Targeting interleukin-6 as a treatment approach for peritoneal carcinomatosis

Peritoneal carcinomatosis (PC) is a complex manifestation of abdominal cancers, with a poor prognosis and limited treatment options. Recent work identifying high concentrations of the cytokine interleukin-6 (IL-6) and its soluble receptor (sIL-6-Rα) in the peritoneal cavity of patients with PC has highlighted this pathway as an emerging potential therapeutic target. This review article provides a comprehensive overview of the current understanding of the potential role of IL-6 in the development and progression of PC. We discuss mechansims by which the IL-6 pathway may contribute to peritoneal tumor dissemination, mesothelial adhesion and invasion, stromal invasion and proliferation, and immune response modulation. Finally, we review the prospects for targeting the IL-6 pathway in the treatment of PC, focusing on common sites of origin, including ovarian, gastric, pancreatic, colorectal and appendiceal cancer, and mesothelioma.

Stem Cell Therapy Enriched Fat Grafting for the Reconstruction of Craniofacial Deficits

Fat grafting is an effective treatment for craniofacial deformities. Stromal vascular fraction (SVF) is a concentrated form of adipose derived stem cells that can be isolated from fat. The aim of this clinical trial was to assess the impact of SVF enrichment on craniofacial fat grafting.

Methods

Twelve subjects with at least two regions of craniofacial volume deficit were enrolled, and they underwent fat grafting with SVF-enriched or standard fat grafting to each area. All patients had bilateral malar regions injected with SVF-enriched graft on one side and control standard fat grafting to the contralateral side. Outcome assessments included demographic information, volume retention determined by CT scans, SVF cell populations assessed by flow cytometry, SVF cell viability, complications, and appearance ratings. Follow-up was 9 months.

Results

All patients had improvement in appearance. There were no serious adverse events. There was no significant difference in volume retention between the SVF-enriched and control regions overall (50.3% versus 57.3%, P = 0.269) or comparing malar regions (51.4% versus 56.7%, P = 0.494). Patient age, smoking status, obesity, and diagnosis of diabetes did not impact volume retention. Cell viability was 77.4% ± 7.3%. Cellular subpopulations were 60.1% ± 11.2% adipose derived stem cells, 12.2 ± 7.0% endothelial cells, and 9.2% ± 4.4% pericytes. A strong positive correlation was found between CD146+ CD31-pericytes and volume retention (R = 0.863, P = 0.027).

Conclusions

Autologous fat transfer for reconstruction of craniofacial defects is effective and safe, leading to reliable volume retention. However, SVF enrichment does not significantly impact volume retention.

Immunomodulatory drugs downregulate IKZF1 leading to expansion of hematopoietic progenitors with concomitant block of megakaryocytic maturation

The immunomodulatory drugs, lenalidomide and pomalidomide yield high response rates in multiple myeloma patients, but are associated with a high rate of thrombocytopenia and increased risk of secondary hematologic malignancies. Here, we demonstrate that the immunomodulatory drugs induce self-renewal of hematopoietic progenitors and upregulate megakaryocytic colonies by inhibiting apoptosis and increasing proliferation of early megakaryocytic progenitors via down-regulation of IKZF1. In this process, the immunomodulatory drugs degrade IKZF1 and subsequently down-regulate its binding partner, GATA1. This results in the decrease of GATA1 targets such as ZFPM1 and NFE2, leading to expansion of megakaryocytic progenitors with concomitant inhibition of maturation of megakaryocytes. The down-regulation of GATA1 further decreases CCND1 and increases CDKN2A expression. Overexpression of GATA1 abrogated the effects of the immunomodulatory drugs and restored maturation of megakaryocytic progenitors. Our data not only provide the mechanism for the immunomodulatory drugs induced thrombocytopenia but also help to explain the higher risk of secondary malignancies and long-term cytopenia induced by enhanced cell cycling and subsequent exhaustion of the stem cell pool.

Adipose Stem Cell Function Maintained with Age: An Intra-Subject Study of Long-Term Cryopreserved Cells

Background

The progressive decline in tissue mechanical strength that occurs with aging is hypothesized to be due to a loss of resident stem cell number and function. As such, there is concern regarding use of autologous adult stem cell therapy in older patients. To abrogate this, many patients elect to cryopreserve the adipose stromal-vascular fraction (SVF) of lipoaspirate, which contains resident adipose stem cells (ASC). However, it is not clear yet if there is any clinical benefit from banking cells at a younger age.

Objectives

We performed a comparative analysis of SVF composition and ASC function from cells obtained under GMP conditions from the same three patients with time gap of 7 to 12 years.

Methods

SVF, cryobanked under good manufacturing practice (GMP) conditions, was thawed and cell yield, viability, and cellular composition were assessed. In parallel, ASC proliferation and efficiency of tri-lineage differentiation were evaluated.

Results

The results showed no significant differences existed in cell yield and SVF subpopulation composition within the same patient between harvest procedures 7 to 12 years apart. Further, no change in proliferation rates of cultured ASCs was found, and expanded cells from all patients were capable of tri-lineage differentiation.

Conclusions

By harvesting fat from the same patient at two time points, we have shown that despite the natural human aging process, the prevalence and functional activity of ASCs in an adult mesenchymal stem cell, is highly preserved.

Level of Evidence

5.

Abstract B150: Juxtacrine signaling between the tumor-associated macrophages and the breast cancer stem cells contribute to the cancer stem cell niche by inducing a cytokine signaling network

The cell-biological program termed the epithelial-mesenchymal transition (EMT) confers on cancer cells mesenchymal traits and an ability to enter the cancer stem cell (CSC) state. In addition, EMT upregulates the expression of cell surface receptors that enable CSCs to interact with their surrounding microenvironment in order to sustain their stem cell state. We discovered that EphA4 and CD90, two cell surface proteins upregulated in the carcinoma cells by the EMT, mediate juxtacrine signalling between the CSCs and tumor-associated monocytes and macrophages (TAMs). When engaged with its counter-receptor on TAMs, EphA4 on the CSCs activates Src and PLCγ1, the latter resulting in the translocation of NF-κB into the nucleus, which cooperates with Twist to drive the rapid induction of a variety of cytokines in the CSCs. Among the secreted cytokines IL-8 and IL-6 maintain the CSC-state by reinforcing the expression of the EMT-inducing transcription factors, whereas other cytokines GM-CSF, M-CSF and IL-10 recruit monocytes and induce their differentiation into M2-like macrophages. Together these cytokines perpetuate the CSC-promoting interactions between CSCs and TAMs. Indeed, admixed TAMs promote the tumor-initiating ability of CSCs whereas ablation of endogenous macrophages substantially diminished tumor initiation. Importantly, the juxtaposition of TAMs with the mesenchymal-like CD90high CSCs can be observed at the invading edge in primary human breast tumor sections and xenograft tumors. On the contrary, we rarely find TAMS infiltrating beyond the edge of tumors into the regions where the CD90neg non-stem carcinoma cells reside. These findings underscore the importance of TAMs as critical components of the CSC niche and highlight their potential as therapeutics targets.

Citation Format: Haihui Lu, Wai Leong Tam, Vera Donnenberg, Xin Ye, Rohit Bhargava, Robert Weinberg. Juxtacrine signaling between the tumor-associated macrophages and the breast cancer stem cells contribute to the cancer stem cell niche by inducing a cytokine signaling network. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr B150.

Abstract 187: Prevention of Circulating Progenitor Surge After Vascular Injury Effectively Reduces Restenosis

Background: Restenosis is an aberrant healing response that leads to failure of half of all vascular interventions and circulating progenitor cells have been implicated in restenotic pathology. Based on our previous findings of a surge specific to macrovascular injury, we hypothesized that a surge among progenitors and vascular injury signaling would be evident in the murine model and that an approach to prevent this surge would reduce restenosis.

Methods: C57BL6 mice underwent injury of the femoral artery following either a depleting antibody to the progenitor marker sca-1 or a control antibody (n=8 per group). A third group had a non-vascular surgery (n=5). Antibody was administered pre-op and then until day 9. Blood and bone marrow were collected on days 1, 3, and 9 and analyzed by flow cytometry for progenitor markers CD34 and c-kit. Plasma was analyzed for the vascular injury signal, stromal cell-derived factor 1/CXCL12 (sdf1alpha). Vessel explants were imaged with lectin microscopy. Finally, animals treated with either sca-1 depleting antibody (n=4) or an isotype control (n=3) underwent vessel explant at 28 days and a lumen ratio was calculated.

Results: Microscopy confirmed injury of endothelial monolayer and serologically, wire injury increased sdf1alpha by over 3 fold. Injury of the femoral artery resulted in a surge of CD34+/c-kit+ progenitors by over 2.2 fold relative to non-operative controls with a peak on day 1. Furthermore, this surge was prevented by treatment with a sca-1 antibody (P= 0.004). At 28 days, progenitor depletion increased the lumen from 20% among isotype treated controls to 79% among animals treated with direct progenitor depletion (P=0.04).

Conclusions: It has not been previously demonstrated whether changes among progenitor cells impact restenotic pathology. Our findings suggest that a surge occurs in both a key vascular injury cytokine and among circulating progenitor cells after macrovascular injury. We have further demonstrated the efficacy of a depleting sca-1 antibody to mitigate progenitor surge and most importantly to reduce restenosis in a significant fashion. Future studies of strategies to block circulating progenitor cells may provide new therapies for this prevalent life and limb threatening disease.

Thalidomide derivative CC-4047 inhibits osteoclast formation by down-regulation of PU.1

CC-4047, an immunomodulatory analog of thalidomide, inhibits multiple myeloma with unknown effects on the human osteoclast lineage. Early osteoclast progenitors are of hematopoietic origin and differentiate into mature bone resorbing multinucleated osteoclasts. We investigated the effects of CC-4047 and thalidomide on human osteoclastogenesis, using in vitro receptor activator of NFkappa-B ligand/macrophage colony-stimulating factor-stimulated bone marrow cell cultures. Treating bone marrow cultures with CC-4047 for 3 weeks decreased osteoclast formation accompanied by complete inhibition of bone resorption. The inhibitory effect was similar when cultures were treated for 3 weeks or for only the first week (90% inhibition), indicating that CC-4047 inhibits early stages of osteoclast formation. Inhibition of osteoclastogenesis by CC-4047 was mediated by a shift of lineage commitment to granulocyte colony-forming units at the expense of granulocyte-macrophage colony-forming units. Further studies revealed that this shift in lineage commitment was mediated through down-regulation of PU.1. Treatment with thalidomide resulted in significantly less potent inhibition of osteoclast formation and bone resorption. These results provide evidence that CC-4047 blocks osteoclast differentiation during early phases of osteoclastogenesis. Therefore, CC-4047 might be a valuable drug for targeting both tumors and osteoclastic activity in patients with multiple myeloma and other diseases associated with osteolytic lesions.