Does colon cancer ever metastasize to bone first? a temporal analysis of colorectal cancer progression.

BACKGROUND: It is well recognized that colorectal cancer does not frequently metastasize to bone. The aim of this retrospective study was to establish whether colorectal cancer ever bypasses other organs and metastasizes directly to bone and whether the presence of lung lesions is superior to liver as a better predictor of the likelihood and timing of bone metastasis. METHODS: We performed a retrospective analysis on patients with a clinical diagnosis of colon cancer referred for staging using whole-body 18F-FDG PET and CT or PET/CT. We combined PET and CT reports from 252 individuals with information concerning patient history, other imaging modalities, and treatments to analyze disease progression. RESULTS: No patient had isolated osseous metastasis at the time of diagnosis, and none developed isolated bone metastasis without other organ involvement during our survey period. It took significantly longer for colorectal cancer patients to develop metastasis to the lungs (23.3 months) or to bone (21.2 months) than to the liver (9.8 months). Conclusion: Metastasis only to bone without other organ involvement in colorectal cancer patients is extremely rare, perhaps more rare than we previously thought. Our findings suggest that resistant metastasis to the lungs predicts potential disease progression to bone in the colorectal cancer population better than liver metastasis does.

Bisphosphonates for metastatic bone disease in lung cancer

Bisphosphonates have proven effectiveness in preventing skeletal-related events (SREs) in advanced breast cancer, prostate cancer and multiple myeloma. The purpose of this study was to assess efficacy of bisphosphonates in preventing SREs, in controlling pain, and in increasing life expectancy in lung cancer patients with bone metastases.^ We performed an electronic search in MEDLINE, EMBASE, Web of Science, and Cochrane library databases up to April 4, 2010. Hand searching and searching in clinicaltrials.gov were also performed. Two independent reviewers selected all clinical trials that included lung cancer patients with bone metastases treated with bisphosphonates. We excluded articles that involved cancers other than lung, patients without bone metastasis and treatment other than bisphosphonates. Outcome questions answered were efficacy measured as overall pain control, overall improvement in survival and reduction in skeletal-related events or SREs (fracture, cord compression, radiation or surgery to the bone, hypercalcemia of malignancy). The quality of each study was evaluated using the Cochrane Back Review group questionnaire to assess risk of bias (0-worst to 11-best). Data extraction and quality assessments were independently performed by two assessors. Meta-analyses were performed where more than one study with similar outcomes were found.^ We identified eight trials that met our inclusion criteria. Three studies evaluated zoledronic acid, three pamidronate, three clodronate and two ibandronate. Two were placebocontrol trials while two had multi-group comparisons (radiotherapy, radionucleotides, and chemotherapy) and two had different bisphosphonate as active controls. Quality scores ranged from 1-4 out of 11 suggesting high risk of bias. Studies failed to report adequate explanation of randomization procedures, concealment of randomization and blinding. Metaanalysis showed that patients treated with zoledronic acid alone had lower rates of developing SREs compared to placebo at 21 months (RR=0.80, 95% CI=0.66-0.97, p=0.02). Meta-analyses also showed increased pain control when a bisphosphonate was added to the existing treatment modality like chemotherapy or radiation (RR=1.17, 95% CI=1.03-1.34, p=0.02). However, pain control was not statistically significantly different among various bisphosphonates when other treatment modalities were not present. Despite improvement in SRE and pain control, bisphosphonates failed to show improvement in overall survival (Difference in means=109.1 days, 95% CI= -51.52 – 269.71, p=0.183).^ Adding biphosphonates to standard care improved pain control and reduced SREs. Biphosphonates did not improve overall survival. Further larger studies with higher quality are required to stengthen the evidence.^ Keywords/MeSH terms Bisphosphonates/diphosphonates: generic, chemical and trade names.^

Collagen I modulates growth and gene expression in prostate cancer cells

Prostate cancer is the second leading cause of male cancer-related deaths in the United States. Interestingly, prostate cancer preferentially metastasizes to skeletal tissue. Once in the bone microenvironment, advanced prostate cancer becomes highly resistant to therapeutic modalities. Several factors, such as extracellular matrix (ECM) components, have been implicated in the spread and propagation of prostatic carcinoma. In these studies, we have utilized the PC3 cell line, derived from a human bone metastasis, to investigate the influence of the predominant bone ECM protein, type I collagen, on prostate cancer cell proliferation and gene expression. We have also initiated the design and production of ribozymes to specific gene targets that may influence prostate cancer bone metastasis. ^ Our results demonstrate that PC3 cells rapidly adhere and spread on collagen I to a greater degree than on fibronectin (FN) or poly-L-lysine (PLL). Flow cytometry analysis reveals the presence of the α1, α2 and α3 collagen binding integrin subunits. The use of antibody function blocking studies reveals that PC3 cells can utilize α2β 1 and α3β1 integrins to adhere to collagen I. Once plated on collagen I, the cells exhibit increased rates of proliferation compared with cells plated on FN or tissue culture plastic. Additionally, cells plated on collagen I show increased expression of proteins associated with progression through G1 phase of the cell cycle. Inhibitor studies point to a role for phosphatidylinositol 3-kinase (PI3K), MAP kinase (MAPK), and p70 S6 kinase in collagen I-mediated PC3 cell proliferation and cyclin D1 expression. To further characterize the effect of type I collagen on prostate cancer bone metastasis, we utilized a cDNA microarray strategy to monitor type I collagen-mediated changes in gene expression. Results of this analysis revealed a gene expression profile reflecting the increased proliferation occurring on type I collagen. Microarray analysis also revealed differences in the expression of specific gene targets that may impact on prostate cancer metastasis to bone. ^ As a result of our studies on the interaction of prostate cancer cells and the skeletal ECM, we sought to develop novel molecular tools for future gene therapy of functional knockdown experiments. To this end, we developed a series of ribozymes directed against the α2 integrin and at osteopontin, a protein implicated in the metastasis of various cancers, including prostate. These ribozymes should facilitate the future study of the mechanism of prostate cancer cell proliferation, and disease progression occurring at sites of skeletal metastasis where a type I collagen-based environment predominates. ^ Together these studies demonstrate the involvement of bone ECM proteins on prostate cancer cell proliferation and suggest that they may play a significant role on the growth of prostate metastases once in the bone microenvironment. ^

COX-2 expression in operable triple negative breast cancer: A hospital based cross-sectional study

Objectives. Triple Negative Breast Cancer (TNBC) lack expression of estrogen receptors (ER), progesterone receptors (PR), and absence of Her2 gene amplification. Current literature has identified TNBC and over-expression of cyclo-oxygenase-2 (COX-2) protein in primary breast cancer to be independent markers of poor prognosis in terms of overall and distant disease free survival. The purpose of this study was to compare COX-2 over-expression in TNBC patients to those patients who expressed one or more of the three tumor markers (i.e. ER, and/or PR, and/or Her2).^ Methods. Using a secondary data analysis, a cross-sectional design was implemented to examine the association of interest. Data collected from two ongoing protocols titled "LAB04-0657: a model for COX-2 mediated bone metastasis (Specific aim 3)" and "LAB04-0698: correlation of circulating tumor cells and COX-2 expression in primary breast cancer metastasis" was used for analysis. A sample of 125 female patients was analyzed using Chi-square tests and logistic regression models. ^ Results. COX-2 over-expression was present in 33% (41/125) and 28% (35/124) patients were identified as having TNBC. TNBC status was associated with elevated COX-2 expression (OR= 3.34; 95% CI= 1.40–8.22) and high tumor grade (OR= 4.09; 95% CI= 1.58–10.82). In a multivariable analysis, TNBC status was an important predictor of COX-2 expression after adjusting for age, menopausal status, BMI, and lymph node status (OR= 3.31; 95% CI: 1.26–8.67; p=0.01).^ Conclusion. TNBC is associated with COX-2 expression—a known marker of poor prognosis in patients with operable breast cancer. Replication of these results in a study with a larger sample size, or a future randomized clinical trial demonstrating an improved prognosis with COX-2 suppression in these patients would support this hypothesis.^

Clinical and epidemiological characteristics of breast cancer metastases

Introduction. Breast cancer is a highly variable disease, and long-term outcomes for individual patients are difficult to predict. We evaluated a retrospective cohort of early stage breast cancer (ESBC) patients based on a variety of clinical and epidemiological factors, specifically looking at the distribution of metastasis and associations with these clinical and epidemiological factors. ^ Methods. Patients were derived from the Early Stage Breast Cancer Repository (ESBCR) with a breast cancer diagnosed between 1985 and 2000. We conducted univariate and multivariate analysis of the data to evaluate associations between characteristics and occurrence of overall, visceral, and bone metastasis. Visceral metastasis was defined as lung, liver, peritoneal, lymph node (thoracic, abdominal, pelvis), and contralateral breast cancer. ^ Results. Overall, 394 (16%) patients developed a metastasis. Of these, 83% were visceral and 17% were bone. Multivariate analyses identified the following variables to be associated with metastasis: Any metastasis: age at diagnosis, stage, ER/PR status, hormone treatment, and type of surgery (1)Visceral metastasis: age at diagnosis, stage, hormone treatment, and type of surgery (2) Bone metastasis –Alcohol use, stage, and ER/PR status ^ Discussion/conclusion. ER-/PR- status has previously been found to be associated with bone metastasis, as we confirm in our cohort. We report an association between alcohol use and bone metastasis whereas previous studies find an association with recurrence. Distribution of metastases varies from previous studies. Typically, previous studies reported bone metastasis >30%, yet our study found 17%. Previous studies varied in design, and definition of visceral metastasis. Future research is needed to further elucidate prognostic factors associated with specific metastases A more thorough understanding of what might predict which ESBC patients will develop metastases can help direct future treatment. Future studies of this nature could include the Perou intrinsic subtypes, biomarkers like Ki-67, and genetic analyses such as Oncotype DX or MammaPrint.^

Osterix inhibits bone destruction in osteosarcoma through transcriptional repression of Interleukin-1alpha expression

Osteosarcoma, a malignant bone tumor, rapidly destroys the cortical bone. We demonstrated that mouse K7M2 osteosarcoma cells were deficient in osterix (osx), a zinc finger-containing transcription factor required for osteoblasts differentiation and bone formation. These cells formed lytic tumors when injected into the tibia. The destruction of bone is mediated by osteoclasts in osteosarcoma. The less expression of osterix with osteolytic phenotype was also observed in more tumor cell lines. Replacement of osterix in K7M2 cells suppressed lytic bone destruction, inhibited tumor growth in vitro and in vivo, and suppressed lung metastasis in vivo and the migration of K7M2 to lung conditioned medium in vitro. By contrast, inhibiting osterix by vector-based small interfering RNA (siRNA) in two cell lines (Dunn and DLM8) that expressed high levels of osterix converted osteoblastic phenotype to lytic. Recognizing and binding of Receptor Activator of NF-κB (RANK) on osteoclast precursors by its ligand RANKL is the key osteoclastogenic event. Increased RANKL results in more osteoclast activity. We investigated whether K7M2-mediated bone destruction was secondary to an effect on RANKL. The conditioned medium from K7M2 could upregulate RANKL in normal osteoblast MC3T3, which might lead to more osteoclast formation. By contrast, the conditioned medium from K7M2 cells transfected with osx-expressing plasmid did not upregulate RANKL. Furthermore, Interleukin-1alpha (IL-1α) was significantly suppressed following osx transfection. IL-1α increased RANKL expression in MC3T3 cells, suggesting that osx may control RANKL via a mechanism involving IL-1α. Using a luciferase reporter assay, we demonstrated that osx downregulated IL-1α through a transcription-mediated mechanism. Following suppression of osterix in Dunn and DLM8 cells led to enhanced IL-1α promoter activity and protein production. Site-directed mutagenesis and Chromatin immunoprecipitation (ChIP) indicated that osterix downregulated IL-1α through a Sp1-binding site on the IL-1α promoter. These data suggest that osterix is involved in the lytic phenotype of osteosarcoma and that this is mediated via transcriptional repression of IL-1α. ^

The Role Of IL-8-Mediated Src Family Kinase Activation In Tumor-Tumor And Tumor-Stromal Interactions In Metastasis Of Prostate Cancer

Men with localized prostate cancer (PCa) have a 100% five-year survival rate, but this rate drops to 33% for men with metastatic disease. A better understanding of the metastatic process is needed to develop better therapies for PCa. Aberrant activation of protein tyrosine kinases, including Src Family Kinases (SFKs) contribute to metastasis through numerous functions, one of which leads to increased expression of cytokines, such as IL-8. However, the relationship between Src activity and IL-8 regulation is not completely understood. In cell line models, I determined that IL-8 activates Src and in turn Src activates IL-8 demonstrating a feed forward loop contributing to the migration and invasion of PCa cells. However, IL-8 is also produced by tumor-associated stromal cells. In bone marrow derived stromal cells (HS5), I demonstrated a feed forward loop occurs as was observed in tumor cells. HS5 conditioned media increased Src activity in PCa cells. By silencing IL-8 in HS5 cells, Src activity was decreased to control levels in PCa cells as was migration and invasion. Thus, stromal cells producing IL-8 contribute to metastatic properties of PCa by a paracrine mechanism. To examine the effect of stromal cells on tumor growth and metastatic potential of PCa in vivo, I mixed HS5 and PCa cells and co-injected them intraprostatically. I determined that tumor growth and metastases were increased. By silencing IL-8 in HS5 cells and co-injecting them with PCa cells intraprostatically, tumor growth and metastases were still increased relative to injection of PCa cells alone, but decreased relative to co-injections with PCa cells and HS5 cells. These studies demonstrated: (1) a feed forward loop in both tumor and stromal cells, whereby IL-8 activates Src, derepressing IL-8 expression in PCa cells in vitro; (2) stromal produced IL-8 activates Src and contributes to the migration and invasion of PCa cells in vitro; and (3) stromal produced IL-8 is responsible, in part, for increases in PCa tumor growth and metastatic potential. Together, these studies demonstrated that IL-8-mediated Src activity increases the metastatic potential of PCa and therapeutic agents interfering with the IL-8/SFK signaling axis may be useful for prevention and treatment of metastases.

Fas ligand and soluble Fas -opposing molecules in melanoma lung metastasis

Deregulation of apoptotic cell death can result in aberrant accumulation of cells and increased tumor incidence. Fas (CD95) and Fas ligand (FasL) are a receptor-ligand pair whose activation induces apoptosis in many cell types. Previously, we demonstrated that low metastatic, Fas+ K1735-P murine melanoma cells spontaneously metastasize to the lung following orthotopic injection into FasL-deficient (gld) mice compared to wild-type (wt) controls. We further demonstrated that the expression of the Fas antagonist soluble Fas (sFas) directly correlates with disease stage in patients with melanoma, breast, and colon cancer. These findings document a role for host-derived FasL, in the control of metastatic disease and suggest a role for tumor-associated sFas in acquiring metastatic potential. To directly test whether FasL expressed on lymphocytes or on lung stromal cells restricts metastasis, bone marrow chimeras were generated between C3H wt and C3H gld mice. Chimeric animals were injected subcutaneously with 5 × 105 K1735-P and the incidence and number of spontaneous lung metastases scored. The data show that wt mice receiving gld marrow had a greater number of lung metastases (median 9.5, range 2–31) than gld mice reconstituted with wt marrow (median 1, range 0–31; p < 0.016). Interestingly, both groups had fewer metastases compared to gld controls (median 18.5, range 0–46) but more than wt controls (median 2, range 0–7). These observations provide the first evidence that both hematopoietic- and nonhematopoietic-host derived FasL, are important in the control of melanoma metastasis to the lung. To directly test whether tumor-associated sFas expression can enhance metastasis, K1735-P cells were transfected with three isoforms of sFas (Exo4Del, Exo6Del, and Exo3, 4, 6Del). RT-PCR and ELISA analysis confirmed the expression of sFas RNA and protein respectively. Following intravenous injection of 5 × 104 cells, sFas transfected cells formed significantly more experimental lung metastases [Exo6Del clone 3 (median 22, range 0–36), Exo6Del clone 7 (median 31, range 4–50), Exo3, 4, 6Del (median 22.5, range 13–48)] compared to vector control cells (median 6.5, range 3–29). Together, these data provide the first evidence that sFas is sufficient to enhance the metastatic potential of Fas+ melanoma cells. ^