Purpose: To report our 5-year experience with intra-arterial chemotherapy (IAC) in the intravitreal chemotherapy (IvitC) era. Methods: Retrospective review of retinoblastoma treated with primary unilateral IAC in the IvitC era (2012–2017). Results: There were 34 eyes treated with IAC alone versus 20 eyes treated with IAC plus IvitC for vitreous seeds. IAC (IAC alone vs. IAC plus IvitC) consisted of melphalan (41 vs. 10%) or melphalan plus topotecan (59 vs. 90%, p = 0.03). IvitC consisted of melphalan (60%) or melphalan plus topotecan (40%). Tumor control and globe salvage were achieved in 100% of group B and C eyes without IvitC. Despite more extensive vitreous seeds in the IvitC group (p < 0.01), comparison of IAC alone versus IAC plus IvitC revealed no difference in tumor control for group D (88 vs. 69%, p = 0.36) or group E (67 vs. 100%, p = 0.25) and no difference in globe salvage for group D (88 vs. 69%, p = 0.36) or group E (58 vs. 57%, p = 0.39). Conclusions: IAC is effective as primary therapy for unilateral group B, C, D, and E retinoblastoma. IvitC is an important adjuvant therapy to achieve comparable globe salvage rates for group D and E eyes with persistent active vitreous seeds.

: Triple Negative Breast Cancer (TNBC) is the most aggressive and prevailing breast cancer subtype. The chemotherapeutics used in the treatment of TNBC suffer with chemoresistance, dose limiting toxicities and off-target side effects. As a result, conventional chemotherapeutics are unable to prevent tumor growth, metastasis and result in failure of therapy. Various new targets such as BCSCs surface markers (CD44, CD133, ALDH1), signaling pathways (IL-6/JAK/STAT3, notch), pro and anti-apoptotic proteins (Bcl-2, Bcl-xL, DR4, DR5), hypoxic factors (HIF-1α, HIF2α) and drug efflux transporters (ABCC1, ABCG2 and ABCB1) have been exploited to treat TNBC. Further, to improve the efficacy and safety of conventional chemotherapeutics, researchers have tried to deliver anticancer agents specifically to the TNBCs using nanocarrier based drug delivery. In this review, an effort has been made to highlight the various factors responsible for the chemoresistance in TNBC, novel molecular targets of TNBC and nano-delivery systems employed to achieve site specific drug delivery to improve efficacy and reduce off-target side effects.

Triple-negative breast cancer (TNBC) is the most aggressive and heterogeneous cancer subtypes. High rates of metastasis, poor prognosis, and drug resistance are the major problems associated with TNBC. The current chemotherapeutics eliminate only the bulk tumor cells (non-BCSCs) and do not affect breast cancer stem cells (BCSCs). The BCSCs which are left behind after chemotherapy is reported to promote recurrence and metastasis of TNBC. Death receptor-5 (DR-5) is exclusively expressed in TNBCs and mediates the extrinsic pathway of apoptosis. DR-5, therefore, can be exploited for targeted drug delivery and to induce apoptosis. Gamma-secretase mediated Notch signaling in BCSCs regulates its proliferation, differentiation, and metastasis. The endogenous ligand, Delta-like ligand 4 (DLL4), is reported to activate this Notch signaling in TNBC. Blocking this signaling pathway using both gamma-secretase inhibitors (GSIs) and DLL4 monoclonal antibody (mAb) may produce synergistic benefits. Further, the GSIs (DAPT, LY-411575, RO4929097, MK0752, etc.) suffer from poor bioavailability and off-target side effects such as diarrhea, suppression of lymphopoiesis, headache, hypertension, fatigue, and ventricular dysfunctions. In this hypothesis, we discuss Solid lipid nanoparticles (SLNs) based drug delivery systems containing GSIs and surface modified with DR-5 and DLL4 monoclonal antibodies (mAb) to effectivity target and treat TNBC. The delivery system is designed to deliver the drug cargo precisely to TNBCs through its DR-5 receptors and hence expected to reduce the off-target side effects of GSIs. Further, DLL4 mAb and GSIs are expected to act synergistically to block the Notch signal mediated BCSCs proliferation, differentiation, and metastasis.

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