Cancer metastasis: experimental approaches, theoretical concepts, and impacts for treatment strategies

Reducing the Risk of Needle Tract Seeding or Tumor Cell Dissemination during Needle Biopsy Procedures

PURPOSE

Many women fear that breast needle biopsies increase the risk of cancer spread. The purpose of this review article is to discuss the breast cancer literature regarding the risk of needle-biopsy-induced cancer cell displacement and its impact on local and regional recurrence and breast cancer survival.

METHODS

A literature review is performed to discuss the risks and mitigation of needle-biopsy-induced cancer cell displacement.

RESULTS

Needle-biopsy-induced cancer cell displacement is a common event. The risk is influenced by the biopsy technique and the breast cancer type. Evidence suggests that the risk of needle-biopsy-induced cancer cell displacement may potentially increase the odds of local recurrence but has no impact on regional recurrence and long-term survival.

CONCLUSIONS

Technical modifications of needle biopsy procedures can reduce the risk of breast needle-biopsy-induced cancer cell displacement and potentially reduce the risk of local recurrence, especially in patients for whom whole breast radiation is to be omitted.

Increased Circulating Epithelial Tumor Cells (CETC/CTC) over the Course of Adjuvant Radiotherapy Is a Predictor of Less Favorable Outcome in Patients with Early-Stage Breast Cancer

BACKGROUND

Adjuvant radiotherapy (RT) is an integral component of a multidisciplinary treatment strategy for early-stage breast cancer. It significantly reduces the incidence of loco-regional recurrence but also of distant events. Distant events are due to tumor cells disseminated from the primary tumor into lymphatic fluid or blood, circulating epithelial tumor cells (CETC/CTC), which can reach distant tissues and regrow into metastases. The purpose of this study is to determine changes in the number of CETC/CTC in the course of adjuvant RT, and to evaluate whether they are correlated to local recurrence and distant metastases in breast cancer patients.

METHODS

Blood from 165 patients irradiated between 2002 and 2012 was analyzed 0-6 weeks prior to and 0-6 weeks after RT using the maintrac® method, and patients were followed over a median period of 8.97 (1.16-19.09) years.

RESULTS

Patients with an increase in CETC/CTC numbers over the course of adjuvant RT had a significantly worse disease-free survival (p = 0.004) than patients with stable or decreasing CETC/CTC numbers. CETC/CTC behavior was the most important factor in predicting subsequent relapse-free survival. In particular, patients who had received neoadjuvant chemotherapy were disproportionately more likely to develop metastases when cell counts increased over the course of RT (p = 0.003; hazard ratio 4.886).

CONCLUSIONS

Using the maintrac® method, CETC/CTC were detected in almost all breast cancer patients after surgery. The increase in CETC/CTC numbers over the course of RT represents a potential predictive biomarker to judge relative risk/benefit in patients with early breast cancer. The results of this study highlight the need for prospective clinical trials on CETC/CTC status as a predictive criterion and for individualization of treatment.

CLINICAL TRIAL REGISTRATION

The trial is registered (2 May 2019) at trials.gov under NCT03935802.

Efecto bimodal de la ciclofosfamida en la terapia antineoplásica

La Ciclofosfamida (Cy) es el agente alquilante más utilizado en el tratamento quimioterápico de diversas neoplasias humanas; habitualmente se la administra em combinación con otros citostáticos para lograr una mayor eficacia terapêutica. La mayoría de los protoeolos clínicos la emplean en dosis altas y suministrada en repetidas ocaciones a lo largo del tratamento antineoplásico, con Ias ya conocidas acciones colaterales, entre ellas la inmunodepresión. Sin embargo, en diferentes modelos experimentales en animales portadores de un tumor, la administración de uma dosis única y relativamente baja en un determinado momento de la respuesta inmune antitumoral, produce inmunopotenciación, a través de una inhibieión selectiva sobre los linfocitos T supresores. Posteriormente se demostró un efecto interesante y novedoso de éstas dosis bajas de Cy: su acción preferencial sobre células tumorales com fenotipo metastásico (probablemente debido a una inmunomodulación selectiva sobre dichas subpoblaciones celulares), ya que se observo una inhibieión total en la formación de Ias metástasis sin afectar el desarrollo dei tumor primário. Estos resultados senalan el efecto bimodal de la Cy sobre el sistema inmune dei huésped cuando se la utiliza en el tratamiento antineoplásico em diferentes dosis y esquemas de administración. La utilización de sustancias naturales denominadas “modificadores de la respuesta biológica”, ha derivado en lo que se conoce como cuarta modalidad terapêutica contra el cáncer. Se propone que la Cy sea considerada también dentro de ese contexto.

Precision Medicine Gains Momentum: Novel 3D Models and Stem Cell-Based Approaches in Head and Neck Cancer

Despite the current progress in the development of new concepts of precision medicine for head and neck squamous cell carcinoma (HNSCC), in particular targeted therapies and immune checkpoint inhibition (CPI), overall survival rates have not improved during the last decades. This is, on the one hand, caused by the fact that a significant number of patients presents with late stage disease at the time of diagnosis, on the other hand HNSCC frequently develop therapeutic resistance. Distinct intratumoral and intertumoral heterogeneity is one of the strongest features in HNSCC and has hindered both the identification of specific biomarkers and the establishment of targeted therapies for this disease so far. To date, there is a paucity of reliable preclinical models, particularly those that can predict responses to immune CPI, as these models require an intact tumor microenvironment (TME). The "ideal" preclinical cancer model is supposed to take both the TME as well as tumor heterogeneity into account. Although HNSCC patients are frequently studied in clinical trials, there is a lack of reliable prognostic biomarkers allowing a better stratification of individuals who might benefit from new concepts of targeted or immunotherapeutic strategies. Emerging evidence indicates that cancer stem cells (CSCs) are highly tumorigenic. Through the process of stemness, epithelial cells acquire an invasive phenotype contributing to metastasis and recurrence. Specific markers for CSC such as CD133 and CD44 expression and ALDH activity help to identify CSC in HNSCC. For the majority of patients, allocation of treatment regimens is simply based on histological diagnosis and on tumor location and disease staging (clinical risk assessments) rather than on specific or individual tumor biology. Hence there is an urgent need for tools to stratify HNSCC patients and pave the way for personalized therapeutic options. This work reviews the current literature on novel approaches in implementing three-dimensional (3D) HNSCC in vitro and in vivo tumor models in the clinical daily routine. Stem-cell based assays will be particularly discussed. Those models are highly anticipated to serve as a preclinical prediction platform for the evaluation of stable biomarkers and for therapeutic efficacy testing.

[The tumor stem cell niche of head and neck - point of intersection with therapeutic potential?]

An increasing amount of evidence suggests the existence of a stem cell-like population in head and neck squamous cell carcinoma (HNSCC). These cells have been termed cancer stem cells (CSC) due to the shared properties with somatic stem cells, such as the ability to self-renew and differentiate. Furthermore, the CSC are thought to be resistant to antineoplastic treatments and are therefore clinically relevant. As with somatic stem cells, CSC are thought to reside in a specialized supportive microenvironment, called the stem cell niche. One possible strategy to target the CSC could be through affecting functions of the stem cell niche.Stromal cell-derived factor-1 (SDF-1) is a multifunctional cytokine, which is secreted by e. g. stromal cells within the niche. SDF-1 is known to be the major regulator of stem cell trafficking between the niche and the peripheral vascular system. It elicits the chemotactic activity through interaction with a transmembrane receptor CXCR4, expressed by CSC. The SDF-1-CXCR4-axis is thought to play a crucial role in the interaction between CSC and their supportive cells in the tumor niche. A better understanding of these interactions could help in gaining further insight into the pathophysiology of progression/recurrence of malignant diseases and aid in finding new strategies for therapy.Specialized cell culture models are of advantage for deciphering the mechanisms of interaction between CSC and their niche. We anticipate that the recent technological advancements in bioprinting and the development of complex 3D cell culture model systems will contribute to our understanding of these mechanisms and to the establishment of individualized therapies.Here were provide an overview of the current knowledge on the CSC-tumor stem cell niche interactions in HNSCC with a focus on the SDF-1-CXCR4 axis.

Identification of metastatic cell nucleus in human prostate cancer by electron microscopy

AIM

Metastatic prostate cancer is responsible for a large proportion of deaths worldwide. The aim of this study was to identify metastatic cells and determine if stromal invasion by cancer cells differs from those during metastasis.

METHODS & RESULTS

Tissue biopsy/prostatectomy samples, visualized by transmission electron microscopy, identified that metastatic cells are a lineage of stem cells, which have dedifferentiated into cancerous columnar/cuboidal cells. These cells demonstrate nuclear plasticity; the loss of nuclear membranes and boundary between nucleus and cytoplasm; and the presence of electron dense molecules, which can readily pass through basement membranes and enter the capillary, ready for dissemination to metastatic sites.

CONCLUSION

This is the first study to demonstrate differences between invasive and metastatic cell types.

A hypothesis on paradoxical privileged portal vein metastasis of hepatocellular carcinoma. Can organ evolution shed light on patterns of human pathology, and vice versa?

Unlike other carcinomas, hepatocellular carcinoma (HCC) metastasizes to distant organs relatively rarely. In contrast, it routinely metastasizes to liver vasculature/liver, affecting portal veins 3-10 times more often than hepatic veins. This portal metastatic predominance is traditionally rationalized within the model of a reverse portal flow, due to accompanying liver cirrhosis. However, this intuitive model is not coherent with facts: 1) reverse portal flow occurs in fewer than 10% of cirrhotic patients, while portal metastasis occurs in 30-100% of HCC cases, and 2) portal vein prevalence of HCC metastasis is also characteristic of HCC in non-cirrhotic livers. Therefore, we must assume that the route for HCC metastatic dissemination is the same as for other carcinomas: systemic dissemination via the draining vessel, i.e., via the hepatic vein. In this light, portal prevalence versus hepatic vein of HCC metastasis appears as a puzzling pattern, particularly in cases when portal HCC metastases have appeared as the sole manifestation of HCC. Considering that other GI carcinomas (colorectal, pancreatic, gastric and small bowel) invariably disseminate via portal vein, but very rarely form portal metastasis, portal prevalence of HCC metastasis appears as a paradox. However, nature does not contradict itself; it is rather our wrong assumptions that create paradoxes. The 'portal paradox' becomes a logical event within the hypothesis that the formation of the unique portal venous system preceded the appearance of liver in evolution of chordates. The analysis suggests that the appearance of the portal venous system, supplying hormones and growth factors of pancreatic family, which includes insulin, glucagon, somatostatin, and pancreatic polypeptide (HGFPF) to midgut diverticulum in the early evolution of chordates (in an Amphioxus-like ancestral animal), promoted differentiation of enterocytes into hepatocytes and their further evolution to the liver of vertebrates. These promotional-dependent interactions are conserved in the vertebrate lineage. I hypothesize that selective homing and proliferation of malignant hepatocytes (i.e., HCC cells) in the portal vein environment are due to a uniquely high concentration of HGFPF in portal blood. HGFPF are also necessary for liver function and renewal and are significantly extracted by hepatocytes from passing blood, creating a concentration gradient of HGFPF between the portal blood and hepatic vein outflow, making post-liver vasculature and remote organs less favorable spaces for HCC growth. It also suggested that the portal vein environment (i.e., HGFPF) promotes the differentiation of more aggressive HCC clones from already-seeded portal metastases, explaining the worse outcome of HCC with the portal metastatic pattern. The analysis also offers new hypothesis on the phylogenetic origin of the hepatic diverticulum of cephalochordates, with certain implications for the modeling of the chordate phylogeny.

The Role of Single Voxel MR Spectroscopy, T2 Relaxation Time and Apparent Diffusion Coefficient in Determining the Cellularity of Brain Tumors by MATLAB Software

Introduction: Brain tumors if timely diagnosed are sure to be treated through shorter processes. MRI amongst others is of Para clinical methods greatly effective in diagnosis phase. Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps provide some information that could reflect tissue cellularity. Neurosurgeons, in particular to detect the tumor cellularity, must send the specimens taken through biopsy to the pathology unit. This study is aimed at determining the tumor cellularity in brain. Materials and Methods: In this cross-sectional study, 32 patients (18 males and 14 females of the range 18 – 77 y/o) between April 2014 and February 2016 who were referred to the neurosurgery department of Shohada-E Tajrish Hospital of Tehran participated. Imaging was made using single voxel MR Spectroscopy, ADC and T2W Multi Echo Pulse Sequence in addition to routine pulse sequences and the images were analyzed using MATLAB software to determine the cellularity of brain tumors in comparison to the biopsy. Results: findings showed that by decreasing T2 relaxation time, the amount of ADC, N-Acetyl Aspartate (NAA) and also, increase Choline metabolite, lead to registering tumors in the lower class on the designed table and these tumors have a higher degree of consistency and cellularity. T2 Relaxation time, the tumors will stand at higher class on the designed table. Also the results indicated that 85% diagnostic weight of T2 relaxation time and 83% diagnostic weight of ADC compared with biopsy could reveal the brain tumor cellularity (P>0.05). Conclusion: some cellular metabolite changes such as NAA and Choline, ADC value and T2 relaxation time feature could effectively be used to distinguish and illustrate the degree of cellularity of brain tumors especially Intra-axial brain tumors (with about 85%. vs. biopsy). We recommend to more data should be used to increase the accuracy percentage of this technique.

Privileged portal metastasis of hepatocellular carcinoma in light of the coevolution of a visceral portal system and liver in the chordate lineage: a search for therapeutic targets

Hepatocellular carcinoma (HCC) disseminates systemically, but metastases occur in distant organs only in minority of patients, whereas HCC routinely metastasizes to liver and its vessels. HCC cells disseminate via hepatic veins, but portal veins are affected by metastasis more frequently than are hepatic veins, and correlates with poor prognosis. In this review, I suggest that privileged HCC portal metastasis occurs because of high levels of pancreatic family hormones and growth factors (PHGFs) in the portal blood. The analysis suggests that the appearance of the portal system carrying PHGFs in the evolution of invertebrate chordate (Amphioxus) led to the evolution of the liver in vertebrate; given that the portal pattern of HCC metastasis and selection of more-aggressive clones are PHGF dependent, PHGFs and their ligands constitute therapeutic targets.

Determination of intra-axial brain tumors cellularity through the analysis of T2 Relaxation time of brain tumors before surgery using MATLAB software

Introduction

Timely diagnosis of brain tumors could considerably affect the process of patient treatment. To do so, para-clinical methods, particularly MRI, cannot be ignored. MRI has so far answered significant questions regarding tumor characteristics, as well as helping neurosurgeons. In order to detect the tumor cellularity, neuro-surgeons currently have to sample specimens by biopsy and then send them to the pathology unit. The aim of this study is to determine the tumor cellularity in the brain.

Methods

In this cross-sectional study, 32 patients (18 males and 14 females from 18–77 y/o) were admitted to the neurosurgery department of Shohada-E Tajrish Hospital in Tehran, Iran from April 2012 to February 2014. In addition to routine pulse sequences, T2W Multi echo pulse sequences were taken and the images were analyzed using the MATLAB software to determine the brain tumor cellularity, compared with the biopsy

Results

These findings illustrate the need for more T2 relaxation time decreases, the higher classes of tumors will stand out in the designed table. In this study, the results show T2 relaxation time with a 85% diagnostic weight, compared with the biopsy, to determine the brain tumor cellularity (p<0.05).

Conclusion

Our results indicate that the T2 relaxation time feature is the best method to distinguish and present the degree of intra-axial brain tumors cellularity (85% accuracy compared to biopsy). The use of more data is recommended in order to increase the percent accuracy of this techniques.

Effect of Amentoflavone on the Inhibition of Pulmonary Metastasis Induced by B16F-10 Melanoma Cells in C57BL/6 Mice

This study was an investigation of the antimetastatic activity of amentoflavone using B16F-10 melanoma—induced experimental lung metastasis in C57BL/6 mice. Amentoflavone treatment significantly reduced tumor nodule formation accompanied by reduced lung collagen hydroxyproline, hexosamine, and uronic acid levels. Serum sialic acid and γglutamyl transpeptidase levels were also significantly inhibited after amentoflavone treatment. Amentoflavone treatment up-regulated the lung tissue inhibitor of metalloprotease-1 and tissue inhibitor of metalloprotease-2 expression. The cytokine profile and growth factors such as interleukin-1β , interleukin-6, tumor necrosis factor-α, granulocyte monocyte— colony stimulating factor, vascular endothelial growth factor, interleukin-2, and tissue inhibitor of metalloprotease-1 in the serum of these animals were markedly altered after amentoflavone treatment. This altered level of cytokines after amentoflavone treatment was also accompanied by enhanced natural killer cell antibody—dependent cellular cytotoxicity. The study reveals that amentoflavone treatment could alter proinflammatory cytokine production and could inhibit the activation and nuclear translocation of p65, p50, c-Rel subunits of nuclear factor—κB, and other transcription factors such as c-fos, activated transcription factor—2, and cyclic adenosine monophosphate response element—binding protein in B16F-10 melanoma cells.

L-asparaginase inhibits invasive and angiogenic activity and induces autophagy in ovarian cancer

Recent work identified L-asparaginase (L-ASP) as a putative therapeutic target for ovarian cancer. We suggest that L-ASP, a dysregulator of glycosylation, would interrupt the local microenvironment, affecting the ovarian cancer cell-endothelial cell interaction and thus angiogenesis without cytotoxic effects. Ovarian cancer cell lines and human microvascular endothelial cells (HMVEC) were exposed to L-ASP at physiologically attainable concentrations and subjected to analyses of endothelial tube formation, invasion, adhesion and the assessment of sialylated proteins involved in matrix-associated and heterotypic cell adhesion. Marked reduction in HMVEC tube formation in vitro, HMVEC and ovarian cancer cell invasion, and heterotypic cell-cell and cell-matrix adhesion was observed (P < 0.05-0.0001). These effects were associated with reduced binding to ß1integrin, activation of FAK, and cell surface sialyl Lewis(X) (sLe(x)) expression. No reduction in HMVEC E-selectin expression was seen consistent with the unidirectional inhibitory actions observed. L-ASP concentrations were non-toxic to either ovarian cancer or HMVEC lines in the time frame of the assays. However, early changes of autophagy were observed in both cell types with induction of ATG12, beclin-1, and cleavage of LC-3, indicating cell injury did occur. These data and the known mechanism of action of L-ASP on glycosylation of nascent proteins suggest that L-ASP reduces of ovarian cancer dissemination and progression through modification of its microenvironment. The reduction of ovarian cancer cell surface sLe(x) inhibits interaction with HMVEC and thus HMVEC differentiation into tubes, inhibits interaction with the local matrix reducing invasive behaviour, and causes cell injury initiating autophagy in tumour and vascular cells.

Clinical relevance of cyclooxygenase-2 and matrix metalloproteinases (MMP-2 and MT1-MMP) in human breast cancer tissue

Breast cancer (BC) is the most common neoplasm among women in most developed countries, including Egypt. Elevated levels of certain proteins in human BC are associated with unfavorable prognosis and progressive stages of the disease. The aim of our study was to evaluate the protein expression profile and prognostic significance of cyclooxygenase-2 (COX-2), matrix metalloproteinase-2 (MMP-2), MMP-9 and membrane type 1-MMP (MT1-MMP) and their interaction in operable BC patients. The protein expression of COX-2, MMP-2 and MT1-MMP were evaluated by western blot technique, whereas enzymatic activity of MMP-2 and MMP-9 was determined by zymography in 47 breast cancer patients as well as normal adjacent tissues. Also, the correlation between these proteins and age, tumor size, LN stage, TNM stage, estrogen receptor, progesterone receptor, disease-free survival, and overall survival (OS) has been investigated. As compared to adjacent normal tissues, COX-2, MMP-2 and MT1-MMP were over-expressed in 43, 64, and 60 % of tumor tissues, respectively. In the same pattern, the activity of MMP-2 (62 %) and MMP-9 (45 %) was elevated in BC tissues. Multivariate analysis showed a positive correlation between the protein expression of COX-2, MMP-2, and MT1-MMP and the activity of MMP-2 and MMP-9 in BC patients. However, the enzymatic activity showed no correlation with clinicopathological features. This study confirms the preclinical evidence that COX-2 increased the expression of MT1-MMP, which in turn activates MMP-2. The lack of correlation with clinicopathological features, OS or disease-free survival ascertains the complexity of tumor progression and metastasis with many pro- and counter regulatory factors.

Monte Carlo simulation-based approach to model the size distribution of metastatic tumors

The size distribution of metastatic tumors and its time evolution are traditionally described by integrodifferential equations and stochastic models. Here we develop a simple Monte Carlo approach in which each event of metastasis is treated as a chance event through random-number generation. We demonstrate the accuracy of this approach on a specific growth and metastasis model by showing that it quantitatively reproduces the size distribution and the total number of tumors as a function of time. The approach also yields statistical distribution of patient-to-patient variations, and has the flexibility to incorporate many real-life complexities.

Submental lymph node metastasis from invasive ductal breast carcinoma

This case report presents a 52-year-old woman with a submental swelling which arose 3 years after wide local excision and axillary lymphadenectomy for breast carcinoma. Histopathological examination after excision biopsy of this lesion confirmed the presence of invasive breast carcinoma in a submental lymph node. Computed tomography of the head, neck, thorax, abdomen and pelvis demonstrated multiple brain and pulmonary metastases. Further management was palliative and the patient died 5 months later. This is the first description of a breast carcinoma metastasising to the submental region. Metastatic breast carcinoma should be considered in the differential diagnosis of head and neck lymphadenopathy in patients with previously diagnosed breast carcinoma.

Circulating tumor cells in prostate cancer: a potential surrogate marker of survival

Prostate-specific antigen (PSA) levels in blood are widely used in prostate cancer (PCa) for the management of this disease at every stage of progression. Currently, PSA levels combined with clinical stage and Gleason score provide the best predictor of survival and the main element to monitor treatment efficiency. However, these areas could be improved by utilizing emerging biomarkers. Recently, circulating tumor cells (CTCs) and disseminating tumor cells (DTCs) have been detected in PCa and may be a new surrogate candidate. Here we provide a systematic review of the literature in order to describe the current evidence of CTC/DTC surrogacy regarding outcome of prostate cancer patients. We also discuss several markers that could be used to increase the sensitivity and specificity of CTC/DTC detection. CTC/DTC detection is performed using a wide variety of techniques. Initially, reverse transcriptase polymerase chain reaction (RT-PCR) based methods were utilized with weak correlation between their positive detection and patients' outcome. More recent immunological techniques have indicated a reproducible correlation with outcome. Such surrogate markers may enable clinicians to provide early detection for inefficient treatments and patients with poor prognosis that are candidates for treatment intensification. Dissecting the micrometastasis phenomenon in CTCs/DTCs is a key point to increase surrogacy of this biomarker.

Logical structures extracted from metastasis experiments

An inductive argument of metastasis with a metaphor of seed and soil was made by Stephen Paget in 1889. It is commonly held that metastasis is dependent on both the organ from which the primary tumors originate, and the organs to which the tumor cells travel. The assumption is based on the statistical observation of a number of autopsy samples. Here I attempt to establish a theory on the mechanisms of metastasis with experimental evidence. I propose that dysregulation of pro-inflammatory Toll-like receptor 4 signaling, stimulated by its endogenous ligands, establishes pre-metastatic soil. Once specific parameters are established, deductive judgments could be possible to predict to which organ a given tumor metastasizes.

Metastatic dormancy imposed by the primary tumor: does it exist in humans?

BACKGROUND

In cancer patients, occult micrometastases may become apparent shortly after removal of the primary tumor. Animal experiments have shown that metastatic dormancy is maintained by apoptosis, and that primary tumor removal induces a flare-up of angiogenesis, leading to metastatic outgrowth. This phenomenon has led to the hypothesis that the primary tumor generates certain factors that inhibit angiogenesis at distant sites. It is still unknown whether such a phenomenon is operative in human cancer as well. Should it occur, it might have important therapeutic consequences.

MATERIALS AND METHODS

Evidence for such a mechanism may be obtained from studies that analyze a series of tissue samples of metastases, taken before or after surgical removal of the primary lesion.

RESULTS

Data from our laboratory on colorectal cancer have shown that, in the absence of the primary tumor, vascular density in the metastases is increased as well as their metabolic activity, as measured by (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET). Mitotic activity is increased mildly, while levels of apoptosis are collapsed.

CONCLUSION

These data indicate that a mechanism of primary-tumor-induced inhibition of angiogenesis exists, maintaining metastatic dormancy. We now suggest that this mechanism may be exploited to avoid the use of exogenous, potentially harmful angiogenesis inhibitors such as bevacizumab in a neoadjuvant setting. Treatment of patients with the primary tumor still in situ could thus be restricted to chemotherapy, since the synergistic effect of an angiogenesis inhibitor would be generated by the primary tumor itself. In the present paper the clinical relevance and possible consequences of our findings and suggestions are discussed.

Preoperative core needle biopsy does not increase local recurrence rate in breast cancer patients

OBJECTIVE

Several case reports and clinical studies in the literature demonstrate needle track seeding after core needle biopsy in patients with breast cancer in up to 50% of cases. The impact of this observation on local recurrence and overall survival rate is, however, not fully investigated.

PATIENTS AND DESIGN

We retrospectively analysed 719 patients after breast conserving surgery and postoperative radiotherapy for stage I and II breast cancer. We divided this group into patients with (189) and without (530) preoperative core needle biopsy. Demographic data, local recurrence and overall survival rate were compared between these two groups.

RESULT

Preoperative core needle biopsy did not significantly influence the local free recurrence rate (median follow-up time of 78 and 71 months, respectively). The prognostic factors and the postoperative therapy did not differ significantly between the two groups.

CONCLUSION

Preoperative core needle biopsy seems to have no detrimental impact on local recurrence and overall survival after breast conserving surgery and postoperative radiotherapy.

Long-term prognostic value of detection of circulating colorectal cancer cells using CGM2 reverse transcriptase-polymerase chain reaction assay

BACKGROUND

The criteria commonly used for prognosis of colorectal cancer remain histoprognostic and are based on primarily TNM classification. The lack of discrimination of purely histoprognostic criteria is evidenced by the development of different outcomes in similarly staged patients. The aim of this work was to study the long-term prognostic value of preoperative detection of circulating enterocytes in the blood of colorectal cancer patients using the CGM2 reverse transcriptase-polymerase chain reaction (RT-PCR) assay.

METHODS

A nested RT-PCR with specific primers for CGM2 was used preoperatively to detect circulating enterocytes in 121 patients (64 men, 57 women; mean age, 70 years) with colorectal neoplasms.

RESULTS

Circulating enterocytes were detected in 58/121 (48%) patients. The positivity rate was not correlated with American Joint Committee on Cancer (AJCC) staging (stage I, 11/28 (39%); stage II, 13/34 (38%); stage III, 15/23 (65%); stage IV, 17/32 (53%); sterilized (after radiotherapy, no residual neoplasm) 2/4 (50%); not significant [NS]), but circulating enterocytes were detected more frequently in patients with metastatic lymph nodes (60% vs 41%, P = .06). Overall 5-year survival rates (mean +/- SD) were 40 +/- 13% and 45 +/- 13% for patients without and with circulating enterocytes, respectively (P = NS). Similarly, recurrence-free survival rates were 71 +/- 4% versus 72 +/- 14% (P = NS). Using univariate analysis, AJCC stage (P < .0001) was correlated with survival. AJCC stage (P = .007) and obstructive neoplasms (P = .043) were correlated with recurrence-free survival. Using multivariate analysis, AJCC stage was correlated with survival and recurrence-free survival.

CONCLUSIONS

Preoperative detection of circulating enterocytes using CGM2 RT-PCR assay provides no specific prognostic information and cannot be used as a decision criterion for adjuvant therapy.

T cell-mediated immunotherapy of metastases: state of the art in 2005

Advances in cellular and molecular immunology have led to the development of strategies for effective augmentation of antitumour immune responses in cancer patients. This review focuses on the manipulation of T cell immunity either by active specific immunotherapy (ASI) using tumour vaccines, or by adoptive immunotherapy (ADI) with immune T cells. Such therapies offer exquisite specificity of tumour recognition based on the ability of the T cell to distinguish single amino acid differences in any protein from any compartment of the tumour cell. Examples are presented of clinical survival benefits for cancer patients by postoperative ASI with a modified autologous tumour vaccine of high quality. Furthermore, clinical studies employing ADI with T cells activated and expanded ex vivo have demonstrated 'proof of principle' that tumour-specific T cells are capable of mediating anticancer activity in vivo, as measured by regression of metastatic tumours. Translation of these findings into a standardised immunotherapy is, however, not easy and will require coordination and cooperation among academic, private and federal sectors.

A mathematical model of tumour angiogenesis, regulated by vascular endothelial growth factor and the angiopoietins

Angiogenesis--the growth of new blood vessels from existing ones--is a prerequisite for the growth of solid tumours beyond a diameter of approximately 2 mm. In recent years, the angiopoietins have emerged as important regulators of angiogenesis. They mediate a delicate balance between vascular quiescence, regression and new growth, but their mechanism of action is not fully understood. This work attempts to provide a mathematical description of the role of the angiopoietins in angiogenesis. The model is formulated within the framework of reinforced random walks, which allows easy transition between the continuum (macroscopic) and discrete (microscopic) forms. Model predictions are in qualitative agreement with experimental observations, and may have implications for anti-cancer therapies based on the prevention of angiogenesis.

Effect of Withania somnifera on B16F-10 melanoma induced metastasis in mice

Withania somnifera, a plant with known immunopotentiating activity and its bioactive fraction-Withanolide D were studied for their anti-metastatic activity using B16F-10 melanoma cells in C57BL/6 mice. Simultaneous administration of Withania extract (122 +/- 10 tumour nodules) and Withanolide (126 +/- 9 lung tumour nodules) could significantly (p < 0.001) inhibit the metastatic colony formation of the melanoma in lungs. 72.58% by extract and 69.84% by Withanolide treated, as compared to the untreated control animals also increased the survival days. Lung collagen hydroxyproline content was highly elevated in the control animals (23.5 +/- 0.9 micro g/mg protein), which was reduced by the simultaneous administration of both the extract (16.3 +/- 2.0 micro g/mg protein) and Withanolide (15.3 +/- 1.8 micro g/mg protein). The level of lung hexosamines (4.85 +/- 0.20 mg/100 mg tissue) and uronic acids (330.1 +/- 23.7 micro g/100 mg tissue) content was also elevated in the control animals. The elevated level of hexosamine was significantly reduced by the treatment with extract (1.92 +/- 0.05) and Withanolide (1.85 +/- 0.05). Similarly, the uronic acid content was also been reduced by the simultaneous administration of both Withania extract (194.2 +/- 17.4) and Withanolide (183.2 +/- 8.8). The control animals had 35.3 +/- 3.8 U/L gamma-glutamyl transpeptidase (gamma-GT), which was reduced by 50% by the treatment of extract and Withanolide to 17.5 +/- 4.0 U/L and 16.3 +/- 4.4 U/L respectively. There was a significant reduction in the levels of sialic acid in the serum of Withania extract (60.7 +/- 7.7) and Withanolide (67.16 +/- 5.8) treated animals compared to the higher level (102.2 +/- 8.7) in the control animals. Histopathological analysis of the lung tissues also correlated with these findings. Prophylactic administrations of both extract as well as Withanolide were ineffective in inhibiting the metastasis of B16F-10 melanoma cells.

[Conditions for the development of a program of reverse transcriptase-polymerase chain reaction for molecular staging of prostatic cancer]

OBJECTIVE

To determine accurately the conditions for the development of tests using RT-PCR for PSA in patients with prostate cancer.

METHOD

Gen amplification of PSA in cultures of the human prostate tumoral cell line LNCaP with RT-PCR under hot-start conditions, and verification through enzyme restriction digestion of the PCR product. Also, calculation of the PCR test limit of detection through serial dilutions of LNCaP cells in peripheral blood mononucleate cells.

RESULTS

A highly specific, easy to perform, reproducible RT-PCR protocol has been developed. The lowest limit of detection reached was 1 PSA synthesising cell per 10(6) peripheral blood mononucleate cells.

CONCLUSIONS

RT-PCR is a highly sensitive technique that allows detection of small numbers of PSA producing cells in peripheral blood. This experience allows to establish with precision the conditions for the development of RT-PCR tests for PSA.

Inhibitory effect of a polysaccharide from Tinospora cordifolia on experimental metastasis

Administration of the polysaccharide fraction from Tinospora cordifolia was found to be very effective in reducing the metastatic potential of B16F-10 melanoma cells. There was a 72% inhibition in the metastases formation in the lungs of syngeneic C57BL/6 mice, when the drug was administered simultaneously with tumour challenge. Biochemical parameters such as lung collagen hydroxyproline, hexosamines and uronic acids that are markers of neoplastic development were reduced significantly (P<0.001) in the treated animals compared with the untreated control animals. The treatment could also reduce serum gamma-glutamyltranspeptidase (gamma-GT) and sialic acid levels as compared to the control animals.

Prognostic significance of UDP-N-acetyl-alpha-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase-3 (GalNAc-T3) expression in patients with gastric carcinoma

Aberrant glycosylation occurs during development of gastric carcinomas. The initiation of mucin-type O-glycosylation is regulated by GalNAc-T3 (UDP-N-acetylgalactosamine:polypeptide N-acetylgalactosaminyltransferase-3). However, the clinical significance of GalNAc-T3 expression in human gastric carcinoma has not yet been demonstrated. In the present study, we investigated the relationship between immunohistochemical GalNAc-T3 expression and various clinicopathologic factors, including prognosis, in 117 gastric carcinoma patients. Of 117 gastric carcinomas examined, 59 (50.4%) showed strong expression of GalNAc-T3. Strong expression was detected in 38 of 59 (64.4%) differentiated type and in 21 of 58 (36.2%) undifferentiated gastric carcinomas, indicating that the expression of GalNAc-T3 correlated significantly with tumor differentiation (P=0.0023, chi2 test). Overall 5-year survival rate in patients with strong GalNAc-T3 expression (71.0%) was significantly better than that of patients with weak expression (49.3%) (P=0.0197, log-rank test). Multivariate analysis identified GalNAc-T3 expression as an independent prognostic factor (P=0.0158, Cox proportional hazards model). Our data suggest that GalNAc-T3 expression may be a useful marker for prognosis and differentiation of gastric carcinomas.

Tumour-Induced Angiogenesis: A Review

Angiogenesis, the formation of new blood vessels, has become a broad subject and is a very active area for current research. This paper describes the main biological events involved in angiogenesis and their importance in cancer progression. In the first section, a fundamental overview of tumour biology is presented. In the second section, the biology of healthy blood vessels is described and, in the third section, the mechanisms of cell migration and proliferation, which are crucial to angiogenesis, are discussed. In the fourth section, a detailed account of tumour-induced angiogenesis is given, whilst the pro- and anti-angiogenic factors involved are reviewed in the fifth section. Finally, the processes of tumour invasion and metastasis are examined in the sixth section.

Local recurrence of breast cancer after breast conservation therapy in patients examined by means of stereotactic core-needle biopsy

PURPOSE

To evaluate the incidence of locally recurrent breast cancer in patients treated with breast conservation surgery and radiation therapy to determine if increased local recurrence is observed in women examined by means of stereotactic core-needle biopsy (SCNB).

MATERIALS AND METHODS

Records of 551 consecutive patients with breast cancer who were treated with conservation surgery and radiation therapy were reviewed retrospectively. The 551 cases were divided into three groups: those examined by means of SCNB (n = 86), those examined by means of excisional biopsy preceded by needle localization (n = 242), and those in which the masses were palpable and who underwent biopsy without imaging guidance (n = 223). The local recurrence rate and the Mantel-Haenszel statistic for survival curves were calculated for each group. To test for statistical significance, chi(2) analysis was performed for categorical variables and a t test or analysis of variance was performed for calculation of continuous variables.

RESULTS

With a mean follow-up of 4.9 years (range, 2.0-8.9 years), tumor recurrence rate in the SCNB group was 2.3% (two of 86), resulting in a 5-year actuarial recurrence-free rate of 0.96 +/- 0.03. For the needle-localized biopsy group, recurrence rate was 5.4% (13 of 242), with a 5-year actuarial tumor recurrence-free rate of 0.88 +/- 0.03. For the non-image-guided biopsy group, the recurrence rate was 10.3% (23 of 223), with a 5-year actuarial recurrence-free rate of 0.84 +/- 0.03. These rates were not significantly different when the SCNB group was compared with the needle-localized biopsy group. However, the recurrence-free rate was significantly greater for the SCNB group than that for the non-image-guided biopsy group (P =.03).

CONCLUSION

In the present series to date, cancers diagnosed by means of SCNB were not associated with an increased incidence of local recurrence after breast conservation surgery and radiation therapy.

Mechanisms of tumour invasion and metastasis: emerging targets for therapy

The progression of a tumour from one of benign and delimited growth to one that is invasive and metastatic is the major cause of poor clinical outcome in cancer patients. The invasion and metastasis of tumours is a highly complex and multistep process that requires a tumour cell to modulate its ability to adhere, degrade the surrounding extracellular matrix, migrate, proliferate at a secondary site and stimulate angiogenesis. Knowledge of the process has greatly increased and this has resulted in the identification of a number of molecules that are fundamental to the process. The involvement of these molecules has been shown to relate not only to the survival and proliferation of the tumour cell but, also to the processes of tumour cell adhesion, migration, and the tumour cells ability to degrade and escape the primary site as well as play a role in angiogenesis. These molecules may provide important therapeutic targets that represent the ability to target specific steps in the process of invasion and metastasis and provide additional therapies. The review focuses on representative key targets in each of these processes and summarises the state of play in each case.

Endothelial expression of vascular cell adhesion molecule-1 correlates with metastatic pattern in spontaneous melanoma

OBJECTIVE

Adhesive interactions between tumor cell surface receptors and endothelial cell adhesion molecules are thought to contribute to tumor cell arrest and extravasation during hematogenous metastasis. Recent reports suggest that melanoma cell integrin alpha4beta1 (very late antigen-4, VLA-4) interaction with the inducible cell adhesion molecule, vascular cell adhesion molecule-1 (VCAM-1), is critical for tumor cell arrest. However, no information is available regarding microvascular VCAM-1 expression during spontaneous melanoma metastasis. The objectives of this study were to evaluate VCAM-1 expression in pulmonary and extrapulmonary vascular beds during melanoma progression, and to determine whether there is an organ-specific profile for VCAM-1 expression which corresponds with the clinical pattern of melanoma metastasis.

METHODS

The dual-radiolabeled monoclonal antibody (mAb) technique for quantification of VCAM-1 in different vascular beds was applied to a physiological model of melanoma (B16-BL6) metastasis. Measurements of VCAM-1 were obtained when primary tumors reached 5 mm in size, and every 7 days following removal of the primary lesion. Histological examinations were performed, and mice were placed into 2 groups, based on the presence (+colonies) or absence (-colonies) of pulmonary metastases. VCAM-1 measurements obtained from several organ systems were then compared between these 2 groups of mice. Localization of VCAM-1 was achieved through immunohistochemical staining of tissues. Plasma collected from each experimental animal, as well as melanoma-conditioned media, was assayed to determine levels of the cytokines tumor necrosis factor-alpha (TNF-alpha) and interleukin-1alpha (IL-1alpha).

RESULTS

Data collected from the dual-radiolabeled mAb technique indicate that 3 weeks following removal of the primary lesion, there is a tendency for VCAM-1 expression to increase in cardiac, hepatic, and cerebral vascular beds. Four weeks following primary resection, when pulmonary metastatic burden was maximal, VCAM-1 was significantly upregulated in each of these vascular beds. Results obtained from the lung indicate that VCAM-1 remains unchanged in pulmonary vessels at all time points examined. Immunohistochemical staining of heart and brain support the radiolabeled mAb measurements, and reveals that these organs exhibit an inflammatory phenotype in mice with heavy pulmonary tumor burden. Furthermore, 25% of these mice had histological evidence of melanoma metastases in heart and brain. Transplantation of liver fragments from mice with advanced pulmonary metastases into subcutaneous tissue of donor mice resulted in the formation of melanotic outgrowths. Plasma levels of the cytokines TNF-alpha and IL-1alpha were negligible in both groups of mice.

CONCLUSIONS

Our results indicate that upregulation of VCAM-1 is not a prerequisite for the formation of pulmonary metastases during spontaneous melanoma metastases. However, once lung metastases become well established, organ-specific increases in VCAM-1 expression become apparent. Furthermore, these organ-specific increments in VCAM-1 expression correspond with documented clinical patterns of melanoma metastasis. The enhanced expression of VCAM-1 is independent of systemic levels of TNF-alpha and IL-1alpha, but may be the result of melanoma-induced alterations at the local level, as we found evidence of melanoma cell occupation in heart, brain, and liver in pulmonary metastases-bearing mice.

Cell surface-expressed Thomsen-Friedenreich antigen in colon cancer is predominantly carried on high molecular weight splice variants of CD44

Increased mucosal expression of TF, the Thomsen-Friedenreich oncofetal blood group antigen (galactose beta1-3 N-acetylgalactosamine alpha-) occurs in colon cancer and colitis. This allows binding of TF-specific lectins, such as peanut agglutinin (PNA), which is mitogenic to the colorectal epithelium. To identify the cell surface TF-expressing glycoprotein(s), HT29 and Caco2 colon cancer cells were surface-labeled with Na[(125)I] and subjected to PNA-agarose affinity purification and electrophoresis. Proteins, approximately 110-180 kDa, present in HT29 but not Caco2 were identified by Western blotting as high molecular weight splice variants of CD44 (CD44v). Selective removal of TF antigen by Streptococcus pneumoniae endo-alpha-N-acetylgalactosaminidase substantially reduced PNA binding to CD44v. Immunoprecipitated CD44v from HT29 cell extracts also expressed sialyl-Tn (sialyl 2-6 N-acetylgalactosaminealpha-). Incubation of PNA 15 microg/ml with HT29 cells caused no additional proliferative effect in the presence of anti-CD44v6 mAb. In colon cancer tissue extracts (N = 3) PNA bound to CD44v but not to standard CD44. These data show that CD44v is a major PNA-binding glycoprotein in colon cancer cells. Because CD44 high molecular weight splice variants are present in colon cancer and inflammatory bowel disease tissue but are absent from normal mucosa, these results may also explain the increased PNA reactivity in colon cancer and inflammatory bowel disease. The coexpression of oncofetal carbohydrate antigens TF and sialyl-Tn on CD44 splice variants provides a link between cancer-associated changes in glycosylation and CD44 splicing, both of which correlate with increased metastatic potential.

Circulating tumorous cells in patients with hepatocellular carcinoma. Clinical impact and future directions

The circulation of liver-derived cells in patients with hepatocellular carcinoma (HCC) has been demonstrated by reverse transcriptase-polymerase chain reaction (RT-PCR) analyses. Contrasting results have been reported until now about the clinical impact of these assays, mainly due to technical differences. The use of RT-PCR approaches is now clearly, not suitable for recognition of circulating tumorous cells (CTC) when the test is performed after invasive medical or surgical procedures. Furthermore, the RT-PCR approach is incapable of analyzing the expression of invasion-related genes in CTC. Recently, new assays have been proposed to isolate CTC. They allow immunomorphological and molecular characterization of individual tumor cells. Based on these new results, new therapeutic approaches of metastases should be developed in the near future.

Microenvironment-induced cancer metastasis

PURPOSE

To present and evaluate clinical data suggesting that cancer metastasis may be induced by the microenvironment of the primary tumour and to discuss possible mechanisms of microenvironment-induced metastasis, based on a critical review of relevant data from studies of experimental tumours and cells in culture.

CONCLUSIONS

Low oxygen tension in the primary tumour is associated with metastasis in soft tissue sarcoma, cervix carcinoma and carcinoma of the head and neck. Multiple mechanisms may be involved in hypoxia-induced metastasis. Thus, hypoxia followed by reoxygenation may induce point mutations and DNA strand breakage leading to deletions, amplifications and genomic instability. Hypoxia may also provide a physiological pressure in tumours selecting for metastatic cell phenotypes. Moreover, hypoxia may induce a temporary increase in the expression of gene products involved in the metastatic cascade, either through gene amplifications or through normal physiological processes by activating oxygen sensors, hypoxia signal transduction pathways and DNA transcription factors. Low glucose concentration, high lactate concentration and low extracellular pH may induce metastasis by similar mechanisms as hypoxia. Tumour reoxygenation during radiation therapy may promote microenvironment-induced metastasis by rescuing hypoxic or nutritionally deprived metastatic cells from dying. Ionizing radiation can elicit a stress response in tumour cells similar to that elicited by hypoxia. Radiation therapy may therefore adversely affect the rate of metastasis in patients who do not achieve control of the primary tumour by enhancing the expression of gene products of importance in metastasis.

A dynamical model for the growth and size distribution of multiple metastatic tumors

Metastasis is the spread of tumors culminating in the establishment of one or more secondary tumors at remote sites. In deciding the best treatment for cancer therapy, estimations of the colony size of metastatic tumors and predictions of the future spread of colonies are needed. A dynamical model for the colony size distribution of multiple metastatic tumors is presented here. The dynamics is described by equations that incorporate both the colonization by metastasis and the growth of each colony. When the colony growth is subject to the Gompertz function, the explicit solution obtained tends to an asymptotic stable distribution that shows a monotonically decreasing or U-shaped pattern according to the values of clinically significant parameters, such as the colonization coefficient and the fractal dimension of blood vessels. This predicted colony size distribution agrees well with successive data of a clinically observed size distribution of multiple metastatic tumors of liver cancer. The combined analysis of the theoretical colony size distribution and clinical data will give useful information on the diagnosis and the therapy for cancer patients.

Reading for empathy

As our preoccupation with empathy grows, we cast about for means of inculcating it. Literature has been proposed as an enabling factor for physicians in developing a creative imagination. This essay, using a number of examples, points out that reading for pleasure in areas not necessarily related to medicine, can yield insights into its practice. Thus, sensitizing students and young physicians to the nuances of human interaction described by great writers could constitute part of basic and continuing medical education and might be one way of instilling empathy.

Detection of human papillomavirus types 16 and 18 mRNA in peripheral blood of advanced cervical cancer patients and its association with prognosis

PURPOSE

To evaluate the feasibility of detecting human papillomavirus E6 (HPVE6) gene mRNA in the peripheral blood of patients with locally advanced cervical cancer, and the relationship of the circulating HPV viral-specific mRNA with clinicopathologic factors and prognosis of locally advanced cervical cancer.

PATIENTS AND METHODS

The presence of types 16 and 18 HPVE6 gene mRNA was determined by reverse transcription followed by nested polymerase chain reaction. Thirty-five patients with locally advanced cervical cancer who were positive for HPV type 16 or 18 DNA were included in the study. All patients received external-beam radiation therapy followed by intracavitary brachytherapy.

RESULTS

Eighteen (51.4%) of 35 HPV DNA-positive cervical cancer patients had HPV-specific mRNA in their peripheral blood cells, compared with none of 17 HPV DNA-negative cervical cancer patients and none of 12 control volunteers. The presence of HPVE6 gene mRNA in peripheral blood was associated with bulky tumor volume (> 4 cm) and pelvic lymph node metastasis (tumor volume, P = .03; lymph node status, P = .03). After a median follow-up of 22 months, patients who were positive for peripheral-blood HPVE6 gene mRNA had a significantly higher risk of recurrence than those who were negative (10 of 18 v three of 17, P = .02; mean recurrent time, 20.7 months v 12.6 months, P = .02). There was also a statistically significant association of peripheral-blood HPVE6 gene mRNA positivity with distant metastasis (eight of 18 vone of 17; P = .01).

CONCLUSION

Results of this study seem to suggest that the presence of HPVE6 gene mRNA in peripheral blood may provide an early marker that identifies patients who are at risk for metastasis.

Liver colonization by human colon cancer cells is reduced by antisense inhibition of MUC2 mucin synthesis

BACKGROUND & AIMS

Alterations in the production of epithelial mucins have been correlated with advanced tumor stage in the colon, but direct evidence for a role of specific mucin genes in liver metastasis is lacking. The current study was designed to establish more directly the role of MUC2 in colon cancer metastasis.

METHODS

MUC2 levels were manipulated in highly metastatic human colon cancer cells using eukaryotic expression constructs designed to express a portion of MUC2 complementary DNA in antisense orientation. To assess the effect of MUC2 levels on metastatic potential, liver colonization was assessed in athymic mice after splenic-portal inoculation.

RESULTS

Stable integration of the MUC2 antisense construct into metastatic colon cancer cells (LS LiM6) resulted in an 80% reduction in MUC2-specific messenger RNA and a concomitant decrease in MUC2 apomucin protein. This reduction was associated with a 50% reduction in synthesis of mature glucosamine-labeled mucin, almost complete inhibition of secretion of sialyl-LeX and sialyl-Tn antigens, and a 40% decrease in binding of colon cancer cells to E-selectin. Reduction in MUC2 levels was associated with a marked decrease in liver colonization.

CONCLUSIONS

This study provides direct evidence that MUC2 plays an important role in colon cancer metastasis.

Altered expression of sialylated carbohydrate antigens in HT29 colonic carcinoma cells

To determine whether cell growth conditions impacted carbohydrate expression, HT29 cells were gradually transferred from a conventional glucose-containing media to a glucose-free galactose containing media. Indirect immunofluorescence on acetone fixed cells showed increased expression of sialyl Lewis A antigen (CA19-9), sialyl Lewis C (DUPAN2) and Tn/sialyl-Tn on the surface of HT29 cells grown in the glucose-free galactose containing media compared to those grown in the glucose containing media. Sialyltransferases responsible for the synthesis for these sialylated epitopes were Increased in the galactose-fed HT29 cells. Media overlying the cells was subjected to isopycnic ultracentrifugation in cesium chloride and the fractions derived from both glucose and galactose media with equivalent buoyant densities of 1.56 g/L, which are predicted to contain mucin glycoforms, were further separated by HPLC using a Mono-Q anion exchange column. The chromatograph of eluent from the sample derived from the cells growing in the galactose containing media showed an increased peak that reacted with the anti-sialyl Lewis A antibody, CA19-9. These results show that alteration of in vitro culture conditions may cause HT29 colonic carcinoma cells to alter the expression of sialylated carbohydrates.

Localization of galectin-3 in normal and diseased pancreatic tissue

CONCLUSION

Galectin-3 is expressed in both human and hamster pancreatic tumors and tumor cell lines and this expression is increased over normal.

BACKGROUND

Galectin-3 is overexpressed in many gastrointestinal tumors. This study examined the expression of galectin-3 in human and hamster pancreatic tumors to determine if galectin-3 could be used as a marker for pancreatic cancer.

METHODS

Membranes were prepared from human and hamster pancreatic tumor cell lines. Galectin-3 was visualized by immunoblot analysis of separated membrane proteins using the monoclonal antibody (MAb) M3/38. Paraffin-embedded sections from normal, pancreatitis, and cancerous human pancreatic tissue and normal, N-nitrosobis(2-oxopropyl)amine (BOP)-treated hyperplastic, and cancerous hamster pancreatic tissues were processed immunohistochemically for galectin-3 using the MAb M3/38.

RESULTS

Galectin-3 was heavily expressed in cytoplasmic and nuclear regions of 50% of normal human pancreatic tissue. Expression of galectin-3 in ductal cells in chronic pancreatitis and cancerous pancreatic tissue was increased over normal and was more uniform (>95% cells/duct stained). Normal hamster pancreatic ducts showed weak or no expression of galectin-3. Hyperplastic pancreatic ductal cells from BOP-treated hamsters heavily expressed galectin-3 (60-95% cells/duct stained). Galectin-3 expression in ductal cells in cancerous pancreatic lesions was increased to >95%. Galectin-3 was also detected in the pancreatic nerves in all human tissue specimens tested.

A BALB/c 3T3-transformed cell line suitable for transfection assay of metastasis-inducing genes

A clonal cell line, 1-1ras1000, transformed by the activated c-Ha-ras oncogene, does not form metastases after i.v. injection into mice (experimental metastasis assay). Here, we show that this cell line is useful as a recipient to detect metastasis-inducing genes, using a transfection assay. Cells (1-1ras1000) were susceptible to metastasis induction by transfection with either v-src or genomic DNA from a v-src-and v-fos-transferred highly metastatic rat cell line (SR202). The susceptibility of 1-1ras1000 cells for lung metastasis induction was suitable for a genomic transfection assay to detect a metastasis-inducing gene in the transfected cells which had incorporated genomic DNA from donor metastatic tumor cells. When DNAs extracted from 7 human tumors were tested for metastasis induction, 2 DNAs from nonmalignant tumors (non-tumorigenic tumors in athymic nude mice) (2/2) were negative and 4 DNAs from malignant tumors (4/5) were positive in 1-1ras1000 cells for primary transfection. in one of the resulting metastases, the ability to metastasize was also transferred in the second and third cycles of genomic DNA transfection at high frequencies. All of the resulting metastases carried the human repetitive Alu sequence. Neither re-arrangements of the endogenous c-Haras nor changes of protein amounts were detected. Recipient 1-1ras1000 cells had a negligible rate of spontaneously metastatic conversion during in vitro cultivation and transfection processes. The resulting metastasized cells were easily isolated from the lung after culturing in selection medium containing G418 (geneticin). Isolated cells stably retained the ability to form metastatic lung nodules when re-injected into mice. Thus, 1-1ras1000 cells appear to be a useful system for the isolation of metastasis-inducing genes from human metastatic tumors.

Increased sialyl Lewis A expression and fucosyltransferase activity with acquisition of a high metastatic capacity in a colon cancer cell line

A human colon cancer cell line, OCUC-LM1(LM), was established from a liver metastasis in our laboratory. Intrasplenic injection of LM into nude mice was repeated three and five times, and the daughter cell lines were designated as LM-H3 and LM-H5 respectively. The level of sialyl Lewis A (SLA) in the supernatant of LM-H3 and LM-H5 was 3 and 4.5 times higher than that of LM respectively. Flow cytometric analysis of SLA expression showed that the peak channel for LM was 113; for LM-H3, 126; and for LM-H5, 146. The mean fluorescence intensity of LM was 102.3 +/- 43.5; for LM-H3, 126.2 +/- 28.4; and for LM-H5, 144.8 +/- 23.4. In endothelial cell adhesion assays, the percentages of adherent LM-H3 and LM-H5 cells were significantly higher than for LM. The activity of alpha1-->4 fucosyltransferase was higher in LM-H3 and LM-H5 than in LM, but there was no difference in alpha2-->3 sialyltransferase activities for type 1 chain among the cell lines. Our results suggest that SLA expression is associated with acquisition of a high capacity for liver metastasis of colon cancer; increased SLA expression is due mainly to increased fucosyltransferase activity.

The biochemistry of cancer dissemination

The progression of a tumor cell from one of benign delimited proliferation to invasive and metastatic growth is the major cause of poor clinical outcome of cancer patients. Recent research has revealed that this complex process requires many components for successful dissemination and growth of the tumor cell at secondary sites. These include angiogenesis, enhanced extracellular matrix degradation via tumor and host-secreted proteases, tumor cell migration, and modulation of tumor cell adhesion. Each individual component is multifaceted and is discussed within this review with respect to historical and recent findings. The identification of components and their interrelationship have yielded new therapeutic targets leading to the development of agents that may prove effective in the treatment of cancer and its metastatic progression.

The biology of colorectal cancer metastasis

Metastasis is a complex process involving a series of tumor-host interactions that follow tumor initiation and progression. Metastatic cancer cells must be capable of completing all stages of this process to establish secondary foci at distant sites. Most studies infer the functional significance of various observations based on models designed to emphasize the contributions of single molecules or ligand-receptor pairs. While providing useful insights into potential mechanisms of tumorigenesis and metastasis, additional studies are needed to elucidate the complex dynamic interactions involved in these processes. Nonetheless, a better understanding of how tumor cells metastasize is leading to new therapies to prevent and treat micrometastatic disease.

Independence of metastatic ability and extravasation: metastatic ras-transformed and control fibroblasts extravasate equally well

Escape of cancer cells from the circulation (extravasation) is thought to be a major rate-limiting step in metastasis, with few cells being able to extravasate. Furthermore, highly metastatic cells are believed to extravasate more readily than poorly metastatic cells. We assessed in vivo the extravasation ability of highly metastatic ras-transformed NIH 3T3 cells (PAP2) versus control nontumorigenic nontransformed NIH 3T3 cells and primary mouse embryo fibroblasts. Fluorescently labeled cells were injected intravenously into chicken embryo chorioallantoic membrane and analyzed by intravital videomicroscopy. The chorioallantoic membrane is an appropriate model for studying extravasation, since, at the embryonic stage used, the microvasculature exhibits a continuous basement membrane and adult permeability properties. The kinetics of extravasation were assessed by determining whether individual cells (n = 1481) were intravascular, extravascular, or in the process of extravasation, at 3, 6, and 24 h after injection. Contrary to expectations, our results showed that all three cell types extravasated with the same kinetics. By 24 h after injection > 89% of observed cells had completed extravasation from the capillary plexus. After extravasation, individual fibroblasts of all cell types demonstrated preferential migration within the mesenchymal layer toward arterioles, not to venules or lymphatics. Thus in this model and for these cells, extravasation is independent of metastatic ability. This suggests that the ability to extravasate in vivo is not necessarily predictive of subsequent metastasis formation, and that postextravasation events may be key determinants in metastasis.

Mucin glycoproteins in neoplasia

Mucins are high molecular weight glycoproteins that are heavily glycosylated with many oligosaccharide side chains linked O-glycosidically to the protein backbone. With the recent application of molecular biological methods, the structures of apomucins and regulation of mucin genes are beginning to be understood. At least nine human mucin genes have been identified to date. Although a complete protein sequence is known for only three human mucins (MUC1, MUC2, and MUC7), common motifs have been identified in many mucins. The pattern of tissue and cell-specific expression of these mucin genes are emerging, suggesting a distinct role for each member of this diverse mucin gene family. In epithelial cancers, many of the phenotypic markers for pre-malignant and malignant cells have been found on the carbohydrate and peptide moieties of mucin glycoproteins. The expression of carbohydrate antigens appears to be due to modification of peripheral carbohydrate structures and the exposure of inner core region carbohydrates. The expression of some of the sialylated carbohydrate antigens appears to correlate with poor prognosis and increased metastatic potential in some cancers. The exposure of peptide backbone structures of mucin glycoproteins in malignancies appears to be due to abnormal glycosylation during biosynthesis. Dysregulation of tissue and cell-specific expression of mucin genes also occurs in epithelial cancers. At present, the role of mucin glycoproteins in various stages of epithelial cell carcinogenesis (including the preneoplastic state and metastasis), in cancer diagnosis and immunotherapy is under investigation.