Silk-Based 3D Porous Scaffolds for Tissue Engineering

Silk fibroin, extracted from the silk of the Bombyx mori silkworm, stands out as a biomaterial due to its nontoxic nature, excellent biocompatibility, and adjustable biodegradability. Porous scaffolds, a type of biomaterial, are crucial for creating an optimal microenvironment that supports cell adhesion and proliferation, thereby playing an essential role in tissue remodeling and repair. Therefore, this review focuses on 3D porous silk fibroin-based scaffolds, first summarizing their preparation methods and then detailing their regenerative effects on bone, cartilage, tendon, vascular, neural, skin, hepatic, and tracheal epithelial tissue engineering in recent years.

Epidemiology of Triple Negative Breast Cancer in China

Background:The classification of tumors based on the gene expression may define intrinsic breast cancer subtypes in which the effect of risk factors could be more obvious. We sought to assess the risk factors for triple negative breast cancer on Chinese population.Methods: A retrospective study of 5761 patients was carried out from a large database of breast cancer patients undergoing surgery between January 1, 1991 and June 31, 2008 in Cancer Hospital, Fudan University, Shanghai, China. Univariate analyses were performed by chi-square test of Student's t test and multivariate analyses by logistic regression.Results: A total of 1108 women were identified as having triple negative breast cancer and were compared with the 4653 women with non-triple negative. Regardless the pathological discrepancy, women with triple negative breast cancers were significantly more likely to be younger age(P=0.001; OR=1.615, 95%CI=1.207-2.160), premenopausal (P = 0.003; OR = 1.570, 95% CI = 1.171-2.106) and parous women (P = 0.001; OR = 1.741, 95% CI = 1.269-2.387).There seems no associations with increasing risk of triple negative breast cancer for breastfeeding (P=0.126), younger age at menarche (P=0.129), first degree family history (P=0.111) and oral contraceptive usage (P=0.251).Conclusion:Based on this large population study in Chinese breast cancer patients, the risk factors for triple negative phenotype may be somewhat different from those for Western women. Therefore, a better knowledge of this issue is warranted due to it may have impact on clinical outcomes and may offer some insight into the process of carcinogenesis and therapeutic efficacy.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2065.

Time distributions and prognosis factors of breast cancer recurrence in different sites after operation

Abstract #2080

Objective Our study aims to analyze the breast caner patients with different sites of recurrence, and to have knowledge of the regular patterns and influence factors of metastastic breast cancer.
 Methods We performed a retrospective study of 210 female breast cancer patients who were continuously followed up in our hospital from January 2005 to May 2007 and had complete data of metastasis. The clinical and biological characteristics were compared between the patients with organ metastases (lung, liver, brain) and non-viscera metastases (lymph node, bone).
 Results Cox regression analysis-hazard function showed that patients with elder age (RR=0.927 95%CI 0.877∼0.981, P=0.008) and HER-2 negative(RR=0.253 95%CI 0.076∼0.836, P=0.024)tended to develop non-viscera metastases, while patients with larger tumors (RR=3.832 95%CI 1.073∼13.687, P=0.039) tended to develop organ metastasesp.
 
 When stratified by the prognostic factors, the annual risk hazard curve of the patients with high risk of recurrence had double peaks at the second year and the ninth years after mastectomy respectively, and it was significantly higher than those of the patients with middle and low risk.[figure1]Annual risk hazard curves of both local relapse and metastasis also showed a double-peaked pattern. The curves for lymph node, bone, lung and liver metastasis showed a similar pattern, but all the peaks of curve emerged later than that of the local relapse.
 
 Conclusion Patients with different clinical and biological characteristics may develop recurrence in different sites. There are certain regular patterns of time distribution for different metastasis sites after mastectomy. The local recurrence may be the foreboding for the metastasis and we should pay attention to the local relapse signs especially in the patients with high risk.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2080.

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Abstract P4-09-10: Nomogram for predicting lymph node involvement in patients with invasive micropapillary carcinoma of breast: A SEER population-based study

Background: Invasive micropapillary carcinoma (IMPC) is an unusual and distinct subtype of invasive breast tumor with high propensity for regional lymph node metastases. Because of its lymphotropic nature at initial presentation, IMPC is considered to have an unfavorable prognosis when compared with invasive ductal carcinoma (IDC). The aim of this study was to identify risk factors accounting for its lymphotropic features and to develop a nomogram to predict the probability of lymph node involvement in IMPC.

Patients and Methods: A retrospective review of the clinical and pathology records was performed in patients diagnosed with IMPC between 2003 and 2014 from Surveillance, Epidemiology, and End Results (SEER) database. Training set comprised patients diagnosed between 2003 and 2009, while validation set included patients diagnosed thereafter. Ethical approval of the study was granted by the Institutional Review Board of Fudan University Shanghai Cancer Center. Multiple logistic regression analysis was conducted. A logistic regression model was used to construct the nomogram in the training set and then validated in the validation set. Nomogram performance was quantified with respect to discrimination and calibration.

Results: Overall, 1407 patients diagnosed with IMPC were enrolled, of which 527 in training set and 880 in validation set. The demographic characteristics were comparable within sets. Larger lesion, younger age at diagnosis, black ethnic and lack of hormone receptor expression were significantly related to regional nodes involvement. The AUC of the nomogram was 0.735 (95 percent confidence interval 0.692 to 0.777), demonstrating a good prediction performance. A calibration curve for the nomogram was plotted to evaluate the agreement between actual (observed) outcomes and expected probabilities. The slope of the calibration curve was close to 1, which indicated excellent calibration of the nomogram. The performance of the nomogram was further validated in the validation set, in which AUC was 0.734 (95 percent confidence interval 0.701 to 0.767).

Conclusions: The striking difference between IMPC and IDC remains the increased lymph node involvement in IMPC and therefore merits aggressive treatment. The nomogram based on the clinical parameters was established, which could accurately predict regional lymph node status. This nomogram would facilitate evaluating lymph node state preoperatively and thus treatment decision-making of individual patients, especially in neoadjuvant settings.

Citation Format: Ye F, Hu X, Shao Z. Nomogram for predicting lymph node involvement in patients with invasive micropapillary carcinoma of breast: A SEER population-based study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P4-09-10.

[Study of the expression and function of c-kit receptor on the bone marrow mononuclear cells of the patients with myelodysplastic syndromes]

OBJECTIVE

To determine the expression and function of c-kit receptor on bone marrow mononuclear cells (BMMNC) of the patients with myelodysplastic syndromes.

METHODS

c-kit protein (CD(117)) was detected by direct immunofluorescence assay, c-kit mRNA by reverse transcriptive polymerase chain reaction (RT-PCR) and the function of c-kit receptor by cell culture.

RESULTS

c-kit protein expression in MDS was significantly higher than that in control [(8.58 +/- 5.28)% vs (3.04 +/- 1.49)%, P < 0.05]. c-kit protein expression in RA patients was significantly lower than that in RAEB/RAEB-t patients [(5.12 +/- 2.13)% vs (10.01 +/- 5.07)%, P < 0.05]. The rate of c-kit protein expression was (32.43 +/- 18.16)% in AML cases transformed from MDS (t-AML). c-kit mRNA expression in MDS was correlated with c-kit protein expression. Addition of interleukin-3 (IL-3), erythropoietin (Epo) and stem cell factor (SCF) to the semi-solid culture of BMMNC showed significant stimulating effects on CFU-GM and BFU-E formation in normal controls, but did not in MDS patients.

CONCLUSION

The protein and mRNA expressions of c-kit receptor on BMMNC in MDS are higher than those in normal control, and the function of this receptor in MDS is abnormal.

p53 independent G1 arrest and apoptosis induced by adriamycin

The biological activity of adriamycin was investigated in human breast carcinoma (HBC) cells, Adriamycin inhibited the growth of a number of HBC cell lines and induced G1 arrest followed by apoptosis. In MCF-7 cells that harbor wild-type p53, adriamycin-induced G1 arrest and apoptosis was accompanied by p53-independent regulation of WAF1/CIP1 as well as bax mRNA levels. In MDA-MB-231 cells which possess a mutant p53, adriamycin-induced G1 arrest and apoptosis was also associated with a concomitant up-regulation of WAF1/CIP1 mRNA while these cells did not express bax or bcl-2 messages. Thus, adriamycin induces G1 arrest and apoptosis via a unique pathway which appears to involve activation of downstream effectors of p53-independent manner.

[Treatment of chronic aplastic anemia with triolandren and cyclosporin A]

OBJECTIVE

To explore more effective regimen for chronic aplastic anemia (CAA).

METHODS

Forty-five cases of CAA were treated with triolandren (TLD) (15 cases) or TLD and cyclosporin A (CsA) (30 cases).

RESULTS

The response rate of TLD-CsA group (83.3%) was higher than that of TLD group (60.0%), furthermore, the recovery of bone marrow colony-forming cell (CFC) number of the responding patients was more complete and rapid in TLD-CsA group than in TLD group. Bone marrow CFC number had no significant change of all nonresponding patients in both groups.

CONCLUSION

The response rate of TLD-CsA was higher than that of TLD alone, and the recovery of bone marrow CFC number of the responding patients was more complete and rapid in TLD-CsA group.

[Serum level of granulocyte colony stimulating factor in severe aplastic anemia patients]

OBJECTIVE

To investigate the relationship between serum level of granulocyte colony stimulating factor (G-CSF) and clinical status, treatment outcome and prognosis in severe aplastic anemia (SAA-I) patients.

METHODS

Serum G-CSF level was detected by ELISA assay in 36 SAA-I patients.

RESULTS

Pre-treatment serum G-CSF levels of 27/36 (75%) SAA-I patients were above normal. These patients achieved better curative outcomes in a shorter period of treatment.

CONCLUSION

Detection of serum G-CSF level in SAA-I patients is helpful for judging the clinical status and prognosis.

[Genistein exerts multiple suppressive effects on human breast carcinoma cells]

OBJECTIVE

To study the suppressive effects of genistein on progression of breast carcinoma.

METHODS

In vitro cell culture, animal studies, zymography, Northern and Western blot were used in this study.

RESULTS

Genistein inhibited in vitro invasion of MCF-7 and MDA-MB-231 cells. This inhibition was associated with down-regulation of MMP-9 and up-regulation of TIMP-1. These effects were also demonstrated in vivo. Genistein inhibited growth of the breast cancer cells transplanted in nude mice. The growth inhibitory effect was associated with increased tumor cell apoptosis, and up-regulated p21WAF1/CIP1 expression. Furthermore, genistein inhibited angiogenesis as shown by decreased vessel density and decreased production and release of VEGF and TGF-beta 1.

CONCLUSION

Genistein exerts multiple suppressive effects on breast carcinoma. It may help halt its progression.

[Prognostic significance of cyclin-dependent kinase inhibitor p27kip1 expression in human breast cancer]

OBJECTIVE

To study the expression of p27kip1 in breast cancer in relation to biological behavior and prognosis.

METHODS

p27kip1 expression at protein level was determined by immunohistochemistry technique in 181 patients with breast cancer. In addition, p27WAF1/CIP1, p53 and mdm2 were examined in 106 cases of this series. Data about apoptotic index, bcl-2 and bax protein expression were available in the other 91 patients.

RESULTS

Of the 181 patients, p27kip1 expression was low in 121 (66.9%) and high in 60 (33.1%), respectively. p27kip1 expression level was correlated with histological grade, tumor size, axillary lymph node status, post-operative recurrence, invasion and metastasis. It was also correlated with bcl-2, bax, p53, p21WAF1/CIP1, and mdm2 expression levels. Univariate analysis demonstrated better disease-free survival in patients with higher p27kip1 expression than in those with lower expression. However, by Cox multivariate analysis, p27kip1 expression level was not found to be of independent prognostic significance.

CONCLUSION

As an inhibitor of cyclin-dependent kinase, p27kip1 favors prognosis of human breast cancer not only by arresting cell cycle in G1 phase but also inducing cancer cell apoptosis.

[Expression of c-kit receptor on the hemopoietic stem/precursor cells of aplastic anemia patients]

OBJECTIVE

To explore the expression of c-kit receptor(CD117) on the hemopoietic stem/precursor cells of aplastic anemia patients and its role in the genesis of aplastic hematopoiesis failure.

METHODS

c-kit expression on the bone marrow mononuclear cells(MNC) and CD34 positive cells from 11 chronic aplastic anemia (CAA), 9 severe aplastic anemia(SAA), 10 non-aplastic anemia(NAA) patients (5 iron deficiency anemia and 5 autoimmune hemolytic anemia) and 5 healthy controls was measured with flow cytometric immunofluorescence assay and anti-CD117 monoclonal antibody.

RESULTS

The CD117 positive rates of MNC in CAA, SAA, NAA and control groups were (2.08 +/- 1.96)%, (0.89 +/- 0.32)%, (0.67 +/- 0.39)% and (0.45 +/- 0.16)%, respectively, and the rates were significantly higher in CAA and SAA groups than in NAA and control groups(P < 0.05). The CD117 and CD34 double positive cells of MNC in CAA, SAA, NAA and control groups were (0.87 +/- 0.57)%, (0.65 +/- 0.41)%, (0.46 +/- 0.26)% and (0.41 +/- 0.15)%, respectively, and were significantly higher in CAA and SAA groups than in NAA and control groups (P < 0.05). The CD117 positive cells of CD34 positive cells were also higher in CAA[(71.6 +/- 12.4)%] and SAA[(88.9 +/- 23.5)%] groups than in NAA[(41.8 +/- 10.3)%] and control [(46.3 +/- 9.7)%] groups (P < 0.01).

CONCLUSION

Hemopoietic stem/precursor cells of aplastic anemia patients expressed more c-kit receptors than those of NAA patients and healthy controls. The hematopoiesis failure occurred in aplastic anemia is not attributed to low expression of c-kit receptor on the hemopoietic stem/precursor cells.

[Growth inhibitory effect of retinoic acid in human breast cancer cells correlates with retinoic acid receptor alpha (RAR alpha) expression]

The relationship between the effect of retinoic acid (RA) on the growth of breast cancer cell and their estrogen receptor (ER) status as well as the relationship between RA effect and the expression of retinoic acid receptorsd (RAR alpha) were studied by cell growth assay, Northern Blot and gene transfection. It was found that RA could only inhibit the growth of ER-positive but not ER-negative breast cancer cells. RAR alpha mRNA level was significantly higher in ER-positive breast cancer cell lines than that in ER-negative breast cancer cell line. The expressions of other subtypes of RAR in ER-positive cells were not significantly different from those in ER-negative ones. When, RAR alpha cDNA was introduced and ixpressed in RA-resistant, ER-negative MDA-MB-231 breast cancer cell line, its growth was strongly inhibited by RA. These results indicate that RAR alpha plays a major role in the retinoi-dmediated inhibition of growth in human breast cancer cells.

[Correlation between the serum levels of interleukin-2 and soluble interleukin-2 receptor and the response to immunosuppressive therapy in severe aplastic anemia patients]

OBJECTIVE

To explore factors influencing the effectiveness of immunosuppressive therapy in severe aplastic anemia (SAA).

METHODS

The serum levels of interleukin-2 (IL-2) and soluble IL-2 receptor (sIL-2R) of 22 SAA patients and 15 normal controls were measured by immunoenzyme assay.

RESULTS

Comparing with the normal controls, 40.9% and 63.6% of the SAA patients had higher serum levels of IL-2 (>840ng/L) and of sIL 2R (>320 x 10(3) U/L), respectively. Those who had higher IL-2 levels and higher sIL-2R levels got better responses to cyclosporin A(CsA) and CsA plus antilymphocyte globulin (ALG).

CONCLUSION

The serum levels of IL-2 and sIL-2R were correlated with the responsiveness to immunosuppressive therapy in SAA patients and might be useful for directing treatment.

Enhanced Tissue Regeneration Through Immunomodulatory Extracellular Vesicles Encapsulated in Diversified Silk-Based Injectable Hydrogels

Mesenchymal stem cells (MSCs) immunologically trained using lipopolysaccharide (LPS) display enhanced immunomodulatory capabilities. Extracellular vesicles (EVs) derived from MSCs are widely used in regenerative medicine owing to their bioactive properties without the drawbacks of cell therapy. However, it remains unclear whether EVs derived from LPS-stimulated (trained) MSCs (L-EVs) inherit the enhanced reparative potential from their parent cells. Thus, this study first aims to explore the effect of immunological training on the bioactivity of L-EVs. LPS-trained bone marrow-derived MSCs (BMSCs) secrete more EVs, and these EVs significantly promote M2 macrophage polarization. Subsequently, hydrogel systems based on thixotropic injectable silk fibroin are prepared for in vivo EV delivery. These hydrogels have controllable gelation time and exhibit outstanding reparative effects on rat skin wounds and alveolar bone defects. Finally, it is revealed that L-EVs promote M2 macrophage polarization by inhibiting the nuclear translocation of PKM2. Overall, this study shows that the immunological training of BMSCs effectively improves the therapeutic effects of their EVs and provides a convenient and diversified EV delivery strategy using an injectable silk fibroin hydrogel. This strategy has broad clinical application prospects for tissue regeneration.