Operative injury accelerates tumor growth by inducing mobilization and recruitment of bone marrow-derived stem cells

Effects of UCMSCs Delivered through Different Transplantation Approaches on Acute Radiation Enteritis in Rats

Radiation enteritis is the most common and serious complication of abdominal or pelvic radiation therapy. Mesenchymal stem cells (MSCs), as well as cell protection agents, inhibit apoptosis and promote the proliferation of injured tissues. 3 human umbilical cords MSCs (UCMSCs) were injected into the tail vein or peritoneal cavity of a rat model of radiation enteritis. The temporary protective effect was assessed by identification of donor cells, detection of cellular immune parameters and inflammatory cytokine levels, quantitation of jejunum mucosal preservation and examination of the rat remaining life. Only the rats in the intraperitoneal injection group exhibited a few positive donor cells 7 days after transplantation. CD₄⁺/CD₈⁺ T cells, a cellular immune parameter, decreased in the abdominal exudate of intraperitoneal injection group, compared with the model-only control and tail vein groups (both P < .05). Both serum and abdominal exudate TNF-α and IL-6 levels in the intraperitoneally injected rats rapidly decreased and were significantly different from those in the model-only control and tail vein injection groups (all P < .05). Mucosal surface area and survival time increased in the intraperitoneal injection group compared with the vehicle and tail vein injection groups (all P = .000). Therefore, the administration of UCMSCs with intraperitoneal injection approach postponed death in a rat model of radiation enteritis, which was associated with reduced serum levels of proinflammatory cytokines (TNF-α, IL-6). However, UCMSCs injected via the tail vein triggered an intense cellular immune response in the serum that adversely affects their survival. This treatment failed to suppress circulating serum and abdominal exudate levels of TNF-α and IL-6 and could not provide a therapeutic benefit for prolonging life against acute radiation enteritis.

Distant metastasis dynamics following subsequent surgeries after primary breast cancer removal

Background

The aim of the research was to separate the distant metastasis (DM) enhancing effect due to breast tumour removal from that due to surgical manoeuvre by itself.

Methods

DM dynamics following surgery for ipsilateral breast tumour recurrence (IBTR), contralateral breast cancer (CBC) and delayed reconstruction (REC), which was performed after the original breast cancer surgical removal, was analysed. A total of 338 patients with IBTR, 239 with CBC and 312 with REC were studied.

Results

The DM dynamics following IBTR, CBC and REC, when assessed with time origin at their surgical treatment, is similar to the analogous pattern following primary tumour removal, with a first major peak at about 18 months and a second lower one at about 5 years from surgery. The time span between primary tumour removal and the second surgery is influential on DM risk levels for IBTR and CBC patients, not for REC patients.

Conclusions

The role of breast tumour removal is different from the role of surgery by itself. Our findings suggest that the major effect of reconstructive surgery is microscopic metastasis acceleration, while breast tumour surgical removal (either primary or IBTR or CBC) involves both tumour homeostasis interruption and microscopic metastasis growth acceleration. The removal of a breast tumour would eliminate its homeostatic restrains on metastatic foci, thus allowing metastasis development, which, in turn, would be supported by the forwarding action of the mechanisms triggered by the surgical wounding.

Mesenchymal stem cells deliver and release conditionally replicative adenovirus depending on hepatic differentiation to eliminate hepatocellular carcinoma cells specifically

Currently, it is a key challenge to remove the postsurgical residuals and metastasis of hepatocellular carcinoma (HCC). Oncolytic adenoviral virotherapy is an attractive treatment modality for cancer; however, the difficulty remains regarding its intravenous administration. The aim of this study was to develop a targeted therapeutic system which has great potential to overcome the postsurgical residuals and metastasis of HCC. In this system, we developed a conditionally replicative adenovirus (CRAd) loaded on human umbilical cord-derived mesenchymal stem cells (HUMSCs), in which the CRAd contained an adenovirus E1A gene dual regulated by α-fetoprotein promoter and microRNA-122 target sequence. When HUMSCs homed to the tumor sites and differentiated into hepatocyte-like cells within tumor microenvironment, the CRAds were packaged and released strictly to the local tumor. Subsequently, the CRAd lysed tumor cells selectively with the post-infection regulation. The study showed the specific oncolytic effect of the CRAd to HCC cells and the production of the CRAd by differentiated HUMSCs in vitro. Furthermore, we proved the hepatocyte-like transformation of HUMSC in the microenvironment of orthotopic or heterotopic hepatoma. Finally, this therapeutic system exhibited dramatic tumor inhibition on both orthotopic and subcutaneous hepatic xenograft tumor model mice with less toxicity on normal organs. The study results have demonstrated that this targeted therapeutic strategy is a promising method to resolve the problem of postsurgical residuals and metastasis of HCC.

The angiogenic related functions of bone marrow mesenchymal stem cells are promoted by CBDL rat serum via the Akt/Nrf2 pathway

Hepatopulmonary syndrome (HPS) is a complication of severe liver disease. It is characterized by an arterial oxygenation defect. Recent studies have demonstrated that pulmonary angiogenesis contributes to the abnormal gas exchange found in HPS. Additionally, mesenchymal stem cells (MSCs) are considered the stable source of VEGF-producing cells and have the potential to differentiate into multiple cell types. However, it has not been determined whether bone marrow mesenchymal stem cells (BM-MSCs) are mobilized and involved in the pulmonary angiogenesis in HPS. In this study, a CFU-F assay showed that the number of peripheral blood MSCs was increased in common bile duct ligation (CBDL) rats; however, there was no significant difference found in the number of BM-MSCs. In vitro, CBDL rat serum induced the overexpression of CXCR4 and PCNA in BM-MSCs. Consistently, the directional migration as well as the proliferation ability of BM-MSCs were enhanced by CBDL rat serum, as determined by a transwell migration and MTT assays. Moreover, the secretion of VEGF by BM-MSCs increased after treatment with CBDL rat serum. We also found that the expression of phospho-Akt, phospho-ERK, and Nrf2 in BM-MSCs was significantly up-regulated by CBDL rat serum in a time dependent manner, and the blockage of the Akt/Nrf2 signalling pathway with an Akt Inhibitor or Nrf2 siRNA, instead of an ERK inhibitor, attenuated the migration, proliferation and paracrine capacity of BM-MSCs. In conclusion, these findings indicated that the number of MSCs increased in the peripheral blood of CBDL rats, and the Akt/Nrf2 pathway plays a vital role in promoting the angiogenic related functions of BM-MSCs, which could be a potent contributor to pulmonary angiogenesis in HPS.

Enhanced tumor growth in the remaining lung after major lung resection

BACKGROUND

Pneumonectomy induces active growth of the remaining lung in order to compensate for lost lung tissue. We hypothesized that tumor progression is enhanced in the activated local environment.

METHODS

We examined the effects of mechanical strain on the activation of lung growth and tumor progression in mice. The mechanical strain imposed on the right lung after left pneumonectomy was neutralized by filling the empty space that remained after pneumonectomy with a polypropylene prosthesis.

RESULTS

The neutralization of the strain prevented active lung growth. According to an angiogenesis array, stronger monocyte chemoattractant protein-1 (MCP-1) expression was found in the strain-induced growing lung. The neutralization of the strain attenuated the release of MCP-1 from the lung cells. The intravenous injection of Lewis lung cancer cells resulted in the enhanced development of metastatic foci in the strain-induced growing lung, but the enhanced development was canceled by the neutralization of the strain. An immunohistochemical analysis revealed the prominent accumulation of tumor-associated macrophages in tumors arising in the strain-induced growing lung, and that there was a relationship between the accumulation and the MCP-1 expression status.

CONCLUSIONS

Our results suggested that mechanical lung strain, induced by pulmonary resection, triggers active lung growth, thereby creating a tumor-friendly environment. The modification of that environment, as well as the minimizing of surgical stress, may be a meaningful strategy to improve the therapeutic outcome after lung cancer surgery.

SDF-1α mediates wound-promoted tumor growth in a syngeneic orthotopic mouse model of breast cancer

Increased growth of residual tumors in the proximity of acute surgical wounds has been reported; however, the mechanisms of wound-promoted tumor growth remain unknown. Here, we used a syngeneic, orthotopic mouse model of breast cancer to study mechanisms of wound-promoted tumor growth. Our results demonstrate that exposure of metastatic mouse breast cancer cells (4T1) to SDF-1α, which is increased in wound fluid, results in increased tumor growth. Both, wounding and exposure of 4T1 cells to SDF-1α not only increased tumor growth, but also tumor cell proliferation rate and stromal collagen deposition. Conversely, systemic inhibition of SDF-1α signaling with the small molecule AMD 3100 abolished the effect of wounding, and decreased cell proliferation, collagen deposition, and neoangiogenesis to the levels observed in control animals. Furthermore, using different mouse strains we could demonstrate that the effect of wounding on tumor growth and SDF-1α levels is host dependent and varies between mouse strains. Our results show that wound-promoted tumor growth is mediated by elevated SDF-1α levels and indicate that the effect of acute wounds on tumor growth depends on the predetermined wound response of the host background and its predetermined wound response.

Nicaraven attenuates radiation-induced injury in hematopoietic stem/progenitor cells in mice

Nicaraven, a chemically synthesized hydroxyl radical-specific scavenger, has been demonstrated to protect against ischemia-reperfusion injury in various organs. We investigated whether nicaraven can attenuate radiation-induced injury in hematopoietic stem/progenitor cells, which is the conmen complication of radiotherapy and one of the major causes of death in sub-acute phase after accidental exposure to high dose radiation. C57BL/6 mice were exposed to 1 Gy γ-ray radiation daily for 5 days in succession (a total of 5 Gy), and given nicaraven or a placebo after each exposure. The mice were sacrificed 2 days after the last radiation treatment, and the protective effects and relevant mechanisms of nicaraven in hematopoietic stem/progenitor cells with radiation-induced damage were investigated by ex vivo examination. We found that post-radiation administration of nicaraven significantly increased the number, improved the colony-forming capacity, and decreased the DNA damage of hematopoietic stem/progenitor cells. The urinary levels of 8-oxo-2′-deoxyguanosine, a marker of DNA oxidation, were significantly lower in mice that were given nicaraven compared with those that received a placebo treatment, although the levels of intracellular and mitochondrial reactive oxygen species in the bone marrow cells did not differ significantly between the two groups. Interestingly, compared with the placebo treatment, the administration of nicaraven significantly decreased the levels of the inflammatory cytokines IL-6 and TNF-α in the plasma of mice. Our data suggest that nicaraven effectively diminished the effects of radiation-induced injury in hematopoietic stem/progenitor cells, which is likely associated with the anti-oxidative and anti-inflammatory properties of this compound.

Placental extract protects bone marrow-derived stem/progenitor cells against radiation injury through anti-inflammatory activity

Placental extracts have been reported to have anti-oxidative and anti-inflammatory activities. Because there is increasing evidence that ionizing radiation induces the release of reactive oxygen species (ROS) and inflammatory cytokines, we examined the protective effects of a placental extract against radiation injury. C57BL/6 mice were exposed to 1 Gy of γ-ray radiation every day for 5 days, and placental extract (1 mg/day) was administrated orally soon after each exposure. At 2 days after the last irradiation, mice were euthanized to examine the numbers, colony-forming capacity, and DNA damage of stem/progenitor cells in the peripheral blood and bone marrow. To understand the related mechanisms, we also measured the levels of intracellular and mitochondrial ROS, and 8-OHdG in the plasma and urine, and IL-6 and TNF-α in the plasma. Compared with the placebo treatment, oral administration of placental extract significantly increased the number and colony-forming capacity, but decreased the DNA damage of bone marrow stem/progenitor cells. However, neither the levels of intracellular and mitochondrial ROS in bone marrow cells, nor the levels of 8-OHdG in the urine and plasma significantly differed between groups. Interestingly, in comparison with the placebo treatment, placental extract significantly decreased the levels of the inflammatory cytokines IL-6 and TNF-α in the plasma. Placental extract significantly attenuated the acute radiation injury to bone marrow-derived stem/progenitor cells, and this protection is likely to be related to the anti-inflammatory activity of the placental extract.

Reduction of breast cancer relapses with perioperative non-steroidal anti-inflammatory drugs: new findings and a review

To explain a bimodal pattern of hazard of relapse among early stage breast cancer patients identified in multiple databases, we proposed that late relapses result from steady stochastic progressions from single dormant malignant cells to avascular micrometastases and then on to growing deposits. However in order to explain early relapses, we had to postulate that something happens at about the time of surgery to provoke sudden exits from dormant phases to active growth and then to detection. Most relapses in breast cancer are in the early category. Recent data from Forget et al. suggest an unexpected mechanism. They retrospectively studied results from 327 consecutive breast cancer patients comparing various perioperative analgesics and anesthetics in one Belgian hospital and one surgeon. Patients were treated with mastectomy and conventional adjuvant therapy. Relapse hazard updated Sept 2011 are presented. A common Non-Steroidal Anti-Inflammatory Drug (NSAID) analgesic used in surgery produced far superior disease-free survival in the first 5 years after surgery. The expected prominent early relapse events in months 9-18 are reduced 5-fold. If this observation holds up to further scrutiny, it could mean that the simple use of this safe, inexpensive and effective anti-inflammatory agent at surgery might eliminate early relapses. Transient systemic inflammation accompanying surgery could facilitate angiogenesis of dormant micrometastases, proliferation of dormant single cells, and seeding of circulating cancer stem cells (perhaps in part released from bone marrow) resulting in early relapse and could have been effectively blocked by the perioperative anti-inflammatory agent.

The mobilization and recruitment of c-kit+ cells contribute to wound healing after surgery

Delayed wound healing is a serious clinical problem in patients after surgery. A recent study has demonstrated that bone marrow-derived c-kit-positive (c-kit⁺) cells play important roles in repairing and regenerating various tissues and organs. To examine the hypothesis that surgical injury induces the mobilization and recruitment of c-kit+ cells to accelerate wound healing. Mice were subjected to a left pneumonectomy. The mobilization of c-kit+ cells was monitored after surgery. Using green fluorescent protein (GFP⁺) bone marrow-transplanted chimera mice, we investigated further whether the mobilized c-kit+ cells were recruited to effect wound healing in a skin puncture model. The group with left pneumonectomies increased the c-kit⁺ and CD34⁺ stem cells in peripheral blood 24 h after surgery. At 3 days after surgery, the skin wound size was observed to be significantly smaller, and the number of bone marrow-derived GFP⁺ cells and GFP⁺/c-kit+ cells in the wound tissue was significantly greater in mice that had received pneumonectomies, as compared with those that had received a sham operation. Furthermore, some of these GFP⁺ cells were positively expressed specific markers of macrophages (F4/80), endothelial cells (CD31), and myofibroblasts (αSMA). The administration of AMD3100, an antagonist of a stromal-cell derived factor (SDF)-1/CXCR4 signaling pathway, reduced the number of GFP⁺ cells in wound tissue and completely negated the accelerated wound healing. Surgical injury induces the mobilization and recruitment of c-kit+ cells to contribute to wound healing. Regulating c-kit+ cells may provide a new approach that accelerates wound healing after surgery.

Tanshinone IIA inhibits metastasis after palliative resection of hepatocellular carcinoma and prolongs survival in part via vascular normalization

Background

Promotion of endothelial normalization restores tumor oxygenation and obstructs tumor cells invasion, intravasation, and metastasis. We therefore investigated whether a vasoactive drug, tanshinone IIA, could inhibit metastasis by inducing vascular normalization after palliative resection (PR) of hepatocellular carcinoma (HCC).

Methods

A liver orthotopic double-tumor xenograft model in nude mouse was established by implantation of HCCLM3 (high metastatic potential) and HepG2 tumor cells. After removal of one tumor by PR, the effects of tanshinone IIA administration on metastasis, tumor vascularization, and survival were evaluated. Tube formation was examined in mouse tumor-derived endothelial cells (TECs) treated with tanshinone IIA.

Results

PR significantly accelerated residual hepatoma metastases. Tanshinone IIA did not inhibit growth of single-xenotransplanted tumors, but it did reduce the occurrence of metastases. Moreover, it inhibited PR-enhanced metastases and, more importantly, prolonged host survival. Tanshinone IIA alleviated residual tumor hypoxia and suppressed epithelial-mesenchymal transition (EMT) in vivo; however, it did not downregulate hypoxia-inducible factor 1α (HIF-1α) or reverse EMT of tumor cells under hypoxic conditions in vitro. Tanshinone IIA directly strengthened tube formation of TECs, associated with vascular endothelial cell growth factor receptor 1/platelet derived growth factor receptor (VEGFR1/PDGFR) upregulation. Although the microvessel density (MVD) of residual tumor tissue increased after PR, the microvessel integrity (MVI) was still low. While tanshinone IIA did not inhibit MVD, it did dramatically increase MVI, leading to vascular normalization.

Conclusions

Our results demonstrate that tanshinone IIA can inhibit the enhanced HCC metastasis associated with PR. Inhibition results from promoting VEGFR1/PDGFR-related vascular normalization. This application demonstrates the potential clinical benefit of preventing postsurgical recurrence.

Promising development from translational or perhaps anti-translational research in breast cancer

Background

A great deal of the public’s money has been spent on cancer research but demonstrable benefits to patients have not been proportionate. We are a group of scientists and physicians who several decades ago were confronted with bimodal relapse patterns among early stage breast cancer patients who were treated by mastectomy. Since the bimodal pattern was not explainable with the then well-accepted continuous growth model, we proposed that metastatic disease was mostly inactive before surgery but was driven into growth somehow by surgery. Most relapses in breast cancer would fall into the surgery-induced growth category thus it was highly important to understand the ramifications of this process and how it may be curtailed. With this hypothesis, we have been able to explain a wide variety of clinical observations including why mammography is less effective for women age 40–49 than it is for women age 50–59, why adjuvant chemotherapy is most effective for premenopausal women with positive lymph nodes, and why there is a racial disparity in outcome.

Methods

We have been diligently looking for new clinical or laboratory information that could provide a connection or correlation between the bimodal relapse pattern and some clinical factor or interventional action and perhaps lead us towards methods to prevent surgery-initiated tumor activity.

Results

A recent development occurred when a retrospective study appeared in an anesthesiology journal that suggested the perioperative NSAID analgesic ketorolac seems to reduce early relapses following mastectomy. Collaborating with these anesthesiologists to understand this effect, we independently re-examined and updated their data and, in search of a mechanism, focused in on the transient systemic inflammation that follows surgery to remove a primary tumor. We have arrived at several possible explanations ranging from mechanical to biological that suggest the relapses avoided in the early years do not show up later.

Conclusions

We present the possibility that a nontoxic and low cost intervention could prevent early relapses. It may be that preventing systemic inflammation post surgery will prevent early relapses. This could be controlled by the surgical anesthesiologist’s choice of analgesic drugs. This development needs to be confirmed in a randomized controlled clinical trial and we have identified triple negative breast cancer as the ideal subset with which to test this. If successful, this would be relatively easy to implement in developing as well as developed countries and would be an important translational result.

NSAID analgesic ketorolac used perioperatively may suppress early breast cancer relapse: particular relevance to triple negative subgroup

To explain a bimodal relapse hazard among early stage breast cancer patients treated by mastectomy we postulated that relapses within 4 years of surgery resulted from something that happened at about the time of surgery to provoke sudden exits from dormant phases to active growth. Relapses at 10 months appeared to be surgery-induced angiogenesis of dormant avascular micrometastases. Another relapse mode with peak about 30 months corresponded to sudden growth from a single cell. Late relapses were not synchronized to surgery. This hypothesis could explain a wide variety of breast cancer observations. We have been looking for new data that might provide more insight concerning the various relapse modes. Retrospective data reported in June 2010 study of 327 consecutive patients compared various perioperative analgesics and anesthetics in one Belgian hospital and one surgeon. Patients were treated with mastectomy and conventional adjuvant therapy. Follow-up was average 27.3 months with range 13-44 months. Updated hazard as of September 2011 for this series is now presented. NSAID ketorolac, a common analgesic used in surgery, is associated with far superior disease-free survival in the first few years after surgery. The expected prominent early relapse events are all but absent. In the 9-18 month period, there is fivefold reduction in relapses. If this observation holds up to further scrutiny, it could mean that the simple use of this safe and effective anti-inflammatory agent at surgery might eliminate most early relapses. Transient systemic inflammation accompanying surgery could be part of the metastatic tumor seeding process and could have been effectively blocked by perioperative anti-inflammatory agents. In addition, antiangiogenic properties of NSAIDs could also play a role. Triple negative breast cancer may be the ideal group with which to test perioperative ketorolac to prevent early relapses.