potato acid phosphatase abolished the Sp1 DNA-binding activity, demonstrating a possible correlation between phosphorylation of Sp1 and DNA-binding activity. These results implicate a potential role for Sp1 in mediating signal transduction pathways in response to mitogenic signals.

Vibrational analysis of substituted benzonitriles. II. Transferability of force constants--the case of dicyanobenzenes

A zero-order normal coordinate analysis was made for p-, m- and o-dicyanobenzenes and their deuterated isomers by transferring the force constants from Part I. The observed and calculated frequencies agree with an average error of 18.7 cm-1, demonstrating the transferability of the force field obtained in Part 1. On the basis of the calculated potential energy distributions and eigen vectors, several assignments suggested by earlier workers have been revised.

Vibrational analysis of substituted benzonitriles. I. Vibrational spectra, normal coordinate analysis and transferability of force constants of monohalogenated benzonitriles

The Raman and Fourier--transform infrared spectra of p- and o-fluorobenzonitriles, p-, m- and o-chlorobenzonitriles and p-, m- and o-bromobenzonitriles were measured. Raman polarisation measurements were made wherever possible. A normal coordinate analysis was carried out for both the in-plane and out-of-plane vibrations of these molecules along with m-fluorobenzonitrile using a 71-parameter modified valence force field. An overlay least-squares-technique was employed to refine the force constants using 269 frequencies of nine molecules. The reliability of the force constants so obtained was tested by making a zero-order calculation for both in-plane and out-of-plane vibrations of p-, m- o-dicyanobenzenes and their deuterated isomers; 2-chloro, 6-fluorobenzonitrile, s-trichlorobenzonitrile, p- and m-methoxybenzonitriles and m-nitrobenzonitrile; and for the in-plane vibrations of p-, m-, o-aminobenzonitrile and 2-chloro, 5-aminobenzonitrile. Unambiguous vibrational assignments of all the fundamentals were made using the potential energy distributions and eigenvectors.

Vibrational analysis of substituted benzonitriles. IV. Transferability of force constants--the case of some aminobenzonitriles

A zero-order normal coordinate analysis was made for the n-plane vibrations of p-, m- and o-aminobenzonitrile and 2-chloro, 5-aminobenzonitrile by transferring the force constants from our earlier work. The observed and calculated frequencies agree with an average error of 19.3 cm-1. Unambiguous vibrational assignments of in-plane fundamentals of the four molecules have been made, and several assignments suggested by earlier workers have been revised.

Vibrational analysis of substituted benzonitriles. III. Transferability of force constants--the case of some halogeno-, methoxy- and nitro-benzonitriles

A zero-order normal coordinate analysis of both the in-plane and out-of-plane vibrations was made for 2-chloro, 6-fluorobenzonitrile, s-trichlorobenzonitrile, p- and m-methoxybenzonitriles and m-nitrobenzonitrile, transferring the force constants from our earlier work. The observed and calculated frequencies agree with an average error of 16.8 cm-1, demonstrating the transferability of the force constants obtained previously. On the basis of calculated potential energy distributions and eigenvectors, several assignments suggested by earlier workers have been revised.

Transcription factor Sp3 antagonizes activation of the ornithine decarboxylase promoter by Sp1

Ornithine decarboxylase (ODC) expression is important for proliferation and is elevated in many tumor cells. We previously showed that Sp1 is a major positive regulator of ODC transcription. In this paper we have investigated transcriptional regulation of rat ODC by the closely related factor Sp3. While over-expression of Sp1 caused a dramatic activation of the ODC promoter, over-expression of Sp3 caused little or no activation in either Drosophila SL2 cells (lacking endogenous Sp1 or Sp3) or in H35 rat hepatoma cells. Furthermore, co-transfection studies demonstrated that Sp3 abolished trans -activation of the ODC promoter by Sp1. DNase I footprint studies and electrophoretic mobility shift assays demonstrated that both recombinant Sp1 and Sp3 bind specifically to several sites within the ODC promoter also protected by nuclear extracts, including overlapping GC and CT motifs located between -116 and -104. This CT element is a site of negative ODC regulation. Mutation of either element reduced binding, but mutation of both sites was required to eliminate binding of either Sp1 or Sp3. These results demonstrate that ODC is positively regulated by Sp1 and negatively regulated by Sp3, suggesting that the ratio of these transcription factors may be an important determinant of ODC expression during development or transformation.

Disruption of transcription in vitro and gene expression in vivo by DNA adducts derived from a benzo[a]pyrene diol epoxide located in heterologous sequences

Previous studies indicated a high affinity of the transcription factor Sp1 for DNA adducts derived from benzo[a]pyrene diol epoxide (BPDE) in sequences that are not normal binding sites for Sp1. We tested for functional effects of this phenomenon in three systems in which transcription is Sp1-dependent. In an in vitro, Sp1-dependent transcription system addition of heterologous plasmid DNA containing BPDE adducts abolished production of a specific run-off transcript. This inhibition was not seen with unmodified plasmid DNA, and could be overcome by addition of purified Sp1 protein. In SL2 insect cells, high-level expression of an Sp1-dependent reporter gene, which was dependent on co-transfection of an Sp1 expression vector, was inhibited >95% by co-transfection of heterologous DNA containing BPDE adducts. This inhibition could be partially overcome by increasing the amount of the Sp1 expression vector in the transfections. In human C33A cells, expression of a transfected reporter gene driven by a GC box containing fragment of the human E2F1 promoter was enhanced by co-transfection of an Sp1 expression plasmid. Expression was inhibited 3-6-fold by co-transfection of heterologous DNA containing BPDE-DNA adducts. A similar inhibition was seen in human SAOS-2 cells, which lack functional p53 protein. These data are consistent with functionally significant sequestration of the Sp1 transcription factor by BPDE-DNA adducts in all three systems. Altered availability of transcription factors such as Sp1 in carcinogen-treated cells may disrupt patterns of gene expression.

Characterization of novel phorbol ester- and serum-responsive sequences of the rat ornithine decarboxylase gene promoter

Ornithine decarboxylase (ODC), the key regulatory enzyme in mammalian polyamine biosynthesis, is rapidly induced by mitogens and tumor promoters. We used transient expression assays and DNA-protein binding studies to examine the regulation of ODC promoter activity by phorbol esters and serum growth factors. A fragment of the ODC 5' flanking region (nt-1156 to +13) was sufficient to confer 12-O-tetradecanoylphorbol-13-acetate (TPA)-responsive expression to a luciferase reporter gene when transfected into H35 cells. However, induction by TPA was not observed in Rat2 fibroblasts, although refeeding of serum-starved Rat2 cells with fresh serum-containing medium rapidly induced a fivefold to sixfold increase in ODC promoter activity, maximal about 8 h after refeeding. Deletion analysis demonstrated that several sequences contributed to basal ODC promoter activity but that nt -92 to +13 was sufficient for induction by TPA or by serum. This sequence lacked canonical TPA-responsive elements, and an activator protein-1 (AP-1) consensus oligonucleotide failed to compete effectively for proteins binding to this region. Two of four protein complexes observed by gel-shift analysis of nt -92 to +13 were competitively inhibited by wild-type but not mutant oligonucleotides encompassing a variant cyclic AMP-response element (CRE) (ODC nt -50 to -42); however, a consensus CRE did not compete. Mutagenesis of this site demonstrated that it contributes to basal expression of the ODC promoter but not to TPA or serum responsiveness. Thus, we conclude that the proximal ODC promoter (nt -92 to +13) responds to TPA and serum stimulation in a cell-type-specific manner that is not mediated by canonical AP-1 elements.

Chest wall resection for Ewing's sarcoma of the rib: an unnecessary procedure. 1988. Updated in 1995

Approximately 10% of all cases of Ewing's sarcoma arise from a rib. Conventional management has included chest wall resection (3 or more ribs) and radiation therapy. These forms of therapy have led to complications such as scoliosis and local deformity. The addition of radiation therapy can result in damage to the lung and adjacent viscera and also potentiate pulmonary restrictive disease. Between 1971 and 1978, 9 patients were treated with surgery, radiation therapy, and combination chemotherapy (three- or four-drug regimen). Only 2 patients (22%) survive. Since 1979, 14 patients were entered into a new protocol consisting of sequential induction chemotherapy, followed by delayed surgical resection whenever feasible. Three patients had complete resection of their primary lesion at onset. Initially, 7 patients had either biopsy (N = 4) or incomplete chest wall resection N = 3). All 4 patients with biopsy only at diagnosis had excellent responses to induction chemotherapy, allowing delayed resection of the involved rib without chest wall resection. Overall, 12 of 14 patients (86%) treated since 1979 survive, with only 2 receiving radiation therapy for residual disease in the primary rib site.

Aspartate transcarbamoylase genes of Pseudomonas putida: requirement for an inactive dihydroorotase for assembly into the dodecameric holoenzyme

The nucleotide sequences of the genes encoding the enzyme aspartate transcarbamoylase (ATCase) from Pseudomonas putida have been determined. Our results confirm that the P. putida ATCase is a dodecameric protein composed of two types of polypeptide chains translated coordinately from overlapping genes. The P. putida ATCase does not possess dissociable regulatory and catalytic functions but instead apparently contains the regulatory nucleotide binding site within a unique N-terminal extension of the pyrB-encoded subunit. The first gene, pyrB, is 1,005 bp long and encodes the 334-amino-acid, 36.4-kDa catalytic subunit of the enzyme. The second gene is 1,275 bp long and encodes a 424-residue polypeptide which bears significant homology to dihydroorotase (DHOase) from other organisms. Despite the homology of the overlapping gene to known DHOases, this 44.2-kDa polypeptide is not considered to be the functional product of the pyrC gene in P. putida, as DHOase activity is distinct from the ATCase complex. Moreover, the 44.2-kDa polypeptide lacks specific histidyl residues thought to be critical for DHOase enzymatic function. The pyrC-like gene (henceforth designated pyrC') does not complement Escherichia coli pyrC auxotrophs, while the cloned pyrB gene does complement pyrB auxotrophs. The proposed function for the vestigial DHOase is to maintain ATCase activity by conserving the dodecameric assembly of the native enzyme. This unique assembly of six active pyrB polypeptides coupled with six inactive pyrC' polypeptides has not been seen previously for ATCase but is reminiscent of the fused trifunctional CAD enzyme of eukaryotes.

Regulation of rat ornithine decarboxylase promoter activity by binding of transcription factor Sp1

Ornithine decarboxylase (ODC) is the rate-limiting enzyme of polyamine biosynthesis. We investigated the transcriptional regulation of the rat ODC gene using transient expression assays. The 5'-flanking region (-1156 to +13) of the ODC gene was sufficient to mediate strong basal expression of a luciferase reporter. Sequences between -345 and -93 contributed to basal promoter activity. This region, containing five potential Sp1 binding sites, was analyzed by electrophoretic mobility shift assays. Three specific DNA-protein complexes were identified using H35 nuclear extracts and the -345/-93 ODC probe. Binding to all three was eliminated by competition with an oligonucleotide containing an Sp1 binding site, but not by a mutant Sp1 oligonucleotide. Preincubation with an antibody against Sp1 supershifted complexes associated with one or more of Sp1 binding sites 1-4 as well as with site 5. DNase I footprinting revealed two protected regions: PR-I (-92 to -130) and PR-II (-304 to -332). PR-I contains a putative binding site for Sp1 that was protected by recombinant Sp1 protein. Transfection studies in Schneider SL2 cells demonstrated that the ODC promoter is transactivated up to 350-fold by Sp1 and that this transactivation is dependent on the presence of Sp1 binding sites 1-4. Thus, although the ODC promoter binds multiple nuclear proteins, Sp1 or a related protein appears to be a critical determinant of ODC transcription, possibly through cooperative interactions between Sp1 and additional transcription factors.

Acute appendicitis in children with leukemia and other malignancies: still a diagnostic dilemma

Of 6,099 children treated for malignancy, 16 (ages 3.5 to 18 years) developed acute appendicitis between 1962 and 1989. Fourteen had leukemia (ALL 10, AML 4). One each had rhabdomyosarcoma and Ewing's sarcoma. Active malignancy at diagnosis was noted in 10, 4 of whom had severe neutropenia (absolute neutrophil count less than 500/mm3). Of all the leukemics (2,794/6,099), abdominal pain during induction was a frequent complaint. The incidence of appendicitis, however, was low (0.5%). Nine of the 16 patients presented classically, facilitating prompt diagnosis and treatment. Six diagnoses were delayed. Three of these patients presented atypically with vague, nonlocalized pain, abdominal distention, lack of abdominal guarding, fever, dehydration, diarrhea, and unusual symptoms such as upper gastrointestinal bleeding. In each of these 6 patients the appendix was ruptured. Delays led to complications and deaths. Three patients required perioperative transfusions to treat excessive bleeding and two patients with ruptured appendicitis developed wound abscesses. Two patients died; in one, ruptured appendix was diagnosed only at autopsy. The other patient died of uncontrolled sepsis. Typhlitis occurring during induction chemotherapy may present similarly and is the main differential diagnosis. Typhlitis will usually improve with medical treatment alone. Nausea and vomiting (13/16), right lower quadrant pain (13/16), guarding (14/16), tachycardia (12/16), fever (10/16), and rebound tenderness (10/16) were the most frequent signs and symptoms of appendicitis. Persistent localized abdominal pain and guarding, lack of improvement with medical treatment, clinical deterioration, and the development of a mass were our indications for laparotomy. Despite major improvements in therapy, there is still a 37.5% error rate in our ability to accurately diagnose appendicitis in pediatric cancer patients.

Wilms' tumor: reduced-dose radiotherapy in advanced-stage Wilms' tumor with favorable histology

Fifty-two children with favorable histology Wilms' tumor who had residual abdominal disease (Surgical Stages III and IV) were treated from 1979 to 1988 on a protocol designed to assess the effectiveness of reduced radiation doses. All patients received three-agent chemotherapy, beginning within 1 week after surgery. To permit assessment of disease response to initial chemotherapy, radiation therapy was delayed for a median of 28 days after surgery (range, 14-71 days). Total doses of abdominal radiation were limited to 12 Gy, given as 150 cGy daily fractions; 18 patients with Stage IV disease received 12 Gy bilateral pulmonary irradiation. Two year disease-free survival was 85% and 71% for Stage III and IV, respectively (p = .24). Abdominal relapses occurred in 3 cases (5.7%). The interval between surgery and initiation of irradiation was not related to disease-free survival. Of several patient and disease-related factors analyzed, only patient age was related to outcome. Disease-free survival was 100% at 3 years for children under the age of 3 versus 78% for children greater than age 3 (p = .05). Reduced-dose abdominal radiotherapy in conjunction with multi-agent chemotherapy and surgery provided excellent disease control with minimal toxicity in advanced-stage, favorable histology Wilms' tumor.

Malignant melanoma in children: its management and prognosis

Malignant melanoma is rare in children, representing 1% to 3% of all pediatric malignancies. Thirty-three children with malignant melanoma were treated at St Jude Children's Research Hospital from 1967 to 1988. Their ages ranged from 1 day to 20 years (median, 12 years); 23 were boys and 10 were girls; and 5 of the 33 (15%) were black. Four of the 33 children had been treated for a previous malignancy. In 3, melanoma arose within a bathing trunk nevus. The extremity was the most common site (13), followed by the trunk (9), head and neck (7), and perineum (1). In 3 patients the primary site could not be determined. Upon initial presentation to St Jude Hospital, 17 patients had localized disease (stage I), 10 had regional node involvement (stage II), and the remaining 6 patients had disseminated disease (stage III). Using both Clark's level and Breslow's thickness as indicators, the incidence, initial stage, prognosis, and survival were compared. By Clark's level, 7 patients, (6 of whom were stage I) were level II or III, and 22 patients were level IV or V. Though 16 of 22 level IV and V patients were initially stage I, 10 patients eventually developed progressive disease. Similar observations were noted when using Breslow's thickness to evaluate the primary. In 5 of 27 evaluable patients, Breslow's depth of invasion was less than 1.5 mm. All 5 of these patients were diagnosed with stage I disease and have not shown progressive disease.

Adjuvant chemotherapy for osteosarcoma of the extremity. Long-term results of two consecutive prospective protocol studies

Seventy-six patients with classic high-grade osteosarcoma of an extremity received adjuvant chemotherapy by two protocols, initiated in 1972 and 1977, respectively, after appropriate amputations. Chemotherapy consisted of high-dose methotrexate, doxorubicin, and cyclophosphamide. Dose intensity of high-dose methotrexate and doxorubicin was greater for the patients treated with the protocol initiated in 1977. The proportion of long-term disease-free survivors on the two protocols are 46% and 56%. A better outcome (P = 0.042) was seen for the latter group, which received more intensive chemotherapy. Overall, metastases developed in 35 patients; in 19 who were receiving chemotherapy and in 16 after chemotherapy. The outcome for these two protocols, compared with two control groups that were given no chemotherapy or ineffective chemotherapy (biweekly vincristine and cyclophosphamide), confirms the results of controlled studies that showed an advantage of adjuvant chemotherapy after amputation for osteosarcoma.

Management and prognosis of head and neck sarcomas

Between 1962 and 1988, a total of 104 patients with head and neck rhabdomyosarcoma (RMS) and 17 patients with nonrhabdomyosarcoma (NRMS) were evaluated and treated at St. Jude Children's Research Hospital. All parameningeal sites (middle ear, orbit, or nasopharynx) were excluded from further analysis; thus, 50 patients represent the cohort of head and neck sarcomas for this review. Survival was good in this group of patients, 28 of 50 being alive and disease-free at last follow-up. Twenty of the 38 patients with RMS were alive and disease-free. Similarly, 8 of the 12 patients with NRMS were disease-free at a median follow-up of 5 years. However, the site and size of the primary tumor impacted on the extent of the initial resection and further treatment in addition to surgery. Although the treatment policy evolved over time to a stage-specific strategy for treatment modalities, the data suggest that surgery alone may be sufficient initial therapy for a subset of patients. For patients in whom complete resection is not achieved, the addition of radiotherapy and chemotherapy may result in improved survival.

Two decades of experience with testicular tumors in children at St Jude Children's Research Hospital

From 1968 to 1988, 24 children and adolescents with malignant testicular tumors were treated at St Jude Children's Research Hospital. Pure yolk sac tumors (YST) were present in 13 cases; 11 patients had other types of nonseminomatous malignant germ cell tumors. Children with localized and totally resectable disease (stage I) were treated by orchiectomy alone; all others also received chemotherapy. Five of ten patients treated before the implementation of a multiagent chemotherapy protocol in 1979 have died. By contrast, all of the 14 patients treated on this protocol are alive. The improved survival during the past decade is attributable to better diagnostic imaging techniques, the availability of serum tumor markers to monitor disease activity, and more effective chemotherapy. Orchiectomy alone is sufficient treatment for patients with clinical stage I disease who show appropriate reductions in tumor marker levels after surgery. Modern platinum-based chemotherapy provides disease control in patients with higher stage disease.

Teratoid Wilms' tumor: the St Jude experience

The term "teratoid" Wilms' tumor has been used recently to describe an unusual type of tumor in which, although classic nephroblastoma tissue is present, there is a significant diversity of cell types and tissues present. Examination of tissue samples from 290 patients treated at St Jude Children's Research Hospital from 1964 to 1987 disclosed that three children had teratoid Wilms' tumor. All three children had renal tumors and two of them presented with bilateral pyeloureteral obstruction, uremia, and hypertension. When compared with classic nephroblastoma, two of the children with teratoid elements responded poorly to chemotherapy and irradiation, although no metastatic disease was identified. One child died with sepsis and renal failure; the other two are surviving disease-free for 7 1/2 years and 26+ months since diagnosis. Because of the tendency for bilateral involvement, ureteral obstruction, and uremia, and their relative resistance to chemotherapy and irradiation, surgery is the principal form of therapy for patients with these tumors.

Reduced therapy for Wilms' tumor: analysis of treatment results from a single institution

From 1968 to 1986, 192 patients from 0 to 17 years of age were enrolled in three consecutive protocol-controlled studies of Wilms' tumor at St Jude Children's Research Hospital. Tumors were completely excised at the time of diagnosis whenever possible, and patients were subsequently treated with chemotherapy and radiotherapy according to the initial extent of disease. All patients received dactinomycin and vincristine, with doxorubicin added to the regimens in studies 2 and 3. Chemotherapy was extended to 18 months in study 2 (n = 53), but was limited to 12 months for most patients in study 3 (n = 107). In the third study, radiation was eliminated altogether for patients with stage I or II tumors and was reduced to 12 Gy for those with more advanced disease. Intensification of chemotherapy in study 2 improved the 5-year relapse-free survival rate over that in study 1 (82% v 52%), but the accompanying increase in toxicity was considered unacceptable. Comparison of 2-year relapse-free survival rates in studies 2 and 3 indicated that the reduction of therapy in the latter trial did not jeopardize disease control: 88% v 86% for patients with stage II or III disease, favorable histology; 75% v 57% for the same stages, unfavorable histology; and 57% v 61% for stage IV patients. At least 80% of all patients enrolled in study 3 will be long-term survivors. We conclude that rescheduling of effective antitumor drugs and eliminating or reducing radiotherapy are feasible alternatives in the treatment of Wilms' tumor with favorable histologic features.

Chest wall resection for Ewing's sarcoma of the rib: an unnecessary procedure

Approximately 10% of all cases of Ewing's sarcoma arise from a rib. Conventional management has included chest wall resection (3 or more ribs) and radiation therapy. These forms of therapy have led to complications such as scoliosis and local deformity. The addition of radiation therapy can result in damage to the lung and adjacent viscera and also potentiate pulmonary restrictive disease. Between 1971 and 1978, 9 patients were treated with surgery, radiation therapy, and combination chemotherapy (three- or four-drug regimen). Only 2 patients (22%) survive. Since 1979, 14 patients were entered into a new protocol consisting of sequential induction chemotherapy, followed by delayed surgical resection whenever feasible. Three patients had complete resection of their primary lesion at onset. Initially, 7 patients had either biopsy (N = 4) or incomplete chest wall resection N = 3). All 4 patients with biopsy only at diagnosis had excellent responses to induction chemotherapy, allowing delayed resection of the involved rib without chest wall resection. Overall, 12 of 14 patients (86%) treated since 1979 survive, with only 2 receiving radiation therapy for residual disease in the primary rib site.

Thoracotomy for pulmonary metastatic osteosarcoma. An analysis of prognostic indicators of survival

Removal of pulmonary metastases of osteosarcoma by thoracotomy is an accepted treatment; however, few investigators have analyzed the value of various prognostic factors in estimating survival. A review of all patients undergoing thoracotomy for recurrent osteosarcoma with pulmonary metastases treated at St. Jude Children's Research Hospital is reported. Since 1968, two thirds (39/59) of all patients who developed pulmonary metastases have had a total of 66 thoracotomies. Nine patients are alive with no evidence of disease, and six additional patients are alive with disease. Analyzed in 39 evaluable patients, the prognostic factors that correlate with survival by univariate analysis are: sex, number of nodules detected radiographically and resected, completeness of resection, and tumor location (bilateral versus unilateral). By Cox regression analysis, only sex and the number of nodules detected either radiographically or during surgery, and resected, had statistically significant correlation with survival. Thoracotomy is curative for some patients with pulmonary metastatic osteosarcoma and Prognostic factors predictive for survival are defined.

CARBON NUTRITION AND THE REGULATION OF UPTAKE HYDROGENASE ACTIVITY IN FREE-LIVING AND SYMBIOTIC ANABAENA CYCADEAE

Anabaena cycadeae was grown with N₂ as nitrogen source, either photoautotrophically in light or with glucose as carbon source in darkness. The rate of growth was much slower in darkness but the heterocyst frequency was much the same; nitrogenase activity (on a chlorophyll basis) was about half that of light-grown cells. Light-grown organisms contained uptake hydrogenase activity but dark-grown organisms did not. The addition of glucose to light-grown organisms was followed by the disappearance of uptake hydrogenase activity over the following 48 hours and the disappearance was independent of light. Heterocyst frequency and nitrogenase activity were much less affected by glucose addition. A. cycadeae growing symbiotically in cycad roots had much higher heterocyst frequency and nitrogenase activity than the free-living form but no detectable uptake hydrogenase activity. It is suggested that the rate of supply of carbohydrate to the heterocyst controls the development of uptake hydrogenase activity and that the absence of this activity in the symbiotic cyanobacteria indicates that the organisms in the cycad roots have an ample supply of carbohydrate.

Treatment of childhood rhabdomyosarcoma at St. Jude Children's Research Hospital, 1962--78

Between March 1962 and December 1978, 153 children with rhabdomyosarcoma (RMS) received treatment at St. Jude Children's Research Hospital. As of January 1979, 62 of these patients were still alive. Between 1962 and 1968, 20 patients were not treated by protocol, and, between 1968 and 1979, another 13 have been registered as "nonprotocol"; 6 of these 33 patients survive. Since 1968, 120 patients received treatment by 3 stage-related, multiple-modality programs. In the first protocol, chemotherapy consisted of vincristine, cyclophosphamide, and dactinomycin; 14 of 34 patients have survived after 6 to more than 10 years. In the second treatment program, which used adriamycin in addition to the 3 drugs cited above, 20 of 56 subjects remain free of disease after more than 2 to 5.5 years; toxicity of the multiple agents given in combination with radiotherapy proved intolerable and led to a modified 4-agent protocol for patients admitted since early 1977. Of 30 in this latter group, 22 are alive. Forty of 44 patients who remained free of RMS for more than 2 years continue to survive.

Retroperitoneal rhabdomyosarcoma in children. Results of multimodality therapy

The clinical course of 18 consecutive children treated for primary retroperitoneal rhabdomyosarcoma was reviewed. At diagnosis, 8 patients had regional unresected tumor and 10 patients had disseminated tumor, including 3 patients with documented bone marrow infiltration by tumor. Following combined modality therapy, 14 of 18 patients achieved a greater than 50% tumor response (11 complete and 3 partial responses); 4 patients failed to respond and died of progressive disease within eight months of diagnosis. Among the 14 patients responding, 7 patients had subsequent reextension of active tumor three to 16 months (median, 9 months) following the onset of therapy. Three of the 7 remaining patients died of treatment complications, 2 of intestinal obstruction and 1 of disseminated histoplasmosis, within the first year of therapy and at post-mortem examination had no demonstrable tumor. Four patients are alive and free of active tumor for 10+, 10+, 32+ and 33+ months from diagnosis. Treatment complications have included hematopoietic depression, mucositis, enteritis, intestinal obstruction, excessive weight loss, malnutrition, and life-threatening infection. These results illustrate limitations in current combined modality therapy of retroperitoneal rhabdomyosarcoma and the necessity for future treatment modifications to both reduce morbidity and to improve survival.