Effect of estrogen and antiestrogen therapy in rats bearing mesenchymal tumors.

We applied both hormonal and antiestrogen treatment in female Wistar rats to analyze the estrogen dependence of the growth of sarcomas induced with 9,10-dimethyl-1,2-benzanthracene. Animals bearing tumors of 10 mm in diameter were divided at random into five groups and submitted to different treatments during 24 weeks. The treatment with ovariectomy and tamoxifen in tumor-bearing animals resulted in tumor growth suppression and prolonged survival by a protection against the lethal tumor. On the other hand, the estrogen treatment exerted an adverse effect showing a faster growth of the tumors and a great decrease in survival. In summary, the antiestrogen treatment can have an antitumor effect in mesenchymal tumors, possibly by modifying the immunological status of the host.     

Radiation therapy and Toll-like receptor signaling: implications for the treatment of cancer

The identification of pathogen-associated molecular patterns, conserved microbial structures that act on Toll-like receptors, has led to a novel avenue of investigation aimed at developing a new generation of cancer immunotherapies. Ligation of Toll-like receptors results in the induction of robust immune responses that may be directed against tumor-associated antigens. Recent data suggest that such strategies may result in enhanced antitumor immunity. Nonetheless, as clinically effective immunotherapy for cancer remains a somewhat distant goal, attention has shifted toward multimodality approaches to cancer therapy, sometimes combining novel immune interventions and conventional treatments. The traditional view of radiation therapy as immunosuppressive has now been challenged, prompting a re-evaluation of its potential as an adjunct to immunotherapy. Radiation therapy can enhance the expression of tumor-associated antigens, induce immune-mediated targeting of tumor stroma, and diminish regulatory T cell activity. Recent evidence suggests that radiation therapy may also activate effectors of innate immunity through TLR-dependent mechanisms, thereby augmenting the adaptive immune response to cancer. In this paper, we will review evidence for enhanced tumor-directed immunity resulting from radiation exposure and early promising data suggesting synergistic effects of radiation and TLR-targeted immunotherapies.     

The Wnt signaling pathway: implications for therapy in osteosarcoma

Osteosarcoma is the most common primary bone malignancy, with a high propensity for local invasion, early metastasis and relapse. While the molecular mechanisms behind osteosarcoma development and metastasis have not yet been fully elucidated, research has highlighted an important role for Wnt signaling. Several Wnt ligands, receptors and coreceptors are highly expressed in osteosarcoma cell lines, while Wnt inhibitors are downregulated. As a result, research has begun to identify mechanisms with which to inhibit Wnt signaling. The use of Wnt pathway inhibitors and the targeting of c-Met, a Wnt regulated proto-oncogene, may be two possible mechanisms for treatment of osteosarcoma. In addition, as the Wnt signaling pathway is a regulator of stem cells, reagents that function as Wnt inhibitors are currently under investigation as inhibitors of cancer stem cell proliferation. Research involving the Wnt signaling pathway and cancer stem cells holds promise for novel treatment options in the future.     

Breast conservation therapy as a treatment option for the elderly. The M. D. Anderson experience

BACKGROUND: Although almost half of all incidents of breast carcinoma occur in women age > or = 65 years, not enough is known about appropriate care for patients in this age group. The objective of the current study was to evaluate the role of breast conservation therapy in the management of breast carcinoma in women age > or = 65 years. METHODS: From 1970 to 1994, 1325 patients with carcinoma of the breast were treated with breast conservation therapy (segmental mastectomy and radiation therapy with or without axillary lymph node dissection) at The University of Texas M. D. Anderson Cancer Center. From this patient group, the authors identified 184 elderly women (> or = 65 years) with Stage 0-III disease at the time of diagnosis. RESULTS: The median patient age was 70 years (range, 65-88 years). The distribution of disease by stage among the women was Stage 0 disease in 12 patients (7%), Stage I disease in 107 patients (58%), Stage II disease in 63 patients (34%), and Stage III disease in 2 patients (1%). Comorbid conditions that may have influenced treatment planning were reported in 91 patients (50%). An axillary lymph node dissection was performed in 135 patients (73%), with positive axillary lymph nodes found in 30 patients (22%). Adjuvant chemotherapy was given to 10 patients (5%), and tamoxifen therapy was given to 63 patients (34%). Complications from treatment were reported in 24 patients (13%). With a median follow-up of 7.3 years (range, 0.25-23.5 years), 9 patients developed locoregional disease recurrence (5%), 10 patients developed contralateral breast carcinoma (5%), and 21 patients developed distant metastasis (11%). At last follow-up, 113 patients (61%) were alive, 15 patients (8%) were dead of disease, and 56 patients (30%) were dead of other causes. The 5-year and 10-year disease specific survival rates were 96% and 91%, respectively. CONCLUSIONS: Breast conservation therapy with segmental mastectomy and postoperative radiation therapy with or without axillary lymph node dissection provides excellent local control and disease free survival in elderly women with breast carcinoma. This treatment should be considered as the standard of care for elderly patients without severe comorbid disease.     

The role of Notch signaling in human cervical cancer: implications for solid tumors

The detection of intracellular forms of Notch1 in human cervical cancers more than a decade ago prompted an investigation into the possible role of this pathway in driving these cancers. These tumors are consistently characterized by features of deregulated ligand-dependent signaling. Although Notch signaling complements the function of papillomavirus oncogenes in transformation assays of human keratinocytes, there are dose-dependent effects, which inhibit growth of established cervical cancer cell lines. Two pro-oncogenic effector mechanisms that have been suggested to operate in this context by Notch signaling are the activation of PI3K/Akt pathway and the upregulation of c-Myc. Collectively, there is a complex interplay between Notch signaling and papillomaviruses in the context of cervical carcinogenesis. Better animal model systems and identification of human cervical cancer stem cells should help clarify the possible stage specific and pleiotropic effects and regulation of Notch signaling.     

Interstitial pressure gradients in tissue-isolated and subcutaneous tumors: implications for therapy

High interstitial fluid pressure (IFP) in solid tumors is associated with reduced blood flow as well as inadequate delivery of therapeutic agents such as monoclonal antibodies. In the present study, IFP was measured as a function of radial position within two rat tissue-isolated tumors (mammary adenocarcinoma R3230AC, 0.4-1.9 g, n = 9, and Walker 256 carcinoma, 0.5-5.0 g, n = 6) and a s.c. tumor (mammary adenocarcinoma R3230AC, 0.6-20.0 g, n = 7). Micropipettes (tip diameters 2 to 4 microns) connected to a servo-null pressure-monitoring system were introduced to depths of 2.5 to 3.5 mm from the tumor surface and IFP was measured while the micropipettes were retrieved to the surface. The majority (86%) of the pressure profiles demonstrated a large gradient in the periphery leading to a plateau of almost uniform pressure in the deeper layers of the tumors. Within isolated tumors, pressures reached plateau values at a distance of 0.2 to 1.1 mm from the surface. In s.c. tumors the sharp increase began in skin and levelled off at the skin-tumor interface. These results demonstrate for the first time that the IFP is elevated throughout the tumor and drops precipitously to normal values in the tumor's periphery or in the immediately surrounding tissue. These results confirm the predictions of our recently published mathematical model of interstitial fluid transport in tumors (Jain and Baxter, Cancer Res., 48: 7022-7032, 1988), offer novel insight into the etiology of interstitial hypertension, and suggest possible strategies for improved delivery of therapeutic agents.     

Temozolomide as monotherapy is effective in treatment of advanced malignant neuroendocrine tumors.

PURPOSE: A retrospective analysis of the toxicity and efficacy of temozolomide in advanced neuroendocrine tumors. EXPERIMENTAL DESIGN: Thirty-six patients with advanced stages of neuroendocrine tumor (1 gastric, 7 thymic and 13 bronchial carcinoids, 12 pancreatic endocrine tumors, 1 paraganglioma, 1 neuroendocrine foregut, and 1 neuroendocrine cecal cancer) were treated with temozolomide (200 mg/m(2)) for 5 days every 4 weeks. Patients had previously received a mean of 2.4 antitumoral medical regimens. Tumor response was evaluated radiologically according to the Response Evaluation Criteria in Solid Tumors every 3 months on an intent-to-treat basis. The circulating tumor marker plasma chromogranin A was also assessed. The expression of O(6)-methylguanine DNA methyltransferase, an enzyme implicated in chemotherapy resistance, was studied by immunohistochemistry (n=23) and compared with response to temozolomide. RESULTS: Median overall time to progression was 7 months (95% confidence interval, 3-10). Radiologic response was seen in 14% of patients and stable disease in 53%. Side effects were mainly hematologic; 14% experienced grade 3 or 4 thrombocytopenia (National Cancer Institute toxicity criteria). Ten patients had tumors with O(6)-methylguanine DNA methyltransferase immunoreactivity in <10% of nuclei, whereas four patients showed radiologic responses. CONCLUSIONS: Temozolomide as monotherapy had acceptable toxicity and antitumoral effects in a small series of patients with advanced malignant neuroendocrine tumors and four of these showed radiologic responses.     

Emerging pathways in the development of chondrosarcoma of bone and implications for targeted treatment

Chondrosarcoma is a malignant cartilage-forming tumour of bone, of which distinct clinicopathological subtypes are known. Conventional chondrosarcoma is notorious for its locally aggressive behaviour as well as for its resistance to chemotherapy and radiotherapy; so far surgery is the only effective therapeutic option. During the past 10 years, substantial new insights have been gained about molecular cell biology, molecular cytogenetics, and immunopathology, leading to better understanding of chondrosarcoma development at the molecular level, which will ultimately lead to better clinical understanding and possibly to the development of targeted treatment.     

TRAIL receptor signaling and therapeutic option in bone tumors: the trap of the bone microenvironment

Tumor Necrosis Factor-Related Apoptosis Inducing Ligand (TRAIL/TNFSF10) has been reported to specifically induce malignant cell death being relatively nontoxic to normal cells. Since its identification 15 years ago, the antitumor activity and therapeutic value of TRAIL have been extensively studied. Five receptors quickly emerged, two of them being able to induce programmed cell death in tumor cells. This review takes a comprehensive look at this ligand and its receptors, and its potential role in primary bone tumors (osteosarcoma and Ewing's sarcoma) therapy. The main limit of clinical use of TRAIL being the innate or acquired resistance mechanisms, different possibilities to sensitize resistant cells are discussed in this review, together with the impact of bone microenvironment in the regulation of TRAIL activity.     

High-dose therapy and autologous peripheral-blood stem-cell transplantation as salvage treatment for HIV-associated lymphoma in patients receiving highly active antiretroviral therapy.

PURPOSE: High-dose therapy (HDT) and peripheral-blood stem-cell transplantation (PBSCT) in HIV-associated lymphoma (HIV-Ly) has been recently reported in selected patients. We describe the results of a multi-institutional program of HDT and PBSCT as salvage therapy in HIV-Ly responsive to highly active antiretroviral therapy (HAART) in unselected patients. PATIENTS AND METHODS: Patients with resistant or relapsed HIV-Ly after first-line chemotherapy (CT) underwent PBSC collection after a course of second-line CT or cyclophosphamide and granulocyte colony-stimulating factor. Patients with chemotherapy-sensitive disease received carmustine, etoposide, cytarabine, and melphalan (BEAM regimen) and PBSC reinfusion. Effective HAART was maintained during the entire program. RESULTS: Sixteen consecutive patients entered the program. Adequate collection of PBSC was obtained in 80% of patients (median CD34+ cells 6.8 x 106/kg). Three patients had early progression. Ten patients (62%) received PBSCT with prompt engraftment in all patients (neutrophils and platelet engraftment after a median of 10 days [range, 8 to 10 days] and 13 days [range, 8 to 18 days], respectively). No patients died as a result of opportunistic or other infections or treatment-related complications. Eight of nine assessable patients achieved complete remission (one patient after radiotherapy for residual disease) and one patient achieved partial remission. Two patients experienced relapse and died at +10 and +14 months. Six patients are alive and disease free at a median of 8 months after transplantation. CONCLUSION: Our data confirm that HDT plus PBSCT is feasible and active as salvage therapy in HIV-Ly on a multi-institutional basis and in unselected HAART-responding patients. HIV infection should no longer preclude the opportunity of HDT in patients with lymphoma.     

Assessment of improved organ at risk sparing for meningioma: Light ion beam therapy as boost versus sole treatment option

Purpose

To compare photons, protons and carbon ions and their combinations for treatment of atypical and anaplastical skull base meningioma.

Material and methods

Two planning target volumes (PTV_initial/PTV_boost) were delineated for 10 patients (prescribed doses 50 Gy(RBE) and 10 Gy(RBE)). Plans for intensity modulated photon (IMXT), proton (IMPT) and carbon ion therapy (¹²C) were generated assuming a non-gantry scenario for particles. The following combinations were compared: IMXT + IMXT/IMPT/¹²C; IMPT + IMPT/¹²C; and ¹²C + ¹²C. Plan quality was evaluated by target conformity and homogeneity (CI, HI), V_95%, D_2% and D_50% and dose-volume-histogram (DVH) parameters for organs-at-risk (OAR). If dose escalation was possible, it was performed until OAR tolerance levels were reached.

Results

CI was worst for IMXT. HI < 0.05 ± 0.01 for ¹²C was significantly better than for IMXT. For all treatment options dose escalation above 60 Gy(RBE) was possible for four patients, but impossible for six patients. Compared to IMXT + IMXT, ion beam therapy showed an improved sparing for most OARs, e.g. using protons and carbon ions D_50% was reduced by more than 50% for the ipsilateral eye and the brainstem.

Conclusion

Highly conformal IMPT and ¹²C plans could be generated with a non-gantry scenario. Improved OAR sparing favors both sole ¹²C and/or IMPT plans.     

Microvascular pressure is the principal driving force for interstitial hypertension in solid tumors: implications for vascular collapse.

The interstitial fluid pressure (IFP) has been found to be as high as 20 to 50 mm Hg in both experimental and human solid tumors. While the IFP is an important determinant of the delivery of therapeutic agents to neoplastic cells in vivo, the mechanisms responsible for interstitial hypertension are not completely understood. The high vascular permeability of tumor blood vessels and the absence of a functional lymphatic circulation suggest that the hydrostatic microvascular pressure (MVP) is the main force governing IFP in tumors. To test this hypothesis, we simultaneously measured IFP and MVP in 13 tissue-isolated R3230AC mammary adenocarcinomas transplanted in rats. The MVP in superficial postcapillary venules of diameters between 25 and 250 microns was measured with the micropuncture technique. MVP was compared to the IFP in the periphery (measured with micropuncture technique) and in the center (measured with wick-in-needle technique). Similar to our previous study, IFP rose rapidly and reached maximum values at a depth of 0.2 to 1.0 mm from the tumor surface. These maximum IFP values [16.5 +/- 7.1 mm Hg (SD)] were equal to IFP in the tumor center [18.4 +/- 9.3 mm Hg] [R2 = 0.86, P greater than 0.8]. Superficial MVP (17.3 +/- 6.1 mm Hg) was equal to both central (P greater than 0.9) and superficial IFP (P greater than 0.7). These results demonstrate that the main driving force for IFP in tumors is the MVP. Furthermore, the concept that blood vessel collapse is induced by higher hydrostatic pressures in the tumor interstitium compared to that in the vascular lumen is not supported by the present finding that elevated IFP is accompanied by equally elevated MVP.     

Randomized study of paclitaxel and tamoxifen deposition into human brain tumors: implications for the treatment of metastatic brain tumors.

PURPOSE: Drug resistance in brain tumors is partially mediated by the blood-brain barrier of which a key component is P-glycoprotein, which is highly expressed in cerebral capillaries. Tamoxifen is a nontoxic inhibitor of P-glycoprotein. This trial assessed, in primary and metastatic brain tumors, the differential deposition of paclitaxel and whether tamoxifen could increase paclitaxel deposition. EXPERIMENTAL DESIGN: Patients for surgical resection of their primary or metastatic brain tumors were prospectively randomized to prior paclitaxel alone (175 mg/m(2)/i.v.) or tamoxifen for 5 days followed by paclitaxel. Central and peripheral tumor, surrounding normal brain and plasma, were analyzed for paclitaxel and tamoxifen. RESULTS: Twenty-seven patients completed the study. Based on a multivariate linear regression model, no significant differences in paclitaxel concentrations between the two study arms were found after adjusting for treatment group (tamoxifen versus control). However, in analysis for tumor type, metastatic brain tumors had higher paclitaxel concentrations in the tumor center (1.93-fold, P = 0.10) and in the tumor periphery (2.46-fold, P = 0.039) compared with primary brain tumors. Pharmacokinetic analyses showed comparable paclitaxel areas under the serum concentration between treatment arms. CONCLUSIONS: Paclitaxel deposition was not increased with this tamoxifen schedule as the low plasma concentrations were likely secondary to concurrent use of P-450-inducing medications. However, the statistically higher paclitaxel deposition in the periphery of metastatic brain tumors provides functional evidence corroborating reports of decreased P-glycoprotein expression in metastatic versus primary brain tumors. This suggests that metastatic brain tumors may respond to paclitaxel if it has proven clinical efficacy for the primary tumor's histopathology.     

Neutron or photon irradiation for prostate tumors: enhancement of cytokine therapy in a metastatic tumor model.

We have shown that implantation of human prostate carcinoma PC-3 cells in the prostates of nude mice led to the formation of prostate tumors with metastases to para-aortic lymph nodes. We found that day 6 prostate tumors were responsive to systemic injections of interleukin 2 (IL-2) therapy. We have now investigated the combination of primary tumor irradiation and IL-2 for metastatic prostate cancer in this preclinical tumor model. The effect of neutron radiation was compared with that of photon radiation. Advanced prostate tumors (approximately 0.4 cm) were irradiated, and a day later, mice were treated with systemic IL-2 for three weekly cycles. In separate experiments, mice were either sacrificed on day 30 to assess prostate tumor size and tumor histology or followed for survival. A dose-dependent inhibition of prostate tumor growth was caused either by photons or neutrons, but neutrons were more effective than photons with a relative biological effectiveness of 2. The tumor inhibition obtained with 250 cGy neutrons and 500 cGy photons was significant (>75%) and was further increased (> or = 90%) by addition of IL-2 therapy. In survival studies, the combination of radiation and IL-2 showed a significant survival advantage compared with untreated mice (P < or = 0.005) or radiation alone (P < or = 0.003) and an increase in median survival compared with IL-2 alone. Histologically, the combined regimen resulted in a greater degree of tumor destruction, inflammatory response, and vascular damage than that observed with each modality alone. After this combined treatment, no tumor was histologically detected in the para-aortic lymph nodes of these mice, and the lymph nodes were significantly smaller. These findings showed that primary tumor irradiation, either with neutrons or photons, enhanced IL-2 therapeutic effect for the treatment of advanced prostate cancer. This combined modality induced an antitumor response that controlled the growth of prostate tumors and their metastases.     

AKT inhibition by triciribine alone or as combination therapy for growth control of gastroenteropancreatic neuroendocrine tumors

Up-regulation of phosphatidylinositol-3-kinase (PI3K)-AKT signaling facilitates tumor cell growth and inhibits cell demise. The AKT-pathway also plays an important role in cytostatic therapy resistance and response to hypoxia and angiogenesis. Using real-time cell proliferation assay we examined the potency of triciribine in three distinct neuroendocrine gastrointestinal tumor cell lines. Also we investigated triciribine's induction of apoptosis and effects on a broad range of cancer-associated gene products. Furthermore, we characterized the role of PTEN as a possible predictor of sensitivity to triciribine in GEP-NETs. We also looked for additive anti-neoplastic effects of triciribine when combined with conventional cytostatic drugs or other targeted drugs, affecting different molecules of the PI3K-AKT-pathway and we assessed the potency of triciribine to inhibit tumor growth in vivo, by using the chick chorioallantoic membrane assay. Treatment of insulinoma (CM) or gut neuroendocrine tumor cells (STC-1) with triciribine significantly reduced tumor cell growth by 59% and 65%, respectively. By contrast, the highly expressing PTEN carcinoid cell line BON did not respond, even at higher doses. Combinations of triciribine with classic cytostatic drugs as well as drugs targeting other molecules of the PI3K-AKT-pathway led to synergistic anti-proliferative effects. Additional in vivo-evaluations confirmed the anti-neoplastic potency of triciribine. Thus, our data show that inhibition the AKT-pathway potently reduces the growth of GEP-NET cells alone or in combination therapies. AKT inhibition may provide a rationale for future evaluations.