Max Seidensticker

Mesenchymal stem cells derived from bone marrow have recently been described to localize to breast carcinomas and to integrate into the tumor-associated stroma. In the present study, we investigated whether adipose tissue-derived stem cells (ASCs) could play a role in tumor growth and invasion. Compared with bone marrow-derived cells, ASCs as tissue-resident stem cells are locally adjacent to breast cancer cells and may interact with tumor cells directly. Here, we demonstrate that ASCs cause the cancer to grow significantly faster when added to a murine breast cancer 4T1 cell line. We further show that breast cancer cells enhance the secretion of stromal cell-derived factor-1 from ASCs, which then acts in a paracrine fashion on the cancer cells to enhance their motility, invasion and metastasis. The tumor-promoting effect of ASCs was abolished by knockdown of the chemokine C-X-C receptor 4 in 4T1 tumor cells. We demonstrated that ASCs home to tumor site and promote tumor growth not only when co-injected locally but also when injected intravenously. Furthermore, we demonstrated that ASCs incorporate into tumor vessels and differentiate into endothelial cells. The tumor-promoting effect of tissue-resident stem cells was also tested and validated using a human breast cancer line MDA-MB-231 cells and human adipose tissue-derived stem cells. Our findings indicate that the interaction of local tissue-resident stem cells with tumor stem cells plays an important role in tumor growth and metastasis.

AIMS: We assessed whether freshly isolated human adipose tissue-derived cells (fhADCs) or cultured human adipose tissue-derived stem cells (hASCs) have beneficial effects on cardiac function after myocardial infarction (MI), whether the injected cells can survive long term, and whether their effects result from direct differentiation or paracrine mechanisms. METHODS AND RESULTS: Myocardial infarction was experimentally induced in severe combined immunodeficient mice, and either fhADCs, cultured hASCs, or phosphate-buffered saline was injected into the peri-infarct region. Myocardial function improved significantly in mice treated with hASCs or fhADCs 4 weeks after MI. Immunofluorescence revealed that grafted hASCs and fhADCs underwent cardiomyogenic differentiation pathway, as indicated by expression of connexin 43 and troponin I in a fusion-independent manner. Some of the injected cells integrated with host cardiomyocytes through connexin 43, and others were incorporated into newly formed vessels. Human adipose tissue-derived stem cells survived in injured hearts up to 4 months, as detected by luciferase-based bioluminescence imaging. Vascular density was significantly increased, and fewer apoptotic cells were present in the peri-infarct region of cell-injected mice. CONCLUSION: This is the first study to systematically compare the effects of fhADCs and hASCs on myocardial regeneration. Both cell types engraft into infarcted myocardium, survive, and improve myocardial function, suggesting that fhADCs, like hASCs, are a promising alternative cell source for myocardial repair after MI.

PURPOSE This trial investigated the addition of panitumumab to triplet chemotherapy with fluorouracil/folinic acid, oxaliplatin, and irinotecan (FOLFOXIRI) in a two-to-one randomized, controlled, open-label, phase II trial in patients with untreated RAS wild-type (WT) metastatic colorectal cancer. PATIENTS AND METHODS The primary end point was objective response rate (ORR) according to RECIST (version 1.1). The experimental arm (modified FOLFOXIRI [mFOLFOXIRI] plus panitumumab) was considered active if the ORR was ≥ 75%. The experimental ORR was compared with an estimated ORR of 60% based on historical data, verified by a randomized control group (FOLFOXIRI). The power of the trial was 80%, with a potential type I error of 0.05. Secondary end points included secondary resection rate, toxicity, progression-free survival, and overall survival. RESULTS A total of 63 patients were randomly assigned to the experimental arm and 33 patients to the control arm. The ORR of the mFOLFOXIRI plus panitumumab arm exceeded 75% and was higher when compared with that of FOLFOXIRI (87.3% v 60.6%; odds ratio, 4.469; 95% CI, 1.61 to 12.38; P = .004). The secondary resection rate was improved with the addition of panitumumab (33.3% v 12.1%; P = .02). Progression-free survival was similar in the study arms, whereas overall survival showed a trend in favor of the panitumumab-containing arm (hazard ratio for death, 0.67; 95% CI, 0.41 to 1.11; P = .12). CONCLUSION The addition of panitumumab to mFOLFOXIRI in patients with RAS WT metastatic colorectal cancer improved the ORR and rate of secondary resection of metastases and represents a treatment option in selected and fit patients in need of highly active first-line therapy. Future studies should determine whether the addition of panitumumab to mFOLFOXIRI prolongs survival.

UNLABELLED: In patients with liver malignancies potentially amenable to curative extended right hepatectomy but insufficient size of the future liver remnant (FLR), portal vein embolization (PVE) of the tumor-bearing liver is used to induce contralateral liver hypertrophy but leaves the tumor untreated. Radioembolization (RE) treats the tumor in the embolized lobe along with contralateral hypertrophy induction. We performed a matched-pair analysis to compare the capacity for hypertrophy induction of these two modalities. Patients with right-hepatic secondary liver malignancies with no or negligible left-hepatic tumor involvement who were treated by right-lobar PVE (n = 141) or RE (n = 35) at two centers were matched for criteria known to influence liver regeneration following PVE: 1) baseline FLR/Total liver volume ratio (<25 versus ≥ 25%); 2) prior platinum-containing systemic chemotherapy; 3) embolization of segments 5-8 versus 4-8; and 4) baseline platelet count (<200 versus ≥ 200 Gpt/L).The primary endpoint was relative change in FLR volume from baseline to follow-up. Twenty-six matched pairs were identified. FLR volume increase from baseline to follow-up (median 33 [24-56] days after PVE or 46 [27-79] days after RE) was significant in both groups but PVE produced significantly more FLR hypertrophy than RE (61.5 versus 29%, P < 0.001). Time between treatment and follow-up was not correlated with the degree of contralateral hypertrophy achieved in both groups. Although group differences in patient history and treatment setting were present and some bias cannot be excluded, this was minimized by the matched-pair design, as remaining group differences after matching were found to have no significant influence on contralateral hypertrophy development. CONCLUSION: PVE induces significantly more contralateral hypertrophy than RE with therapeutic (nonlobectomy) doses. However, contralateral hypertrophy induced by RE is substantial and RE minimizes the risk of tumor progression in the treated lobe, possibly making it a suitable modality for selected patients.