Clinical and immunomodulatory effects of celecoxib plus interferon-alpha in metastatic renal cell carcinoma patients with COX-2 tumor immunostaining

Lipids as Targets for Renal Cell Carcinoma Therapy

Kidney cancer is among the top ten most common cancers to date. Within the kidney, renal cell carcinoma (RCC) is the most common solid lesion occurring. While various risk factors are suspected, including unhealthy lifestyle, age, and ethnicity, genetic mutations seem to be a key risk factor. In particular, mutations in the von Hippel-Lindau gene (Vhl) have attracted a lot of interest since this gene regulates the hypoxia inducible transcription factors HIF-1α and HIF-2α, which in turn drive the transcription of many genes that are important for renal cancer growth and progression, including genes involved in lipid metabolism and signaling. Recent data suggest that HIF-1/2 are themselves regulated by bioactive lipids which make the connection between lipids and renal cancer obvious. This review will summarize the effects and contributions of the different classes of bioactive lipids, including sphingolipids, glycosphingolipids, eicosanoids, free fatty acids, cannabinoids, and cholesterol to renal carcinoma progression. Novel pharmacological strategies interfering with lipid signaling to treat renal cancer will be highlighted.

Pharmacodynamic biomarkers in metronomic chemotherapy: multiplex cytokine measurements in gastrointestinal cancer patients

Metronomic chemotherapy has shown promising antitumor activity in a number of malignancies. We previously reported a phase II clinical trial of metronomic UFT (a 5-fluorouracil prodrug; 100 mg/twice per day p.o.) and cyclophosphamide (CTX; 500 mg/m2 i.v. bolus on day 1 and then 50 mg/day p.o.) plus celecoxib (200 mg/twice a day p.o.) in 38 patients with advanced refractory gastrointestinal tumors. The mechanisms of action of metronomic chemotherapy include inhibition of angiogenesis, direct cytotoxic effects on cancer cells, and, at least for drugs such as CTX, activation of the immune system. To further evaluate the latter, we carried out an immune system multiplex 14-cytokine profiling of plasma samples that were available (for day 0, day 28, and day 56) from 31 of the 38 patients in the above-noted clinical trial. Our results show that pre-treatment plasma-level cutoffs of interferon gamma (> 12.84 pg/ml), sCD40L (< 2168 pg/ml), interferon alpha 2 (> 55.11 pg/ml), and IL-17a (< 15.1 pg/ml) were predictive markers for those patients with better progression-free survival (p < .05 for each cytokine). After 28 days of metronomic therapy, the plasma levels of sCD40L, IL-17a, and IL-6 (< 130 pg/ml) could serve as predictors of improved progression-free survival, as could levels interferon gamma and sCD40L after 56 days of therapy. We observed minimal changes in cytokine profiles, from baseline, as a consequence of the metronomic therapy, with the exception of an elevation of IL-6 and IL-8 levels 28 days (and 56 days) after treatment started (p < 0.05). Our results indicate that a selective cytokine elevation involves IL-6 and IL-8, following metronomic chemotherapy administration. In addition, interferon gamma and sCD40L may be potential biomarkers for gastrointestinal cancer patients that are likely to benefit from metronomic chemotherapy. Our study contributes to our understanding of the mechanisms of action of metronomic chemotherapy, and the cytokine profiling we describe may guide future selection of gastrointestinal cancer patients for UFT/CTX/celecoxib combination metronomic chemotherapy.

COX-2 Expression in Renal Cell Carcinoma and Correlations with Tumor Grade, Stage and Patient Prognosis

BACKGROUND

Cyclooxygenase 2 (COX-2) is important as an enzyme in the pathway leading to the production of prostaglandin E2 (PGE2) and arachidonic acid. This pathway is known to play a role in inflammation, tumor growth, invasiveness and metastasis, inhibition of apoptosis and angiogenesis. Inhibition of COX-2 has been shown to be a promising antitumor and antiangiogenic strategy in several tumor types, including renal cell carcinoma (RCC). Therefore, we decided to evaluate the immunohistochemical expression of this marker and its association with several clinicopathological characteristics in a series of cases.

MATERIALS AND METHODS

COX-2 expression was examined immunohistochemically in tumor tissues obtained from 96 patients who underwent radical (94 cases) or partial (2 cases) nephrectomy. Correlations between COX-2 expression and clinicopathologic findings including pathologic stage, nuclear grade and other indicator of prognosis were examined.

RESULTS

Of 96 tumors, 20.9% were positive for COX-2 expression. A correlation was found between COX-2 expression and tumor histological subtype (P=0.03).The papillary subtype showed maximum expression of this marker (43.8%) and the clear subtype minimum (14.7%). There were also possible links between COX-2 expression and pathologic stage, nuclear grade and nodal involvement but the results were not statistically significant (P=0.8, P= 0.14 and P=0.06, respectively). No correlation was found between COX2 expression and patient age, gender, tumor size, metastasis or survival.

CONCLUSIONS

In our study, COX-2 expression was correlated with the histological subtype of RCC. Additional research is required to determine the link between COX-2 expression and prognosis and also evaluation of probable effectiveness of COX-2 inhibitor drugs in treatment of RCC patients.

The role of prostaglandin E2 in renal cell cancer development: future implications for prognosis and therapy

COX-2 plays a crucial pathophysiological role in the development of renal cell cancer (RCC). Recently, it has been shown that COX-2 inhibition enhances the efficacy of immunotherapy and tyrosine kinase inhibitor-based treatment. At the same time, molecular analyses revealed particular contribution of a COX-2 product - prostaglandin E2 (PGE2) - in RCC development. PGE2 was shown to activate Akt/RGC2/RalA signaling cascade in RCC cells. It also demonstrated upregulation of the expression of HIF-1α and PI3K/Akt/mTOR signaling pathway. All together, these data suggest that targeted anti-PGE2 therapies may offer an interesting therapeutic option for RCC patients in the future.

Inflammation and cancer: till death tears them apart

Advances in biotechnology have enabled the collection of an immeasurable amount of information from genomic, transcriptomic, metabolomic and proteomic studies of tumours within their microenvironments. The dissection of cytokine and chemokine networks has provided new clues to the interactions between cancer cells and their surrounding inflammatory landscape. To bridge the gap between chronic inflammation and cancer, dynamic participants in the tumour microenvironment have been identified, including tumour-associated macrophages (TAMs) and regulatory T cells (Tregs). Both of these cell types are notable for their ability to cause immunosuppressive conditions and support the evasion of tumour immune surveillance. It is clear now that the tumour-promoting inflammatory environment has to be included as one of the major cancer hallmarks. This review explores the recent advances in the understanding of cancer-related inflammation and how this is being applied to comparative oncology studies in humans and domestic species, such as the dog.

Effects of Treg cells and IDO on human epithelial ovarian cancer cells under hypoxic conditions

The aim of the present study was to explore the effect of hypoxia on ovarian cancer. A total of 6 samples were analyzed: SKOV3‑IP cells (ovarian cancer cell line); SKOV3‑IP and regulatory T (Treg) cells; SKOV3‑IP and cytotoxic T lymphocytes (CTLs); SKOV3‑IP and natural killer (NK) cells; SKOV3‑IP co-cultured with CTLs and Treg cells; and SKOV3‑IP co-cultured with Treg cells and NK cells. The expression of indoleamine 2,3‑dioxygenase (IDO) was detected by reverse transcription-polymerase chain reaction (RT‑PCR) and western blot analysis. An enzyme‑linked immunosorbent assay (ELISA) was used to detect the concentration of transforming growth factor‑β (TGF‑β), interferon‑γ (IFN‑γ), interleukin‑2 (IL‑2), interleukin‑10 (IL‑10), and perforin. Moreover, ovarian cancer cell apoptosis and invasive ability were examined using flow cytometry and a Transwell chamber assay. IDO expression was significantly reduced in hypoxia and enhanced by Treg cells. Treg cells inhibited the IL‑2, IFN‑γ and perforin secretion, and significantly (P<0.05) increased the IL‑10 and TGF‑β levels. The effects of Treg cells were enhanced with prolongation of the cell exposure to hypoxic conditions. In addition, Treg cells attenuated the promotive effect of CTLs and NK cells on cancer cell apoptosis. In addition, Treg cells significantly increased the SKOV3‑IP invasive ability (P=0.00109) under hypoxic conditions. Our results suggest that IDO and Treg cells may serve as important therapeutic targets for patients with ovarian cancer.

The Multifaceted Roles Neutrophils Play in the Tumor Microenvironment

Neutrophils are myeloid cells that constitute 50-70 % of all white blood cells in the human circulation. Traditionally, neutrophils are viewed as the first line of defense against infections and as a major component of the inflammatory process. In addition, accumulating evidence suggest that neutrophils may also play a key role in multiple aspects of cancer biology. The possible involvement of neutrophils in cancer prevention and promotion was already suggested more than half a century ago, however, despite being the major component of the immune system, their contribution has often been overshadowed by other immune components such as lymphocytes and macrophages. Neutrophils seem to have conflicting functions in cancer and can be classified into anti-tumor (N1) and pro-tumor (N2) sub-populations. The aim of this review is to discuss the varying nature of neutrophil function in the cancer microenvironment with a specific emphasis on the mechanisms that regulate neutrophil mobilization, recruitment and activation.

YB-1 suppression induces STAT3 proteolysis and sensitizes renal cancer to interferon-α

Renal cell carcinoma (RCC) accounts for 80-95 % of kidney tumors, and approximately 30 % of RCC patients have metastatic disease at diagnosis. Conventional chemotherapy is not effective in patients with metastatic RCC (MRCC); therefore, immunotherapy with interferon-α (IFN-α) has been employed to improve survival. However, the response rate of MRCC to IFN-α therapy is low. We previously reported that a signal transducer and activator 3 (STAT3) polymorphism was a useful diagnostic marker to predict the response to IFN-α therapy in patients with MRCC. Therefore, we hypothesized the inhibition of STAT3 in the addition of IFN-α therapy might be useful. Moreover, the blockage of STAT3 itself has been reported to enhance the antitumor effects. However, because IFN-α is thought to elicit its therapeutic effect via enhancement of an antitumor immune response mediated by lymphocytes that can be activated by IFN-α administrations, it is probable that the suppression of STAT3 in vivo relates to autoimmune disorders. In the present study, we found Y-box binding protein-1 (YB-1) was poorly expressed in T lymphocytes, as compared with cancer tissues. YB-1 was reported to have an important effect on the STAT3 pathway. Suppression of STAT3 by YB-1 inhibition did not seem to enhance the potential risk for autoimmune disorders. Moreover, we found sensitivity to IFN-α was increased by YB-1 suppression, and this suppression did not down-regulate IFN-α activation of T lymphocytes.

The role of pro-inflammatory cytokines and immune cells in colorectal carcinoma progression

Cytokines exhibit a pleiotropic effect in the regulation of the immune cell function, tumor growth and antitumor immune responses. A total of 30 patients with colorectal carcinoma were enrolled on this study and their levels of interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF)-α, serum granulocyte colony-stimulating factor (sG-CSF) and serum macrophage colony-stimulating factor (sM-CSF) were measured preoperatively using ELISA. Tumor-infiltrating granulocyte (TIG), tumor-associated macrophage (TAM), G-CSF and M-CSF expression in tumor cells were examined using immunostaining. This study revealed abnormal levels of cytokines in patients, including IL-1β (1/30, 3.3%), IL-6 (16/30 53.3%), IL-81 (15/30, 50%), TNF-α (4/21, 19%), sG-CSF (17/30, 56.7%) and sM-CSF (4/21, 19%). There was a positive linear correlation between IL-6 and sM-CSF (P=0.017, R=0.517). sG-CSF was significantly associated with a deeper tumor invasion (P=0.039) and a more advanced tumor stage (P=0.023). The granulocyte/lymphocyte (G/L) ratio was associated with abnormal levels of sG-CSF. Logistic univariate analysis revealed that TIGs were a risk factor for lymph node metastasis (0.019) and TAMs were a risk factor for depth of invasion (0.029), but this was not confirmed in logistic multivariate analysis. In conclusion, IL-6, IL-8, sM-CSF and sG-CSF may indirectly promote tumor growth, progression and metastasis by changing the leukocyte populations in the blood and the tumor microenvironment.

Cox-2 inhibition enhances the activity of sunitinib in human renal cell carcinoma xenografts

BACKGROUND

Sunitinib (Su), a tyrosine kinase inhibitor of VEGFR, is effective at producing tumour response in clear cell renal cell carcinoma (cRCC), but resistance to therapy is inevitable. As COX-2 is a known mediator of tumour growth, we explored the potential benefit of COX-2 inhibition in combination with VEGFR inhibition in attempts at delaying tumour progression on Su.

METHODS

COX-2 expression was compared with areas of hypoxia in tumours that progressed on Su vs untreated tumours. Mice bearing human cRCC xenografts were treated with Su and the COX-2 inhibitor, celecoxib, and the effects on tumour growth were assessed. Sequential vs concurrent regimens were compared.

RESULTS

COX-2 expression was increased in cRCC xenografts in areas of tumour hypoxia. The combination of Su and celecoxib achieved longer times to tumour progression compared to treatment with either agent alone or to untreated control animals in four models. This effect was seen with concurrent but not with sequential therapy.

CONCLUSION

COX-2 inhibition can extend the effectiveness of VEGFR inhibition. This effect is dependent on the timing of therapy. Clinical trials combining Su and COX-2 inhibitors should be considered as a means delaying time to progression on sunitinib in patients with metastatic cRCC.

Tumor-associated macrophages mediate immunosuppression in the renal cancer microenvironment by activating the 15-lipoxygenase-2 pathway

Renal cell carcinoma (RCC), the most common human kidney cancer, is frequently infiltrated with tumor-associated macrophages (TAM) that can promote malignant progression. Here, we show that TAMs isolated from human RCC produce substantial amounts of the proinflammatory chemokine CCL2 and immunosuppressive cytokine IL-10, in addition to enhanced eicosanoid production via an activated 15-lipoxygenase-2 (15-LOX2) pathway. TAMs isolated from RCC tumors had a high 15-LOX2 expression and secreted substantial amounts of 15(S)-hydroxyeicosatetraenoic acid, its major bioactive lipid product. Inhibition of lipoxygenase activity significantly reduced production of CCL2 and IL-10 by RCC TAMs. In addition, TAMs isolated from RCC were capable of inducing in T lymphocytes, the pivotal T regulatory cell transcription factor forkhead box P3 (FOXP3), and the inhibitory cytotoxic T-lymphocyte antigen 4 (CTLA-4) coreceptor. However, this TAM-mediated induction of FOXP3 and CTLA-4 in T cells was independent of lipoxygenase and could not be reversed by inhibiting lipoxygenase activity. Collectively, our results show that TAMs, often present in RCCs, display enhanced 15-LOX2 activity that contributes to RCC-related inflammation, immunosuppression, and malignant progression. Furthermore, we show that TAMs mediate the development of immune tolerance through both 15-LOX2-dependent and 15-LOX2-independent pathways. We propose that manipulating LOX-dependent arachidonic acid metabolism in the tumor microenvironment could offer new strategies to block cancer-related inflammation and immune escape in patients with RCC.